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Cover	May 07, 2020
Cover [Abstract]
Document Type	8-K
Document Period End Date	May 07, 2020
Entity Registrant Name	NRG ENERGY, INC.
Entity Incorporation, State or Country Code	DE
Entity File Number	001-15891
Entity Tax Identification Number	41-1724239
Entity Address, Address Line One	804 Carnegie Center
Entity Address, City or Town	Princeton
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	08540
City Area Code	609
Local Phone Number	524-4500
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Title of 12(b) Security	Common Stock, par value $0.01
Trading Symbol	NRG
Security Exchange Name	NYSE
Entity Emerging Growth Company	false
Entity Central Index Key	0001013871
Amendment Flag	true

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Revenues
Total operating revenues		$ 2,195	$ 2,996	$ 2,465	$ 2,165	$ 1,992	$ 2,960	$ 2,461	$ 2,065	$ 9,821	$ 9,478	$ 9,074
Operating Costs and Expenses
Cost of operations										7,303	7,108	6,886
Depreciation and amortization										373	421	596
Impairment losses										5	99	1,534
Selling, general and administrative										827	799	836
Reorganization costs										23	90	44
Development costs										7	11	22
Total operating costs and expenses										8,538	8,528	9,918
Other income - affiliate	$ 84									0	0	87
Gain on sale of assets										7	32	16
Operating Income/(Loss)		209	540	320	221	49	398	174	361	1,290	982	(741)
Other Income/(Expense)
Equity in earnings/(losses) of unconsolidated affiliates										2	9	(14)
Impairment losses on investments										(108)	(15)	(79)
Other income, net										66	18	51
Loss on debt extinguishment, net										(51)	(44)	(49)
Interest expense										(413)	(483)	(557)
Total other expense										(504)	(515)	(648)
Income/(Loss) from Continuing Operations Before Income Taxes										786	467	(1,389)
Income tax (benefit)/expense										(3,334)	7	(44)
Income/(Loss) from Continuing Operations		3,463	374	189	94	(93)	287	27	238	4,120	460	(1,345)
Income/(loss) from discontinued operations, net of income tax		(78)	(2)	13	388	80	(336)	69	(5)	321	(192)	(992)
Net Income/(Loss)		3,385	372	202	482	(13)	(49)	96	233	4,441	268	(2,337)
Less: Net income/(loss) attributable to noncontrolling interest and redeemable interests		$ 2	$ 0	$ 1	$ 0	$ (2)	$ 23	$ 24	$ (46)	3	0	(184)
Net Income/(Loss) Attributable to NRG Energy, Inc.										$ 4,438	$ 268	$ (2,153)
Earnings/(Loss) Per Share Attributable to NRG Energy, Inc. Common Stockholders
Weighted average number of common shares outstanding — basic (in shares)		251,000,000	254,000,000	265,000,000	278,000,000	289,000,000	299,000,000	310,000,000	318,000,000	262,000,000	304,000,000	317,000,000
Income/(loss) from continuing operations per weighted average common share —basic (in usd per share)										$ 15.71	$ 1.51	$ (3.66)
Income/(loss) from discontinued operations per weighted average common share — basic (in usd per share)		$ (0.31)	$ (0.01)	$ 0.05	$ 1.39	$ 0.28	$ (1.12)	$ 0.22	$ (0.02)	1.23	(0.63)	(3.13)
Net Income/(Loss) per Weighted Average Common Share - Basic (in usd per share)		$ 13.48	$ 1.46	$ 0.76	$ 1.73	$ (0.04)	$ (0.24)	$ 0.23	$ 0.88	$ 16.94	$ 0.88	$ (6.79)
Weighted average number of common shares outstanding — diluted (in shares)		253,000,000	256,000,000	267,000,000	280,000,000	289,000,000	299,000,000	314,000,000	322,000,000	264,000,000	308,000,000	317,000,000
Income/(loss) from continuing operations per weighted average common share — diluted (in usd per share)										$ 15.59	$ 1.49	$ (3.66)
Income/(loss) from discontinued operations per weighted average common share — diluted (in usd per share)		$ (0.31)	$ (0.01)	$ 0.05	$ 1.38	$ 0.28	$ (1.12)	$ 0.22	$ (0.02)	1.22	(0.62)	(3.13)
Net Income/(Loss) per Weighted Average Common Share - Diluted (in usd per share)		$ 13.37	$ 1.45	$ 0.75	$ 1.72	$ (0.04)	$ (0.24)	$ 0.23	$ 0.87	$ 16.81	$ 0.87	$ (6.79)

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 3,385	$ 372	$ 202	$ 482	$ (13)	$ (49)	$ 96	$ 233	$ 4,441	$ 268	$ (2,337)
Other Comprehensive (Loss)/Income, net of tax
Unrealized gain on derivatives, net of income tax									0	23	13
Foreign currency translation adjustments, net of income tax									(1)	(11)	12
Available-for-sale securities, net of income tax									(19)	1	(8)
Defined benefit plans, net of income tax									(78)	(35)	46
Other comprehensive (loss)/income									(98)	(22)	63
Comprehensive Income/(Loss)									4,343	246	(2,274)
Less: Comprehensive income/(loss) attributable to noncontrolling interests and redeemable noncontrolling interests									3	14	(179)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.									$ 4,340	$ 232	$ (2,095)

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 345	$ 563
Funds deposited by counterparties	32	33
Restricted cash	8	17
Accounts receivable, net	1,025	1,024
Inventory	383	412
Derivative instruments	860	764
Cash collateral posted in support of energy risk management activities	190	287
Prepayments and other current assets	245	302
Current assets - held-for-sale	0	1
Current assets - discontinued operations	0	197
Total current assets	3,088	3,600
Property, plant and equipment, net	2,593	3,048
Other Assets
Equity investments in affiliates	388	412
Operating lease right-of-use assets, net	464
Goodwill	579	573
Intangible assets, net	789	591
Nuclear decommissioning trust fund	794	663
Derivative instruments	310	317
Deferred income taxes	3,286	46
Other non-current assets	240	289
Non-current assets - held-for-sale	0	77
Non-current assets - discontinued operations	0	1,012
Total other assets	6,850	3,980
Total Assets	12,531	10,628
Current Liabilities
Current portion of long-term debt and finance leases	88	72
Current portion of operating lease liabilities	73
Accounts payable	722	863
Derivative instruments	781	673
Cash collateral received in support of energy risk management activities	32	33
Accrued expenses and other current liabilities	663	680
Current liabilities - held for sale	0	5
Current liabilities - discontinued operations	0	72
Total current liabilities	2,359	2,398
Other Liabilities
Long-term debt and finance leases	5,803	6,449
Non-current operating lease liabilities	483
Nuclear decommissioning reserve	298	282
Nuclear decommissioning trust liability	487	371
Derivative instruments	322	304
Deferred income taxes	17	65
Other non-current liabilities	1,084	1,274
Non-current liabilities - held-for-sale		65
Non-current liabilities - held-for-sale	0	65
Non-current liabilities - discontinued operations	0	635
Total other liabilities	8,494	9,445
Total Liabilities	10,853	11,843
Redeemable noncontrolling interest in subsidiaries	20	19
Commitments and Contingencies
Stockholders' Equity
Common stock; $0.01 par value; 500,000,000 shares authorized; 421,890,790 and 420,288,886 shares issued; and 248,996,189 and 283,650,039 shares outstanding at December 31, 2019 and 2018	4	4
Additional paid-in capital	8,501	8,510
Accumulated deficit	(1,616)	(6,022)
Treasury stock, at cost; 172,894,601 and 136,638,847 shares at December 31, 2019 and 2018	(5,039)	(3,632)
Accumulated other comprehensive loss	(192)	(94)
Total Stockholders' Equity	1,658	(1,234)
Total Liabilities and Stockholders' Equity	$ 12,531	$ 10,628

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	421,890,790	420,288,886
Common stock, shares outstanding (in shares)	248,996,189	283,650,039
Treasury stock, shares (in shares)	172,894,601	136,638,847

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net Income/(Loss)	$ 4,441	$ 268	$ (2,337)
Income/(loss) from discontinued operations, net of income tax	321	(192)	(992)
Income/(loss) from continuing operations	4,120	460	(1,345)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates	14	46	102
Depreciation and amortization	373	421	596
Accretion of asset retirement obligations	51	38	44
Provision for bad debts	95	85	68
Amortization of nuclear fuel	52	48	51
Amortization of financing costs and debt discount/premiums	26	29	29
Loss on debt extinguishment, net	51	44	49
Amortization of emission allowances and out-of-market contracts	38	45	54
Amortization of unearned equity compensation	20	25	35
Net gain on sale of assets and disposal of assets	(23)	(49)	(9)
Impairment losses	113	114	1,614
Changes in derivative instruments	34	37	(170)
Changes in deferred income taxes and liability for uncertain tax benefits	(3,353)	5	13
Changes in collateral deposits in support of risk management activities	105	(105)	(80)
Changes in nuclear decommissioning trust liability	37	60	11
GenOn settlement, net of insurance proceeds	0	(63)	0
Net loss on deconsolidation of Agua Caliente and Ivanpah projects	0	13	0
Cash provided/(used) by changes in other working capital, net of acquisition and disposition effects:
Accounts receivable - trade	5	(83)	(83)
Inventory	22	31	143
Prepayments and other current assets	29	(41)	(187)
Accounts payable	(177)	113	44
Accrued expenses and other current liabilities	(41)	(166)	(88)
Other assets and liabilities	(186)	(104)	(35)
Cash provided by continuing operations	1,405	1,003	856
Cash provided by discontinued operations	8	374	754
Net Cash Provided by Operating Activities	1,413	1,377	1,610
Cash Flows from Investing Activities
Payments for acquisitions of businesses	(355)	(243)	(14)
Capital expenditures	(228)	(388)	(254)
Net proceeds from sale of emission allowances	11	19	66
Investments in nuclear decommissioning trust fund securities	(416)	(572)	(512)
Proceeds from sales of nuclear decommissioning trust fund securities	381	513	501
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	1,294	1,564	430
Deconsolidations of Agua Caliente and Ivanpah projects	0	(268)	0
Net contributions to investments in unconsolidated affiliates	(91)	(39)	(57)
Net (contributions to)/distributions from discontinued operations	(44)	(60)	150
Other	6	(6)	30
Cash provided by continuing operations	558	520	340
Cash used by discontinued operations	(2)	(725)	(979)
Net Cash Provided/(Used) by Investing Activities	556	(205)	(639)
Cash Flows from Financing Activities
Payments of dividends to common stockholders	(32)	(37)	(38)
Payments for share repurchase activity	(1,440)	(1,250)	0
Payments for debt extinguishment costs	(26)	(32)	(42)
Net distributions to noncontrolling interest from subsidiaries	(2)	(16)	(30)
Proceeds/(payments) from issuance of common stock	3	21	(2)
Proceeds from issuance of short and long-term debt	1,916	1,100	1,178
Payments of debt issuance costs	(35)	(19)	(18)
Payments for short and long-term debt	(2,571)	(1,734)	(1,884)
Receivable from affiliate	0	(26)	(125)
Other	(4)	(4)	(8)
Cash used by continuing operations	(2,191)	(1,997)	(969)
Cash provided/(used) by discontinued operations	43	471	(169)
Net Cash (Used)/Provided by Financing Activities	(2,148)	(1,526)	(1,138)
Effect of exchange rate changes on cash and cash equivalents	0	1	(1)
Change in Cash from discontinued operations	49	120	(394)
Net (Decrease)/Increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash	(228)	(473)	226
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period	613	1,086	860
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 385	$ 613	$ 1,086

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	NRG Yield, Inc.	Common Stock	Additional Paid-In Capital	Additional Paid-In Capital NRG Yield, Inc.	Accumulated Deficit	Treasury Stock	Accumulated Other Comprehensive Loss	Noncon- trolling Interest	Noncon- trolling Interest NRG Yield, Inc.
Beginning balance at Dec. 31, 2016	$ 4,446		$ 4	$ 8,358		$ (3,787)	$ (2,399)	$ (135)	$ 2,405
Increase (Decrease) in Stockholders' Equity
Net loss (income)	(2,251)					(2,153)			(98)
Other comprehensive income	51							51
Other comprehensive income (loss)	63
Sale of assets to NRG Yield, Inc		$ (5)			$ (25)					$ 20
ESPP share purchases	6			(3)		(4)	13
Equity-based compensation	25			25
Issuance of common stock	4			4
Common stock dividends	(38)					(38)
Distributions to noncontrolling interest and dividends paid	(65)	(108)							(65)	(108)
Contributions from noncontrolling interests	160								160
Early adoption of new accounting standards	(257)			17		(286)		12
Ending balance at Dec. 31, 2017	1,968		4	8,376		(6,268)	(2,386)	(72)	2,314
Increase (Decrease) in Stockholders' Equity
Adoption of new accounting standards	15					15
Net loss (income)	294					268			26
Other comprehensive income (loss)	(22)							(22)
Sale of assets to NRG Yield, Inc		16			$ 8					8
ESPP share purchases	2			(2)			4
Share repurchases	(1,250)						(1,250)
Equity-based compensation	6			6
Issuance of common stock	21			21
Common stock dividends	(37)					(37)
Distributions to noncontrolling interest and dividends paid	(43)	$ (61)							(43)	$ (61)
Contributions from noncontrolling interests	304								304
Early adoption of new accounting standards
Sale of NRG Yield and other business	(2,548)								(2,548)
Equity component of convertible senior notes	101			101
Ending balance at Dec. 31, 2018	(1,234)		4	8,510		(6,022)	(3,632)	(94)	0
Increase (Decrease) in Stockholders' Equity
Net loss (income)	4,438					4,438
Other comprehensive income (loss)	(98)							(98)
ESPP share purchases	3			1			2
Share repurchases	(1,409)						(1,409)
Equity-based compensation	(16)			(16)
Issuance of common stock	6			6
Common stock dividends	(32)					(32)
Ending balance at Dec. 31, 2019	$ 1,658		$ 4	$ 8,501		$ (1,616)	$ (5,039)	$ (192)	$ 0

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Dividends paid per share (in usd per share)	$ 0.12	$ 0.12	$ 0.12

Nature of Business	12 Months Ended
Nature of Business	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business General NRG Energy, Inc., or NRG or the Company, is an integrated power company built on dynamic retail brands with diverse generation assets. NRG brings the power of energy to customers by producing and selling electricity and related products and services in major competitive power markets in the U.S. and Canada in a manner that delivers value to all of NRG's stakeholders. NRG is a customer-driven business focused on perfecting the integrated model by balancing retail load with generation supply within its deregulated markets. The Company sells energy, services, and innovative, sustainable products and services directly to retail customers under the names NRG, Reliant, Green Mountain Energy, Stream and XOOM Energy, as well as other brand names owned by NRG, supported by approximately 23,000 MW of generation as of December 31, 2019. The Company began managing its integrated model based on the combined results of the retail and wholesale generation businesses with a geographical focus in 2020. As a result, the Company changed its business segments from Retail and Generation to Texas, East and West/Other beginning in the first quarter of 2020. The Company's updated segment structure reflects how management currently makes financial decisions and allocates resources. The Company's businesses are segregated as follows: •Texas, which includes all activity related to customer, plant and market operations in Texas; •East, which includes the remaining activity related to customer operations and all activity related to plant and market operations in the East; •West/Other, which includes the following assets and activities: (i) all activity related to plant and market operations in the West, (ii) activity related to the Cottonwood power plant that was sold to Cleco on February 4, 2019 and is being leased back until 2025, (iii) the remaining renewables activity, including the Company’s equity method investments in Ivanpah Master Holdings, LLC and Agua Caliente, the remaining Home Solar assets and the NFL stadium solar generating assets, and (iv) activity related to the Company’s equity method investment for the Gladstone power plant in Australia; and •Corporate activities. All affected disclosures presented herein have been recast to reflect these changes for all periods presented. For further discussion of segment reporting, refer to Note 19, Segment Reporting. Discontinued Operations On December 31, 2018, as described in Note 4, Acquisitions, Discontinued Operations and Dispositions, the Company concluded that the sale of its South Central Portfolio to Cleco, excluding the Cottonwood facility, met held-for-sale criteria and should be presented as a discontinued operation, as the sale represented a strategic shift in the business in which NRG operates. The financial information for all historical periods was recast in 2018 to reflect the presentation of these entities as discontinued operations. On August 31, 2018, as described in Note 4, Acquisitions, Discontinued Operations and Dispositions, the Company deconsolidated NRG Yield, Inc. and its Renewables Platform for financial reporting purposes. The financial information for all historical periods was recast in 2018 to reflect the presentation of these entities, as well as the Carlsbad project, as discontinued operations. As a result of the sale of NRG Yield, the Company no longer controls the Agua Caliente project. Due to this change in control, the Company deconsolidated the Agua Caliente project from its financial results and began accounting for the project as an equity method investment. On June 14, 2017, or the Petition Date, GenOn, along with GenOn Americas Generation and certain of their directly and indirectly-owned subsidiaries, or collectively the GenOn Entities, filed voluntary petitions for relief under the Chapter 11 Cases, of the U.S. Bankruptcy Code. As a result of the bankruptcy filings and beginning on June 14, 2017, GenOn and its subsidiaries were deconsolidated from NRG's consolidated financial statements. NRG determined that this disposal of GenOn and its subsidiaries was a discontinued operation and, accordingly, the financial information for all historical periods was recast to reflect GenOn as a discontinued operation. GenOn's plan of reorganization was confirmed on December 14, 2018.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

The Company's consolidated financial statements have been prepared in accordance with U.S. GAAP. The ASC, established by the FASB, is the source of authoritative U.S. GAAP to be applied by nongovernmental entities. In addition, the rules and interpretative releases of the SEC under authority of federal securities laws are also sources of authoritative U.S. GAAP for SEC registrants.

The consolidated financial statements include NRG's accounts and operations and those of its subsidiaries in which the Company has a controlling interest. All significant intercompany transactions and balances have been eliminated in consolidation. The usual condition for a controlling financial interest is ownership of a majority of the voting interests of an entity. However, a controlling financial interest may also exist through arrangements that do not involve controlling voting interests. As such, NRG applies the guidance of ASC 810, Consolidations, or ASC 810, to determine when an entity that is insufficiently capitalized or not controlled through its voting interests, referred to as a VIE, should be consolidated.

Net Income/(Loss) attributable to NRG Energy, Inc.

The following table reflects the net income/(loss) attributable to NRG Energy, Inc. after removing the net loss attributable to the noncontrolling interest and redeemable noncontrolling interest:


	Year Ended December 31,
(In millions)	2019		2018		2017
Income/(loss) from continuing operations, net of income tax	$	4,117	$	465	$	(977)
Income/(loss) from discontinued operations, net of income tax	321		(197)		(1,176)
Net income/(loss) attributable to NRG Energy, Inc. stockholders	$	4,438	$	268	$	(2,153)

Discontinued Operations

As described in Note 4, Acquisitions, Discontinued Operations and Dispositions, the Company has determined that the South Central Portfolio, NRG Yield Inc. and its Renewables Platform, Carlsbad, and GenOn all qualified for treatment as discontinued operations. The financial information for all historical periods was recast in prior years to reflect the presentation of discontinued operations within the corporate segment.

Cash and Cash Equivalents

Cash and cash equivalents include highly liquid investments with an original maturity of three months or less at the time of purchase.

Funds Deposited by Counterparties

Funds deposited by counterparties consist of cash held by the Company as a result of collateral posting obligations from its counterparties. Some amounts are segregated into separate accounts that are not contractually restricted but, based on the Company's intention, are not available for the payment of general corporate obligations. Depending on market fluctuations and the settlement of the underlying contracts, the Company will refund this collateral to the hedge counterparties pursuant to the terms and conditions of the underlying trades. Since collateral requirements fluctuate daily and the Company cannot predict if any collateral will be held for more than twelve months, the funds deposited by counterparties are classified as a current asset on the Company's balance sheet, with an offsetting liability for this cash collateral received within current liabilities.

Restricted Cash

The following table provides a reconciliation of cash and cash equivalents, restricted cash and funds deposited by counterparties reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the statements of cash flows.


	Year Ended December 31,
(In millions)	2019		2018		2017
Cash and cash equivalents	$	345	$	563	$	770
Funds deposited by counterparties	32		33		37
Restricted cash	8		17		279
Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statements of cash flows	$	385	$	613	$	1,086

Restricted cash consists primarily of funds held to satisfy the requirements of certain debt agreements and funds held within the Company's projects that are restricted in their use.

Trade Receivables and Allowance for Doubtful Accounts

Trade receivables are reported in the balance sheet at outstanding principal adjusted for any write-offs and the allowance for doubtful accounts. For its retail receivables, the Company accrues an allowance for doubtful accounts based on estimates of uncollectible revenues by analyzing counterparty credit ratings (for commercial and industrial customers), historical collections, accounts receivable aging and other factors. Accounts receivable balances are written-off against the allowance for doubtful accounts when a receivable is determined to be uncollectible. In addition, the Company considers a reserve for doubtful accounts based on the credit worthiness of the customers and continually reviews and adjusts for current economic trends that might impact the level of future credit losses. The reserve represents management's best estimate of uncollectible amounts. As of December 31, 2019 and 2018, the allowance for doubtful accounts was $43 million and $32 million, respectively.

Inventory

Inventory is valued at the lower of weighted average cost or market, and consists principally of fuel oil, coal and raw materials used to generate electricity or steam. The Company removes these inventories as they are used in the production of electricity or steam. Spare parts inventory is valued at weighted average cost. The Company removes these inventories when they are used for repairs, maintenance or capital projects. The Company expects to recover the fuel oil, coal, raw materials, and spare parts costs in the ordinary course of business. Finished goods inventory is valued at the lower of cost or net realizable value with cost being determined on a first-in first-out basis. The Company removes these inventories as they are sold to customers. Sales of inventory are classified as an operating activity in the consolidated statements of cash flows.

Property, Plant and Equipment

Property, plant and equipment are stated at cost or, in the case of business acquisitions, fair value; however, impairment adjustments are recorded whenever events or changes in circumstances indicate that their carrying values may not be recoverable. NRG also classifies nuclear fuel related to the Company's 44% ownership interest in STP as part of the Company's property, plant, and equipment. Significant additions or improvements extending asset lives are capitalized as incurred, while repairs and maintenance that do not improve or extend the life of the respective asset are charged to expense as incurred. Depreciation, other than nuclear fuel, is computed using the straight-line method, while nuclear fuel is amortized based on units of production over the estimated useful lives. Certain assets and their related accumulated depreciation amounts are adjusted for asset retirements and disposals with the resulting gain or loss included in cost of operations in the consolidated statements of operations.

Asset Impairments

Long-lived assets that are held and used are reviewed for impairment whenever events or changes in circumstances indicate carrying values may not be recoverable. Such reviews are performed in accordance with ASC 360. An impairment loss is indicated if the total future estimated undiscounted cash flows expected from an asset are less than its carrying value. An impairment charge is measured by the difference between an asset's carrying amount and fair value with the difference recorded in operating costs and expenses in the consolidated statements of operations. Fair values are determined by a variety of valuation methods, including third-party appraisals, sales prices of similar assets, and present value techniques.

Investments accounted for by the equity method are reviewed for impairment in accordance with ASC 323, Investments-Equity Method and Joint Ventures, or ASC 323, which requires that a loss in value of an investment that is an other-than-temporary decline should be recognized. The Company identifies and measures losses in the value of equity method investments based upon a comparison of fair value to carrying value. For further discussion of these matters, refer to Note 11, Asset Impairments.

Development Costs and Capitalized Interest

Development costs include project development costs, which are expensed in the preliminary stages of a project and capitalized when the project is deemed to be commercially viable. Commercial viability is determined by one or a series of actions including, among others, Board of Director approval pursuant to a formal project plan that subjects the Company to significant future obligations that can only be discharged by the use of a Company asset. When a project is available for operations, capitalized interest and capitalized project development costs are reclassified to property, plant and equipment and depreciated on a straight-line basis over the estimated useful life of the project's related assets. Capitalized costs are charged to expense if a project is abandoned or management otherwise determines the costs to be unrecoverable.

Interest incurred on funds borrowed to finance capital projects is capitalized until the project under construction is ready for its intended use. The amount of interest capitalized for the years ended December 31, 2019, 2018, and 2017, was $3 million, $7 million, and $20 million, respectively.

Debt Issuance Costs

Debt issuance costs are capitalized and amortized as interest expense on a basis which approximates the effective interest method over the term of the related debt. Debt issuance costs are presented as a direct deduction from the carrying amount of the related debt.

Intangible Assets

Intangible assets represent contractual rights held by the Company. The Company recognizes specifically identifiable intangible assets including customer contracts, customer relationships, energy supply contracts, marketing partnerships, power purchase agreements, trade names, emission allowances, and fuel contracts when specific rights and contracts are acquired. These intangible assets are amortized based on expected volumes, expected delivery, expected discounted future net cash flows, straight line or units of production basis. As of December 31, 2019 and 2018, the Company had accumulated amortization related to its intangible assets of $1.3 billion and $1.2 billion, respectively.

Emission allowances held-for-sale, which are included in other non-current assets on the Company's consolidated balance sheet, are not amortized; they are carried at the lower of cost or fair value and reviewed for impairment in accordance with ASC 360.

Goodwill

In accordance with ASC 350, Intangibles-Goodwill and Other, or ASC 350, the Company recognizes goodwill for the excess cost of an acquired entity over the net value assigned to assets acquired and liabilities assumed. NRG performs goodwill impairment tests annually, during the fourth quarter, and when events or changes in circumstances indicate that the carrying value may not be recoverable.

The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The more-likely-than-not threshold is defined as having a likelihood of more than 50 percent. If it is not more-likely-than-not that the fair value of a reporting unit is less than its carrying amount, there is no goodwill impairment.

In the absence of sufficient qualitative factors indicating that it is more-likely-than-not that no impairment occurred, the Company performs a quantitative assessment by determining the fair value of the reporting unit and comparing the fair value to its book value. If the fair value of the reporting unit exceeds its book value, goodwill of the reporting unit is not considered impaired. If the book value exceeds fair value, the Company recognizes an impairment loss equal to the difference between book value and fair value.

For further discussion of goodwill and goodwill impairment losses recognized refer to Note 12, Goodwill and Other Intangibles.

Income Taxes

The Company accounts for income taxes using the liability method in accordance with ASC 740, Income Taxes, or ASC 740, which requires that the Company use the asset and liability method of accounting for deferred income taxes and provide deferred income taxes for all significant temporary differences.

The Company has two categories of income tax expense or benefit — current and deferred, as follows:

•Current income tax expense or benefit consists solely of current taxes payable less applicable tax credits, and

•Deferred income tax expense or benefit is the change in the net deferred income tax asset or liability, excluding amounts charged or credited to accumulated other comprehensive income

The Company reports some of its revenues and expenses differently for financial statement purposes than for income tax return purposes, resulting in temporary and permanent differences between the Company's financial statements and income tax returns. The tax effects of such temporary differences are recorded as either deferred income tax assets or deferred income tax liabilities in the Company's consolidated balance sheets. The Company measures its deferred income tax assets and deferred income tax liabilities using income tax rates that are expected to be in effect when the deferred tax is realized.

The Company accounts for uncertain tax positions in accordance with ASC 740, which applies to all tax positions related to income taxes. Under ASC 740, tax benefits are recognized when it is more-likely-than-not that a tax position will be sustained upon examination by the authorities. The benefit recognized from a position is the amount of benefit that has surpassed the more-likely-than-not threshold, as it is more than 50% likely to be realized upon settlement. The Company recognizes interest and penalties accrued related to uncertain tax benefits as a component of income tax expense.

In accordance with ASC 805 and as discussed further in Note 20, Income Taxes, changes to existing net deferred tax assets or valuation allowances or changes to uncertain tax benefits, are recorded to income tax (benefit)/expense.

Contract Amortization

Assets and liabilities recognized through acquisitions related to the sale of electric capacity and energy in future periods for which the fair value has been determined to be significantly less or more than market are amortized to revenue over the term of each underlying contract based on actual generation and/or contracted volumes.

Lease Revenue

Certain of the Company’s revenues are obtained through leases of rooftop residential solar systems, which are accounted for as operating leases in accordance with ASC 842, Leases. Pursuant to the lease agreements, the customers’ monthly payments are pre-determined fixed monthly amounts and may include an annual fixed percentage escalation to reflect the impact of utility rate increases over the lease term, which is 20 years. The Company records operating lease revenue on a straight-line basis over the life of the lease term. Certain customers made initial down payments that are being amortized over the life of the lease. The difference between the payments received and the revenue recognized is recorded as deferred revenue.

Lessor Accounting

Certain of the Company's revenues are obtained through PPAs or other contractual agreements. Many of these agreements are accounted for as operating leases under ASC 842.

Certain of these leases have no minimum lease payments and all of the rent is recorded as contingent rent on an actual basis when the electricity is delivered. Judgment is required by management in determining the economic life of each generating facility, in evaluating whether certain lease provisions constitute minimum payments or represent contingent rent and other factors in determining whether a contract contains a lease and whether the lease is an operating lease or finance lease. Contingent rental income recognized in the years ended December 31, 2019, 2018, and 2017 was $5 million, $104 million, and $253 million, respectively.

Gross Receipts and Sales Taxes

In connection with its retail sales, the Company records gross receipts taxes on a gross basis in revenues and cost of operations in its consolidated statements of operations. During the years ended December 31, 2019, 2018, and 2017, the Company's revenues and cost of operations included gross receipts taxes of $109 million, $99 million, and $92 million, respectively. Additionally, the Company records sales taxes collected from its taxable retail customers and remitted to the various governmental entities on a net basis; thus, there is no impact on the Company's consolidated statement of operations.

Cost of Energy for Retail Operations

The cost of energy for electricity sales and services to retail customers is included in cost of operations and is based on estimated supply volumes for the applicable reporting period. A portion of the cost of energy, $103 million, $105 million, and $107 million as of December 31, 2019, 2018, and 2017, respectively, was accrued and consisted of estimated transmission and distribution charges not yet billed by the transmission and distribution utilities. In estimating supply volumes, the Company considers the effects of historical customer volumes, weather factors and usage by customer class. Transmission and distribution delivery fees are estimated using the same method used for electricity sales and services to retail customers. In addition, ISO fees are estimated based on historical trends, estimated supply volumes and initial ERCOT ISO settlements. Volume estimates are then multiplied by the supply rate and recorded as cost of operations in the applicable reporting period.

Derivative Financial Instruments

The Company accounts for derivative financial instruments under ASC 815, which requires the Company to record all derivatives on the balance sheet at fair value unless they qualify for a NPNS exception. Changes in the fair value of non-hedge derivatives are immediately recognized in earnings. Changes in the fair value of derivatives accounted for as cash flow hedges, if elected for hedge accounting, are deferred and recorded as a component of accumulated OCI until the hedged transactions occur and are recognized in earnings.

The Company's primary derivative instruments are power purchase or sales contracts, fuels purchase contracts, and other energy related commodities used to mitigate variability in earnings due to fluctuations in market prices and interest rates. On an ongoing basis, the Company assesses the effectiveness of all derivatives that are designated as hedges for accounting purposes in order to determine that each derivative continues to be highly effective in offsetting changes in fair values or cash flows of hedged items. Internal analyses that measure the statistical correlation between the derivative and the associated hedged item determine the effectiveness of such a contract designated as a hedge. If it is determined that the derivative instrument is not highly effective as a hedge, hedge accounting will be discontinued prospectively. In this case, the gain or loss previously deferred in accumulated OCI would be frozen until the underlying hedged instrument is delivered unless the transactions being hedged are no longer probable of occurring in which case the amount in OCI would be immediately reclassified into earnings. If the derivative instrument is terminated, the effective portion of this derivative deferred in accumulated OCI will be frozen until the underlying hedged item is delivered. The Company had no cash flow hedges as of December 31, 2019.

Revenues and expenses on contracts that qualify for the NPNS exception are recognized when the underlying physical transaction is delivered. While these contracts are considered derivative financial instruments under ASC 815, they are not recorded at fair value, but on an accrual basis of accounting. If it is determined that a transaction designated as NPNS no longer meets the scope exception, the fair value of the related contract is recorded on the balance sheet and immediately recognized through earnings.

NRG's trading activities are subject to limits in accordance with the Company's Risk Management Policy. These contracts are recognized on the balance sheet at fair value and changes in the fair value of these derivative financial instruments are recognized in earnings.

Foreign Currency Translation and Transaction Gains and Losses

The local currencies are generally the functional currency of NRG's foreign operations. Foreign currency denominated assets and liabilities are translated at end-of-period rates of exchange. Revenues, expenses, and cash flows are translated at the weighted-average rates of exchange for the period. The resulting currency translation adjustments are not included in the Company's consolidated statements of operations for the period, but are accumulated and reported as a separate component of stockholders' equity until sale or complete or substantially complete liquidation of the net investment in the foreign entity takes place. Foreign currency transaction gains or losses are reported within other income/(expense) in the Company's consolidated statements of operations. For the years ended December 31, 2019, 2018, and 2017, amounts recognized as foreign currency transaction gains/(losses) were immaterial. The Company's cumulative translation adjustment balances as of December 31, 2019, 2018, and 2017 were $(13) million, $(13) million and $(2) million, respectively.

Concentrations of Credit Risk

Financial instruments which potentially subject the Company to concentrations of credit risk consist primarily of trust funds, accounts receivable, notes receivable, derivatives, and investments in debt securities. Trust funds are held in accounts managed by experienced investment advisors. Certain accounts receivable, notes receivable, and derivative instruments are concentrated within entities engaged in the energy industry. These industry concentrations may impact the Company's overall exposure to credit risk, either positively or negatively, in that the customers may be similarly affected by changes in economic, industry or other conditions. Receivables and other contractual arrangements are subject to collateral requirements under the terms of enabling agreements. However, the Company believes that the credit risk posed by industry concentration is offset by the diversification and creditworthiness of its customer base. See Note 5, Fair Value of Financial Instruments, for a further discussion of derivative concentrations.

Fair Value of Financial Instruments

The carrying amount of cash and cash equivalents, funds deposited by counterparties, receivables, accounts payable, and accrued liabilities approximate fair value because of the short-term maturity of these instruments. See Note 5, Fair Value of Financial Instruments, for a further discussion of fair value of financial instruments.

Asset Retirement Obligations

The Company accounts for AROs in accordance with ASC 410-20, Asset Retirement Obligations, or ASC 410-20. Retirement obligations associated with long-lived assets included within the scope of ASC 410-20 are those for which a legal obligation exists under enacted laws, statutes, and written or oral contracts, including obligations arising under the doctrine of promissory estoppel, and for which the timing and/or method of settlement may be conditional on a future event. ASC 410-20 requires an entity to recognize the fair value of a liability for an ARO in the period in which it is incurred and a reasonable estimate of fair value can be made.

Upon initial recognition of a liability for an ARO, the Company capitalizes the asset retirement cost by increasing the carrying amount of the related long-lived asset by the same amount. Over time, the liability is accreted to its future value, while the capitalized cost is depreciated over the useful life of the related asset. See Note 14, Asset Retirement Obligations, for a further discussion of AROs.

Pensions and Other Postretirement Benefits

The Company offers pension benefits through a defined benefit pension plan. In addition, the Company provides postretirement health and welfare benefits for certain groups of employees. The Company accounts for pension and other postretirement benefits in accordance with ASC 715, Compensation — Retirement Benefits, or ASC 715. The Company recognizes the funded status of the Company's defined benefit plans in the statement of financial position and records an offset for gains and losses as well as all prior service costs that have not been included as part of the Company's net periodic benefit cost to other comprehensive income. The determination of the Company's obligation and expenses for pension benefits is dependent on the selection of certain assumptions. These assumptions determined by management include the discount rate, the expected rate of return on plan assets and the rate of future compensation increases. The Company's actuarial consultants assist in determining assumptions for such items as retirement age. The assumptions used may differ materially from actual results, which may result in a significant impact to the amount of pension obligation or expense recorded by the Company.

The Company measures the fair value of its pension assets in accordance with ASC 820, Fair Value Measurements and Disclosures, or ASC 820.

Stock-Based Compensation

The Company accounts for its stock-based compensation in accordance with ASC 718, Compensation — Stock Compensation, or ASC 718. The fair value of the Company's non-qualified stock options and market stock units are estimated on the date of grant using the Black-Scholes option-pricing model and the Monte Carlo valuation model, respectively. NRG uses the Company's common stock price on the date of grant as the fair value of the Company's restricted stock units and deferred stock units. Forfeiture rates are estimated based on an analysis of the Company's historical forfeitures, employment turnover, and expected future behavior. The Company recognizes compensation expense for both graded and cliff vesting awards on a straight-line basis over the requisite service period for the entire award.

Investments Accounted for by the Equity Method

The Company has investments in various domestic energy projects, as well as one Australian project. The equity method of accounting is applied to such investments in affiliates, which include joint ventures and partnerships, because the ownership structure prevents the Company from exercising a controlling influence over the operating and financial policies of the projects. Under this method, equity in pre-tax income or losses of domestic partnerships and, generally, in the net income or losses of its Australian project, are reflected as equity in earnings of unconsolidated affiliates. Distributions from equity method investments that represent earnings on the Company's investment are included within cash flows from operating activities and distributions from equity method investments that represent a return of the Company's investment are included within cash flows from investing activities.

Tax Equity Arrangements

The Company’s redeemable noncontrolling interest in subsidiaries represents third-party interests in the net assets under certain tax equity arrangements, which are consolidated by the Company, that have been entered into to finance the cost of solar energy systems under operating leases. The Company has determined that the provisions in the contractual agreements of these structures represent substantive profit sharing arrangements. Further, the Company has determined that the appropriate methodology for calculating the redeemable noncontrolling interest that reflects the substantive profit sharing arrangements is a balance sheet approach utilizing the HLBV method. Under the HLBV method, the amounts reported as redeemable noncontrolling interests represent the amounts the investors that are party to the tax equity arrangements would hypothetically receive at each balance sheet date under the liquidation provisions of the contractual agreements, assuming the net assets of the funding structures were liquidated at their recorded amounts. The investors’ interests in the results of operations of the funding structures are determined as redeemable noncontrolling interests at the start and end of each reporting period, after taking into account any capital transactions between the structures and the funds’ investors. The calculations utilized to apply the HLBV method include estimated calculations of taxable income or losses for each reporting period.

Redeemable Noncontrolling Interest

To the extent that the third-party has the right to redeem their interests for cash or other assets, the Company has included the noncontrolling interest attributable to the third party as a component of temporary equity in the mezzanine section of the consolidated balance sheet. The following table reflects the changes in the Company's redeemable noncontrolling interest balance for the years ended December 31, 2019, 2018, and 2017.


	(In millions)
Balance as of December 31, 2016	$	46
Distributions to redeemable noncontrolling interest	(2)
Contributions from redeemable noncontrolling interest	99
Non-cash adjustments to redeemable noncontrolling interest	7
Comprehensive loss attributable to redeemable noncontrolling interest	(72)
Balance as of December 31, 2017	78
Distributions to redeemable noncontrolling interest	(3)
Contributions from redeemable noncontrolling interest	26
Non-cash adjustments to redeemable noncontrolling interest	(8)
Net income attributable to redeemable noncontrolling interest - continuing operations	1
Net loss attributable to redeemable noncontrolling interest - discontinued operations	(27)
Sale of NRG Yield and the Renewables Platform ^(a)	(48)
Balance as of December 31, 2018	19
Distributions to redeemable noncontrolling interest	(2)


Net income attributable to redeemable noncontrolling interest - continuing operations	3


Balance as of December 31, 2019	$	20

(a) See Note 4, Acquisitions, Discontinued Operations and Dispositions, for further information regarding the sale of NRG Yield and its Renewables Platform

Sale-Leaseback Arrangements

NRG is party to sale-leaseback arrangements that provide for the sale of certain assets to a third party and simultaneously leases back the same asset to the Company. If the seller-lessee transfers control of the underlying assets to the buyer-lessor, the arrangement is accounted for under ASC 842-40, Sale-Leaseback Transactions. These arrangements are classified as operating leases on the Company's consolidated balance sheets. See Note 10, Leases, for further discussion.

Marketing and Advertising Costs

The Company expenses its marketing and advertising costs as incurred and includes them within selling, general and administrative expenses. The costs of tangible assets used in advertising campaigns are recorded as fixed assets or deferred advertising costs and amortized as advertising costs over the shorter of the useful life of the asset or the advertising campaign. The Company has several long-term sponsorship arrangements. Payments related to these arrangements are deferred and expensed over the term of the arrangement. Advertising expenses for the years ended December 31, 2019, 2018, and 2017 were $66 million, $73 million, and $66 million, respectively.

Reorganization Costs

Reorganization costs include costs incurred by the Company related to the Transformation Plan implementation and primarily reflect severance and contract modifications. Reorganization costs for the years ended December 31, 2019, 2018 and 2017 were $23 million, $90 million and $44 million, respectively.

Business Combinations

The Company accounts for its business combinations in accordance with ASC 805, Business Combinations, or ASC 805, which requires an acquirer to recognize and measure in its financial statements the identifiable assets acquired, the liabilities assumed, and any noncontrolling interest in the acquiree at fair value at the acquisition date. The Company also recognizes and measures the goodwill acquired or a gain from a bargain purchase in the business combination. In addition, transaction costs are expensed as incurred.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates.

In recording transactions and balances resulting from business operations, the Company uses estimates based on the best information available. Estimates are used for such items as plant depreciable lives, tax provisions, uncollectible accounts, actuarially determined benefit costs, the valuation of energy commodity contracts, environmental liabilities, legal costs incurred in connection with recorded loss contingencies, and assets acquired and liabilities assumed in business combinations, among others. In addition, estimates are used to test long-lived assets and goodwill for impairment and to determine the fair value of impaired assets. As better information becomes available or actual amounts are determinable, the recorded estimates are revised. Consequently, operating results can be affected by revisions to prior accounting estimates.

Reclassifications

Certain prior year amounts have been reclassified for comparative purposes. The reclassifications did not affect results from operations, net assets or cash flows.

Recent Accounting Developments - Guidance Adopted in 2019

ASU 2016-02 - In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or Topic 842, which was further amended through various updates issued by the FASB thereafter, with the objective to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and to improve financial reporting by expanding the related disclosures. The guidance in Topic 842 provides that a lessee that may have previously accounted for a lease as an operating lease under current GAAP should recognize the assets and liabilities that arise from a lease on the balance sheet. In addition, Topic 842 expands the required quantitative and qualitative disclosures with regards to lease arrangements. The Company adopted the standard and its subsequent corresponding updates effective January 1, 2019 using the modified retrospective approach, as further described in Note 10, Leases. The Company recognized operating lease liabilities of $404 million and right of use assets of $321 million upon adoption.

Recent Accounting Developments - Guidance Not Yet Adopted

ASU 2019-12 - In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, to simplify various aspects related to accounting for income taxes. The guidance in ASU 2019-12 amends the general principles in Topic 740 to eliminate certain exceptions for recognizing deferred taxes for investment, performing intraperiod allocation and calculating income taxes in interim periods. This ASU also includes guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years,. Early adoption is permitted, including adoption in an interim period. The Company is currently in the process of assessing the impact of this guidance on the consolidated financial statements.

ASU 2018-17 - In October 2018, the FASB issued ASU No. 2018-17, Consolidations (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities, or ASU No. 2018-17, in response to stakeholders’ observations that Topic 810, Consolidations, could be improved thereby improving general purpose financial reporting. Specifically, ASU No. 2018-17 requires application of the variable interest entity (VIE) guidance to private companies under common control and consideration of indirect interest held through related parties under common control for determining whether fees paid to decision makers and service providers are variable interests. The amendments are effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. All entities are required to apply the amendments retrospectively with a cumulative-effect adjustment to opening retained earnings of the earliest period presented. The Company will adopt the amendments during the first quarter of 2020 and does not expect the adoption to have a material impact on its results of operations, cash flows, or statement of financial position.

ASU 2018-13 - In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirement for Fair value Measurement), or ASU No. 2018-13. The amendments in ASU No. 2018-13 eliminate such disclosures as the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy and add new disclosure requirements for Level 3 measurements. ASU No. 2018-13 is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Certain disclosures in ASU No. 2018-13 are required to be applied on a retrospective basis and others on a prospective basis. The Company will adopt the amendments during the first quarter of 2020. As the amendments contemplates changes in disclosures only, it will have no impact on the Company's results of operations, cash flows, or statement of financial position.

ASU 2016-13 - In June 2016, the FASB issues ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, or ASU No. 2016-13, which was further amended through various updates issued by the FASB thereafter. The guidance in ASU No. 2016-13 provides a new model for recognizing credit losses on financial assets carried at amortized cost using an estimate of expected credit losses, instead of the "incurred loss" methodology previously required for recognizing credit losses that delayed recognition until it was probable that a loss was incurred. The estimate of expected credit losses is to be based on consideration of past events, current conditions and reasonable and supportable forecasts of future conditions. ASU No. 2016-13 is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The guidance is required to be adopted using a modified retrospective approach through a cumulative-effect adjustment to opening retained earnings as of the effective date and requires additional disclosures. The Company will adopt the guidance during the first quarter of 2020 and does not expect the adoption to have a material impact on its results of operations, cash flows, or statement of financial position.

Revenue Recognition

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

Revenue Recognition

Revenue from Contracts with Customers

On January 1, 2018, the Company adopted the guidance in ASC 606, Revenue from Contracts, or ASC 606, with customers using the modified retrospective method applied to contracts that were not completed as of the adoption date. The Company recognized the cumulative effect of initially applying the new standard as a credit to the opening balance of accumulated deficit, resulting in a decrease of $15 million. The adjustment primarily related to costs incurred to obtain a contract with customers and customer incentives. Following the adoption of the new standard, the Company’s revenue recognition of its contracts with customers remains materially consistent with its historical practice. The 2017 comparative information was not restated and continues to be reported under the accounting standards in effect for that period. The Company's policies with respect to its various revenue streams are detailed below. The Company generally applies the invoicing practical expedient to recognize revenue for the revenue streams detailed below, except in circumstances where the invoiced amount does not represent the value transferred to the customer.

Retail Revenue

Gross revenues for energy sales and services to retail customers are recognized as the Company transfers the promised goods and services to the customer. For the majority of its electricity contracts, the Company’s performance obligation with the

customer is satisfied over time and performance obligations for its electricity products are recognized as the customer takes possession of the product. The Company also allocates the contract consideration to distinct performance obligations in a contract for which the timing of the revenue recognized is different. Additionally, customer discounts and incentives reduce the contract consideration and are recognized over the term of the contract.

Energy sales and services that have been delivered but not billed by period end are estimated. Accrued unbilled revenues are based on estimates of customer usage since the date of the last meter reading provided by the independent system operators or electric distribution companies. Volume estimates are based on daily forecasted volumes and estimated customer usage by class. Unbilled revenues are calculated by multiplying these volume estimates by the applicable rate by customer class. Estimated amounts are adjusted when actual usage is known and billed.

As contracts for retail electricity can be for multi-year periods, the Company has performance obligations under these contracts that have not yet been satisfied. These performance obligations have transaction prices that are both fixed and variable, and that vary based on the contract duration, customer type, inception date and other contract-specific factors. For the fixed price contracts, the amount of any unsatisfied performance obligations will vary based on customer usage, which will depend on factors such as weather and customer activity and therefore it is not practicable to estimate such amounts.

Energy Revenue

Both physical and financial transactions consist of revenues billed to a third party at either market or negotiated contract terms to optimize the financial performance of the Company's generating facilities. Electric energy revenue is recognized upon transmission to the customer over time, using the output method for measuring progress of satisfaction of performance obligations. Physical transactions, or the sale of generated electricity to meet supply and demand, are recorded on a gross basis in the Company's consolidated statements of operations. The Company applies the invoicing practical expedient in recognizing energy revenue. Under the practical expedient, revenue is recognized based on the invoiced amount which is equal to the value to the customer of NRG’s performance obligation completed to date. Financial transactions used to hedge the sale of electricity are recorded net within operating revenues in the consolidated statements of operations in accordance with ASC 815.

Capacity Revenue

Capacity revenues consist of revenues billed to a third party at either market or negotiated contract terms for making installed generation and demand response capacity available in order to satisfy system integrity and reliability requirements. Capacity revenues are recognized over time, using the output method for measuring progress of satisfaction of performance obligations. The Company applies the invoicing practical expedient in recognizing capacity revenue. Under the practical expedient, revenue is recognized based on the invoiced amount which is equal to the value to the customer of NRG’s performance obligation completed to date.

Performance Obligations

As of December 31, 2019, estimated future fixed fee performance obligations are $564 million, $604 million, $303 million, $42 million, and $8 million for fiscal years 2020, 2021, 2022, 2023, and 2024, respectively. These performance obligations are for cleared auction MWs in the PJM, ISO-NE, NYISO and MISO capacity auctions and are subject to penalties for non performance.

Renewable Energy Credits

Renewable energy credits are usually sold through long-term contracts. Revenue from the sale of self-generated RECs is recognized when related energy is generated and simultaneously delivered even in cases where there is a certification lag as it has been deemed to be perfunctory.

In a bundled contract to sell energy, capacity and/or self-generated RECs, all performance obligations are deemed to be delivered at the same time and hence, timing of recognition of revenue for all performance obligations is the same and occurs over time. In such cases, it is often unnecessary to allocate transaction price to multiple performance obligations.

Sale of Emission Allowances

The Company records its inventory of emission allowances as part of intangible assets. From time to time, management may authorize the transfer of emission allowances in excess of expected usage from the Company's emission bank to intangible assets held-for-sale for trading purposes. The Company records the sale of emission allowances on a net basis within operating revenue in the Company's consolidated statements of operations.

Disaggregated Revenue

The following tables represent the Company’s disaggregation of revenue from contracts with customers for the years ended December 31, 2019 and 2018:


	For the Year Ended December 31, 2019
(In millions)	Texas		East		West/Other		Corporate/Eliminations		Total
Retail revenue
Mass Market	$	5,027	$	1,230	$	—	$	(3)	$	6,254
Business Solutions	1,205		74		—		—		1,279
Total retail revenue	6,232		1,304		—		(3)		7,533
Energy revenue^(a)	529		322		318		—		1,169
Capacity revenue^(a)	—		664		36		—		700
Mark-to-market for economic hedging activities^(b)	47		(29)		16		(1)		33

Other revenue^(a)	261		58		70		(3)		386
Total operating revenue	7,069		2,319		440		(7)		9,821
Less: Lease revenue	—		1		19		—		20
Less: Realized and unrealized ASC 815 revenue	1,562		183		67		(2)		1,810

Total revenue from contracts with customers	$	5,507	$	2,135	$	354	$	(5)	$	7,991





(a) The following amounts of energy, capacity and other revenue relate to derivative instruments and are accounted for under ASC 815:
(In millions)	Texas		East		West/Other		Corporate/Eliminations		Total
Energy revenue	$	1,459	$	98	$	39	$	(1)	$	1,595
Capacity revenue	—		109		—		—		109
Other revenue	56		5		12		—		73
(b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815


	For the Year Ended December 31, 2018
(In millions)	Texas		East		West/Other		Corporate/Eliminations		Total
Retail revenue
Mass Market	$	4,618	$	974	$	—	$	(1)	$	5,591
Business Solutions	1,238		65		—		—		1,303
Total retail revenue	5,856		1,039		—		(1)		6,894
Energy revenue^(a)	371		546		566		13		1,496
Capacity revenue^(a)	—		746		79		—		825
Mark-to-market for economic hedging activities^(b)	(77)		(35)		(5)		(13)		(130)

Other revenue^(a)(c)	251		75		84		(17)		393
Total operating revenue	6,401		2,371		724		(18)		9,478
Less: Lease revenue	1		1		19		—		21
Less: Realized and unrealized ASC 815 revenue	1,096		210		2		1		1,309

Total revenue from contracts with customers	$	5,304	$	2,160	$	703	$	(19)	8,148





(a) The following amounts of energy, capacity and other revenue relate to derivative instruments and are accounted for under ASC 815:
(In millions)	Texas		East		West/Other		Corporate/Eliminations		Total
Energy revenue	$	1,131	$	90	$	(2)	$	14	$	1,233
Capacity revenue	—		137		—		—		137
Other revenue	42		17		9		1		69

(b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815

Contract Balances

The following table reflects the contract assets and liabilities included in the Company's balance sheet as of December 31, 2019 and 2018:


(In millions)	December 31, 2019		December 31, 2018
Deferred customer acquisition costs	$	133	$	111

Accounts receivable, net - Contracts with customers	1,002		999
Accounts receivable, net - Derivative instruments	18		20
Accounts receivable, net - Affiliate	5		5
Total accounts receivable, net	$	1,025	$	1,024

Unbilled revenues (included within Accounts receivable, net - Contracts with customers)	$	402	$	392

Deferred revenues ^(a)	$	82	$	67

(a) Deferred revenues from contracts with customers for the years ended December 31, 2019 and 2018 were approximately $24 million and $19 million, respectively.

The revenue recognized from contracts with customers during years ended December 31, 2019 and 2018 relating to the deferred revenue balance at the beginning of each period was $13 million and $16 million, respectively. The change in deferred revenue balances during the years ended December 31, 2019 and 2018 was primarily due to the timing difference of when consideration was received and when the performance obligation was transferred.

The Company's customer acquisition costs consist of broker fees, commission payments and other costs that represent incremental costs of obtaining the contract with customers for which the Company expects to recover. The Company amortizes these amounts over the estimated life of the customer contract. As a practical expedient, the Company expenses the incremental costs of obtaining a contract if the amortization period of the asset would have been one year or less.

When the Company receives consideration from the customer that is in excess of the amount due, such consideration is reclassified to deferred revenue, which represents a contract liability. Generally, the Company will recognize revenue from contract liabilities in the next period as the Company satisfies its performance obligations.

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

For cash and cash equivalents, funds deposited by counterparties, accounts and other receivables, accounts payable, restricted cash, and cash collateral posted and received in support of energy risk management activities, the carrying amount approximates fair value because of the short-term maturity of those instruments and are classified as Level 1 within the fair value hierarchy.

The estimated carrying values and fair values of the Company's recorded financial instruments not carried at fair market value are as follows:


	As of December 31,
	2019						2018
(In millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets
Notes receivable	$	11	$	8	$	17	$	14
Liabilities
Long-term debt, including current portion ^(a)	$	5,956	$	6,504	$	6,591	$	6,697

(a) Excludes deferred financing costs, which are recorded as a reduction to long-term debt on the Company's consolidated balance sheets

The fair value of the Company's publicly-traded long-term debt is based on quoted market prices and is classified as Level 2 within the fair value hierarchy. The fair value of debt securities, non-publicly traded long-term debt, and certain notes receivable of the Company are based on expected future cash flows discounted at market interest rates or current interest rates for similar instruments with equivalent credit quality and are classified as Level 3 within the fair value hierarchy. The following table presents the level within the fair value hierarchy for long-term debt, including current portion as of December 31, 2019 and 2018:


	As of December 31, 2019						As of December 31, 2018
(In millions)	Level 2		Level 3		Level 2		Level 3
Long-term debt, including current portion	$	6,388	$	116	$	6,528	$	169

Fair Value Accounting under ASC 820

ASC 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels as follows:

•Level 1 — quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access as of the measurement date. NRG's financial assets and liabilities utilizing Level 1 inputs include active exchange-traded securities, energy derivatives, and trust fund investments.

•Level 2 — inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. NRG's financial assets and liabilities utilizing Level 2 inputs include fixed income securities, exchange-based derivatives, and over the counter derivatives such as swaps, options and forward contracts.

•Level 3 — unobservable inputs for the asset or liability only used when there is little, if any, market activity for the asset or liability at the measurement date. NRG's financial assets and liabilities utilizing Level 3 inputs include infrequently-traded, non-exchange-based derivatives and commingled investment funds, and are measured using present value pricing models.

Recurring Fair Value Measurements

Debt securities, equity securities, and trust fund investments, which are comprised of various U.S. debt and equity securities, and derivative assets and liabilities, are carried at fair market value.

The following tables present assets and liabilities measured and recorded at fair value on the Company's consolidated balance sheets on a recurring basis and their level within the fair value hierarchy:


	As of December 31, 2019
	Fair Value
(In millions)	Total		Level 1		Level 2		Level 3
Investments in securities (classified within other current and non-current assets)	$	20	$	—	$	20	$	—

Nuclear trust fund investments:
Cash and cash equivalents	17		17		—		—
U.S. government and federal agency obligations	68		68		—		—
Federal agency mortgage-backed securities	100		—		100		—
Commercial mortgage-backed securities	29		—		29		—
Corporate debt securities	109		—		109		—
Equity securities	388		388		—		—
Foreign government fixed income securities	5		—		5		—
Other trust fund investments:
U.S. government and federal agency obligations	1		1		—		—
Derivative assets:
Commodity contracts	1,170		84		893		193


Measured using net asset value practical expedient:
Equity securities-nuclear trust fund investments	78		—		—		—
Equity securities	8		—		—		—
Total assets	$	1,993	$	558	$	1,156	$	193
Derivative liabilities:
Commodity contracts	$	1,103	$	143	$	805	$	155

Total liabilities	$	1,103	$	143	$	805	$	155


	As of December 31, 2018
	Fair Value
(In millions)	Total		Level 1		Level 2		Level 3
Investments in securities (classified within other current or non-current assets)	$	39	$	2	$	18	$	19
Nuclear trust fund investments:
Cash and cash equivalents	19		19		—		—
U.S. government and federal agency obligations	46		46		—		—
Federal agency mortgage-backed securities	100		—		100		—
Commercial mortgage-backed securities	22		—		22		—
Corporate debt securities	96		—		96		—
Equity securities	312		312		—		—
Foreign government fixed income securities	4		—		4		—
Other trust fund investments:
U.S. government and federal agency obligations	1		1		—		—
Derivative assets:
Commodity contracts	1,042		137		796		109
Interest rate contracts	39		—		39		—

Measured using net asset value practical expedient:
Equity securities-nuclear trust fund investments	64		—		—		—
Equity securities	8		—		—		—
Total assets	$	1,792	$	517	$	1,075	$	128
Derivative liabilities:
Commodity contracts	$	977	$	224	$	664	$	89

Total liabilities	$	977	$	224	$	664	$	89

The following tables reconcile, for the years ended December 31, 2019 and 2018, the beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements at least annually using significant unobservable inputs:


	For the Year Ended December 31, 2019
	Fair Value Measurement Using Significant Unobservable Inputs (Level 3)
(In millions)	Debt Securities		Derivatives^(a)		Total
Beginning balance as of January 1, 2019	$	19	$	20	$	39
Contracts added from acquisitions	—		(3)		(3)
Total gains/(losses) — realized/unrealized:
Included in earnings	—		(26)		(26)
Included in OCI	—		—		—

Purchases	—		40		40
Sale	(19)		—		(19)
Transfers into Level 3 ^(b)	—		2		2
Transfers out of Level 3 ^(b)	—		5		5
Ending balance as of December 31, 2019	$	—	$	38	$	38
Gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of December 31, 2019	$	—	$	17	$	17

(a)Consists of derivatives assets and liabilities, net

(b)Transfers into/out of Level 3 are related to the availability of external broker quotes, and are valued as of the end of the reporting period. All transfers into/out of Level 3 are from/to Level 2


	For the Year Ended December 31, 2018
	Fair Value Measurement Using Significant Unobservable Inputs (Level 3)
(In millions)	Debt Securities		Derivatives ^(a)		Total
Beginning balance as of January 1, 2018	$	19	$	(15)	$	4
Contracts acquired in XOOM acquisition	—		12		$	12
Total gains realized/unrealized included in earnings	—		(21)		(21)



Purchases	—		41		41


Transfers into Level 3 ^(b)	—		5		5
Transfer out of Level 3 ^(b)	—		(2)		(2)
Ending balance as of December 31, 2018	$	19	$	20	$	39
Losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of December 31, 2018	$	—	$	(17)	$	(17)

(a)Consists of derivatives assets and liabilities, net

(b)Transfers into/out of Level 3 are related to the availability of external broker quotes, and are valued as of the end of the reporting period. All transfers into/out of Level 3 are from/to Level 2

Realized and unrealized gains and losses included in earnings that are related to the energy derivatives are recorded in operating revenues and cost of operations.

Non-derivative fair value measurements

NRG's investments in debt securities are classified as Level 3 and consist of non-traded debt instruments that are valued based on third-party market value assessments.

The trust fund investments are held primarily to satisfy NRG's nuclear decommissioning obligations. These trust fund investments hold debt and equity securities directly and equity securities indirectly through commingled funds. The fair values of equity securities held directly by the trust funds are based on quoted prices in active markets and are categorized in Level 1. In addition, U.S. government and federal agency obligations are categorized as Level 1 because they trade in a highly liquid and transparent market. The fair values of corporate debt securities are based on evaluated prices that reflect observable market information, such as actual trade information of similar securities, adjusted for observable differences and are categorized in Level 2. Certain equity securities, classified as commingled funds, are analogous to mutual funds, are maintained by investment companies, and hold certain investments in accordance with a stated set of fund objectives. The fair value of the equity securities classified as commingled funds are based on net asset values per fund share (the unit of account), derived from the quoted prices in active markets of the underlying equity securities. However, because the shares in the commingled funds are not publicly quoted, not traded in an active market and are subject to certain restrictions regarding their purchase and sale, the commingled funds are measured using net asset value practical expedient. See also Note 7, Nuclear Decommissioning Trust Fund.

Derivative fair value measurements

A portion of the Company's contracts are exchange-traded contracts with readily available quoted market prices. A majority of NRG's contracts are non-exchange-traded contracts valued using prices provided by external sources, primarily price quotations available through brokers or over-the-counter and on-line exchanges. For the majority of NRG markets, the Company receives quotes from multiple sources. To the extent that NRG receives multiple quotes, the Company's prices reflect the average of the bid-ask mid-point prices obtained from all sources that NRG believes provide the most liquid market for the commodity. If the Company receives one quote, then the mid-point of the bid-ask spread for that quote is used. The terms for which such price information is available vary by commodity, region and product. A significant portion of the fair value of the Company's derivative portfolio is based on price quotes from brokers in active markets who regularly facilitate those transactions and the Company believes such price quotes are executable. The Company does not use third party sources that derive price based on proprietary models or market surveys. The remainder of the assets and liabilities represents contracts for which external sources or observable market quotes are not available. These contracts are valued based on various valuation techniques including but not limited to internal models based on a fundamental analysis of the market and extrapolation of observable market data with similar characteristics. Contracts valued with prices provided by models and other valuation techniques make up 16% of derivative assets and 14% of derivative liabilities. The fair value of each contract is discounted using a risk free interest rate. In addition, the Company applies a credit reserve to reflect credit risk, which for interest rate swaps is calculated utilizing the bilateral method based on published default probabilities. For commodities, to the extent that NRG's net exposure under a specific master agreement is an asset, the Company uses the counterparty's default swap rate. If the exposure under a specific master agreement is a liability, the Company uses NRG's default swap rate. For interest rate swaps and commodities, the credit reserve is added to the discounted fair value to reflect the exit price that a market participant would be willing to receive to assume NRG's liabilities or that a market participant would be willing to pay for NRG's assets. As of December 31, 2019 and December 31, 2018 the credit reserve did not result in a significant change in fair value.

The fair values in each category reflect the level of forward prices and volatility factors as of December 31, 2019, and may change as a result of changes in these factors. Management uses its best estimates to determine the fair value of commodity and derivative contracts NRG holds and sells. These estimates consider various factors including closing exchange and over-the-counter price quotations, time value, volatility factors and credit exposure. It is possible, however, that future market prices could vary from those used in recording assets and liabilities from energy marketing and trading activities and such variations could be material.

NRG's significant positions classified as Level 3 include physical and financial power executed in illiquid markets as well as financial transmission rights, or FTRs. The significant unobservable inputs used in developing fair value include illiquid power location pricing which is derived as a basis to liquid locations. The basis spread is based on observable market data when available or derived from historic prices and forward market prices from similar observable markets when not available. For FTRs, NRG uses the most recent auction prices to derive the fair value.

The following tables quantify the significant unobservable inputs used in developing the fair value of the Company's Level 3 positions as of December 31, 2019 and 2018:


	Significant Unobservable Inputs
	December 31, 2019
	Fair Value										Input/Range
(In millions)	Assets		Liabilities		Valuation Technique	Significant Unobservable Input	Low		High		Weighted Average
Power Contracts	$	151	$	139	Discounted Cash Flow	Forward Market Price (per MWh)	$	8	$	218	$	24
FTRs	42		16		Discounted Cash Flow	Auction Prices (per MWh)	(105)		213		0
	$	193	$	155


	Significant Unobservable Inputs
	December 31, 2018
	Fair Value										Input/Range
(In millions)	Assets		Liabilities		Valuation Technique	Significant Unobservable Input	Low		High		Weighted Average
Power Contracts	$	89	$	75	Discounted Cash Flow	Forward Market Price (per MWh)	$	1	$	214	$	31
FTRs	20		14		Discounted Cash Flow	Auction Prices (per MWh)	(90)		34		0
	$	109	$	89

The following table provides sensitivity of fair value measurements to increases/(decreases) in significant unobservable inputs as of December 31, 2019 and 2018:

Significant Unobservable Input

Position

Change In Input

Impact on Fair Value Measurement

Forward Market Price Power

Buy

Increase/(Decrease)

Higher/(Lower)

Forward Market Price Power

Sell

Increase/(Decrease)

Lower/(Higher)

FTR Prices

Buy

Increase/(Decrease)

Higher/(Lower)

FTR Prices

Sell

Increase/(Decrease)

Lower/(Higher)

Under the guidance of ASC 815, entities may choose to offset cash collateral posted or received against the fair value of derivative positions executed with the same counterparties under the same master netting agreements. The Company has chosen not to offset positions as defined in ASC 815. As of December 31, 2019, the Company recorded $190 million of cash collateral posted and $32 million of cash collateral received on its balance sheet.

Concentration of Credit Risk

In addition to the credit risk discussion as disclosed in Note 2, Summary of Significant Accounting Policies, the following item is a discussion of the concentration of credit risk for the Company's financial instruments. Credit risk relates to the risk of loss resulting from non-performance or non-payment by counterparties pursuant to the terms of their contractual obligations. The Company monitors and manages credit risk through credit policies that include: (i) an established credit approval process; (ii) a daily monitoring of counterparties' credit limits; (iii) the use of credit mitigation measures such as margin, collateral, prepayment arrangements, or volumetric limits; (iv) the use of payment netting agreements; and (v) the use of master netting agreements that allow for the netting of positive and negative exposures of various contracts associated with a single counterparty. Risks surrounding counterparty performance and credit could ultimately impact the amount and timing of expected cash flows. The Company seeks to mitigate counterparty risk by having a diversified portfolio of counterparties. The Company also has credit protection within various agreements to call on additional collateral support if and when necessary. Cash margin is collected and held at the Company to cover the credit risk of the counterparty until positions settle.

Counterparty Credit Risk

As of December 31, 2019, counterparty credit exposure, excluding credit exposure from RTOs, ISOs, and registered commodity exchanges and certain long-term agreements, was $239 million and NRG held collateral (cash and letters of credit) against those positions of $51 million, resulting in a net exposure of $233 million. NRG periodically receives collateral from counterparties in excess of their exposure. Collateral amounts shown include such excess while net exposure shown excludes excess collateral received. Approximately 67% of the Company's exposure before collateral is expected to roll off by the end of 2021. Counterparty credit exposure is valued through observable market quotes and discounted at a risk free interest rate. The following tables highlight net counterparty credit exposure by industry sector and by counterparty credit quality. Net counterparty credit exposure is defined as the aggregate net asset position for NRG with counterparties where netting is permitted under the enabling agreement and includes all cash flow, mark-to-market and NPNS, and non-derivative transactions. The exposure is shown net of collateral held, and includes amounts net of receivables or payables.


Category	Net Exposure ^{(a) (b)} (% of Total)
Utilities, energy merchants, marketers and other	84	%
Financial institutions	16


Total	100	%


Category	Net Exposure^{(a) (b)} (% of Total)
Investment grade	56	%
Non-Investment grade/Non-Rated	44

Total	100	%

(a)Counterparty credit exposure excludes uranium and coal transportation contracts because of the unavailability of market prices.

(b)The figures in the tables above exclude potential counterparty credit exposure related to RTOs, ISOs, registered commodity exchanges and certain long term contracts.

The Company currently has $33 million exposure to one wholesale counterparty in excess of 10% of the total net exposure discussed above as of December 31, 2019. Changes in hedge positions and market prices will affect credit exposure and counterparty concentration. Given the credit quality, diversification and term of the exposure in the portfolio, NRG does not anticipate a material impact on the Company's financial position or results of operations from nonperformance by any of NRG's counterparties.

RTOs and ISOs

The Company participates in the organized markets of CAISO, ERCOT, ISO-NE, MISO, NYISO and PJM, known as RTOs or ISOs. Trading in these markets is approved by FERC, or in the case of ERCOT, approved by the PUCT and includes credit policies that, under certain circumstances, require that losses arising from the default of one member on spot market transactions be shared by the remaining participants. As a result, the counterparty credit risk to these markets is limited to NRG’s share of overall market and are excluded from the above exposures.

Exchange Traded Transactions

The Company enters into commodity transactions on registered exchanges, notably ICE and NYMEX. These clearinghouses act as the counterparty and transactions are subject to extensive collateral and margining requirements. As a result, these commodity transactions have limited counterparty credit risk.

Long-Term Contracts

Counterparty credit exposure described above excludes credit risk exposure under certain long term contracts, primarily solar PPAs. As external sources or observable market quotes are not available to estimate such exposure, the Company values these contracts based on various techniques including, but not limited to, internal models based on a fundamental analysis of the market and extrapolation of observable market data with similar characteristics. Based on these valuation techniques, as of December 31, 2019, aggregate credit risk exposure managed by NRG to these counterparties was approximately $548 million for the next five years, including exposure to PG&E through its unconsolidated affiliates, Ivanpah and Agua Caliente.

Retail Customer Credit Risk

The Company is exposed to retail credit risk through the Company's retail electricity providers, which serve C&I customers and the Mass market. Retail credit risk results in losses when a customer fails to pay for services rendered. The losses may result from both nonpayment of customer accounts receivable and the loss of in-the-money forward value. The Company manages retail credit risk through the use of established credit policies that include monitoring of the portfolio and the use of credit mitigation measures such as deposits or prepayment arrangements.

As of December 31, 2019, the Company's retail customer credit exposure to C&I and Mass customers was diversified across many customers and various industries, as well as government entities. The Company is also subject to risk with respect to its residential solar customers. The Company's bad debt expense was $95 million, $85 million, and $68 million for the years ending December 31, 2019, 2018, and 2017, respectively. Current economic conditions may affect the Company's customers' ability to pay bills in a timely manner, which could increase customer delinquencies and may lead to an increase in bad debt expense.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Accounting for Derivative Instruments and Hedging Activities

12 Months Ended

Dec. 31, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Accounting for Derivative Instruments and Hedging Activities

ASC 815 requires the Company to recognize all derivative instruments on the balance sheet as either assets or liabilities and to measure them at fair value each reporting period unless they qualify for a NPNS exception. The Company may elect to designate certain derivatives as cash flow hedges, if certain conditions are met, and defer the change in fair value of the derivatives to accumulated OCI, until the hedged transactions occur and are recognized in earnings.

For derivatives that are not designated as cash flow hedges or do not qualify for hedge accounting treatment, the changes in the fair value will be immediately recognized in earnings. Certain derivative instruments may qualify for the NPNS exception and are therefore exempt from fair value accounting treatment. ASC 815 applies to NRG's energy related commodity contracts, interest rate swaps, and equity contracts.

As the Company engages principally in the trading and marketing of its generation assets and retail businesses, some of NRG's commercial activities qualify for NPNS accounting. Most of the retail load contracts either qualify for the NPNS exception or fail to meet the criteria for a derivative and the majority of the retail supply and fuels supply contracts are recorded under mark-to-market accounting. All of NRG's hedging and trading activities are subject to limits within the Company's Risk Management Policy.

Energy-Related Commodities

To manage the commodity price risk associated with the Company's competitive supply activities and the price risk associated with wholesale power sales from the Company's electric generation facilities and retail power sales from NRG's retail businesses, NRG enters into a variety of derivative and non-derivative hedging instruments, utilizing the following:

•Forward contracts, which commit NRG to purchase or sell energy commodities or purchase fuels in the future;

•Futures contracts, which are exchange-traded standardized commitments to purchase or sell a commodity or financial instrument;

•Swap agreements, which require payments to or from counterparties based upon the differential between two prices for a predetermined contractual, or notional, quantity;

•Option contracts, which convey to the option holder the right but not the obligation to purchase or sell a commodity;

•Extendable swaps, which include a combination of swaps and options executed simultaneously for different periods. This combination of instruments allows NRG to sell out-year volatility through call options in exchange for natural gas swaps with fixed prices in excess of the market price for natural gas at that time. The above-market swap combined with its later-year call option are priced in aggregate at market at the trade's inception; and

•Weather derivative products used to mitigate a portion of lost revenue due to weather.

The objectives for entering into derivative contracts designated as hedges include:

•Fixing the price of a portion of anticipated power purchases for the Company's retail sales;

•Fixing the price for a portion of anticipated future electricity sales that provides an acceptable return on the Company's electric generation operations; and

•Fixing the price of a portion of anticipated fuel purchases for the operation of the Company's power plants.

NRG's trading and hedging activities are subject to limits within the Company's Risk Management Policy. These contracts are recognized on the balance sheet at fair value and changes in the fair value of these derivative financial instruments are recognized in earnings.

As of December 31, 2019, NRG's derivative assets and liabilities consisted primarily of the following:

•Forward and financial contracts for the purchase/sale of electricity and related products economically hedging NRG's generation assets' forecasted output or NRG's retail load obligations through 2034;

•Forward and financial contracts for the purchase of fuel commodities relating to the forecasted usage of NRG's generation assets through 2020; and

•Other energy derivatives instruments extending through 2029.

Also, as of December 31, 2019, NRG had other energy-related contracts that did not meet the definition of a derivative instrument or qualified for the NPNS exception and were therefore exempt from fair value accounting treatment as follows:

•Load-following forward electric sale contracts extending through 2034;

•Power tolling contracts through 2036;

•Coal purchase contracts through 2021;

•Power transmission contracts through 2025;

•Natural gas transportation contracts and storage agreements through 2030; and

•Coal transportation contracts through 2029.

Interest Rate Swaps

NRG was exposed to changes in interest rates through the Company's issuance of variable rate debt. In order to manage the Company's interest rate risk, NRG entered into interest rate swap agreements. As of December 31, 2019, NRG had no interest rate derivative instruments as a result of the early termination of such contracts in connection with the repayment of the 2023 Term Loan Facility during the second quarter of 2019. See Note 13, Debt and Finance Leases, for further discussion.

Volumetric Underlying Derivative Transactions

The following table summarizes the net notional volume buy/(sell) of NRG's open derivative transactions broken out by commodity, excluding those derivatives that qualified for the NPNS exception as of December 31, 2019 and 2018. Option contracts are reflected using delta volume. Delta volume equals the notional volume of an option adjusted for the probability that the option will be in-the-money at its expiration date.


(In millions)		Total Volume
Commodity	Units	December 31, 2019		December 31, 2018
Emissions	Short Ton	3		(2)
Renewables Energy Certificates	Certificates	1		1
Coal	Short Ton	10		13
Natural Gas	MMBtu	(181)		(330)
Oil	Barrels	—		1
Power	MWh	38		1
Capacity	MW/Day	(1)		(1)
Interest	Dollars	$	—	$	1,000

The decrease in the natural gas position was primarily the result of additional retail hedge positions and settlement of generation hedges. The increase in the power position was primarily the result of additional retail hedge positions and the settlement of generation hedges. The decrease in the interest position was the result of the early settlement of the interest rate swaps.

Fair Value of Derivative Instruments

The following table summarizes the fair value within the derivative instrument valuation on the balance sheet:


	Fair Value
	Derivative Assets						Derivative Liabilities
(In millions)	December 31, 2019		December 31, 2018		December 31, 2019		December 31, 2018






Derivatives Not Designated as Cash Flow or Fair Value Hedges:
Interest rate contracts current	$	—	$	17	$	—	$	—
Interest rate contracts long-term	—		22		—		—
Commodity contracts current	860		747		781		673
Commodity contracts long-term	310		295		322		304

Total Derivatives Not Designated as Cash Flow or Fair Value Hedges	$	1,170	$	1,081	$	1,103	$	977

The Company has elected to present derivative assets and liabilities on the balance sheet on a trade-by-trade basis and does not offset amounts at the counterparty master agreement level. In addition, collateral received or paid on the Company's derivative assets or liabilities are recorded on a separate line item on the balance sheet. The following table summarizes the offsetting derivatives by counterparty master agreement level and collateral received or paid:


	Gross Amounts Not Offset in the Statement of Financial Position
(In millions)	Gross Amounts of Recognized Assets/Liabilities		Derivative Instruments		Cash Collateral (Held)/Posted		Net Amount
As of December 31, 2019
Commodity contracts:
Derivative assets	$	1,170	$	(909)	$	(7)	$	254
Derivative liabilities	(1,103)		909		73		(121)
Total commodity contracts	$	67	$	—	$	66	$	133


	Gross Amounts Not Offset in the Statement of Financial Position
(In millions)	Gross Amounts of Recognized Assets/Liabilities		Derivative Instruments		Cash Collateral (Held)/Posted		Net Amount
As of December 31, 2018
Commodity contracts:
Derivative assets	$	1,042	$	(778)	$	(31)	$	233
Derivative liabilities	(977)		778		114		(85)
Total commodity contracts	65		—		83		148
Interest rate contracts:
Derivative assets	39		—		—		39

Total interest rate contracts	39		—		—		39
Total derivative instruments	$	104	$	—	$	83	$	187

Accumulated Other Comprehensive Income

The following table summarizes the effects on NRG's accumulated OCI balance attributable to cash flow hedge derivatives, net of tax, for the years 2018 and 2017. As of December 31, 2019, NRG had no interest rate derivative instruments as a result of the early termination of such contracts in connection with the repayment of the 2023 Term Loan Facility, as further discussed in Note 13, Debt and Finance Leases.


	Interest Rate Contracts
(In millions)	2018		2017
Accumulated OCI beginning balance	$	(54)	$	(66)
Reclassified from accumulated OCI to income:
Due to realization of previously deferred amounts	8		12
Mark-to-market of cash flow hedge accounting contracts	21		—
Sale of NRG Yield and Renewables	$	25	$	—
Accumulated OCI ending balance	$	—	$	(54)

Amounts reclassified from accumulated OCI into income were recorded in discontinued operations.

Impact of Derivative Instruments on the Statement of Operations

Unrealized gains and losses associated with changes in the fair value of derivative instruments not accounted for as cash flow hedges are reflected in current period earnings.

The following table summarizes the pre-tax effects of economic hedges that have not been designated as cash flow hedges, and trading activity on the Company's statement of operations. The effect of commodity hedges is included within operating revenues and cost of operations and the effect of interest rate hedges is included in interest expense.


	Year Ended December 31,
(In millions)	2019		2018		2017
Unrealized mark-to-market results
Reversal of previously recognized unrealized (gains)/losses on settled positions related to economic hedges	$	(68)	$	(73)	$	47
Reversal of acquired loss/(gain) positions related to economic hedges	6		(10)		—
Net unrealized gains on open positions related to economic hedges	42		97		159
Total unrealized mark-to-market (losses)/gains for economic hedging activities	(20)		14		206
Reversal of previously recognized unrealized (gains) on settled positions related to trading activity	(11)		(12)		(25)

Net unrealized gains on open positions related to trading activity	31		29		14
Total unrealized mark-to-market gains/(losses) for trading activity	20		17		(11)
Total unrealized gains	$	—	$	31	$	195


	Year Ended December 31,
(In millions)	2019		2018		2017
Unrealized gains/(losses) included in operating revenues	$	53	$	(113)	$	241
Unrealized (losses)/gains included in cost of operations	(53)		144		(46)
Total impact to statement of operations — energy commodities	$	—	$	31	$	195
Total impact to statement of operations — interest rate contracts	$	(38)	$	—	$	4

The reversal of gain or loss positions acquired as part of acquisitions were valued based upon the forward prices on the acquisition dates. The roll-off amounts were offset by realized gains or losses at the settled prices and are reflected in revenue or cost of operations during the same period.

For the year ended December 31, 2019, 2018 and 2017 the $42 million, $97 million, and $159 million gains from economic hedge positions were primarily the result of an increase in the value of forward purchases of ERCOT heat rate contracts due to ERCOT heat rate expansion.

Credit Risk Related Contingent Features

Certain of the Company's hedging agreements contain provisions that require the Company to post additional collateral if the counterparty determines that there has been deterioration in credit quality, generally termed "adequate assurance" under the agreements, or require the Company to post additional collateral if there were a one notch downgrade in the Company's credit rating. The collateral required for contracts that have adequate assurance clauses that are in net liability positions as of December 31, 2019 was $14 million. The collateral required for contracts with credit rating contingent features that are in a net liability position as of December 31, 2019 was $24 million. The Company is also a party to certain marginable agreements under which it has a net liability position, but the counterparty has not called for the collateral due, which was approximately $3 million as of December 31, 2019.

See Note 5, Fair Value of Financial Instruments, for discussion regarding concentration of credit risk.

Nuclear Decommissioning Trust Fund

12 Months Ended

Dec. 31, 2019

Regulated Operations [Abstract]

Nuclear Decommissioning Trust Fund

NRG's Nuclear Decommissioning Trust Fund assets, which are for the decommissioning of STP, are comprised of securities classified as available-for-sale and recorded at fair value based on actively quoted market prices. Although NRG is responsible for managing the decommissioning of its 44% interest in STP, the predecessor utilities that owned STP are authorized by the PUCT to collect decommissioning funds from their ratepayers to cover decommissioning costs on behalf of NRG. NRC requirements determine the decommissioning cost estimate which is the minimum required level of funding. In the event that funds from the ratepayers that accumulate in the nuclear decommissioning trust are ultimately determined to be inadequate to decommission the STP facilities, the utilities will be required to collect through rates charged to rate payers all additional amounts, with no obligation from NRG, provided that NRG has complied with PUCT rules and regulations regarding decommissioning trusts. Following completion of the decommissioning, if surplus funds remain in the decommissioning trusts, any excess will be refunded to the respective ratepayers of the utilities.

NRG accounts for the Nuclear Decommissioning Trust Fund in accordance with ASC 980, Regulated Operations, or ASC 980, because the Company's nuclear decommissioning activities are subject to approval by the PUCT, with regulated rates that are designed to recover all decommissioning costs and that can be charged to and collected from the ratepayers per PUCT mandate. Since the Company is in compliance with PUCT rules and regulations regarding decommissioning trusts and the cost of decommissioning is the responsibility of the Texas ratepayers, not NRG, all realized and unrealized gains or losses (including other-than-temporary impairments) related to the Nuclear Decommissioning Trust Fund are recorded to the Nuclear Decommissioning Trust liability and are not included in net income or accumulated other comprehensive income, consistent with regulatory treatment.

The following table summarizes the aggregate fair values and unrealized gains and losses for the securities held in the trust funds, as well as information about the contractual maturities of those securities.


	As of December 31, 2019													As of December 31, 2018
(In millions, except otherwise noted)	Fair Value		Unrealized Gains		Unrealized Losses		Weighted- average maturities (in years)	Fair Value		Unrealized Gains		Unrealized Losses		Weighted- average maturities (in years)
Cash and cash equivalents	$	17	$	—	$	—	—	$	19	$	—	$	—	—
U.S. government and federal agency obligations	68		4		—		11	46		1		—		12
Federal agency mortgage-backed securities	100		3		—		24	100		1		2		23
Commercial mortgage-backed securities	29		1		1		24	22		—		1		22
Corporate debt securities	109		6		—		11	96		1		2		11
Equity securities	466		324		—		—	376		231		1		—
Foreign government fixed income securities	5		—		—		10	4		—		—		9
Total	$	794	$	338	$	1		$	663	$	234	$	6

The following table summarizes proceeds from sales of available-for-sale securities and the related realized gains and losses from these sales. The cost of securities sold is determined using the specific identification method.


	Year Ended December 31,
(In millions)	2019		2018		2017
Realized gains	$	18	$	17	$	22
Realized (losses)	(9)		(13)		(8)
Proceeds from sale of securities	381		513		501

Inventory

12 Months Ended

Dec. 31, 2019

Inventory Disclosure [Abstract]

Inventory

Inventory consisted of:


	As of December 31,
(In millions)	2019		2018
Fuel oil	$	73	$	74
Coal	93		97
Natural gas	21		28
Spare parts	196		213

Total Inventory	$	383	$	412

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

The Company's major classes of property, plant, and equipment were as follows:


	As of December 31,					Depreciable
(In millions)	2019		2018		Lives
Facilities and equipment	$	3,262	$	3,763	1-40 years
Land and improvements	324		347
Nuclear fuel	235		212		5 years
Hardware and office equipment and furnishings	422		431		2-10 years
Construction in progress	102		106
Total property, plant, and equipment	4,345		4,859
Accumulated depreciation	(1,752)		(1,811)
Net property, plant, and equipment	$	2,593	$	3,048

The Company recorded long-lived asset impairments during the years ended December 31, 2019 and 2018, as further described in Note 11, Asset Impairments.

Leases

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Leases

2019 Leases

The Company leases generating facilities, land, office and equipment, railcars, and storefront space at retail stores. Operating leases with an initial term greater than twelve months are recognized as right-of-use assets and lease liabilities in the consolidated balance sheets. The Company recognizes lease expense for all operating leases on a straight-line basis over the lease term. In the future, should another systematic basis become more representative of the pattern in which the lessee expects to consume the remaining economic benefit of the right-of-use asset, the Company will use that basis for lease expense.

The Company considers a contract to be or to contain a lease when both of the following conditions apply: 1) an asset is either explicitly or implicitly identified in the contract and 2) the contract conveys to the Company the right to control the use of the identified asset for a period of time. The Company has the right to control the use of the identified asset when the Company has both the right to obtain substantially all the economic benefits from the use of the identified asset and the right to direct how and for what purpose the identified asset is used throughout the period of use.

Lease payments are typically fixed and payable on a monthly, quarterly, semi-annual or annual basis. Lease payments under certain agreements may escalate over the lease term either by a fixed percentage or a fixed dollar amount. Certain leases

may provide for variable lease payments in the form of payments based on usage, a percentage of sales from the location under lease, or index-based (e.g., the U.S. Consumer Price Index) adjustments to lease payments. The Company has no leases which contain residual value guarantees provided by the Company as a lessee.

The Company’s leases may grant the Company an option to renew a lease for an additional term(s) or to terminate the lease after a certain period. As part of its transition from the guidance contained in ASC 840 to the updated guidance in ASC 842, the Company elected not to use the practical expedient of using hindsight to determine the lease term and in assessing impairment of the right-of-use assets.

As permitted by ASC 842, the Company made an accounting policy election for all asset classes not to recognize right-of-use assets and lease liabilities in the consolidated balance sheets for its short-term leases, which are leases that have a lease term of twelve months or less. For the initial measurement of lease liabilities, the Company uses as the discount rate either the rate implicit in the lease, if known, or its incremental borrowing rate, which is the rate of interest that the Company would have to pay to borrow, on a collateralized basis, over a similar term an amount equal to the payments for the lease.

In transition to ASC 842, the Company elected to apply the effective date transition method as of the January 1, 2019 adoption date. In accordance with this method, the Company’s reporting for comparative periods prior to January 1, 2019 presented in the financial statements continues to be in conformity with the guidance in ASC 840. The Company elected the following practical expedients, which allow entities to:

•Not reassess whether any contracts that existed prior to the January 1, 2019 implementation date are or contain leases;

•Not reassess the lease classification for any leases that commenced prior to the January 1, 2019 implementation date, meaning that all commenced capital leases under ASC 840 will be classified as finance leases under ASC 842 and all commenced operating leases under ASC 840 will be classified as operating leases under ASC 842;

•Not reassess initial direct costs for any leases;

•Not reassess whether existing land easements, which were not previously accounted as leases under ASC 840, are or contain leases; and

•Not separate lease and non-lease components for all asset classes, except office space leases and generation facilities leases.

As described in Note 4, Acquisitions, Discontinued Operations and Dispositions, upon the close of the South Central Portfolio sale, the Company entered into an agreement to leaseback the Cottonwood facility through May 2025. The lease was accounted for in accordance with ASC 842-40, Sale and Leaseback Transactions, as an operating lease and accordingly, a right-of-use asset and lease liability were established on the lease commencement date and will be amortized through the end of the lease.

Lease Cost:


(In millions)	For the Year Ended December 31, 2019
Finance lease cost:	$	—
Amortization of right-of-use assets	—
Shares issued under ESPP	—
Interest on lease liabilities	—
Operating lease cost	$	109
Short-term lease cost	3
Variable lease cost	6
Sublease income	(17)
Total lease cost	$	101

Other information:


(In millions)	For the Year Ended December 31, 2019

Cash paid for amounts included in the measurement of lease liabilities:


Operating cash flows from operating leases	$	104


Right-of-use assets obtained in exchange for new operating lease liabilities	215

Lease Term and Discount Rate for operating leases:


	December 31, 2019

Weighted average remaining lease term (in years)	7.8



Weighted average discount rate	5.72	%

As of December 31, 2019, annual payments based on the maturities of NRG's leases are expected to be as follows:


	(In millions)
2020	$	96
2021	87
2022	87
2023	85
2024	75
Thereafter	296
Total undiscounted lease payments	$	726
Less: present value adjustment	(170)
Total discounted lease payments	$	556

2018 Operating Lease Commitments

The below describes the Company's operating lease commitments as reported in the Company's Annual Report on Form 10-K for the year ended December 31, 2018, under Note 21, Commitments and Contingencies, prior to the adoption of ASC 842.

The Company leases 100% interests in the Powerton facility and Unit 7 and Unit 8 of the Joliet facility through 2034 and 2030, respectively, through its indirect subsidiary, Midwest Generation, LLC. The Company accounted for these leases as operating leases and recorded lease expense on a straight-line basis over the lease term. In connection with the acquisition of Midwest Generation, the Company recorded the out-of-market value as a liability of $159 million in 2014. The liability was being amortized through rent expense on a straight-line basis over the term of the lease. The Company recorded lease expense, net of amortization of the out-of-market liability, of approximately $14 million per year. The accounting for these out-of-market contracts changed effective January 1, 2019, upon the adoption of ASC 842.

Future minimum lease commitments under the Powerton and Joliet operating leases as of December 31, 2018 were as follows:


Period	(In millions)
2019	$	1
2020	1
2021	3
2022	6
2023	6
Thereafter	222
Total ^(a)	$	239

^(a) Termination of leases could be at a significant premium to the remaining lease payments

Other Operating Leases

NRG leases certain Company facilities and equipment under operating leases, some of which include escalation clauses, expiring on various dates through 2036. Lease expense under operating leases, other than Powerton and Joliet, was $66 million and $69 million for the years ended December 31, 2018 and 2017, respectively.

Future minimum lease commitments under operating leases, other than Powerton and Joliet, as of December 31, 2018 were as follows:


Period^(a)	(In millions)
2019	$	60
2020	55
2021	43
2022	40
2023	39
Thereafter	95
Total	$	332

^(a) Amounts in the table exclude future sublease income of $29 million associated with long-term leases for office locations

Asset Impairments	12 Months Ended
Asset Impairments	Dec. 31, 2019
Asset Impairment Charges [Abstract]
Asset Impairments	Asset Impairments 2019 Impairment Losses Petra Nova Parish Holdings — During the third quarter of 2019, NRG contributed $95 million in cash to Petra Nova and posted a $12 million letter of credit to cover certain project debt reserve requirements. The cash portion of the contribution was used by Petra Nova to prepay a significant portion of the project debt. As a result, the previously disclosed guarantee of up to $124 million related to the project level debt provided by NRG was canceled and the remaining project debt became non-recourse to NRG. In relation to this contribution, the Company evaluated the project for impairment and determined that the carrying amount of the Company’s equity method investment exceeded the fair value of the investment and that the decline is considered to be other-than-temporary. In determining the fair value, the Company utilized an income approach and considered project specific assumptions for the estimated future project cash flows. The Company measured the impairment loss as the difference between the carrying amount and the fair value of the investment and recorded an impairment loss of $101 million. Other Impairments — For the year ended December 31, 2019, the Company recorded $12 million of impairment losses primarily related to investments and intangibles. 2018 Impairment Losses Guam — During the fourth quarter of 2018, the Company concluded its wholly-owned subsidiary, NRG Solar Guam, LLC, was held for sale after board approval and advanced negotiations to sell the business. Accordingly, the Company recorded the assets and liabilities at fair market value as of December 31, 2018 based on the contractual sale price, which resulted in an impairment loss of $12 million. On February 20, 2019, the Company completed the sale of Guam for cash consideration of approximately $8 million. Keystone and Conemaugh — On September 5, 2018, the Company sold its approximately 3.7% interests in the Keystone and Conemaugh generating stations. NRG recorded impairment losses of $14 million for Keystone and $14 million for Conemaugh to adjust the carrying amount of the assets to fair value based on the contractual sale price. Dunkirk — During the second quarter of 2018, NRG ceased its development of the project to add gas capability at the Dunkirk generating station. The project was put on hold in 2015 pending the resolution of a lawsuit filed by Entergy Corporation against the NYPSC, which challenged the legality of its contract with Dunkirk. The lawsuit was later dropped and development continued, but the delay imposed a new requirement on Dunkirk to enter into the NYISO interconnection study process. The NYISO studies have concluded that extensive electric system upgrades would be necessary for the station to return to service. This would cause the Company to incur a material increase in cost and delay the project schedule that would render the project impractical. Consequently, the Company has recorded an impairment loss of $46 million, reducing the carrying amount of the related assets to $0. Other Impairments — As of December 31, 2018, the Company recorded additional asset impairment losses of $13 million and impairment losses on equity method investments of $15 million. 2017 Impairment Losses South Texas Project — The Company recognized an impairment loss of $1,248 million related to its interest in STP as a result of the decrease in the Company's view of long-term power prices in ERCOT. Indian River — The Company recognized an impairment loss of $36 million for Indian River as a result of the decrease in the Company's view of long-term power prices in PJM. Keystone and Conemaugh — The Company recognized impairment losses of $35 million for Keystone and $35 million for Conemaugh as a result of the decrease in the Company's view of long-term power prices in PJM. Bacliff Project — On June 16, 2017, NRG Texas Power LLC provided notice to BTEC New Albany, LLC that it was exercising its right to terminate the Amended and Restated Membership Interest Purchase Agreement, or MIPA, due to the Bacliff Project, a new peaking facility at the former P.H. Robinson Electric Generating Station, not achieving commercial completion by the contractual expiration date of May 31, 2017. As a result of the MIPA termination, the Company recorded an impairment loss of $41 million to reduce the carrying amount of the related construction in progress to $0 during the second quarter of 2017. Subsequent to the MIPA termination, BTEC filed claims against NRG Texas Power LLC with respect to the termination of the MIPA and NRG filed counterclaims against BTEC. On June 7, 2018, the parties resolved all claims and counterclaims in the lawsuit. Petra Nova Parish Holdings — In connection with the preparation of the annual budget during the fourth quarter of 2017, management revised its view of oil production expectations with respect to Petra Nova Parish Holdings. As a result, the Company reviewed its 50% interest in Petra Nova Parish Holdings for impairment utilizing the other-than-temporary impairment model. In determining fair value, the Company utilized an income approach and considered project specific assumptions for the future project cash flows. The carrying amount of the Company's equity method investment exceeded the fair value of the investment and the Company concluded that the decline is considered to be other-than-temporary. As a result, the Company measured the impairment loss as the difference between the carrying amount and the fair value of the investment and recorded an impairment loss of $69 million. Other Impairments — During the year ended 2017, the Company recorded impairment losses of $29 million in connection with renewable assets that were not divested as part of the sale of NRG Yield and the Renewables Platform. In addition, the Company recorded an impairment loss of $20 million related to excess SO₂ allowances and $10 million in impairment losses for other investments.

Goodwill and Other Intangibles

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangibles

Goodwill

NRG's goodwill balance was $579 million and $573 million as of December 31, 2019 and 2018, respectively. The increase in goodwill is due to the acquisition of Stream Energy. As of December 31, 2019, goodwill consisted of $165 million associated with the acquisition of Midwest Generation and $414 million for retail business acquisitions, including Texas non-commodity, XOOM and Stream Energy.

2017 Impairments of Goodwill

BETM — During the fourth quarter of 2017, the Company concluded that BETM was held for sale following board approval and advanced negotiations to sell the business. Accordingly, the Company recorded the assets and liabilities at fair market value as of December 31, 2018, which resulted in an impairment loss of $90 million to record BETM's goodwill at fair market value. The remaining goodwill balance for BETM of $21 million was included within non-current assets held-for-sale as of December 31, 2018.

Intangible Assets

The Company's intangible assets as of December 31, 2019, primarily reflect intangible assets established with the acquisitions of various companies, including Stream Energy, XOOM, other retail acquisitions, and Texas Genco. Intangible assets are comprised of the following:

•Emission Allowances — These intangibles primarily consist of SO₂ emission allowances established with the 2006 Texas Genco acquisition and also include RGGI emission credits which NRG began purchasing in 2009. These emission allowances are held-for-use and are amortized to cost of operations, with SO₂ allowances and RGGI credits amortized based on units of production. During the year ended December 31, 2018, the Company recorded an impairment loss of $5 million to reduce the value of excess SO₂ allowances to zero. During the year ended December 31, 2019, there were no impairment losses related to SO₂ emissions allowances.

•In-market nuclear fuel contracts — These intangibles were established with the Texas Genco acquisition in 2006 and are amortized to cost of operations over expected volumes over the life of each contract.

•Customer relationships — These intangibles represent the fair value at the acquisition date of acquired businesses' customer base. The customer relationships are amortized to depreciation and amortization expense based on the expected discounted future net cash flows by year.

•Marketing partnerships — These intangibles represent the fair value at the acquisition date of existing agreements with marketing vendors and loyalty and affinity partners for customer acquisition. The marketing partnerships are amortized to depreciation and amortization expense based on the expected discounted future net cash flows by year.

•Trade names — These intangibles are amortized to depreciation and amortization expense on a straight-line basis.

•Other — Consists of renewable energy credits, costs to extend the operating license for STP Units 1 and 2, and energy supply contracts acquired with Stream Energy that represent the fair value at the acquisition date of in-market contracts for the purchase of energy to serve retail electric customers. Renewable energy credits are amortized to cost of operations as they are retired for usage. Energy supply contracts are amortized to depreciation and amortization based on the expected delivery under the respective contracts.

The following tables summarize the components of NRG's intangible assets subject to amortization:


(In millions)
Year Ended December 31, 2019	Emission Allowances		Fuel Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other		Total
January 1, 2019	$	659	$	49	$	478	$	131	$	345	$	80	$	1,742
Purchases	13		—		—		—		—		29		42
Acquisition of businesses ^(a)	—		—		110		154		28		26		318
Usage	(4)		—		—		—		—		(17)		(21)
Write-off of fully amortized balances	(8)		—		(13)		—		—		(9)		(30)
Impairment	—		—		(2)		—		—		—		(2)
Other	2		—		—		—		—		—		2
December 31, 2019	662		49		573		285		373		109		2,051
Less accumulated amortization	(539)		(45)		(345)		(75)		(220)		(38)		(1,262)
Net carrying amount	$	123	$	4	$	228	$	210	$	153	$	71	$	789

(a)The weighted average life of acquired intangibles was: customer relationships 7 years, marketing partnerships 9 years, trade names 12 years, and energy supply contracts 2 years


(In millions)
Year Ended December 31, 2018	Emission Allowances		Fuel Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other		Total
January 1, 2018	$	755	$	49	$	768	$	88	$	342	$	78	$	2,080
Purchases	33		—		—		—		—		28		61
Acquisition of businesses^(a)	—		—		122		43		13		—		178
Usage	(1)		—		—		—		—		(26)		(27)
Write-off of fully amortized balances	(107)		—		(411)		—		(10)		—		(528)
Impairment	(5)		—		(1)		—		—		—		(6)
Other	(16)		—		—		—		—		—		(16)
December 31, 2018	659		49		478		131		345		80		1,742
Less accumulated amortization	(515)		(45)		(314)		(61)		(195)		(21)		(1,151)
Net carrying amount	$	144	$	4	$	164	$	70	$	150	$	59	$	591

(a)The weighted average life of acquired intangibles was: customer relationships 6 years, trade names 7 years, and marketing partnerships 14 years

The following table presents NRG's amortization of intangible assets for each of the past three years:


	Years Ended December 31,
(In millions)	2019		2018		2017
Emission allowances	$	32	$	39	$	71


Customer relationships	44		32		34
Marketing partnerships	15		9		5
Trade names	25		23		23
Other	35		30		33
Total amortization	$	151	$	133	$	166

The following table presents estimated amortization of NRG's intangible assets as of December 31, 2019 for each of the next five years:


(In millions)
Year Ended December 31,	Emission Allowances		Fuel Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other		Total
2020	$	36	$	1	$	68	$	24	$	27	$	33	$	189
2021	35		—		52		24		27		3		141
2022	38		—		36		23		27		3		127
2023	40		1		35		23		26		3		128
2024	35		—		15		23		17		3		93

Intangible assets held-for-sale — From time to time, management may authorize the transfer from the Company's emission bank of emission allowances held-for-use to intangible assets held-for-sale. Emission allowances held-for-sale are included in other non-current assets on the Company's consolidated balance sheet and are not amortized, but rather expensed as sold. As of December 31, 2019 and 2018, the value of emission allowances held-for-sale was $6 million and $12 million, respectively, within the Corporate segment. Once transferred to held-for-sale, these emission allowances are prohibited from moving back to held-for-use.

Out-of-market contracts — Due primarily to business acquisitions, NRG acquired certain out-of-market contracts, which were classified as non-current liabilities on NRG's consolidated balance sheet. These included out-of-market lease contracts acquired with Midwest Generation of $121 million as of December 31, 2018. As a result of the Company's adoption of ASC 842 on January 1, 2019, out-of-market lease contracts are now included as a component of operating lease right-of-use assets. Prior to January 1, 2019, these out-of-market contracts were amortized to cost of operations.

Debt and Finance Leases	12 Months Ended
Debt and Finance Leases	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt and Finance Leases	LIBOR

Asset Retirement Obligations

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

The Company's AROs are primarily related to the environmental obligations for nuclear decommissioning, ash disposal, site closures, fuel storage facilities and future dismantlement of equipment on leased property. In addition, the Company has also identified conditional AROs for asbestos removal and disposal, which are specific to certain power generation operations.

See Note 7, Nuclear Decommissioning Trust Fund, for a further discussion of the Company's nuclear decommissioning obligations. Accretion for the nuclear decommissioning ARO and amortization of the related ARO asset are recorded to the Nuclear Decommissioning Trust Liability to the ratepayers and are not included in net income, consistent with treatment per ASC 980, Regulated Operations.

The following table represents the balance of ARO obligations as of December 31, 2019 and 2018, along with the additions, reductions and accretion related to the Company's ARO obligations for the year ended December 31, 2019:


(In millions)	Nuclear Decommission		Other		Total
Balance as of December 31, 2018	$	282	$	397	$	679
Revisions in estimates for current obligations^(a)	—		27		27
Additions	—		9		9
Spending for current obligations	—		(33)		(33)
Accretion ^(a)	16		30		46
Balance as of December 31, 2019	$	298	$	430	$	728

(a) Total ARO accretion expense includes non-Nuclear Decommissioning Trust accretion and revised asset retirement liabilities on non-operating plants

Benefit Plans and Other Postretirement Benefits

12 Months Ended

Dec. 31, 2019

Retirement Benefits [Abstract]

Benefit Plans and Other Postretirement Benefits

NRG sponsors and operates defined benefit pension and other postretirement plans.

NRG pension benefits are available to eligible non-union and union employees through various defined benefit pension plans. These benefits are based on pay, service history and age at retirement. Most pension benefits are provided through tax-

qualified plans. NRG also provides postretirement health and welfare benefits for certain groups of employees. Cost sharing provisions vary by the terms of any applicable collective bargaining agreements.

NRG maintains two separate qualified pension plans, the NRG Pension Plan for Bargained Employees and the NRG Pension Plan. Participation in the NRG Pension Plan for Bargained Employees depends upon whether an employee is covered by a bargaining agreement.

NRG and GenOn entered into a Restructuring Support Agreement in which NRG agreed to retain GenOn's pension liability for service provided by GenOn employees prior to the completion of the GenOn reorganization. NRG determined that the retention of this liability was probable and recorded the estimated accumulated pension benefit obligation as of December 31, 2017 of $92 million, which reflects a $13 million contribution made by NRG to the plan in 2017, in other non-current liabilities with a corresponding loss from discontinued operations. NRG also agreed to retain the liability for GenOn's post-employment and retiree health and welfare benefits. NRG's obligation for both of these liabilities was revalued upon GenOn's emergence from bankruptcy resulting in an obligation of $23 million as of December 31, 2018.

NRG expects to contribute $56 million to the Company's pension plans in 2020, of which $21 million relates to GenOn.

NRG Defined Benefit Plans

The annual net periodic benefit cost/(credit) related to NRG's pension and other postretirement benefit plans include the following components:


	Year Ended December 31,
	Pension Benefits
(In millions)	2019		2018		2017
Service cost benefits earned	$	10	$	23	$	26
Interest cost on benefit obligation	46		44		43
Expected return on plan assets	(59)		(62)		(58)
Amortization of unrecognized net loss	3		—		4
Settlement/curtailment expense	—		7		—
Net periodic benefit cost	$	—	$	12	$	15


	Year Ended December 31,
	Other Postretirement Benefits
(In millions)	2019		2018		2017
Service cost benefits earned	$	1	$	1	$	1
Interest cost on benefit obligation	3		4		4
Amortization of unrecognized prior service credit	(13)		(10)		(9)
Amortization of unrecognized net (gain)/loss	—		—		(1)
Curtailment gain	—		(10)		—
Net periodic benefit (credit)	$	(9)	$	(15)	$	(5)

A comparison of the pension benefit obligation, other postretirement benefit obligations and related plan assets for NRG's plans on a combined basis is as follows:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Benefit obligation at January 1	$	1,222	$	1,329	$	83	$	128
Service cost	10		23		1		1
Interest cost	46		44		3		4
Plan amendments	—		17		(2)		(28)
Actuarial (gain)/loss	207		(95)		16		(6)
Employee and retiree contributions	—		—		4		3
Curtailment gain	—		(20)		—		(7)
Benefit payments	(88)		(76)		(12)		(12)
Benefit obligation at December 31	1,397		1,222		93		83
Fair value of plan assets at January 1	981		1,104		—		—
Actual return on plan assets	216		(80)		—		—
Employee and retiree contributions	—		—		4		3
Employer contributions	41		33		7		9
Benefit payments	(88)		(76)		(11)		(12)
Fair value of plan assets at December 31	1,150		981		—		—
Funded status at December 31 — excess of obligation over assets	$	(247)	$	(241)	$	(93)	$	(83)

Amounts recognized in NRG's balance sheets were as follows:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Other current liabilities	$	—	$	—	$	7	$	7
Other non-current liabilities	247		241		86		76

Amounts recognized in NRG's accumulated OCI that have not yet been recognized as components of net periodic benefit cost were as follows:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Net loss/(gain)	$	138	$	90	$	7	$	(9)
Prior service cost/(credit)	2		3		(43)		(53)
Total accumulated OCI	$	140	$	93	$	(36)	$	(62)

Net accumulated OCI	$	140	$	93	$	(36)	$	(62)

Other changes in plan assets and benefit obligations recognized in OCI were as follows:


	Year Ended December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Net actuarial loss/(gain)	$	50	$	47	$	16	$	(5)
Amortization of net actuarial (gain)/loss	(3)		—		—		—
Curtailment	—		(27)		—		2
Prior service credit	—		17		(2)		(28)
Amortization of prior service cost	—		—		12		10
Total recognized in OCI	$	47	$	37	$	26	$	(21)
Net periodic benefit cost/(credit)	—		12		(9)		(15)
Net recognized in net periodic pension cost/(credit) and OCI	$	47	$	49	$	17	$	(36)

The Company's estimated unrecognized loss for NRG's pension plan as of December 31, 2019 that will be amortized from accumulated OCI to net periodic cost over the next fiscal year is $5 million. The Company's estimated unrecognized loss and unrecognized prior service credit for NRG's postretirement plan as of December 31, 2019 that will be amortized from accumulated OCI to net periodic cost over the next fiscal year is $1 million and $14 million, respectively.

The following table presents the balances of significant components of NRG's pension plan:


	As of December 31,
	Pension Benefits
(In millions)	2019		2018
Projected benefit obligation	$	1,397	$	1,222
Accumulated benefit obligation	1,362		1,188
Fair value of plan assets	1,150		981

NRG's market-related value of its plan assets is the fair value of the assets. The fair values of the Company's pension plan assets by asset category and their level within the fair value hierarchy are as follows:


	Fair Value Measurements as of December 31, 2019
(In millions)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Total
Common/collective trust investment — U.S. equity	$	—	$	233	$	233
Common/collective trust investment — non-U.S. equity	—		73		73
Common/collective trust investment — non-core assets	—		143		143
Common/collective trust investment — fixed income	—		272		272
Short-term investment fund	12		—		12
Subtotal fair value	$	12	$	721	$	733
Measured at net asset value practical expedient:
Common/collective trust investment — non-U.S. equity					84
Common/collective trust investment — fixed income					279
Common/collective trust investment — non-core assets					24
Partnerships/joint ventures					30
Total fair value					$	1,150


	Fair Value Measurements as of December 31, 2018
(In millions)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Total
Common/collective trust investment — U.S. equity	$	—	$	183	$	183
Common/collective trust investment — non-U.S. equity	—		53		53
Common/collective trust investment — non-core assets	—		117		117
Common/collective trust investment — fixed income	—		256		256
Short-term investment fund	12		—		12
Subtotal fair value	$	12	$	609	$	621
Measured at net asset value practical expedient:
Common/collective trust investment — non-U.S. equity					70
Common/collective trust investment — fixed income					249
Common/collective trust investment — non-core assets					16
Partnerships/joint ventures					25
Total fair value					$	981

In accordance with ASC 820, the Company determines the level in the fair value hierarchy within which each fair value measurement in its entirety falls, based on the lowest level input that is significant to the fair value measurement in its entirety. The fair value of the common/collective trust investments is valued at fair value which is equal to the sum of the market value of all of the fund's underlying investments. Certain common/collective trust investments have readily determinable fair value as they publish daily net asset value, or NAV, per share and are categorized as Level 2. Certain other common/collective trust investments and partnerships/joint ventures use NAV per share, or its equivalent, as a practical expedient for valuation, and thus have been removed from the fair value hierarchy table.

The following table presents the significant assumptions used to calculate NRG's benefit obligations:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
Weighted-Average Assumptions	2019		2018		2019		2018
Discount rate	3.26	%	4.38	%	3.26	%	4.37	%
Rate of compensation increase	3.00	%	3.00	%	—	%	—	%
Health care trend rate	—		—		7.5% grading to 4.5% in 2028		7.8% grading to 4.5% in 2025

The following table presents the significant assumptions used to calculate NRG's benefit expense:


	As of December 31,
	Pension Benefits								Other Postretirement Benefits
Weighted-Average Assumptions	2019		2018		2017		2019	2018	2017
Discount rate	4.38%/4.2%		3.71%/4.04%		4.26	%	4.37%	3.71% /4.08%	4.29	%
Expected return on plan assets	6.35	%	6.17	%	6.85	%	—	—	—
Rate of compensation increase	3.00	%	3.00	%	3.00	%	—	—	—
Health care trend rate	—		—		—		7.8% grading to 4.5% in 2025	8.2% grading to 4.5% in 2025	7.0% grading to 5.0% in 2025

NRG uses December 31 of each respective year as the measurement date for the Company's pension and other postretirement benefit plans. The Company sets the discount rate assumptions on an annual basis for each of NRG's defined benefit retirement plans as of December 31. The discount rate assumptions represent the current rate at which the associated liabilities could be effectively settled at December 31. The Company utilizes the Aon AA Above Median, or AA-AM, yield curve to select the appropriate discount rate assumption for each retirement plan. The AA-AM yield curve is a hypothetical AA yield curve represented by a series of annualized individual spot discount rates from 6 months to 99 years. Each bond issue used to build this yield curve must be non-callable, and have an average rating of AA when averaging available Moody's Investor Services, Standard & Poor's and Fitch ratings.

NRG employs a total return investment approach, whereby a mix of equities and fixed income investments are used to maximize the long-term return of plan assets for a prudent level of risk. Risk tolerance is established through careful consideration of plan liabilities, plan funded status, and corporate financial condition. The Investment Committee reviews the asset mix periodically and as the plan assets increase in future years, the Investment Committee may examine other asset classes such as real estate or private equity. NRG employs a building block approach to determining the long-term rate of return assumption for plan assets, with proper consideration given to diversification and rebalancing. Historical markets are studied and long-term historical relationships between equities and fixed income are preserved, consistent with the widely accepted capital market principle that assets with higher volatility generate a greater return over the long run. Current factors such as inflation and interest rates are evaluated before long-term capital market assumptions are determined. Peer data and historical returns are reviewed to check for reasonableness and appropriateness.

The target allocations of NRG's pension plan assets were as follows for the year ended December 31, 2019:


U.S. equity	20	%
Non-U.S. equity	13	%
Non-core assets	17	%
U.S. fixed income	50	%

Plan assets are currently invested in a diversified blend of equity and fixed-income investments. Furthermore, equity investments are diversified across U.S., non-U.S., global, and emerging market equities, as well as among growth, value, small and large capitalization stocks.

Investment risk and performance are monitored on an ongoing basis through quarterly portfolio reviews of each asset fund class to a related performance benchmark, if applicable, and annual pension liability measurements. Performance benchmarks are composed of the following indices:


Asset Class						Index
U.S. equities						Dow Jones U.S. Total Stock Market Index
Non-U.S. equities						MSCI All Country World Ex-U.S. IMI Index
Non-core assets^(a)						Various (per underlying asset class)
Fixed income securities						Barclays Capital Long Term Government/Credit Index & Barclays Strips 20+ Index

(a)Non-Core Assets are defined as diversifying asset classes approved by the Investment Committee that are intended to enhance returns and/or reduce volatility of the U.S. and non-U.S. equities. Asset classes considered Non-Core include, but may not be limited to: Emerging Market Equity, Emerging Market Debt, Non-US Developed Market Small Cap, High Yield Fixed Income, Real Estate, Bank Loans, Global Infrastructure and other Alternatives.

NRG's expected future benefit payments for each of the next five years, and in the aggregate for the five years thereafter, are as follows:


			Other Postretirement Benefit
(In millions)	Pension Benefit Payments		Benefit Payments		Medicare Prescription Drug Reimbursements
2020	$	84	$	7	$	—
2021	86		6		—
2022	86		6		—
2023	86		6		—
2024	86		6		—
2025-2029	402		19		2

Assumed health care cost trend rates have a significant effect on the amounts reported for the health care plans. The impact of a one-percentage-point change in assumed health care cost trend rates is immaterial on total service and interest costs components but would have the following effect:


(In millions)	1-Percentage- Point Increase		1-Percentage- Point Decrease

Effect on postretirement benefit obligation	$	7	$	(5)

STP Defined Benefit Plans

NRG has a 44% undivided ownership interest in STP, as discussed further in Note 28, Jointly Owned Plants. STPNOC, which operates and maintains STP, provides its employees a defined benefit pension plan, as well as postretirement health and welfare benefits. Although NRG does not sponsor the STP plan, it reimburses STPNOC for 44% of the contributions made towards its retirement plan obligations.

During the third quarter of 2019, STPNOC announced that the defined benefit pension plan will be frozen for non-union employees on December 31, 2021, This resulted in the curtailment of benefits, thereby requiring a remeasurement, including an update to the discount rate used to determine benefit obligations. As a result, NRG recognized a gain of $8 million related to the curtailment of benefits and an increase of $32 million to the pension liability was recorded to other comprehensive income. The Company measures the fair value of its pension assets in accordance with ASC 820, Fair Value Measurements and Disclosures, or ASC 820.

For the years ended December 31, 2019 and December 31, 2018, NRG reimbursed STPNOC $24 million and $13 million, respectively, for its contribution to the plans. In 2020, NRG expects to reimburse STPNOC $7 million for its contribution to the plan.

The Company has recognized the following in its statement of financial position, statement of operations and accumulated OCI related to its 44% interest in STP:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Funded status — STPNOC benefit plans	$	(77)	$	(78)	$	(20)	$	(19)
Net periodic benefit cost/(credit)	9		8		(4)		(7)
Other changes in plan assets and benefit obligations recognized in other comprehensive (loss)/income	(13)		(7)		6		2

Defined Contribution Plans

NRG's employees are also eligible to participate in defined contribution 401(k) plans.

The Company's contributions to these plans were as follows:


	Year Ended December 31,
(In millions)	2019		2018		2017
Company contributions to defined contribution plans	$	22	$	28	$	56

Capital Structure

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

Capital Structure

For the period from December 31, 2016 to December 31, 2019, the Company had 10,000,000 shares of preferred stock authorized and 500,000,000 shares of common stock authorized. The following table reflects the changes in NRG's common shares issued and outstanding for each period presented:


	Common
	Issued	Treasury	Outstanding
Balance as of December 31, 2016	417,583,825	(102,140,814)	315,443,011
Shares issued under ESPP	—	560,769	560,769
Shares issued under LTIPs	739,309	—	739,309

Balance as of December 31, 2017	418,323,134	(101,580,045)	316,743,089
Shares issued under ESPP	—	175,862	175,862
Shares issued under LTIPs	1,965,752	—	1,965,752
Share repurchases	—	(35,234,664)	(35,234,664)
Balance as of December 31, 2018	420,288,886	(136,638,847)	283,650,039
Shares issued under ESPP	—	46,128	46,128
Shares issued under LTIPs	1,601,904	—	1,601,904
Share repurchases	—	(36,301,882)	(36,301,882)
Balance as of December 31, 2019	421,890,790	(172,894,601)	248,996,189

Common Stock

As of December 31, 2019, NRG had 16,029,127 shares of common stock reserved for the maximum number of shares potentially issuable based on the conversion and redemption features of the long-term incentive plans.

Common stock dividends — The Company paid $0.03 quarterly dividend per common share, or $0.12 per share on an annualized basis, for years 2017, 2018 and 2019.

The Company's common stock dividends are subject to available capital, market conditions, and compliance with associated laws, regulations and other contractual obligations. Beginning in the first quarter of 2020, NRG increased the annual dividend to $1.20 per share and expects to target an annual dividend growth rate of 7-9% per share in subsequent years.

On January 21, 2020, NRG declared a quarterly dividend on the Company's common stock of $0.30 per share, or $1.20 per share on an annualized basis, payable on February 18, 2020, to stockholders of record as of February 3, 2020.

Employee Stock Purchase Plan — In March 2019, the Company reopened participation in the ESPP under the Amended and Restated Employee Stock Purchase Plan, which allows eligible employees to elect to withhold between 1% and 10% of their eligible compensation to purchase shares of NRG common stock at the lesser of 95% of its market value on the offering date or 95% of the fair market value on the exercise date. An offering date will occur each April 1 and October 1. An exercise date will occur each September 30 and March 31. The ESPP plan, that was suspended in 2018, allowed eligible employees to elect to withhold up to 10% of their eligible compensation to purchase shares of NRG common stock at the lesser of 85% of its fair market value on the offering date or 85% of the fair market value on the exercise date. An offering date occurred each January 1 and July 1. An exercise date occurred each June 30 and December 31. As of December 31, 2019, there remained 2,885,060 shares of treasury stock reserved for issuance under the ESPP.

Share Repurchases — In 2018, the Company's board of directors authorized the Company to repurchase $1.5 billion of its common stock. The Company executed $1.25 billion of these share repurchases in 2018, with the remaining $0.25 billion completed in the first quarter of 2019. In 2019, the Company's board of directors authorized the Company to repurchase an additional $1.25 billion of its common stock. The Company executed $1.194 billion of these share repurchases in 2019, with the remaining $56 million completed by February 27, 2020. In addition, the Company adopted in the fourth quarter of 2019 a long-term capital allocation policy that targets allocating 50% of cash available for allocation generated each year to growth investments and 50% to be returned to shareholders. The return of capital to shareholders is expected to be completed through the increased dividend discussed above, supplemented by share repurchases.

The following table summarizes the shares repurchases made from 2018 through February 27, 2020:


	Total number of shares and share equivalents purchased	Average price paid per share and share equivalent		Amounts paid for shares and share equivalents purchased (in millions)
2018 repurchases:
Shares repurchased under May 24, 2018 Accelerated Repurchase Agreement	10,829,903			354
Shares repurchased under September 5, 2018 Accelerated Repurchase Agreement	13,307,130			500
Other repurchases	11,097,631			396
Total Share Repurchases during 2018	35,234,664	$35.48		$	1,250


2019 repurchases:
Repurchases under February 28, 2019 Accelerated Share Repurchase Agreement	9,438,671			400
Other repurchases	26,863,211			1,008
Equivalent shares purchased in lieu of tax withholdings on equity compensation issuances^(a)	936,928			36
Total Share Repurchases during 2019	37,238,810	$	38.79	$	1,444
2020 repurchases:
Repurchases made subsequent to December 31, 2019	2,428,545			92
Equivalent shares purchased in lieu of tax withholdings on equity compensation issuances^(a)	709,536			27
Total share repurchases January 1, 2020 through February 27, 2020	3,138,081	$	37.87	$	119

^(a)NRG elected to pay cash for tax withholding on equity awards instead of issuing actual shares to management. The average price per equivalent shares withheld was $38.24 and $38.78 in 2020 and 2019, respectively. See Note 21, Stock-Based Compensation, for further discussion of the equity awards

Investments Accounted for by the Equity Method and Variable Interest Entities

12 Months Ended

Dec. 31, 2019

Equity Method Investments and Joint Ventures [Abstract]

Investments Accounted for by the Equity Method and Variable Interest Entities

Entities that are not Consolidated

NRG accounts for the Company's significant investments using the equity method of accounting. NRG's carrying value of equity investments can be impacted by a number of elements including impairments, unrealized gains and losses on derivatives and movements in foreign currency exchange rates.

The following table summarizes NRG's equity method investments as of December 31, 2019:


(In millions, except percentages)
Name	Economic Interest		Investment Balance
Agua Caliente	35.0	%	213
Gladstone	37.5	%	124
Ivanpah Master Holdings, LLC	54.5	%	20
Watson Cogeneration Company	49.0	%	15
Midway-Sunset Cogeneration Company	50.0	%	9
Other^(a)	Various		7
Total equity investments in affiliates			$	388

(a) Refer to Note 11, Asset Impairments, for discussion of NRG's investment in Petra Nova Parish Holdings, LLC


	As of December 31,
(In millions)	2019		2018
Undistributed earnings from equity investments	$	42	$	34

PG&E Bankruptcy — The Agua Caliente project and two of the three Ivanpah units are party to PPAs with PG&E. Both projects have project financing with the U.S. DOE. On January 29, 2019, PG&E Corp. and subsidiary utility PG&E filed for Chapter 11 bankruptcy protection. As part of their filing, PG&E asked the Bankruptcy Court to confirm exclusive jurisdiction over their "rights to reject" PPAs or other contracts regulated by FERC. As a result of the bankruptcy filing, the Agua Caliente and Ivanpah projects have issued notices of events of default under their respective loan agreements. The Ivanpah project signed a forbearance agreement with the Department of Energy on October 25, 2019. The Company's subsidiaries are working with their partners on the projects and the loan counterparties.

On September 9, 2019, PG&E filed a plan of reorganization that would assume all power purchase agreements, including those held by the Agua Caliente project and the two Ivanpah units. On January 22, 2020 the noteholders agreed to support the PG&E plan, which will continue to provide for assumption of all power purchase agreements. The plan was subsequently amended, and a hearing before the Bankruptcy Court to consider whether the PG&E plan will be approved and confirmed is currently expected to occur on May 27, 2020. NRG's maximum exposure to loss is limited to its equity investment, which was $213 million for Agua Caliente and $20 million for Ivanpah as of December 31, 2019. See Note 13, Debt and Finance Leases for further discussion on Agua Caliente.

Variable Interest Entities

NRG accounts for its interests in certain entities that are considered VIEs under ASC 810, Consolidation, for which NRG is not the primary beneficiary, under the equity method.

Through its consolidated subsidiary, NRG Solar Ivanpah LLC, NRG owns a 54.5% interest in Ivanpah Master Holdings, LLC, or Ivanpah, the owner of three solar electric generating projects located in the Mojave Desert with a total capacity of 393 MW. NRG considers this investment a VIE under ASC 810 and NRG is not considered the primary beneficiary. The Company accounts for its interest under the equity method of accounting.

The Ivanpah solar electric generating projects were funded in large part by loans guaranteed by the U.S. DOE and equity from the projects' partners. During the first quarter of 2018, all interested parties sought a restructuring of Ivanpah's debt in order to avoid a potential event of default with respect to the loans in connection with several recent events. Ensuing negotiations culminated in a settlement during the second quarter of 2018 between the parties which resulted in certain transactions, including the release of reserves totaling $95 million to fund equity distributions to the partners, which reduced the equity at risk, and the prepayment of certain of the debt balance outstanding, and the amendment of certain of Ivanpah's governing documents. The equity distributions and prepayment of debt were funded by the agreed upon release of reserve funds. These events were considered to be a reconsideration event in accordance with ASC 810. As a result, NRG determined that it is not the primary beneficiary and deconsolidated Ivanpah. NRG recognized a loss of $22 million on the deconsolidation and subsequent recognition of Ivanpah as an equity method investment. The deconsolidation of Ivanpah reduced the Company's assets by approximately $1.3 billion, which was primarily property, plant and equipment, and reduced the Company's liabilities by $1.2 billion, which was primarily long-term debt.

Other Equity Investments

Gladstone — Through a joint venture, NRG owns a 37.5% interest in Gladstone, a 1,613 MW coal-fueled power generation facility in Queensland, Australia. The power generation facility is managed by the joint venture participants and the facility is operated by NRG. Operating expenses incurred in connection with the operation of the facility are funded by each of the participants in proportion to their ownership interests. Coal is sourced from local mines in Queensland. NRG and the joint venture participants receive their respective share of revenues directly from the off takers in proportion to the ownership interests in the joint venture. Power generated by the facility is primarily sold to an adjacent aluminum smelter, with excess power sold to the Queensland Government-owned utility under long-term supply contracts. NRG's investment in Gladstone was $124 million as of December 31, 2019.

Entities that are Consolidated

The Company has a controlling financial interest in certain entities which have been identified as VIEs under ASC 810. These arrangements are related to tax equity arrangements entered into with third-parties in order to finance the cost of solar energy systems under operating leases eligible for certain tax credits as further described in Note 2, Summary of Significant Accounting Policies.

The summarized financial information for the Company's consolidated VIEs consisted of the following:


(In millions)	December 31, 2019		December 31, 2018
Current assets	$	3	$	3
Net property, plant and equipment	71		76
Other long-term assets	27		28
Total assets	101		107
Current liabilities	4		2
Long-term debt	24		29
Other long-term liabilities	8		7
Total liabilities	36		38
Redeemable noncontrolling interests	20		19
Net assets less noncontrolling interests	$	45	$	50

Earnings/(Loss) Per Share

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Earnings/(Loss) Per Share

Basic income/(loss) per common share is computed by dividing net income/(loss) by the weighted average number of common shares outstanding. Shares issued and treasury shares repurchased during the year are weighted for the portion of the year that they were outstanding. Diluted income/(loss) per share is computed in a manner consistent with that of basic income/(loss) per share, while giving effect to all potentially dilutive common shares that were outstanding during the period.

Dilutive effect for equity compensation and other equity instruments — The outstanding non-qualified stock options, non-vested restricted stock units, and market stock units and relative performance stock units are not considered outstanding for purposes of computing basic income/(loss) per share. However, these instruments are included in the denominator for purposes of computing diluted income/(loss) per share under the treasury stock method. The 2048 Convertible Senior Notes are convertible, under certain circumstances, into the Company’s common stock, cash or combination thereof (at NRG's option). There is no dilutive effect for the 2048 Convertible Senior Notes due to the Company’s expectation to settle the liability in cash.

The reconciliation of NRG's basic income/(loss) per share to diluted income/(loss) per share is shown in the following table:


	Year Ended December 31,
(In millions, except per share amounts)	2019		2018		2017
Basic income/(loss) per share attributable to NRG, Inc;
Net income/(loss) attributable to NRG Energy, Inc. common stockholders	$	4,438	$	268	$	(2,153)



Weighted average number of common shares outstanding-basic	262		304		317
Income/(Loss) per weighted average common share — basic	$	16.94	$	0.88	$	(6.79)
Diluted income/(loss) per share attributable to NRG, Inc;
Net income/(loss) attributable to NRG Energy, Inc. common stockholders	$	4,438	$	268	$	(2,153)
Weighted average number of common shares outstanding-basic	262		304		317
Incremental shares attributable to the issuance of equity compensation (treasury stock method)	2		4		—
Weighted average number of common shares outstanding-diluted	264		308		317
Income/(Loss) per weighted average common share — diluted	$	16.81	$	0.87	$	(6.79)

The following table summarizes NRG's outstanding equity instruments that are anti-dilutive and were not included in the computation of the Company's diluted income/(loss) per share:


	Year Ended December 31,
(In millions)	2019	2018	2017
Equity compensation plans	—	—	5

Segment Reporting

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Segment Reporting

As of December 31, 2019, the Company's reportable segments were Generation, Retail and Corporate. Retail included Mass market and C&I customers, as well as other distributed and reliability products. Generation included all power plant activities, as well as renewables. The Company began managing its integrated model based on the combined results of the retail and wholesale generation businesses with a geographical focus in 2020. As a result, the Company changed its business segments to Texas, East and West/Other beginning in the first quarter of 2020. The Company's updated segment structure reflects how management currently makes financial decisions and allocates resources. All affected disclosures presented herein have been recast to reflect these changes for all periods presented. For further discussion, refer to Note 1, Nature of Business.

NRG's chief operating decision maker, its chief executive officer, evaluates the performance of its segments based on operational measures including adjusted earnings before interest, taxes, depreciation and amortization, or Adjusted EBITDA, free cash flow and capital for allocation, as well as net income/(loss) and net income/(loss) attributable to NRG Energy, Inc.

On February 4, 2019, the Company completed the sale and deconsolidation of South Central Portfolio. On August 31, 2018, NRG deconsolidated NRG Yield Inc., its Renewables Platform and Carlsbad for financial reporting purposes. In 2018, the financial information for historical periods was recast to reflect the presentation of discontinued operations within the corporate segment. Refer to Note 4, Acquisitions, Discontinued Operations and Dispositions, for further discussion.

The Company had no customer that comprised more than 10% of the Company's consolidated revenues during the years ended December 31, 2019 and 2017. The company had one customer in the Texas segment that comprised 11% of the Company's consolidated revenues during the year ended December 31, 2018.

Intersegment sales are accounted for at market.


	For the Year Ended December 31, 2019
(In millions)	Texas		East		West/Other		Corporate^(a)		Eliminations		Total
Operating revenues^(a)	$	7,069	$	2,319	$	440	$	—	$	(7)	$	9,821
Operating expenses	5,818		1,895		397		50		(7)		8,153
Depreciation and amortization	188		121		33		31		—		373
Impairment losses	1		—		4		—		—		5
Development costs	3		3		1		—		—		7
Total operating cost and expenses	6,010		2,019		435		81		(7)		8,538

Gain on sale of assets	—		1		—		6		—		7
Operating income/(loss)	1,059		301		5		(75)		—		1,290
Equity in (losses)/earnings of unconsolidated affiliates	(4)		—		6		—		—		2
Impairment losses on investments	(103)		—		—		(5)		—		(108)
Other income, net	20		6		10		30		—		66
Loss on debt extinguishment	—		—		(3)		(48)		—		(51)
Interest expense	—		(18)		(10)		(385)		—		(413)
Income/(loss) from continuing operations before income taxes	972		289		8		(483)		—		786
Income tax expense/(benefit)	—		2		1		(3,337)		—		(3,334)
Net income from continuing operations	972		287		7		2,854		—		4,120
Gain from discontinued operations, net of income tax	—		—		—		321		—		321
Net Income	972		287		7		3,175		—		4,441
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests	—		—		3		—		—		3
Net income attributable to NRG Energy, Inc.	$	972	$	287	$	4	$	3,175	$	—	$	4,438

Balance sheet
Equity investments in affiliates	$	6	$	—	$	382	$	—	$	—	$	388
Capital expenditures	136		30		25		37		—		228
Goodwill^(b)	325		254		—		—		—		579
Total assets	$	5,711	$	2,160	$	1,190	$	8,342	$	(4,872)	$	12,531


(a) Inter-segment sales and inter-segment net derivative gains and losses included in operating revenues	$	1	$	8	$	(2)	$	—	$	—	$	7
(b) Goodwill was allocated based on the regions in which the business operates and are expected to benefit using a relative fair value approach


	For the Year Ended December 31, 2018
(In millions)	Texas		East		West/Other		Corporate^(a)		Eliminations		Total
Operating revenues^(a)	$	6,401	$	2,371	$	724	$	—	$	(18)	$	9,478
Operating expenses	5,399		2,024		467		125		(18)		7,997
Depreciation and amortization	156		105		127		33		—		421
Impairment losses	5		82		12		—		—		99
Development costs	3		3		3		2		—		11
Total operating cost and expenses	5,563		2,214		609		160		(18)		8,528

Gain on sale of assets	4		—		(2)		30		—		32
Operating income/(loss)	842		157		113		(130)		—		982
Equity in (losses)/earnings of unconsolidated affiliates	(3)		—		13		(1)		—		9
Impairment losses on investments	(15)		—		—		—		—		(15)
Other income/(loss), net	13		2		4		(1)		—		18
Loss on debt extinguishment	—		—		—		(44)		—		(44)
Interest expense	—		(22)		(39)		(422)		—		(483)
Income/(loss) from continuing operations before income taxes	837		137		91		(598)		—		467
Income tax expense	—		1		—		6		—		7
Net income/(loss) from continuing operations	837		136		91		(604)		—		460
Loss from discontinued operations, net of income tax	—		—		—		(192)		—		(192)
Net Income/(loss)	837		136		91		(796)		—		268
Less: Net income/(loss) attributable to noncontrolling interests and redeemable noncontrolling interests	—		—		5		(5)		—		—
Net income/(loss) attributable to NRG Energy, Inc.	$	837	$	136	$	86	$	(791)	$	—	$	268

Balance sheet
Equity investments in affiliates	$	6	$	—	406		$	—	$	—	$	412
Capital expenditures	143		171		29		45		—		388
Goodwill^(b)	320		253		—		—		—		573
Total assets	$	5,357	$	2,187	$	1,548	$	6,631	$	(5,095)	$	10,628


(a) Inter-segment sales and inter-segment net derivative gains and losses included in operating revenues	$	19	$	(5)	4	$	—	$	—	$	18
(b) Goodwill was allocated based on the regions in which the business operates and are expected to benefit using a relative fair value approach


	For the Year Ended December 31, 2017
(In millions)	Texas		East		West/Other		Corporate^(a)		Eliminations		Total
Operating revenues^(a)	$	6,318	$	2,009	$	788	$	6	$	(47)	$	9,074
Operating expenses	5,393		1,684		498		239		(48)		7,766
Depreciation and amortization	258		112		194		35		(3)		596
Impairment losses	1,317		106		111		—		—		1,534
Development costs	4		6		6		6		—		22
Total operating costs and expenses	6,972		1,908		809		280		(51)		9,918
Other income - affiliate	—		—		—		87		—		87
Gain/(loss) on sale of assets	5		15		(5)		1		—		16
Operating (loss)/income	(649)		116		(26)		(186)		4		(741)
Equity in (losses)/earnings of unconsolidated affiliates	(22)		—		10		(2)		—		(14)
Impairment losses on investments	(69)		—		(6)		(4)		—		(79)
Other (expense)/income, net	(2)		4		22		27		—		51
Loss on debt extinguishment	—		—		—		(49)		—		(49)
Interest expense	—		(29)		(77)		(451)		—		(557)
(Loss)/income from continuing operations before income taxes	(742)		91		(77)		(665)		4		(1,389)
Income tax benefit	—		—		(6)		(38)		—		(44)
Net (loss)/income from continuing operations	(742)		91		(71)		(627)		4		(1,345)
Loss from discontinued operations, net of income tax	—		—		—		(992)		—		(992)
Net (loss)/income	(742)		91		(71)		(1,619)		4		(2,337)
Less: Net income/(loss) attributable to noncontrolling interests and redeemable noncontrolling interests	—		—		1		(189)		4		(184)
Net (loss)/income attributable to NRG Energy, Inc.	$	(742)	$	91	$	(72)	$	(1,430)	$	—	$	(2,153)


(a) Inter-segment sales and inter-segment net derivative gains and losses included in operating revenues			$	41					$	1					(4)						$	9					$	—					$	47

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Income Taxes

The income tax provision from continuing operations consisted of the following amounts:


	Year Ended December 31,
(In millions, except effective income tax rate)	2019			2018			2017
Current

State	$	2		$	6		$	19
Foreign	4			—			—
Total — current	6			6			19
Deferred
U.S. Federal	(3,000)			(16)			(60)
State	(340)			16			(5)
Foreign	—			1			2
Total — deferred	(3,340)			1			(63)
Total income tax (benefit)/expense	$	(3,334)		$	7		$	(44)
Effective income tax rate	(424.2)		%	1.5		%	3.2		%

During the year ended December 31, 2019, NRG released the majority of its valuation allowance against its U.S. federal and state deferred tax assets, resulting in a non-cash benefit to income tax expense of approximately $3.5 billion. In making the determination to release the majority of the valuation allowance as of December 31, 2019, the Company evaluated a number of factors, including its recent history of pre-tax earnings, utilization of $593 million of NOLs in 2019, as well as its forecasted future pre-tax earnings. Based on this evaluation, the Company determined that the majority of its future tax benefits are more-likely-than-not to be realized. Given the Company’s current level of pre-tax earnings and forecasted future pre-tax earnings, the Company expects to generate income before taxes in the U.S. in future periods at a level that would fully utilize its U.S. federal NOL carryforwards and the majority of its state NOL carryforwards prior to their expiration.

The following represented the domestic and foreign components of income/(loss) from continuing operations before income taxes:


	Year Ended December 31,
(In millions)	2019		2018		2017
U.S.	$	771	$	468	$	(1,406)
Foreign	15		(1)		17
Total	$	786	$	467	$	(1,389)

Reconciliations of the U.S. federal statutory tax rate to NRG's effective tax rate were as follows:


	Year Ended December 31,
(In millions, except effective income tax rate)	2019			2018			2017
Income/(loss) from continuing operations before income taxes	$	786		$	467		$	(1,389)
Tax at federal statutory tax rate	165			98			(486)
State taxes	13			18			19
Foreign operations	—			—			2
Permanent differences	(9)			7			—
Valuation allowance - current period activities	(3,492)			(106)			455

Book goodwill impairment	—			—			30
Deferred impact of state tax rate changes	12			—			—
Production tax credits ("PTC")	—			(7)			(8)
Recognition of uncertain tax benefits	(10)			1			(5)


Alternative minimum tax ("AMT") refundable credit	—			(4)			(64)
Tax Act - corporate income tax rate change	—			—			665
Valuation allowance due to corporate income tax rate change	—			—			(660)
Other	(13)			—			8
Income tax (benefit)/expense	$	(3,334)		$	7		$	(44)
Effective income tax rate	(424.2)		%	1.5		%	3.2		%

For the year ended December 31, 2019, NRG's effective income tax rate was lower than the federal statutory tax rate of 21% primarily due to the tax benefit from the release of the valuation allowance.

For the year ended December 31, 2018, NRG's effective income tax rate was lower than the federal statutory tax rate of 21% primarily due to a tax benefit for the change in valuation allowance, the generation of PTCs from various wind facilities and establishment of the previously sequestered AMT credit receivable, partially offset by current state tax expense.

For the year ended December 31, 2017, NRG's effective income tax rate was lower than the federal statutory tax rate of 35% primarily due to tax expense recorded from the revaluation of the existing net deferred tax asset and state taxes, partially offset by the change in valuation allowance, establishing the AMT credit and the generation of PTCs from various wind facilities. The tax expense recorded for revaluation of the net deferred tax asset is required to reflect the reduction in the corporate income tax rate from 35% to 21% in accordance with the Tax Act.

The temporary differences, which gave rise to the Company's deferred tax assets and liabilities consisted of the following:


	As of December 31,
(In millions)	2019		2018
Deferred tax assets:
Deferred compensation, accrued vacation and other reserves	$	81	$	134
Difference between book and tax basis of property	548		554
Goodwill	—		11
Differences between book and tax basis of contracts	—		38
Pension and other postretirement benefits	86		87
Equity compensation	11		9
Bad debt reserve	13		14

U.S. Federal net operating loss carryforwards	2,116		2,241
Foreign net operating loss carryforwards	105		63
State net operating loss carryforwards	360		379

Federal and state tax credit carryforwards	384		381
Federal benefit on state uncertain tax positions	4		6
Intangibles amortization (excluding goodwill)	—		21
Interest disallowance carryforward per §163(j) of the Tax Act	82		102
Inventory obsolescence	7		7
Other	3		—
Discontinued operations	—		17
Total deferred tax assets	3,800		4,064
Deferred tax liabilities:
Emissions allowances	19		15

Derivatives, net	27		37
Goodwill	8		—
Intangibles amortization (excluding goodwill)	15		—
Equity method investments	201		180

Convertible Debt	19		21
Other	—		1
Discontinued operations	—		36
Total deferred tax liabilities	289		290
Total deferred tax assets less deferred tax liabilities	3,511		3,774
Valuation allowance	(242)		(3,812)
Discontinued operations	—		19
Total deferred tax assets/(liabilities), net of valuation allowance	$	3,269	$	(19)

The following table summarizes NRG's net deferred tax position as presented in the consolidated balance sheets:


	As of December 31,
(In millions)	2019		2018
Deferred tax asset	$	3,286	$	46

Deferred tax liability	(17)		(65)
Net deferred tax asset/(liability)	$	3,269	$	(19)

The primary driver for the change from a $19 million net deferred tax liability as of December 31, 2018 to a net deferred tax asset of $3.3 billion as of December 31, 2019 is the release in the Company’s valuation allowance, partially offset by utilization of federal and state NOLs.

Deferred tax assets and valuation allowance

Net deferred tax balance — As of December 31, 2019 and 2018, NRG recorded a net deferred tax asset, excluding valuation allowance, of $3.5 billion and $3.8 billion, respectively. The Company believes certain state net operating losses may not be realizable under the more-likely-than-not measurement and as such, a valuation allowance was recorded as of December 31, 2019 as discussed below.

NOL carryforwards — As of December 31, 2019, the Company had tax effected cumulative U.S. NOLs consisting of carryforwards for federal and state income tax purposes of $2.1 billion and $360 million, respectively. The Company estimates it will need to generate future taxable income to fully realize the net federal deferred tax asset before the expiration of certain carryforwards commences in 2031. In addition, NRG has cumulative foreign NOL carryforwards of $105 million with no expiration date.

Valuation allowance — As of December 31, 2019, the Company's tax-effected valuation allowance was $242 million, consisting of state NOL carryforwards and foreign NOL carryforwards. The valuation allowance was recorded based on the assessment of cumulative and forecasted pre-tax book earnings and the future reversal of existing taxable temporary differences.

Taxes Receivable and Payable

As of December 31, 2019, NRG recorded a current tax payable of $13 million that represents a tax liability due for state income taxes that is primarily comprised of Texas margin tax. NRG has a tax receivable of $1 million, comprised of refunds due from state income tax estimated payments and return filings.

Uncertain tax benefits

NRG has identified uncertain tax benefits with after-tax value of $15 million and $26 million as of December 31, 2019 and 2018, for which NRG has recorded a non-current tax liability of $17 million and $30 million, respectively. The Company recognizes interest and penalties related to uncertain tax benefits in income tax expense. The Company recognized expense of $1 million related to interest in each of the years ended December 31, 2019, 2018 and 2017. As of December 31, 2019 and 2018, NRG had cumulative interest and penalties related to these uncertain tax benefits of $2 million and $4 million, respectively.

Tax jurisdictions — NRG is subject to examination by taxing authorities for income tax returns filed in the U.S. federal jurisdiction and various state and foreign jurisdictions including operations located in Australia.

The Company is no longer subject to U.S. federal income tax examinations for years prior to 2016. With few exceptions, state and local income tax examinations are no longer open for years before 2011.

The following table summarizes uncertain tax benefits activity:


	As of December 31,
(In millions)	2019		2018
Balance as of January 1	$	26	$	30
Increase due to current year positions	2		4

Settlements, payments and statute closure	(13)		(8)
Uncertain tax benefits as of December 31	$	15	$	26

Stock-Based Compensation

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement, Noncash Expense [Abstract]

Stock-Based Compensation

NRG Energy, Inc. Long-Term Incentive Plan

On April 27, 2017, the NRG LTIP was amended to increase the number of shares available for issuance by 3,000,000. As of December 31, 2019 and 2018, a total of 25,000,000 shares of NRG common stock were authorized for issuance under the NRG LTIP. There were 9,935,750 and 8,564,611 shares of common stock remaining available for grants under the NRG LTIP as of December 31, 2019 and 2018, respectively. The NRG LTIP is subject to adjustments in the event of reorganization, recapitalization, stock split, reverse stock split, stock dividend, and a combination of shares, merger or similar change in NRG's structure or outstanding shares of common stock.

Upon adoption of the amended NRG LTIP effective April 27, 2017, no shares of NRG common stock remain available for future issuance under the NRG GenOn LTIP. As of December 31, 2019 and 2018, there were 319,264 and 520,182 shares of common stock remaining available for grants under the NRG GenOn LTIP, respectively.

Restricted Stock Units

As of December 31, 2019, RSUs granted under the Company's LTIPs typically have three-year graded vesting schedules beginning on the grant date. Fair value of the RSUs granted during 2019 is derived from the closing price of NRG common stock on the grant date. The following table summarizes the Company's non-vested RSU awards and changes during the year:


	Units	Weighted Average Grant Date Fair Value per Unit
Non-vested at December 31, 2018	1,458,082	$	16.16
Granted	266,938	37.37
Forfeited	(73,905)	24.73
Vested	(933,876)	14.20

Non-vested at December 31, 2019	717,239	25.56

The total fair value of RSUs vested during the years ended December 31, 2019, 2018, and 2017 was $36 million, $42 million, and $19 million, respectively. The weighted average grant date fair value of RSUs granted during the years ended December 31, 2019, 2018, and 2017 was $37.37, $28.90, and $12.44, respectively.

Deferred Stock Units

DSUs represent the right of a participant to be paid one share of NRG common stock at the end of a deferral period established under the terms of the award. DSUs granted under the Company's LTIPs are fully vested at the date of issuance. Fair value of the DSUs, which is based on the closing price of NRG common stock on the date of grant, is recorded as compensation expense in the period of grant.

The following table summarizes the Company's outstanding DSU awards and changes during the year:


	Units	Weighted Average Grant Date Fair Value per Unit
Outstanding at December 31, 2018	331,915	$	22.94
Granted	57,630	34.84

Converted to Common Stock	(58,322)	28.93

Outstanding at December 31, 2019	331,223	23.98

The aggregate intrinsic values for DSUs outstanding as of December 31, 2019, 2018, and 2017 were approximately $13 million, $13 million, and $12 million, respectively. The aggregate intrinsic values for DSUs converted to common stock for the years ended December 31, 2019, 2018, and 2017 were $2 million, $6 million, and $4 million, respectively. The weighted average grant date fair value of DSUs granted during the years ended December 31, 2019, 2018, and 2017 was $34.84, $33.43, and $16.76, respectively.

Performance Stock Units

PSUs entitle the recipient to stock upon vesting. The amount of the award is subject to the Company's achievement of certain performance measures over the vesting period. PSUs include RPSUs and MSUs. As of December 31, 2019, non-vested PSUs consist primarily of RPSUs.

Relative Performance Stock Units — RPSUs are restricted grants where the quantity of shares increases and decreases alongside the Company's Total Shareholder Return, or TSR, relative to the TSR of the Company's current proxy peer group and the total returns of select indexes, or Peer Group. Each RPSU represents the potential to receive NRG common stock after the completion of the performance period, typically three years of service from the date of grant. The number of shares of NRG common stock to be paid (if any) as of the vesting date for each RPSU will depend on the Company’s percentile rank within the Peer Group. The number of shares of common stock to be paid as of the vesting date for each RPSU is linearly interpolated for TSR performance between the following points: (i) 0% if ranked below the 25th percentile; (ii) 25% if ranked at the 25th percentile; (iii) 100% if ranked at the 55th percentile (or the 65th percentile if the Company's absolute TSR is less than negative 15%); and (iv) 200% if ranked at the 75th percentile or above. The value of the common stock on the date of grant is based on the closing price of NRG common stock on the date of grant.

Market Stock Units — MSUs are restricted grants where the quantity of shares increases and decreases alongside the Company's TSR. Each MSU represents the potential to receive NRG common stock after the completion of the performance period, typically three years of service from the date of grant. The number of shares of common stock to be paid as of the vesting date for each MSU is : (i) zero shares, if the TSR has decreased by more than 25% over the performance period, (ii) three-quarters of one share, if the TSR has decreased by 25% over the performance period; (iii) interpolated between three-quarters of one share and one share, if the TSR has decreased less than 25% over the performance period; (iv) one share, if there is no change in TSR over the performance period; (v) interpolated between one share and two shares, if TSR increases less than 100% during the performance period; and (vi) two shares, if the TSR increases 100% over the performance period. The value of the common stock on the date of grant was based on the closing price of NRG common stock on the date of grant. The Company last granted MSUs during the year ended December 31, 2016.

The following table summarizes the Company's non-vested PSU awards and changes during the year:


	Units	Weighted Average Grant-Date Fair Value per Unit
Non-vested at December 31, 2018	1,710,634	$	19.12
Granted^(a)	936,889	22.50
Forfeited	(37,526)	23.04
Vested^(b)	(1,409,456)	14.72
Non-vested at December 31, 2019^(c)	1,200,541	26.65

(a) The weighted average grant date fair value per unit includes RPSUs that were granted during 2019 with grant date fair value of $45.77 and MSUs with 2016 grant date fair value of $14.72, that due to vesting at 200%, were considered additional grants in 2019

(b) MSUs granted during 2016 vested during 2019 at 200%

The weighted average grant date fair value of PSUs granted during the years ended December 31, 2019, 2018, and 2017, was $22.50, $35.36, and $15.91, respectively.

The fair value of PSUs is estimated on the date of grant using a Monte Carlo simulation model and expensed over the service period, which equals the vesting period. Significant assumptions used in the fair value model with respect to the Company's PSUs are summarized below:


	2019		2018		2017		2016
	RPSUs		RPSUs		RPSUs		MSUs
Expected volatility	40.72	%	47.52	%	43.96	%	34.33	%
Expected term (in years)	3		3		3		3
Risk free rate	2.45	%	2.01	%	1.5	%	1.31	%

For the years ended December 31, 2019 and 2018, expected volatility is calculated based on NRG's historical stock price volatility data over the period commensurate with the expected term of the PSU, which equals the vesting period.

Non-Qualified Stock Options

All NQSOs granted under the Company's LTIP were fully vested as of December 31, 2019, 2018, and 2017. No NQSOs were granted in 2019, 2018 or 2017. NRG recognizes compensation costs for NQSOs over the requisite service period for the entire award. No compensation expense was recognized during 2019, 2018 and 2017 as it was fully recognized in prior years. The maximum contractual term is 10 years for NRG's outstanding NQSOs.

The following table summarizes the Company's NQSO activity and changes during the year:


	Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2018	279,934	$	25.04	2	$	4
Expired	(8,254)	26.76
Exercised	(137,282)	24.67
Outstanding at December 31, 2019	134,398	25.31		1	2
Exercisable at December 31, 2019	134,398	25.31		1	2

The following table summarizes the total intrinsic value of options exercised and the cash received from the exercises of options:


	Year Ended December 31,
(In millions)	2019		2018		2017

Total intrinsic value of options exercised	$	2	$	10	$	1
Cash received from options exercised	3		24		4

Supplemental Information

The following table summarizes NRG's total compensation expense recognized for the years presented, as well as total non-vested compensation costs not yet recognized and the period over which this expense is expected to be recognized as of December 31, 2019, for each of the types of awards issued under the LTIPs. Minimum tax withholdings of $36 million, $19 million, and $5 million for the years ended December 31, 2019, 2018, and 2017, respectively, are reflected as a reduction to additional paid-in capital on the Company's consolidated balance sheets.


							Non-vested Compensation Cost
(In millions, except weighted average data)	Compensation Expense									Unrecognized Total Cost	Weighted Average Recognition Period Remaining (In years)
	Year Ended December 31,									As of December 31,
Award	2019		2018		2017		2019		2019

RSUs	9		12		15		8		1.06
DSUs	2		2		2		—		0.00
MSUs	—		4		5		—		0.50
RPSUs	10		7		3		9		0.71
PRSUs^(a)	11		16		13		10		1.05
Total^(b)	$	32	$	41	$	38	$	27
Tax detriment recognized	$	(12)	$	(4)	$	(5)

(a) Phantom Restricted Stock Units, PRSUs, are liability-classified time-based awards that typically vest ratably over a three-year period. The amount to be paid upon vesting is based on NRG's closing stock price for the period

(b) Does not include compensation expense of $1 million, and $6 million for the years ended 2018, and 2017, respectively, which was recorded in loss from discontinued operations in the Company's consolidated statements of operations

Related Party Transactions

12 Months Ended

Dec. 31, 2019

Related Party Transactions

NRG provides services to some of its equity method investments under operations and maintenance agreements. Fees for the services under these agreements include recovery of NRG's costs of operating the plants. Certain agreements also include fees for administrative service, a base monthly fee, profit margin and/or annual incentive bonus.

The following table summarizes NRG's material related party transactions with third party affiliates:


	Year Ended December 31,
(In millions)	2019		2018		2017
Revenues from Related Parties Included in Operating Revenues
Gladstone	$	4	$	3	$	3
GenConn^(a)	—		4		5
Ivanpah^(b)	35		20		—
Midway-Sunset	5		5		—
Total	$	44	$	32	$	8

(a) As of August 31, 2018, NRG no longer had an ownership interest in GenConn as a result of the sale of its ownership interests in NRG Yield, Inc. and its Renewables Platform

(b) Also includes fees under project management agreements with each project company. Ivanpah became a related party to NRG upon deconsolidation in the second quarter of 2018

Services Agreement and Transition Services Agreement with GenOn

The Company provided GenOn with various management, personnel and other services, which included human resources, regulatory and public affairs, accounting, tax, legal, information systems, treasury, risk management, commercial operations, and asset management, as set forth in the services agreement with GenOn, or the Services Agreement. The annual fees under the Services Agreement was approximately $193 million and management had concluded that this method of charging overhead costs was reasonable. In connection with the Restructuring Support Agreement in 2017, NRG agreed to provide shared services to GenOn under the Services Agreement for an adjusted annualized fee of $84 million.

In December 2017, in conjunction with the confirmation of the GenOn Entities' plan of reorganization, the Services Agreement was terminated and replaced by the transition services agreement. Under the transition services agreement, NRG provided the shared services and other separation services at an annualized rate of $84 million, subject to certain credits and adjustments. GenOn provided notice to NRG of its intent to terminate the transition services agreement effective August 15, 2018 and in connection with the settlement agreement described in Note 4, Acquisitions, Discontinued Operations and Dispositions, all amounts owed and payable to NRG were settled against the $28 million credit provided for in the Restructuring Support Agreement. For the year ended December 31, 2018 , NRG recorded approximately $53 million, under the transition services agreement against selling, general and administrative expenses post-Chapter 11 Filing. For the year ended December 31, 2017 , NRG recorded other income - affiliate related to these services of $87 million prior to the Chapter 11 Filing and $42 million against selling, general and administrative expenses post-Chapter 11 Filing.

Credit Agreement with GenOn

NRG and GenOn were party to a secured intercompany revolving credit agreement. The intercompany revolving credit agreement provided for a $500 million revolving credit facility, all of which was available for revolving loans and letters of credit. As a result of the GenOn bankruptcy, no additional revolving loans or letters of credit were available to GenOn. As of December 31, 2017, $92 million of letters of credit were issued and outstanding. As a result of the GenOn Settlement, as further described in Note 4, Acquisitions, Discontinued Operations and Dispositions, outstanding borrowings were repaid to NRG, except for certain LCs issued which are further discussed below. The facility was terminated on December 14, 2018.

On December 7, 2018, NRG, GenOn and REMA entered into an agreement to support the outstanding LCs from the intercompany revolving credit agreement previously issued. As of December 31, 2019, $14 million was outstanding. GenOn and REMA have provided support for these outstanding LCs through back-to-back letters of credit and cash collateral. The outstanding letters of credit will continue to accrue any contractual fees and expenses until they are terminated.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2019

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Coal, Gas and Transportation Commitments

NRG has entered into long-term contractual arrangements to procure fuel and transportation services for the Company's generation assets.

As of December 31, 2019, the Company's minimum commitments under such outstanding agreements are estimated as follows:


Period	(In millions)
2020	$	124
2021	125
2022	73
2023	53
2024	62
Thereafter	139
Total^(a)	$	576

(a) Actual coal, gas and transportation purchases are significantly higher than these estimated minimum unconditional long- term firm commitments

For the years ended December 31, 2019, 2018, and 2017, the Company purchased $1.2 billion, $1.2 billion, and $1.1 billion, respectively under such arrangements.

Purchased Power Commitments

NRG has purchased power contracts of various quantities and durations, including renewable purchased power agreements under PPAs with third-party project developers, that are not classified as derivative assets and liabilities and do not

qualify as operating leases. These contracts are not included in the consolidated balance sheet as of December 31, 2019. Minimum purchase commitment obligations are as follows as of December 31, 2019:


Period	(In millions)
2020	$	35
2021	49
2022	68
2023	56
2024	56
Thereafter	349
Total	$	613

First Lien Structure

NRG has granted first liens to certain counterparties on a substantial portion of property and assets owned by NRG and the guarantors of its senior debt. NRG uses the first lien structure to reduce the amount of cash collateral and letters of credit that it would otherwise be required to post from time to time to support its obligations under out-of-the-money hedge agreements for forward sales of power or gas used as a proxy for power. To the extent that the underlying hedge positions for a counterparty are out-of-the-money to NRG, the counterparty would have a claim under the first lien program. As of December 31, 2019, hedges under the first lien were in-the-money for NRG on a counterparty aggregate basis.

Jewett Mine Lignite Contract

The Company's Limestone facility historically burned lignite obtained from the Jewett mine, which was operated by Texas Westmoreland Coal Co., or TWCC. On or about March 15, 2019, the Jewett mine and related lignite supply agreement with NRG were acquired by Westmoreland Mining LLC pursuant to a plan of reorganization confirmed by the U.S. Bankruptcy Court for the Southern District of Texas. Active mining under the lignite supply agreement ceased as of December 31, 2016; however, under the terms of the lignite supply agreement, the mine operator remains responsible for undertaking reclamation activities and NRG is responsible for reclamation costs. NRG has recorded an adequate ARO liability. The Railroad Commission of Texas has imposed a bond obligation of approximately $99 million for the reclamation of the Jewett mine, which NRG supports through surety bonds. The cost of the reclamation may exceed the value of the bonds. Additionally, the lignite supply agreement obligates NRG to provide additional performance assurance if required by the Railroad Commission of Texas.

Nuclear Insurance

STP maintains required insurance coverage for liability claims arising from nuclear incidents pursuant to the Price-Anderson Act. The current liability limit per incident is $13.9 billion, subject to change to account for the effects of inflation and the number of licensed reactors. An inflation adjustment must be made at least once every five years with the next due no later than September 10, 2023. Under the Price-Anderson Act, owners of nuclear power plants in the U.S. are required to purchase primary insurance limits of $450 million for each operating site. In addition, the Price-Anderson Act requires an additional layer of protection through mandatory participation in a retrospective rating plan for power reactors resulting in an additional $13.5 billion in funds available for public liability claims. The current maximum assessment per incident, per reactor, is approximately $138 million, taking into account a 5% adjustment for administrative fees, payable at approximately $21 million per year, per reactor. NRG would be responsible for 44% of the maximum assessment, or $9 million per year, per reactor, and a maximum of $61 million per incident. In addition, the U.S. Congress retains the ability to impose additional financial requirements on the nuclear industry to pay liability claims that exceed $14 billion for a single incident. The liabilities of the co-owners of STP with respect to the retrospective premium assessments for nuclear liability insurance are joint and several.

STP purchases insurance for property damage and site decontamination cleanup costs from Nuclear Electric Insurance Limited, or NEIL, and European Mutual Association for Nuclear Insurance, or EMANI, both of which are industry mutual insurance companies, of which STP is a member. STP has purchased $2.75 billion in limits for nuclear events and $1.0 billion in limits for non-nuclear events. The nuclear event limit remains the maximum available from NEIL. The upper $1.25 billion in nuclear events limits (excess of the first $1.5 billion in nuclear events limits) is a single limit blanket policy shared with two Diablo Canyon nuclear reactors, which have no affiliation with the Company. This shared limit is not subject to automatic reinstatement in the event of a loss. The NEIL primary policy covers both nuclear and non-nuclear property damage events, and a NEIL companion policy provides Accidental Outage coverage for the co-owners of STP's lost revenue following a property damage event, at a weekly indemnity limit of $2.5 million per unit up to a maximum of $274 million nuclear per unit and $184 million non-nuclear per unit, and is subject to an eight-week waiting period. NRG also purchases an Accidental Outage policy from NEIL, which provides protection for lost revenue due to an insurable event. This coverage allows for reimbursement up to $1.98 million per week per unit up to a maximum of $216 million nuclear and $144 million non-nuclear, and is subject to an eight-week waiting period. Under the terms of the NEIL and EMANI policies, member companies may be assessed up to ten and six times their annual premiums respectively if the NEIL or EMANI Board of Directors determines their surplus has been depleted due to the payment of property losses at any of the licensed reactors in a single policy year. NEIL and EMANI require that their members maintain an investment grade credit rating or insure their annual retrospective obligation by providing a financial guarantee, letter of credit, deposit premium, or an insurance policy. NRG has purchased an insurance policy from NEIL and EMANI to guarantee the Company's obligation; however note the NEIL aspect of this insurance will only respond to retrospective premium adjustments assessed within twenty-four months after the policy term, whereas NEIL's Board of Directors can make such an adjustment up to 6 years after the policy expires.

Contingencies

The Company's material legal proceedings are described below. The Company believes that it has valid defenses to these legal proceedings and intends to defend them vigorously. NRG records accruals for estimated losses from contingencies when information available indicates that a loss is probable and the amount of the loss, or range of loss, can be reasonably estimated. As applicable, the Company has established an adequate accrual for the applicable legal matters, including regulatory and environmental matters as further discussed in Note 24, Regulatory Matters, and Note 25, Environmental Matters. In addition, legal costs are expensed as incurred. Management has assessed each of the following matters based on current information and made a judgment concerning its potential outcome, considering the nature of the claim, the amount and nature of damages sought, and the probability of success. Unless specified below, the Company is unable to predict the outcome of these legal proceedings or reasonably estimate the scope or amount of any associated costs and potential liabilities. As additional information becomes available, management adjusts its assessment and estimates of such contingencies accordingly. Because litigation is subject to inherent uncertainties and unfavorable rulings or developments, it is possible that the ultimate resolution of the Company's liabilities and contingencies could be at amounts that are different from its currently recorded accruals and that such difference could be material.

In addition to the legal proceedings noted below, NRG and its subsidiaries are party to other litigation or legal proceedings arising in the ordinary course of business. In management's opinion, the disposition of these ordinary course matters will not materially adversely affect NRG's consolidated financial position, results of operations, or cash flows.

Midwest Generation Asbestos Liabilities — The Company, through its subsidiaries, settled the indemnification claims brought by Commonwealth Edison Company and Exelon Generation Company LLC (collectively, "ComEd") as a result of the Company's acquisition of EME. Pursuant to a settlement agreement dated as of May 29, 2019, the Company paid $26 million to ComEd during the second quarter of 2019, which was previously accrued. In addition, ComEd released all claims that were or could have been asserted in its claims in the EME bankruptcy case and certain of the Company's subsidiaries released all permissive and compulsory counter claims they could have asserted in response to the ComEd claims.

Washington-St. Tammany and Claiborne Electric Cooperative v. LaGen — On June 28, 2017, plaintiffs Washington-St. Tammany Electric Cooperative, Inc. and Claiborne Electric Cooperative, Inc. filed a lawsuit against Louisiana Generating, L.L.C., or LaGen, in the United States District Court for the Middle District of Louisiana. The plaintiffs claim breach of contract against LaGen for allegedly improperly charging the plaintiffs for costs related to the installation and maintenance of certain pollution control technology. Plaintiffs seek damages for the alleged improper charges and a declaration as to which charges are proper under the contract. In February 2020, the court dismissed this lawsuit without prejudice for lack of subject matter jurisdiction. On February 4, 2019, NRG sold the South Central Portfolio, including the entities subject to this litigation. However, NRG has agreed to indemnify the purchaser for certain losses suffered in connection therewith.

Sierra club et al. v. Midwest Generation LLC — In 2012, several environmental groups filed a complaint against Midwest Generation with the Illinois Pollution Control Board ("IPCB") alleging violations of environmental law resulting in groundwater contamination. In June 2019, the IPCB found that Midwest Generation violated the law because it had improperly handled coal ash at four facilities in Illinois and caused or allowed coal ash constituents to impact groundwater. On September 9, 2019, Midwest Generation filed a Motion to Reconsider numerous issues, which the court granted in part and denied in part

on February 6, 2020. The IPCB will hold hearings to determine the appropriate relief. Midwest Generation has been working with the Illinois EPA to address the groundwater issues since 2010.

XOOM Energy Litigation — XOOM is a defendant in two purported class action lawsuits pending in Maryland and New York. The plaintiffs generally claim that they did not receive the savings they were promised in their natural gas and electricity bills. The parties in the Maryland lawsuit are briefing summary judgment and class certification. In the New York case, XOOM filed a motion to dismiss, which the court granted on September 21, 2018, later entering judgment in XOOM's favor on September 24, 2018. The plaintiffs in the New York case appealed to the U.S. Court of Appeals for the Second Circuit. On July 26, 2019, the Second Circuit reversed the judgment of the district court and remanded to the district court with instructions that plaintiffs be permitted to proceed on their proposed amended complaint. This matter was known and accrued for at the time of the acquisition.

Regulatory Matters	12 Months Ended
Regulatory Matters	Dec. 31, 2019
Regulatory Matters Disclosure [Abstract]
Regulatory Matters	Regulatory Matters NRG operates in a highly regulated industry and is subject to regulation by various federal and state agencies. As such, NRG is affected by regulatory developments at both the federal and state levels and in the regions in which NRG operates. In addition, NRG is subject to the market rules, procedures, and protocols of the various ISO and RTO markets in which NRG participates. These power markets are subject to ongoing legislative and regulatory changes that may impact NRG's wholesale and retail businesses. In addition to the regulatory proceedings noted below, NRG and its subsidiaries are parties to other regulatory proceedings arising in the ordinary course of business or have other regulatory exposure. In management's opinion, the disposition of these ordinary course matters will not materially adversely affect NRG's consolidated financial position, results of operations, or cash flows. California Station Power — As the result of unfavorable final and non-appealable litigation, the Company accrued a liability associated with consumption of station power at the Company's Encina power plant facility in California after August 30, 2010. The Company has established an appropriate accrual pending potential regulatory action by SDG&E regarding the Company's Encina facility. South Central — On August 4, 2016, NRG received a document hold notice from FERC regarding conduct in the MISO and PJM markets. It required NRG to retain communications related to multiple generating units in the South Central region. Since sending the notice, FERC has been investigating potential violations of MISO rules involving bidding for the Big Cajun 2 facility, as well as other aspects of NRG’s operations in MISO. FERC has the authority to require disgorgement of profits and to impose penalties and NRG retains any liability following the sale of the South Central Portfolio. We expect a preliminary finding from FERC in 2020. ISO-NE — On February 5, 2019, FERC has informed the Company that it has made a preliminary finding that the Company violated FERC's market behavior rules in connection with offers made into the ISO-NE Forward Capacity Auction in 2016. On April 26, 2019, NRG responded to the preliminary findings. The Company understands that FERC is concerned that the Company was inaccurate in its communications with the Market Monitor regarding the costs and risks associated with operating certain units in the forward timeframe. NRG withdrew the bids prior to the 2016 auction in the normal course of our commercial business decision making.

Environmental Matters	12 Months Ended
Environmental Matters	Dec. 31, 2019
Environmental Matters Disclosure [Abstract]
Environmental Matters	Environmental Matters NRG is subject to a wide range of environmental laws in the development, construction, ownership and operation of power plants. These laws generally require that governmental permits and approvals be obtained before construction and during operation of power plants. NRG is also subject to laws regarding the protection of wildlife. The electric generation industry has been facing requirements regarding GHGs, combustion byproducts, water discharge and use, and threatened and endangered species that have been put in place in recent years. However, under the current U.S. presidential administration, some of these rules are being reconsidered and reviewed. In general, future laws are expected to require the addition of emissions controls or other environmental controls or to impose certain restrictions on the operations of the Company's facilities, which could have a material effect on the Company's consolidated financial position, results of operations, or cash flows. Federal and state environmental laws generally have become more stringent over time, although this trend could slow or pause in the near term with respect to federal laws under the current U.S. presidential administration. Air On July 8, 2019, the EPA promulgated the Affordable Clean Energy (ACE) rule, which rescinded the Clean Power Plan (CPP), which sought to broadly regulate CO₂ emissions from the power sector. The ACE rule requires states that have coal-fired EGUs to develop plans to seek heat rate improvements from coal-fired EGUs. Numerous parties have challenged the ACE rule in the D.C. Circuit and numerous parties have filed petitions for reconsideration with the EPA. Water Effluent Limitations Guidelines — In November 2015, the EPA revised the Effluent Limitations Guidelines for Steam Electric Generating Facilities, which would have imposed more stringent requirements (as individual permits were renewed) for wastewater streams from flue gas desulfurization (FGD), fly ash, bottom ash, and flue gas mercury control. On September 18, 2017, the EPA promulgated a final rule that, among other things, postpones the compliance dates to preserve the status quo for FGD wastewater and bottom ash transport water by two years to November 2020 until the EPA completes its next rulemaking. On April 12, 2019, the United States Court of Appeals for the Fifth Circuit addressed challenges to the rule brought by several environmental groups related to legacy wastewaters and coal ash leachate and remanded portions of the rule to the EPA. On November 22, 2019, the EPA proposed amending the 2015 ELG rule by: (x) decreasing the stringency of the selenuim limit (but increasing the stringency of the nitrate and mercury limits) for FGD wastewater; (y) relaxing the zero-discharge requirement for bottom ash transport water; and (z) changing several deadlines. The Company has eliminated its estimate of the environmental capital expenditures that would have been required to comply with permits incorporating the revised guidelines. The Company will revisit these estimates after the EPA finalizes revisions to the rule. Byproducts, Wastes, Hazardous Materials and Contamination In April 2015, the EPA finalized the rule regulating byproducts of coal combustion (e.g., ash and gypsum) as solid wastes under the RCRA. In 2017, the EPA agreed to reconsider the rule. On July 30, 2018, the EPA promulgated a rule that amends the existing ash rule by extending some of the deadlines and providing more flexibility for compliance. On August 21, 2018, the D.C. Circuit found, among other things, that the EPA had not adequately regulated unlined ponds and legacy ponds. On August 14, 2019, the EPA proposed targeted changes to the April 2015 Rule including changes to address the August 2018 D.C. Circuit decision. On December 2, 2019, the EPA released for comment "Closure Part A Proposal" to revise the CCR Rule to address the D.C. Circuit's 2018 decision regarding the adequacy of clay-lined impoundments, obligations to close all unlined impoundments and related deadlines. On February 20, 2020, the EPA proposed the framework for developing and implementing a federal permit program for states that are not approved to administer the CCR rule. We anticipate that the EPA will promulgate new regulations to address these and other issues as it reconsiders other aspects of the existing rule. The Company will determine estimates of the cost of compliance after the rule is revised.

Cash Flow Information

12 Months Ended

Dec. 31, 2019

Supplemental Cash Flow Information [Abstract]

Cash Flow Information

Detail of supplemental disclosures of cash flow and non-cash investing and financing information was:


	Year Ended December 31,
(In millions)	2019		2018		2017
Interest paid, net of amount capitalized	$	372	$	436	$	543
Income taxes paid, net of refunds	8		9		9
Non-cash investing activities:
Additions to fixed assets for accrued capital expenditures	1		20		19

Guarantees

12 Months Ended

Dec. 31, 2019

Guarantees [Abstract]

Guarantees

Guarantees NRG and its subsidiaries enter into various contracts that include indemnification and guarantee provisions as a routine part of the Company's business activities. Examples of these contracts include asset purchases and sale agreements, commodity sale and purchase agreements, retail contracts, joint venture agreements, EPC agreements, operation and maintenance agreements, service agreements, settlement agreements, and other types of contractual agreements with vendors and other third parties, as well as affiliates. These contracts generally indemnify the counterparty for tax, environmental liability, litigation and other matters, as well as breaches of representations, warranties and covenants set forth in these agreements. The Company is obligated with respect to customer deposits associated with the Company's retail businesses. In some cases, NRG's maximum potential liability cannot be estimated, since the underlying agreements contain no limits on potential liability.

The following table summarizes the maximum potential exposures that can be estimated for NRG's guarantees, indemnities, and other contingent liabilities by maturity:


	By Remaining Maturity at December 31,
(In millions)	2019
Guarantees	Under 1 Year		1-3 Years		3-5 Years		Over 5 Years		Total		2018 Total
Letters of credit and surety bonds^(a)	$	878	$	115	$	31	$	—	$	1,024	$	1,253
Asset sales guarantee obligations	4		490		—		204		698		793
Other guarantees	77		5		—		206		288		721
Total guarantees	$	959	$	610	$	31	$	410	$	2,010	$	2,767

(a)December 31, 2019 includes $14 million of letter of credit and surety bonds for the benefit of GenOn where NRG holds cash or letter of credit to back stop the liability

Letters of credit and surety bonds — As of December 31, 2019, NRG and its consolidated subsidiaries were contingently obligated for a total of $1.0 billion under letters of credit and surety bonds. Most of these letters of credit and surety bonds are issued in support of the Company's obligations to perform under commodity agreements and obligations associated with future closure and maintenance of ash sites, as well as for financing or other arrangements. A majority of these letters of credit and surety bonds expire within one year of issuance, and it is typical for the Company to renew them on similar terms.

The material indemnities, within the scope of ASC 460, are as follows:

Asset sales — The purchase and sale agreements which govern NRG's asset or share investments and divestitures customarily contain guarantees and indemnifications of the transaction to third parties. The contracts indemnify the parties for liabilities incurred as a result of a breach of a representation or warranty by the indemnifying party, or as a result of a change in tax laws. These obligations generally have a discrete term and are intended to protect the parties against risks that are difficult to predict or estimate at the time of the transaction. In several cases, the contract limits the liability of the indemnifier. NRG has no reason to believe that the Company currently has any material liability relating to such routine indemnification obligations, except as described in Note 4, Acquisitions, Discontinued Operations and Dispositions.

Other guarantees — NRG has issued other guarantees of obligations including payments under certain agreements with respect to certain of its unconsolidated subsidiaries, payment or performance by fuel providers and payment or reimbursement of credit support and deposits. The Company does not believe that it will be required to perform under these guarantees.

Other indemnities — Other indemnifications NRG has provided cover operational, tax, litigation and breaches of representations, warranties and covenants. NRG has also indemnified, on a routine basis in the ordinary course of business, consultants or other vendors who have provided services to the Company. NRG's maximum potential exposure under these indemnifications can range from a specified dollar amount to an indeterminate amount, depending on the nature of the transaction. Total maximum potential exposure under these indemnifications is not estimable due to uncertainty as to whether claims will be made or how they will be resolved. NRG does not have any reason to believe that the Company will be required to make any material payments under these indemnity provisions.

Because many of the guarantees and indemnities NRG issues to third parties and affiliates do not limit the amount or duration of its obligations to perform under them, there exists a risk that the Company may have obligations in excess of the amounts described above. For those guarantees and indemnities that do not limit the Company's liability exposure, it may not be able to estimate what the Company's liability would be, until a claim is made for payment or performance, due to the contingent nature of these contracts.

Jointly Owned Plants

12 Months Ended

Dec. 31, 2019

Jointly Owned Plants Disclosure [Abstract]

Jointly Owned Plants

Certain NRG subsidiaries own undivided interests in jointly-owned plants, as described below. These plants are maintained and operated pursuant to their joint ownership participation and operating agreements. NRG is responsible for its subsidiaries' share of operating costs and direct expenses and includes its proportionate share of the facilities and related revenues and direct expenses in these jointly-owned plants in the corresponding balance sheet and income statement captions of the Company's consolidated financial statements.

The following table summarizes NRG's proportionate ownership interest in the Company's jointly-owned facilities:


(In millions unless otherwise stated)
As of December 31, 2019	Ownership Interest		Property, Plant & Equipment		Accumulated Depreciation		Construction in Progress
South Texas Project Units 1 and 2, Bay City, TX	44.00	%	$	413	$	(206)	$	8
Cedar Bayou Unit 4, Baytown, TX	50.00	%	218		(93)		7

Unaudited Quarterly Financial Data

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Unaudited Quarterly Financial Data

Refer to Note 4, Acquisitions, Discontinued Operations and Dispositions, Note 11, Asset Impairments, and Note 20, Income Taxes, for a description of the effect of unusual or infrequently occurring events during the quarterly periods. Summarized unaudited quarterly financial data is as follows:


	Quarter Ended
	2019
(In millions, except per share data)	December 31		September 30		June 30		March 31
Operating revenues	$	2,195	$	2,996	$	2,465	$	2,165
Operating income	209		540		320		221
Net income from continuing operations	3,463		374		189		94
(Loss)/income from discontinued operations	(78)		(2)		13		388
Net income	3,385		372		202		482
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests	2		—		1		—

Income available to Common Stockholders	$	3,383	$	372	$	201	$	482
Weighted average number of common shares outstanding — basic	251		254		265		278
(Loss)/income from discontinued operations per weighted average common share — basic	$	(0.31)	$	(0.01)	$	0.05	$	1.39
Net Income per weighted average common share — basic	$	13.48	$	1.46	$	0.76	$	1.73
Weighted average number of common shares outstanding — diluted	253		256		267		280
(Loss)/income from discontinued operations per weighted average common share — diluted	$	(0.31)	$	(0.01)	$	0.05	$	1.38
Net income per weighted average common share — diluted	$	13.37	$	1.45	$	0.75	$	1.72


	Quarter Ended
	2018
(In millions, except per share data)	December 31		September 30		June 30		March 31
Operating revenues	$	1,992	$	2,960	$	2,461	$	2,065
Operating income	49		398		174		361
Net (loss)/income from continuing operations	(93)		287		27		238
Income/(loss) from discontinued operations	80		(336)		69		(5)
Net (loss)/income	(13)		(49)		96		233
Less: Net (loss)/income attributable to noncontrolling interests and redeemable noncontrolling interests	(2)		23		24		(46)

(Loss)/income available to Common Stockholders	$	(11)	$	(72)	$	72	$	279
Weighted average number of common shares outstanding — basic	289		299		310		318
Income/(loss) from discontinued operations per weighted average common share — basic	$	0.28	$	(1.12)	$	0.22	$	(0.02)
Net (loss)/income per weighted average common share — basic	$	(0.04)	$	(0.24)	$	0.23	$	0.88
Weighted average number of common shares outstanding — diluted	289		299		314		322
Income/(loss) from discontinued operations per weighted average common share — diluted	$	0.28	$	(1.12)	$	0.22	$	(0.02)
Net (loss)/income per weighted average common share — diluted	$	(0.04)	$	(0.24)	$	0.23	$	0.87

Condensed Consolidating Financial Information

12 Months Ended

Dec. 31, 2019

Condensed Financial Information Disclosure [Abstract]

Condensed Consolidating Financial Information

As of December 31, 2019, the Company had outstanding $4.4 billion of Senior Notes due 2026 to 2048 and outstanding $1.1 billion of Senior Secured First Lien Notes due from 2024 to 2029, as shown in Note 13, Debt and Finance Leases. These Senior Notes and Senior Secured First Lien Notes are guaranteed by certain of NRG's current and future 100% owned domestic subsidiaries, or guarantor subsidiaries. These guarantees are both joint and several. The non-guarantor subsidiaries include all of NRG's foreign subsidiaries and certain domestic subsidiaries.

Unless otherwise noted below, each of the following guarantor subsidiaries fully and unconditionally guaranteed the Senior Notes and Senior Secured First Lien Notes as of December 31, 2019:


Ace Energy, Inc.	NRG Astoria Gas Turbine Operations Inc.	NRG Oswego Harbor Power Operations Inc.
Allied Home Warranty GP LLC	NRG Business Services LLC	NRG PacGen Inc.
Allied Warranty LLC	NRG Cabrillo Power Operations Inc.	NRG Portable Power LLC
Arthur Kill Power LLC	NRG California Peaker Operations LLC	NRG Power Marketing LLC
Astoria Gas Turbine Power LLC	NRG Cedar Bayou Development Company, LLC	NRG Reliability Solutions LLC
BidURenergy, Inc.	NRG Connected Home LLC	NRG Renter's Protection LLC
Cabrillo Power I LLC	NRG Connecticut Affiliate Services Inc.	NRG Retail LLC
Cabrillo Power II LLC	NRG Construction LLC	NRG Retail Northeast LLC
Carbon Management Solutions LLC	NRG Curtailment Solutions, Inc	NRG Rockford Acquisition LLC
Cirro Group, Inc.	NRG Development Company Inc.	NRG Saguaro Operations Inc.
Cirro Energy Services, Inc.	NRG Devon Operations Inc.	NRG Security LLC
Connecticut Jet Power LLC	NRG Dispatch Services LLC	NRG Services Corporation
Devon Power LLC	NRG Distributed Energy Resources Holdings LLC	NRG SimplySmart Solutions LLC
Dunkirk Power LLC	NRG Distributed Generation PR LLC	NRG South Central Affiliate Services Inc.
Eastern Sierra Energy Company LLC	NRG Dunkirk Operations Inc.	NRG South Central Operations Inc.
El Segundo Power, LLC	NRG ECOKAP Holdings LLC	NRG South Texas LP
El Segundo Power II LLC	NRG El Segundo Operations Inc.	NRG Texas Gregory LLC
Energy Alternatives Wholesale, LLC	NRG Energy Labor Services LLC	NRG Texas Holding Inc.
Energy Choice Solutions LLC	NRG Energy Services Group LLC	NRG Texas LLC
Energy Plus Holdings LLC	NRG Energy Services International Inc.	NRG Texas Power LLC
Energy Plus Natural Gas LLC	NRG Energy Services LLC	NRG Warranty Services LLC
Energy Protection Insurance Company	NRG Generation Holdings, Inc.	NRG West Coast LLC
Everything Energy LLC	NRG Greenco LLC	NRG Western Affiliate Services Inc.
Forward Home Security, LLC	NRG Home & Business Solutions LLC	O'Brien Cogeneration, Inc. II
GCP Funding Company, LLC	NRG Home Services LLC	Oswego Harbor Power LLC
Green Mountain Energy Company	NRG Home Solutions LLC	Reliant Energy Northeast LLC
Gregory Partners, LLC	NRG Home Solutions Product LLC	Reliant Energy Power Supply, LLC
Gregory Power Partners LLC	NRG Homer City Services LLC	Reliant Energy Retail Holdings, LLC
Huntley Power LLC	NRG HQ DG LLC	Reliant Energy Retail Services, LLC
Independence Energy Alliance LLC	NRG Huntley Operations Inc.	RERH Holdings, LLC
Independence Energy Group LLC	NRG Identity Protect LLC	Saguaro Power LLC
Independence Energy Natural Gas LLC	NRG Ilion Limited Partnership	Somerset Operations Inc.
Indian River Operations Inc.	NRG Ilion LP LLC	Somerset Power LLC
Indian River Power LLC	NRG International LLC	Texas Genco GP, LLC
Meriden Gas Turbines LLC	NRG Maintenance Services LLC	Texas Genco Holdings, Inc.
Middletown Power LLC	NRG Mextrans Inc.	Texas Genco LP, LLC
Montville Power LLC	NRG MidAtlantic Affiliate Services Inc.	Texas Genco Services, LP
NEO Corporation	NRG Middletown Operations Inc.	US Retailers LLC
New Genco GP, LLC	NRG Montville Operations Inc.	Vienna Operations Inc.
Norwalk Power LLC	NRG North Central Operations Inc.	Vienna Power LLC
NRG Advisory Services LLC	NRG Northeast Affiliate Services Inc.	WCP (Generation) Holdings LLC
NRG Affiliate Services Inc.	NRG Norwalk Harbor Operations Inc.	West Coast Power LLC
NRG Arthur Kill Operations Inc.	NRG Operating Services, Inc.

NRG conducts much of its business through and derives much of its income from its subsidiaries. Therefore, the Company's ability to make required payments with respect to its indebtedness and other obligations depends on the financial results and condition of its subsidiaries and NRG's ability to receive funds from its subsidiaries. There are no restrictions on the ability of any of the guarantor subsidiaries to transfer funds to NRG. In addition, there may be restrictions for certain non-guarantor subsidiaries.

The following condensed consolidating financial information presents the financial information of NRG Energy, Inc., the guarantor subsidiaries and the non-guarantor subsidiaries in accordance with Rule 3-10 under the SEC's Regulation S-X. The financial information may not necessarily be indicative of results of operations or financial position had the guarantor subsidiaries or non-guarantor subsidiaries operated as independent entities.

In this presentation, NRG Energy, Inc. consists of parent company operations. Guarantor subsidiaries and non-guarantor subsidiaries of NRG are reported on an equity basis. For companies acquired, the fair values of the assets and liabilities acquired have been presented on a push-down accounting basis.

In addition, the condensed parent company financial statements are provided in accordance with Rule 12-04, Schedule I of Regulation S-X, as the restricted net assets of NRG Energy, Inc.'s subsidiaries exceed 25 percent of the consolidated net assets of NRG Energy, Inc. These statements should be read in conjunction with the consolidated statements and notes thereto of NRG Energy, Inc. For a discussion of NRG Energy, Inc.'s long-term debt, see Note 13, Debt and Finance Leases, to the consolidated financial statements. For a discussion of NRG Energy, Inc.'s contingencies, see Note 23, Commitments and Contingencies, to the consolidated financial statements. For a discussion of NRG Energy, Inc.'s guarantees, see Note 27, Guarantees, to the consolidated financial statements.

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS

For the Year Ended December 31, 2019


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Operating Revenues
Total operating revenues	$	8,041	$	1,791	$	—	$	(11)	$	9,821
Operating Costs and Expenses
Cost of operations	5,936		1,351		27		(11)		7,303
Depreciation and amortization	212		130		31		—		373
Impairment losses	1		4		—		—		5
Selling, general and administrative	466		83		278		—		827
Reorganization costs	—		—		23		—		23
Development costs	—		—		7		—		7
Total operating costs and expenses	6,615		1,568		366		(11)		8,538

Gain on sale of assets	1		—		6		—		7
Operating Income/(Loss)	1,427		223		(360)		—		1,290
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	48		—		1,562		(1,610)		—
Equity in earnings of unconsolidated affiliates	—		2		—		—		2
Impairment losses on investments	—		(101)		(7)		—		(108)
Other income, net	23		12		31		—		66

Loss on debt extinguishment, net	—		(3)		(48)		—		(51)
Interest expense	(14)		(14)		(385)		—		(413)
Total other income/(expense)	57		(104)		1,153		(1,610)		(504)
Income from Continuing Operations Before Income Taxes	1,484		119		793		(1,610)		786
Income tax expense/(benefit)	—		4		(3,338)		—		(3,334)
Income from Continuing Operations	1,484		115		4,131		(1,610)		4,120
Income from discontinued operations, net of income tax	9		5		307		—		321
Net Income	1,493		120		4,438		(1,610)		4,441
Less: Net income attributable to redeemable noncontrolling interests	—		3		—		—		3
Net Income Attributable to NRG Energy, Inc.	$	1,493	$	117	$	4,438	$	(1,610)	$	4,438

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME

For the Year Ended December 31, 2019


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Net Income	$	1,493	$	120	$	4,438	$	(1,610)	$	4,441
Other Comprehensive Loss, net of tax

Foreign currency translation adjustments, net	—		(1)		(1)		1		(1)
Available-for-sale securities, net	—		—		(19)		—		(19)
Defined benefit plan, net	(17)		—		(78)		17		(78)
Other comprehensive loss	(17)		(1)		(98)		18		(98)
Comprehensive Income	1,476		119		4,340		(1,592)		4,343
Less: Comprehensive income attributable to redeemable noncontrolling interests	—		3		—		—		3
Comprehensive Income Attributable to NRG Energy, Inc.	$	1,476	$	116	$	4,340	$	(1,592)	$	4,340

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING BALANCE SHEETS

December 31, 2019


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc.		Eliminations^(a)		Consolidated Balance
ASSETS
Current Assets
Cash and cash equivalents	$	—	$	20	$	325	$	—	$	345
Funds deposited by counterparties	32		—		—		—		32
Restricted cash	5		1		2		—		8
Accounts receivable, net	1,293		239		233		(740)		1,025
Inventory	272		111		—		—		383
Derivative instruments	856		45		—		(41)		860
Cash collateral posted in support of energy risk management activities	182		8		—		—		190

Prepayments and other current assets	170		8		67		—		245


Total current assets	2,810		432		627		(781)		3,088
Property, plant and equipment, net	1,483		952		158		—		2,593
Other Assets
Investment in subsidiaries	710		—		4,785		(5,495)		—
Equity investments in affiliates	—		388		—		—		388
Operating lease right-of-use assets, net	81		261		122		—		464

Goodwill	359		220		—		—		579
Intangible assets, net	375		414		—		—		789
Nuclear decommissioning trust fund	794		—		—		—		794
Derivative instruments	308		15		—		(13)		310
Deferred income taxes	421		(19)		2,884		—		3,286
Other non-current assets	145		30		65		—		240


Total other assets	3,193		1,309		7,856		(5,508)		6,850
Total Assets	$	7,486	$	2,693	$	8,641	$	(6,289)	$	12,531
LIABILITIES AND STOCKHOLDERS' EQUITY
Current Liabilities
Current portion of long-term debt	$	—	$	5	$	83	$	—	$	88
Current portion of operating lease liabilities	20		32		21		—		73
Accounts payable	918		141		403		(740)		722

Derivative instruments	797		25		—		(41)		781
Cash collateral received in support of energy risk management activities	32		—		—		—		32

Accrued expenses and other current liabilities	280		44		339		—		663



Total current liabilities	2,047		247		846		(781)		2,359
Other Liabilities
Long-term debt	302		28		5,473		—		5,803
Non-current operating lease liabilities	64		301		118		—		483
Nuclear decommissioning reserve	298		—		—		—		298
Nuclear decommissioning trust liability	487		—		—		—		487

Derivative instruments	334		1		—		(13)		322
Deferred income taxes	—		17		—		—		17

Other non-current liabilities	399		153		532		—		1,084


Total other liabilities	1,884		500		6,123		(13)		8,494
Total Liabilities	3,931		747		6,969		(794)		10,853
Redeemable noncontrolling interest in subsidiaries	—		20		—		—		20
Stockholders' Equity	3,555		1,926		1,672		(5,495)		1,658
Total Liabilities and Stockholders' Equity	$	7,486	$	2,693	$	8,641	$	(6,289)	$	12,531

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS

For the Year Ended December 31, 2019


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Cash Flows from Operating Activities
Net income	$	1,493	$	120	$	4,438	$	(1,610)	$	4,441
Income from discontinued operations	9		5		307		—		321
Net income from continuing operations	1,484		115		4,131		(1,610)		4,120
Adjustments to reconcile net income to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries	(48)		14		(1,562)		1,610		14
Depreciation and amortization	212		130		31		—		373
Accretion of asset retirement obligations	43		8		—		—		51
Provision for bad debts	78		17		—		—		95
Amortization of nuclear fuel	52		—		—		—		52
Amortization of financing costs and debt discount/premiums	—		—		26		—		26
Adjustment for debt extinguishment	—		3		48		—		51
Amortization of emission allowances	24		14		—		—		38
Amortization of unearned equity compensation	—		—		20		—		20
Net gain on sale and disposal of assets	(20)		—		(3)		—		(23)
Impairment losses	1		105		7		—		113
Changes in derivative instruments	20		(24)		38		—		34
Changes in deferred income taxes and liability for uncertain tax benefits	(525)		(168)		(2,660)		—		(3,353)
Changes in collateral deposits in support of energy risk management activities	101		4		—		—		105

Changes in nuclear decommissioning trust liability	37		—		—		—		37


Changes in other working capital	(220)		(118)		(10)		—		(348)
Cash provided by continuing operations	1,239		100		66		—		1,405
Cash provided/(used) by discontinued operations	17		(9)		—		—		8
Net Cash Provided by Operating Activities	1,256		91		66		—		1,413
Cash Flows from Investing Activities


Intercompany dividends	—		—		2,513		(2,513)		—
Payments for acquisitions of businesses	(355)		—		—		—		(355)
Capital expenditures	(164)		(27)		(37)		—		(228)


Net proceeds from sale of emission allowances	11		—		—		—		11
Investments in nuclear decommissioning trust fund securities	(416)		—		—		—		(416)
Proceeds from sales of nuclear decommissioning trust fund securities	381		—		—		—		381
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	1		400		893		—		1,294

Changes in investments in unconsolidated affiliates	—		(91)		—		—		(91)
Net contributions to discontinued operations	—		(44)		—		—		(44)
Other	—		—		6		—		6
Cash (used)/provided by continuing operations	(542)		238		3,375		(2,513)		558
Cash used by discontinued operations	—		(2)		—		—		(2)
Net Cash (Used)/Provided by Investing Activities	(542)		236		3,375		(2,513)		556
Cash Flows from Financing Activities



Intercompany dividends and transfers	(751)		(214)		(1,548)		2,513		—
Payments of dividends to common stockholders	—		—		(32)		—		(32)
Payments for share repurchase activity	—		—		(1,440)		—		(1,440)

Payments for debt extinguishment costs	—		—		(26)		—		(26)
Net distributions to redeemable noncontrolling interests from subsidiaries	—		(2)		—		—		(2)
Proceeds from issuance of common stock	—		—		3		—		3
Proceeds from issuance of long-term debt	—		—		1,916		—		1,916
Payments of debt issuance costs	—		—		(35)		—		(35)
Payments for short and long-term debt	—		(139)		(2,432)		—		(2,571)

Other	(4)		—		—		—		(4)
Cash used by continuing operations	(755)		(355)		(3,594)		2,513		(2,191)
Cash provided by discontinued operations	—		43		—		—		43
Net Cash Used by Financing Activities	(755)		(312)		(3,594)		2,513		(2,148)

Change in cash from discontinued operations	17		32		—		—		49
Net Decrease in Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties	(58)		(17)		(153)		—		(228)
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at Beginning of Period	95		38		480		—		613
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at End of Period	$	37	$	21	$	327	$	—	$	385

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS

For the Year Ended December 31, 2018


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Operating Revenues
Total operating revenues	$	8,119	$	1,385	$	—	$	(26)	$	9,478
Operating Costs and Expenses
Cost of operations	6,147		959		28		(26)		7,108
Depreciation and amortization	238		150		33		—		421
Impairment losses	6		93		—		—		99
Selling, general and administrative	462		63		348		(74)		799
Reorganization costs	4		—		86		—		90
Development costs	—		1		11		(1)		11
Total operating costs and expenses	6,857		1,266		506		(101)		8,528

Gain on sale of assets	4		28		—		—		32
Operating Income/(Loss)	1,266		147		(506)		75		982
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	23		—		1,291		(1,314)		—
Equity in earnings/(losses) of unconsolidated affiliates	—		10		(1)		—		9
Impairment losses on investments	—		(15)		—		—		(15)
Other income/(expense), net	32		(13)		(1)		—		18

Loss on debt extinguishment, net	—		—		(44)		—		(44)
Interest expense	(14)		(49)		(420)		—		(483)
Total other income/(expense)	41		(67)		825		(1,314)		(515)
Income from Continuing Operations Before Income Taxes	1,307		80		319		(1,239)		467
Income tax expense/(benefit)	372		19		(384)		—		7
Income from Continuing Operations	935		61		703		(1,239)		460
Income/(loss) from discontinued operations, net of income tax	62		75		(329)		—		(192)
Net Income	997		136		374		(1,239)		268
Less: Net (loss)/income attributable to noncontrolling interests and redeemable noncontrolling interests	—		(181)		106		75		—
Net Income Attributable to NRG Energy, Inc.	$	997	$	317	$	268	$	(1,314)	$	268

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME

For the Year Ended December 31, 2018


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Net Income	$	997	$	136	$	374	$	(1,239)	$	268
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net	—		29		9		(15)		23
Foreign currency translation adjustments, net	(10)		(10)		(13)		22		(11)
Available-for-sale securities, net	—		—		1		—		1
Defined benefit plan, net	(9)		—		(35)		9		(35)
Other comprehensive (loss)/income	(19)		19		(38)		16		(22)
Comprehensive Income	978		155		336		(1,223)		246
Less: Comprehensive (loss)/income attributable to noncontrolling interests and redeemable noncontrolling interests	—		(166)		104		76		14
Comprehensive Income Attributable to NRG Energy, Inc.	$	978	$	321	$	232	$	(1,299)	$	232

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING BALANCE SHEETS

December 31, 2018


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc.		Eliminations^(a)		Consolidated Balance
ASSETS
Current Assets
Cash and cash equivalents	$	55	$	28	$	480	$	—	$	563
Funds deposited by counterparties	33		—		—		—		33
Restricted cash	7		10		—		—		17
Accounts receivable. net	1,354		115		309		(754)		1,024
Inventory	278		134		—		—		412
Derivative instruments	779		50		16		(81)		764
Cash collateral posted in support of energy risk management activities	275		12		—		—		287

Prepayments and other current assets	180		32		90		—		302
Current assets - held-for-sale	—		1		—		—		1
Current assets - discontinued operations	177		20		—		—		197
Total current assets	3,138		402		895		(835)		3,600
Property, plant and equipment, net	1,938		957		153		—		3,048
Other Assets
Investment in subsidiaries	446		—		4,707		(5,153)		—
Equity investments in affiliates	—		412		—		—		412


Goodwill	359		214		—		—		573
Intangible assets, net	422		169		—		—		591
Nuclear decommissioning trust fund	663		—		—		—		663
Derivative instruments	296		4		22		(5)		317
Deferred income taxes	6		(143)		183		—		46
Other non-current assets	133		71		97		(12)		289
Non-current assets - held-for-sale	—		77		—		—		77
Non-current assets - discontinued operations	405		607		—		—		1,012
Total other assets	2,730		1,411		5,009		(5,170)		3,980
Total Assets	$	7,806	$	2,770	$	6,057	$	(6,005)	$	10,628
LIABILITIES AND STOCKHOLDERS' EQUITY
Current Liabilities
Current portion of long-term debt and finance leases	$	—	$	55	$	17	$	—	$	72

Accounts payable	1,368		(185)		434		(754)		863

Derivative instruments	713		41		—		(81)		673
Cash collateral received in support of energy risk management activities	33		—		—		—		33

Accrued expenses and other current liabilities	291		36		353		—		680

Current liabilities - held-for-sale	—		5		—		—		5
Current liabilities - discontinued operations	24		48		—		—		72
Total current liabilities	2,429		—		804		(835)		2,398
Other Liabilities
Long-term debt and finance leases	244		192		6,025		(12)		6,449

Nuclear decommissioning reserve	282		—		—		—		282
Nuclear decommissioning trust liability	371		—		—		—		371

Derivative instruments	306		3		—		(5)		304
Deferred income taxes	112		61		(108)		—		65

Other non-current liabilities	402		320		552		—		1,274
Non-current liabilities - held-for-sale	—		65		—		—		65
Non-current liabilities - discontinued operations	58		577		—		—		635
Total other liabilities	1,775		1,218		6,469		(17)		9,445
Total Liabilities	4,204		1,218		7,273		(852)		11,843
Redeemable noncontrolling interest in subsidiaries	—		19		—		—		19
Stockholders' Equity	3,602		1,533		(1,216)		(5,153)		(1,234)
Total Liabilities and Stockholders' Equity	$	7,806	$	2,770	$	6,057	$	(6,005)	$	10,628

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS

For the Year Ended December 31, 2018


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Cash Flows from Operating Activities
Net income	$	997	$	136	$	374	$	(1,239)	$	268
Income/(loss) from discontinued operations	62		75		(329)		—		(192)
Net income from continuing operations	935		61		703		(1,239)		460
Adjustments to reconcile net income to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries	(23)		47		(1,231)		1,253		46
Depreciation and amortization	238		150		33		—		421
Accretion of asset retirement obligations	28		10		—		—		38
Provision for bad debts	79		6		—		—		85
Amortization of nuclear fuel	48		—		—		—		48
Amortization of financing costs and debt discount/premiums	—		6		23		—		29
Adjustment for debt extinguishment	—		—		44		—		44
Amortization of emission allowances and out-of-market contracts	36		9		—		—		45
Amortization of unearned equity compensation	—		—		25		—		25
Net (gain)/loss on sale and disposal of assets	(30)		(20)		1		—		(49)
Impairment losses	5		109		—		—		114
Changes in derivative instruments	25		15		11		(14)		37
Changes in deferred income taxes and liability for uncertain tax benefits	372		5		(372)		—		5
Changes in collateral deposits in support of energy risk management activities	(94)		(11)		—		—		(105)

Changes in nuclear decommissioning trust liability	60		—		—		—		60
GenOn settlement, net of insurance proceeds	—		—		(63)		—		(63)
Net loss on deconsolidation of Agua Caliente and Ivanpah projects	—		13		—		—		13
Changes in other working capital	(100)		(166)		16		—		(250)
Cash provided/(used) by continuing operations	1,579		234		(810)		—		1,003
Cash provided by discontinued operations	89		285		—		—		374
Net Cash Provided/(Used) by Operating Activities	1,668		519		(810)		—		1,377
Cash Flows from Investing Activities


Intercompany dividends	—		—		2,006		(2,006)		—
Payments for acquisitions of businesses	(40)		(203)		—		—		(243)
Capital expenditures	(192)		(151)		(45)		—		(388)


Net proceeds from sale of emission allowances	19		—		—		—		19
Investments in nuclear decommissioning trust fund securities	(572)		—		—		—		(572)
Proceeds from sales of nuclear decommissioning trust fund securities	513		—		—		—		513
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	14		8		1,542		—		1,564
Deconsolidation of Agua Caliente and Ivanpah projects	—		(268)		—		—		(268)
Changes in investments in unconsolidated affiliates	—		(39)		—		—		(39)
Net contributions to discontinued operations	—		(60)		—		—		(60)
Other	—		—		(6)		—		(6)
Cash (used)/provided by continuing operations	(258)		(713)		3,497		(2,006)		520
Cash used by discontinued operations	—		(725)		—		—		(725)
Net Cash (Used)/Provided by Investing Activities	(258)		(1,438)		3,497		(2,006)		(205)
Cash Flows from Financing Activities



Intercompany dividends and transfers	(1,267)		86		(825)		2,006		—
Payments of dividends to common stockholders	—		—		(37)		—		(37)
Payments for treasury stock	—		—		(1,250)		—		(1,250)

Payments for debt extinguishment costs	—		—		(32)		—		(32)
Net distributions to noncontrolling interests from subsidiaries	—		(16)		—		—		(16)
Proceeds from issuance of common stock	—		—		21		—		21
Proceeds from issuance of long-term debt	—		163		937		—		1,100
Payments of debt issuance costs	—		—		(19)		—		(19)
Payments for short and long-term debt	—		(138)		(1,596)		—		(1,734)
Receivable from affiliate	—		—		(26)		—		(26)
Other	—		(4)		—		—		(4)
Cash (used)/provided by continuing operations	(1,267)		91		(2,827)		2,006		(1,997)
Cash provided by discontinued operations	—		471		—		—		471
Net Cash (Used)/Provided by Financing Activities	(1,267)		562		(2,827)		2,006		(1,526)
Effect of exchange rate changes on cash and cash equivalents	—		1		—		—		1
Change in cash from discontinued operations	89		31		—		—		120
Net Increase/(Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties	54		(387)		(140)		—		(473)
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at Beginning of Period	41		425		620		—		1,086
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at End of Period	$	95	$	38	$	480	$	—	$	613

(a) All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS

For the Year Ended December 31, 2017


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc.		Eliminations^(a)		Consolidated Balance
Operating Revenues
Total operating revenues	$	7,818	$	1,304	$	—	$	(48)	$	9,074
Operating Costs and Expenses
Cost of operations	5,998		862		72		(46)		6,886
Depreciation and amortization	343		221		32		—		596
Impairment losses	1,346		188		—		—		1,534
Selling, general and administrative	410		64		364		(2)		836
Reorganization costs	6		—		38		—		44
Development costs	—		4		18		—		22
Total operating costs and expenses	8,103		1,339		524		(48)		9,918
Other income - affiliate	—		—		87		—		87
Gain on sale of assets	4		12		—		—		16
Operating Loss	(281)		(23)		(437)		—		(741)
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	18		—		28		(46)		—
Equity in losses of unconsolidated affiliates	—		(10)		(4)		—		(14)
Impairment losses on investments	—		(75)		(4)		—		(79)
Other income, net	9		14		28		—		51

Loss on debt extinguishment, net	—		—		(49)		—		(49)
Interest expense	(14)		(91)		(452)		—		(557)
Total other income/(expense)	13		(162)		(453)		(46)		(648)
Loss from Continuing Operations Before Income Taxes	(268)		(185)		(890)		(46)		(1,389)
Income tax (benefit)/expense	(598)		(62)		616		—		(44)
Income/(Loss) from Continuing Operations	330		(123)		(1,506)		(46)		(1,345)
Income/(loss) from discontinued operations, net of income tax	91		(420)		(663)		—		(992)
Net Income/(Loss)	421		(543)		(2,169)		(46)		(2,337)
Less: Net loss attributable to noncontrolling interests and redeemable noncontrolling interests	—		(168)		(16)		—		(184)
Net Income/(Loss) Attributable to NRG Energy, Inc.	$	421	$	(375)	$	(2,153)	$	(46)	$	(2,153)

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS)

For the Year Ended December 31, 2017


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Net Income/(Loss)	$	421	$	(543)	$	(2,169)	$	(46)	$	(2,337)
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net	1		13		25		(26)		13
Foreign currency translation adjustments, net	6		7		—		(1)		12
Available-for-sale securities, net	—		—		(8)		—		(8)
Defined benefit plan, net	(13)		30		46		(17)		46
Other comprehensive (loss)/income	(6)		50		63		(44)		63
Comprehensive Income/(Loss)	415		(493)		(2,106)		(90)		(2,274)
Less: Comprehensive loss attributable to noncontrolling interest and redeemable noncontrolling interests	—		(103)		(16)		(60)		(179)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	$	415	$	(390)	$	(2,090)	$	(30)	$	(2,095)

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS

For the Year Ended December 31, 2017


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Cash Flows from Operating Activities
Net income/(loss)	$	421	$	(543)	$	(2,169)	$	(46)	$	(2,337)
Income/(loss) from discontinued operations	91		(420)		(663)		—		(992)
Net income/(loss) from continuing operations	330		(123)		(1,506)		(46)		(1,345)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries	(18)		12		60		48		102
Depreciation and amortization	343		221		32		—		596
Accretion of asset retirement obligations	37		7		—		—		44
Provision for bad debts	56		—		12		—		68
Amortization of nuclear fuel	51		—		—		—		51
Amortization of financing costs and debt discount/premiums	—		13		16		—		29
Adjustment for debt extinguishment	—		—		49		—		49
Amortization of emission allowances and out-of-market contracts	42		12		—		—		54
Amortization of unearned equity compensation	—		—		35		—		35
Net loss/(gain) on sale and disposal of assets	2		(11)		—		—		(9)
Impairment losses	1,346		264		4		—		1,614
Changes in derivative instruments	(214)		50		(4)		(2)		(170)
Changes in deferred income taxes and liability for uncertain tax benefits	(300)		(9)		322		—		13
Changes in collateral deposits in support of energy risk management activities	(98)		18		—		—		(80)

Changes in nuclear decommissioning trust liability	11		—		—		—		11


Changes in other working capital	(15)		(396)		205		—		(206)
Cash provided/(used) by continuing operations	1,573		58		(775)		—		856
Cash provided by discontinued operations	116		638		—		—		754
Net Cash Provided/(Used) by Operating Activities	1,689		696		(775)		—		1,610
Cash Flows from Investing Activities

Intercompany dividends	—		—		1,665		(1,665)		—

Payments for acquisitions of businesses	(14)		—		—		—		(14)
Capital expenditures	(180)		(43)		(31)		—		(254)


Net proceeds from sale of emission allowances	66		—		—		—		66
Investments in nuclear decommissioning trust fund securities	(512)		—		—		—		(512)
Proceeds from sales of nuclear decommissioning trust fund securities	501		—		—		—		501
Proceeds from sale of assets, net of cash disposed	33		54		343		—		430
Changes in investments in unconsolidated affiliates	—		(57)		—		—		(57)
Net distributions from discontinued operations	—		—		150		—		150
Other	18		12		—		—		30
Cash (used)/provided by continuing operations	(88)		(34)		2,127		(1,665)		340
Cash used by discontinued operations	(13)		(966)		—		—		(979)
Net Cash (Used)/Provided by Investing Activities	(101)		(1,000)		2,127		(1,665)		(639)
Cash Flows from Financing Activities

Intercompany dividends and transfers	(1,447)		(4)		(214)		1,665		—


Payment of dividends to common stockholders	—		—		(38)		—		(38)



Payments for debt extinguishment costs	—		—		(42)		—		(42)
Net distributions to noncontrolling interests from subsidiaries	—		(30)		—		—		(30)
Payments for issuance of common stock	—		—		(2)		—		(2)
Proceeds from issuance of long-term debt	—		94		1,084		—		1,178
Payment of debt issuance costs	—		(2)		(16)		—		(18)
Payments for short and long-term debt	—		(183)		(1,701)		—		(1,884)
Receivable from affiliate	—		—		(125)		—		(125)
Other	—		(8)		—		—		(8)
Cash used by continuing operations	(1,447)		(133)		(1,054)		1,665		(969)
Cash used by discontinued operations	(109)		(60)		—		—		(169)
Net Cash Used by Financing Activities	(1,556)		(193)		(1,054)		1,665		(1,138)
Effect of exchange rate changes on cash and cash equivalents	—		(1)		—		—		(1)
Change in cash from discontinued operations	(6)		(388)		—		—		(394)
Net Increase/(Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties	38		(110)		298		—		226
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at Beginning of Period	3		535		322		—		860
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at End of Period	$	41	$	425	$	620	$	—	$	1,086

(a) All significant intercompany transactions have been eliminated in consolidation

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS

12 Months Ended

Dec. 31, 2019

SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS

SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS

For the Years Ended December 31, 2019, 2018, and 2017


(In millions)	Balance at Beginning of Period		Charged to Costs and Expenses		Charged to Other Accounts		Deductions			Balance at End of Period
Allowance for doubtful accounts, deducted from accounts receivable
Year Ended December 31, 2019	$	32	$	95	$	—	$	(84)	^(a)	$	43
Year Ended December 31, 2018	28		83		—		(79)		^(a)	32
Year Ended December 31, 2017	28		57		—		(57)		^(a)	28
Income tax valuation allowance, deducted from deferred tax assets
Year Ended December 31, 2019	$	3,794	$	(3,543)	$	(9)	$	—		$	242
Year Ended December 31, 2018	1,863		1,934		(128)		125		^(b)	3,794
Year Ended December 31, 2017	4,116		(151)		(15)		(2,087)		^(c)	1,863

(a) Represents principally net amounts charged as uncollectible

(b) Represents removal of NRG Yield, Inc. and its Renewables Platform due to their sale on August 31, 2018

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Discontinued Operations

On December 31, 2018, as described in Note 4, Acquisitions, Discontinued Operations and Dispositions, the Company concluded that the sale of its South Central Portfolio to Cleco, excluding the Cottonwood facility, met held-for-sale criteria and should be presented as a discontinued operation, as the sale represented a strategic shift in the business in which NRG operates. The financial information for all historical periods was recast in 2018 to reflect the presentation of these entities as discontinued operations.

On August 31, 2018, as described in Note 4, Acquisitions, Discontinued Operations and Dispositions, the Company deconsolidated NRG Yield, Inc. and its Renewables Platform for financial reporting purposes. The financial information for all historical periods was recast in 2018 to reflect the presentation of these entities, as well as the Carlsbad project, as discontinued operations. As a result of the sale of NRG Yield, the Company no longer controls the Agua Caliente project. Due to this change in control, the Company deconsolidated the Agua Caliente project from its financial results and began accounting for the project as an equity method investment.

On June 14, 2017, or the Petition Date, GenOn, along with GenOn Americas Generation and certain of their directly and indirectly-owned subsidiaries, or collectively the GenOn Entities, filed voluntary petitions for relief under the Chapter 11 Cases, of the U.S. Bankruptcy Code. As a result of the bankruptcy filings and beginning on June 14, 2017, GenOn and its subsidiaries were deconsolidated from NRG's consolidated financial statements. NRG determined that this disposal of GenOn and its subsidiaries was a discontinued operation and, accordingly, the financial information for all historical periods was recast to reflect GenOn as a discontinued operation. GenOn's plan of reorganization was confirmed on December 14, 2018.

Basis of Presentation

Principles of Consolidation

Segment Reporting

Cash and Cash Equivalents

Cash and cash equivalents include highly liquid investments with an original maturity of three months or less at the time of purchase.

Funds Deposited by Counterparties

Restricted Cash


	Year Ended December 31,
(In millions)	2019		2018		2017
Cash and cash equivalents	$	345	$	563	$	770
Funds deposited by counterparties	32		33		37
Restricted cash	8		17		279
Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statements of cash flows	$	385	$	613	$	1,086

Restricted cash consists primarily of funds held to satisfy the requirements of certain debt agreements and funds held within the Company's projects that are restricted in their use.

Trade Receivables and Allowance for Doubtful Accounts

Trade Receivables and Allowance for Doubtful AccountsTrade receivables are reported in the balance sheet at outstanding principal adjusted for any write-offs and the allowance for doubtful accounts. For its retail receivables, the Company accrues an allowance for doubtful accounts based on estimates of uncollectible revenues by analyzing counterparty credit ratings (for commercial and industrial customers), historical collections, accounts receivable aging and other factors. Accounts receivable balances are written-off against the allowance for doubtful accounts when a receivable is determined to be uncollectible. In addition, the Company considers a reserve for doubtful accounts based on the credit worthiness of the customers and continually reviews and adjusts for current economic trends that might impact the level of future credit losses. The reserve represents management's best estimate of uncollectible amounts.

Inventory

Property, Plant and Equipment

Asset Impairments

Development Costs and Capitalized Interest

Interest incurred on funds borrowed to finance capital projects is capitalized until the project under construction is ready for its intended use.

Debt Issuance Costs

Debt Issuance CostsDebt issuance costs are capitalized and amortized as interest expense on a basis which approximates the effective interest method over the term of the related debt. Debt issuance costs are presented as a direct deduction from the carrying amount of the related debt.

Intangible Assets

Goodwill

Income Taxes

The Company has two categories of income tax expense or benefit — current and deferred, as follows:

•Current income tax expense or benefit consists solely of current taxes payable less applicable tax credits, and

•Deferred income tax expense or benefit is the change in the net deferred income tax asset or liability, excluding amounts charged or credited to accumulated other comprehensive income

Revenue Recognition

Contract Amortization Assets and liabilities recognized through acquisitions related to the sale of electric capacity and energy in future periods for which the fair value has been determined to be significantly less or more than market are amortized to revenue over the term of each underlying contract based on actual generation and/or contracted volumes.

Lease Revenue and Lessor Accounting

Lease Revenue

Lessor Accounting

Certain of the Company's revenues are obtained through PPAs or other contractual agreements. Many of these agreements are accounted for as operating leases under ASC 842.

Sale-Leaseback Arrangements

Gross Receipts and Sales Taxes

Cost of Energy for Retail Operations

Derivative Financial Instruments

Foreign Currency Translation and Transaction Gains and Losses

Foreign Currency Translation and Transaction Gains and LossesThe local currencies are generally the functional currency of NRG's foreign operations. Foreign currency denominated assets and liabilities are translated at end-of-period rates of exchange. Revenues, expenses, and cash flows are translated at the weighted-average rates of exchange for the period. The resulting currency translation adjustments are not included in the Company's consolidated statements of operations for the period, but are accumulated and reported as a separate component of stockholders' equity until sale or complete or substantially complete liquidation of the net investment in the foreign entity takes place. Foreign currency transaction gains or losses are reported within other income/(expense) in the Company's consolidated statements of operations.

Concentrations of Credit Risk

Fair Value of Financial Instruments

Asset Retirement Obligations

Pensions and Other Postretirement Benefits

The Company measures the fair value of its pension assets in accordance with ASC 820, Fair Value Measurements and Disclosures, or ASC 820.

Stock-Based Compensation

Investments Accounted for by the Equity Method

Investments Accounted for by the Equity MethodThe Company has investments in various domestic energy projects, as well as one Australian project. The equity method of accounting is applied to such investments in affiliates, which include joint ventures and partnerships, because the ownership structure prevents the Company from exercising a controlling influence over the operating and financial policies of the projects. Under this method, equity in pre-tax income or losses of domestic partnerships and, generally, in the net income or losses of its Australian project, are reflected as equity in earnings of unconsolidated affiliates. Distributions from equity method investments that represent earnings on the Company's investment are included within cash flows from operating activities and distributions from equity method investments that represent a return of the Company's investment are included within cash flows from investing activities.

Tax Equity Arrangements

Redeemable Noncontrolling Interest

Redeemable Noncontrolling InterestTo the extent that the third-party has the right to redeem their interests for cash or other assets, the Company has included the noncontrolling interest attributable to the third party as a component of temporary equity in the mezzanine section of the consolidated balance sheet.

Sale-Leaseback Arrangements

Lease Revenue

Lessor Accounting

Certain of the Company's revenues are obtained through PPAs or other contractual agreements. Many of these agreements are accounted for as operating leases under ASC 842.

Sale-Leaseback Arrangements

Marketing and Advertising Costs

Marketing and Advertising Costs The Company expenses its marketing and advertising costs as incurred and includes them within selling, general and administrative expenses. The costs of tangible assets used in advertising campaigns are recorded as fixed assets or deferred advertising costs and amortized as advertising costs over the shorter of the useful life of the asset or the advertising campaign. The Company has several long-term sponsorship arrangements. Payments related to these arrangements are deferred and expensed over the term of the arrangement.

Reorganization Costs

Reorganization CostsReorganization costs include costs incurred by the Company related to the Transformation Plan implementation and primarily reflect severance and contract modifications. Reorganization costs for the years ended

Business Combinations

Use of Estimates

Reclassifications

Certain prior year amounts have been reclassified for comparative purposes. The reclassifications did not affect results from operations, net assets or cash flows.

Recent Accounting Developments

Recent Accounting Developments - Guidance Adopted in 2019

Recent Accounting Developments - Guidance Not Yet Adopted

Nuclear Decommissioning Policy

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Net income/(loss) attributable to continuing and discontinued operations

The following table reflects the net income/(loss) attributable to NRG Energy, Inc. after removing the net loss attributable to the noncontrolling interest and redeemable noncontrolling interest:


	Year Ended December 31,
(In millions)	2019		2018		2017
Income/(loss) from continuing operations, net of income tax	$	4,117	$	465	$	(977)
Income/(loss) from discontinued operations, net of income tax	321		(197)		(1,176)
Net income/(loss) attributable to NRG Energy, Inc. stockholders	$	4,438	$	268	$	(2,153)

Reconciliation of cash, cash equivalents, and restricted cash and cash equivalents


	Year Ended December 31,
(In millions)	2019		2018		2017
Cash and cash equivalents	$	345	$	563	$	770
Funds deposited by counterparties	32		33		37
Restricted cash	8		17		279
Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statements of cash flows	$	385	$	613	$	1,086

Detail of supplemental disclosures of cash flow and non-cash investing and financing information was:


	Year Ended December 31,
(In millions)	2019		2018		2017
Interest paid, net of amount capitalized	$	372	$	436	$	543
Income taxes paid, net of refunds	8		9		9
Non-cash investing activities:
Additions to fixed assets for accrued capital expenditures	1		20		19

Changes in redeemable noncontrolling interest

The following table reflects the changes in the Company's redeemable noncontrolling interest balance for the years ended December 31, 2019, 2018, and 2017.


	(In millions)
Balance as of December 31, 2016	$	46
Distributions to redeemable noncontrolling interest	(2)
Contributions from redeemable noncontrolling interest	99
Non-cash adjustments to redeemable noncontrolling interest	7
Comprehensive loss attributable to redeemable noncontrolling interest	(72)
Balance as of December 31, 2017	78
Distributions to redeemable noncontrolling interest	(3)
Contributions from redeemable noncontrolling interest	26
Non-cash adjustments to redeemable noncontrolling interest	(8)
Net income attributable to redeemable noncontrolling interest - continuing operations	1
Net loss attributable to redeemable noncontrolling interest - discontinued operations	(27)
Sale of NRG Yield and the Renewables Platform ^(a)	(48)
Balance as of December 31, 2018	19
Distributions to redeemable noncontrolling interest	(2)


Net income attributable to redeemable noncontrolling interest - continuing operations	3


Balance as of December 31, 2019	$	20

(a) See Note 4, Acquisitions, Discontinued Operations and Dispositions, for further information regarding the sale of NRG Yield and its Renewables Platform

Revenue Recognition (Tables)

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

Disaggregation of revenue

The following tables represent the Company’s disaggregation of revenue from contracts with customers for the years ended December 31, 2019 and 2018:


	For the Year Ended December 31, 2019
(In millions)	Texas		East		West/Other		Corporate/Eliminations		Total
Retail revenue
Mass Market	$	5,027	$	1,230	$	—	$	(3)	$	6,254
Business Solutions	1,205		74		—		—		1,279
Total retail revenue	6,232		1,304		—		(3)		7,533
Energy revenue^(a)	529		322		318		—		1,169
Capacity revenue^(a)	—		664		36		—		700
Mark-to-market for economic hedging activities^(b)	47		(29)		16		(1)		33

Other revenue^(a)	261		58		70		(3)		386
Total operating revenue	7,069		2,319		440		(7)		9,821
Less: Lease revenue	—		1		19		—		20
Less: Realized and unrealized ASC 815 revenue	1,562		183		67		(2)		1,810

Total revenue from contracts with customers	$	5,507	$	2,135	$	354	$	(5)	$	7,991





(a) The following amounts of energy, capacity and other revenue relate to derivative instruments and are accounted for under ASC 815:
(In millions)	Texas		East		West/Other		Corporate/Eliminations		Total
Energy revenue	$	1,459	$	98	$	39	$	(1)	$	1,595
Capacity revenue	—		109		—		—		109
Other revenue	56		5		12		—		73
(b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815


	For the Year Ended December 31, 2018
(In millions)	Texas		East		West/Other		Corporate/Eliminations		Total
Retail revenue
Mass Market	$	4,618	$	974	$	—	$	(1)	$	5,591
Business Solutions	1,238		65		—		—		1,303
Total retail revenue	5,856		1,039		—		(1)		6,894
Energy revenue^(a)	371		546		566		13		1,496
Capacity revenue^(a)	—		746		79		—		825
Mark-to-market for economic hedging activities^(b)	(77)		(35)		(5)		(13)		(130)

Other revenue^(a)(c)	251		75		84		(17)		393
Total operating revenue	6,401		2,371		724		(18)		9,478
Less: Lease revenue	1		1		19		—		21
Less: Realized and unrealized ASC 815 revenue	1,096		210		2		1		1,309

Total revenue from contracts with customers	$	5,304	$	2,160	$	703	$	(19)	8,148





(a) The following amounts of energy, capacity and other revenue relate to derivative instruments and are accounted for under ASC 815:
(In millions)	Texas		East		West/Other		Corporate/Eliminations		Total
Energy revenue	$	1,131	$	90	$	(2)	$	14	$	1,233
Capacity revenue	—		137		—		—		137
Other revenue	42		17		9		1		69

(b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815

Contract assets and liabilities

The following table reflects the contract assets and liabilities included in the Company's balance sheet as of December 31, 2019 and 2018:


(In millions)	December 31, 2019		December 31, 2018
Deferred customer acquisition costs	$	133	$	111

Accounts receivable, net - Contracts with customers	1,002		999
Accounts receivable, net - Derivative instruments	18		20
Accounts receivable, net - Affiliate	5		5
Total accounts receivable, net	$	1,025	$	1,024

Unbilled revenues (included within Accounts receivable, net - Contracts with customers)	$	402	$	392

Deferred revenues ^(a)	$	82	$	67

(a) Deferred revenues from contracts with customers for the years ended December 31, 2019 and 2018 were approximately $24 million and $19 million, respectively.

Acquisitions, Discontinued Operations and Dispositions (Tables)

12 Months Ended

Dec. 31, 2019

Discontinued Operations and Disposal Groups [Abstract]

Schedule of Purchase Price Allocation

The purchase price was allocated as follows:


	(In millions)
Account receivable	$	98
Accounts payable	(73)
Other net current and non-current working capital	5
Marketing partnership	154
Customer relationships	85
Trade name	28
Other intangible assets	26
Goodwill ^(a)	6
Stream Purchase Price	$	329

(a) Goodwill arising from the acquisition is attributed to the value of the platform acquired and the synergies expected from combining the operations of Stream Energy with NRG's existing businesses. Goodwill of $5 million and $1 million was assigned to the Texas and East segments, respectively, and is not deductible for tax purposes

Schedule of Allocation of Purchase Price

The acquisition increased NRG's retail portfolio by approximately 395,000 RCEs or 300,000 customers. The purchase price was allocated as follows:


	(In millions)
Net current and non-current working capital	$	46
Other intangible assets	133
Goodwill	34
XOOM Purchase Price	$	213

Summary of Results of Discontinued Operations

Summarized results of South Central discontinued operations were as follows:


	Year Ended December 31,
(In millions)	2019		2018		2017
Operating revenues	$	31	$	410	$	422
Operating costs and expenses	(23)		(346)		(335)
Other income	—		2		—


Gain from operations of discontinued components	8		66		87
Gain on disposal of discontinued operations, net of tax	20		—		—
Gain from discontinued operations, including disposal, net of tax	$	28	$	66	$	87

The following table summarizes the major classes of assets and liabilities classified as discontinued operations of South Central:


(In millions)	December 31, 2018
Cash and cash equivalents	$	89
Accounts receivable, net	49
Inventory	35
Other current assets	5
Current assets - discontinued operations	178
Property, plant and equipment, net	408
Other non-current assets	1
Non-current assets - discontinued operations	409
Accounts payable	19
Other current liabilities	5
Current liabilities - discontinued operations	24
Out-of-market contracts, net	50
Other non-current liabilities	11
Non-current liabilities - discontinued operations	$	61

Summarized results of NRG Yield, Inc. and Renewables Platform and Carlsbad discontinued operations were as follows:


	Year Ended December 31,
(In millions)	2019		2018		2017
Operating revenues	$	19	$	909	$	1,164
Operating costs and expenses	(9)		(661)		(1,114)

Other expenses	(5)		(174)		(288)
Gain/(loss) from operations of discontinued components, before tax	5		74		(238)
Income tax expense	—		4		52
Gain/(loss) from discontinued operations, net of tax	5		70		(290)
Gain/(loss) on disposal of discontinued operations, net of tax	265		(134)		—
Income/(expense) from California property tax indemnification	22		(153)		—
Income/(expense) from other commitments, indemnification and fees	4		(75)		—
Income/(loss) on disposal of discontinued operations, net of tax	291		(362)		—
Income/(loss) from discontinued operations, net of tax	$	296	$	(292)	$	(290)

The following table summarizes the major classes of assets and liabilities classified as discontinued operations:


(In millions)	December 31, 2018 ^(a)

Restricted Cash	$	4
Accounts receivable, net	10
Other current assets	5
Current assets - discontinued operations	19
Property, plant and equipment, net	590

Intangible assets, net	9
Other non-current assets	4
Non-current assets - discontinued operations	603
Current portion of long term debt and capital leases	20
Accounts payable	27
Other current liabilities	1
Current liabilities - discontinued operations	48
Long-term debt and capital leases	572
Other non-current liabilities	2
Non-current liabilities - discontinued operations	$	574

Summarized results of discontinued operations were as follows:


	Year Ended December 31,
(In millions)	2019		2018		2017
Operating revenues	$	—	$	—	$	646
Operating costs and expenses	—		—		(702)

Other expenses	—		—		(98)
Loss from operations of discontinued components, before tax	—		—		(154)
Income tax expense	—		—		9
Loss from discontinued operations	—		—		(163)
Interest income - affiliate	—		3		8
Income/(loss) from discontinued operations, net of tax	—		3		(155)
Pre-tax loss on deconsolidation	—		—		(208)
Settlement consideration, insurance and services credit	—		63		(289)
Pension and post-retirement liability assumption	—		21		(131)
Other	(3)		(53)		(6)
(Loss)/income on disposal of discontinued operations, net of tax	(3)		31		(634)
(Loss)/income from discontinued operations, net of tax	$	(3)	$	34	$	(789)

- Definition

Tabular disclosure of information related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=109222650&loc=d3e1361-107760

Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 13: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Estimated Carrying Amounts and Fair Values of Financial Instruments Not Carried at Fair Value

The estimated carrying values and fair values of the Company's recorded financial instruments not carried at fair market value are as follows:


	As of December 31,
	2019						2018
(In millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets
Notes receivable	$	11	$	8	$	17	$	14
Liabilities
Long-term debt, including current portion ^(a)	$	5,956	$	6,504	$	6,591	$	6,697

(a) Excludes deferred financing costs, which are recorded as a reduction to long-term debt on the Company's consolidated balance sheets


	As of December 31, 2019						As of December 31, 2018
(In millions)	Level 2		Level 3		Level 2		Level 3
Long-term debt, including current portion	$	6,388	$	116	$	6,528	$	169

Assets and Liabilities Measured and Recorded at Fair Value Measured on a Recurring Basis


	As of December 31, 2019
	Fair Value
(In millions)	Total		Level 1		Level 2		Level 3
Investments in securities (classified within other current and non-current assets)	$	20	$	—	$	20	$	—

Nuclear trust fund investments:
Cash and cash equivalents	17		17		—		—
U.S. government and federal agency obligations	68		68		—		—
Federal agency mortgage-backed securities	100		—		100		—
Commercial mortgage-backed securities	29		—		29		—
Corporate debt securities	109		—		109		—
Equity securities	388		388		—		—
Foreign government fixed income securities	5		—		5		—
Other trust fund investments:
U.S. government and federal agency obligations	1		1		—		—
Derivative assets:
Commodity contracts	1,170		84		893		193


Measured using net asset value practical expedient:
Equity securities-nuclear trust fund investments	78		—		—		—
Equity securities	8		—		—		—
Total assets	$	1,993	$	558	$	1,156	$	193
Derivative liabilities:
Commodity contracts	$	1,103	$	143	$	805	$	155

Total liabilities	$	1,103	$	143	$	805	$	155


	As of December 31, 2018
	Fair Value
(In millions)	Total		Level 1		Level 2		Level 3
Investments in securities (classified within other current or non-current assets)	$	39	$	2	$	18	$	19
Nuclear trust fund investments:
Cash and cash equivalents	19		19		—		—
U.S. government and federal agency obligations	46		46		—		—
Federal agency mortgage-backed securities	100		—		100		—
Commercial mortgage-backed securities	22		—		22		—
Corporate debt securities	96		—		96		—
Equity securities	312		312		—		—
Foreign government fixed income securities	4		—		4		—
Other trust fund investments:
U.S. government and federal agency obligations	1		1		—		—
Derivative assets:
Commodity contracts	1,042		137		796		109
Interest rate contracts	39		—		39		—

Measured using net asset value practical expedient:
Equity securities-nuclear trust fund investments	64		—		—		—
Equity securities	8		—		—		—
Total assets	$	1,792	$	517	$	1,075	$	128
Derivative liabilities:
Commodity contracts	$	977	$	224	$	664	$	89

Total liabilities	$	977	$	224	$	664	$	89

Reconciliation of Beginning and Ending Balances for Financial Instruments that are Recognized at Fair Value using Significant Unobservable Inputs


	For the Year Ended December 31, 2019
	Fair Value Measurement Using Significant Unobservable Inputs (Level 3)
(In millions)	Debt Securities		Derivatives^(a)		Total
Beginning balance as of January 1, 2019	$	19	$	20	$	39
Contracts added from acquisitions	—		(3)		(3)
Total gains/(losses) — realized/unrealized:
Included in earnings	—		(26)		(26)
Included in OCI	—		—		—

Purchases	—		40		40
Sale	(19)		—		(19)
Transfers into Level 3 ^(b)	—		2		2
Transfers out of Level 3 ^(b)	—		5		5
Ending balance as of December 31, 2019	$	—	$	38	$	38
Gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of December 31, 2019	$	—	$	17	$	17

(a)Consists of derivatives assets and liabilities, net

(b)Transfers into/out of Level 3 are related to the availability of external broker quotes, and are valued as of the end of the reporting period. All transfers into/out of Level 3 are from/to Level 2


	For the Year Ended December 31, 2018
	Fair Value Measurement Using Significant Unobservable Inputs (Level 3)
(In millions)	Debt Securities		Derivatives ^(a)		Total
Beginning balance as of January 1, 2018	$	19	$	(15)	$	4
Contracts acquired in XOOM acquisition	—		12		$	12
Total gains realized/unrealized included in earnings	—		(21)		(21)



Purchases	—		41		41


Transfers into Level 3 ^(b)	—		5		5
Transfer out of Level 3 ^(b)	—		(2)		(2)
Ending balance as of December 31, 2018	$	19	$	20	$	39
Losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of December 31, 2018	$	—	$	(17)	$	(17)

(a)Consists of derivatives assets and liabilities, net

(b)Transfers into/out of Level 3 are related to the availability of external broker quotes, and are valued as of the end of the reporting period. All transfers into/out of Level 3 are from/to Level 2

Schedule of Significant Unobservable Inputs used in Developing Fair Value of Level 3 Positions

The following tables quantify the significant unobservable inputs used in developing the fair value of the Company's Level 3 positions as of December 31, 2019 and 2018:


	Significant Unobservable Inputs
	December 31, 2019
	Fair Value										Input/Range
(In millions)	Assets		Liabilities		Valuation Technique	Significant Unobservable Input	Low		High		Weighted Average
Power Contracts	$	151	$	139	Discounted Cash Flow	Forward Market Price (per MWh)	$	8	$	218	$	24
FTRs	42		16		Discounted Cash Flow	Auction Prices (per MWh)	(105)		213		0
	$	193	$	155


	Significant Unobservable Inputs
	December 31, 2018
	Fair Value										Input/Range
(In millions)	Assets		Liabilities		Valuation Technique	Significant Unobservable Input	Low		High		Weighted Average
Power Contracts	$	89	$	75	Discounted Cash Flow	Forward Market Price (per MWh)	$	1	$	214	$	31
FTRs	20		14		Discounted Cash Flow	Auction Prices (per MWh)	(90)		34		0
	$	109	$	89

Fair Value Inputs, Sensitivity Analysis

The following table provides sensitivity of fair value measurements to increases/(decreases) in significant unobservable inputs as of December 31, 2019 and 2018:

Significant Unobservable Input

Position

Change In Input

Impact on Fair Value Measurement

Forward Market Price Power

Buy

Increase/(Decrease)

Higher/(Lower)

Forward Market Price Power

Sell

Increase/(Decrease)

Lower/(Higher)

FTR Prices

Buy

Increase/(Decrease)

Higher/(Lower)

FTR Prices

Sell

Increase/(Decrease)

Lower/(Higher)

Net Counterparty Credit Exposure by Industry Sector and by Counterparty Credit Quality

The following tables highlight net counterparty credit exposure by industry sector and by counterparty credit quality. Net counterparty credit exposure is defined as the aggregate net asset position for NRG with counterparties where netting is permitted under the enabling agreement and includes all cash flow, mark-to-market and NPNS, and non-derivative transactions. The exposure is shown net of collateral held, and includes amounts net of receivables or payables.


Category	Net Exposure ^{(a) (b)} (% of Total)
Utilities, energy merchants, marketers and other	84	%
Financial institutions	16


Total	100	%


Category	Net Exposure^{(a) (b)} (% of Total)
Investment grade	56	%
Non-Investment grade/Non-Rated	44

Total	100	%

(a)Counterparty credit exposure excludes uranium and coal transportation contracts because of the unavailability of market prices.

(b)The figures in the tables above exclude potential counterparty credit exposure related to RTOs, ISOs, registered commodity exchanges and certain long term contracts.

Accounting for Derivative Instruments and Hedging Activities (Tables)

12 Months Ended

Dec. 31, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Net Notional Volume Buy/(sell) of NRG's Open Derivative Transactions Broken Out By Commodity


(In millions)		Total Volume
Commodity	Units	December 31, 2019		December 31, 2018
Emissions	Short Ton	3		(2)
Renewables Energy Certificates	Certificates	1		1
Coal	Short Ton	10		13
Natural Gas	MMBtu	(181)		(330)
Oil	Barrels	—		1
Power	MWh	38		1
Capacity	MW/Day	(1)		(1)
Interest	Dollars	$	—	$	1,000

Fair Value Within the Derivative Instrument Valuation On the Balance Sheet

The following table summarizes the fair value within the derivative instrument valuation on the balance sheet:


	Fair Value
	Derivative Assets						Derivative Liabilities
(In millions)	December 31, 2019		December 31, 2018		December 31, 2019		December 31, 2018






Derivatives Not Designated as Cash Flow or Fair Value Hedges:
Interest rate contracts current	$	—	$	17	$	—	$	—
Interest rate contracts long-term	—		22		—		—
Commodity contracts current	860		747		781		673
Commodity contracts long-term	310		295		322		304

Total Derivatives Not Designated as Cash Flow or Fair Value Hedges	$	1,170	$	1,081	$	1,103	$	977

Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received Or Paid

The following table summarizes the offsetting derivatives by counterparty master agreement level and collateral received or paid:


	Gross Amounts Not Offset in the Statement of Financial Position
(In millions)	Gross Amounts of Recognized Assets/Liabilities		Derivative Instruments		Cash Collateral (Held)/Posted		Net Amount
As of December 31, 2019
Commodity contracts:
Derivative assets	$	1,170	$	(909)	$	(7)	$	254
Derivative liabilities	(1,103)		909		73		(121)
Total commodity contracts	$	67	$	—	$	66	$	133


	Gross Amounts Not Offset in the Statement of Financial Position
(In millions)	Gross Amounts of Recognized Assets/Liabilities		Derivative Instruments		Cash Collateral (Held)/Posted		Net Amount
As of December 31, 2018
Commodity contracts:
Derivative assets	$	1,042	$	(778)	$	(31)	$	233
Derivative liabilities	(977)		778		114		(85)
Total commodity contracts	65		—		83		148
Interest rate contracts:
Derivative assets	39		—		—		39

Total interest rate contracts	39		—		—		39
Total derivative instruments	$	104	$	—	$	83	$	187

Effects on the Company's Accumulated OCI Balance Attributable to Cash Flow Hedge Derivatives, Net of Tax


	Interest Rate Contracts
(In millions)	2018		2017
Accumulated OCI beginning balance	$	(54)	$	(66)
Reclassified from accumulated OCI to income:
Due to realization of previously deferred amounts	8		12
Mark-to-market of cash flow hedge accounting contracts	21		—
Sale of NRG Yield and Renewables	$	25	$	—
Accumulated OCI ending balance	$	—	$	(54)

Pre-tax Effects of Economic Hedges That Have Not Been Designated As Cash Flow Hedges, Ineffectiveness On Cash Flow Hedges And Trading Activity on the Company's Statement of Operations


	Year Ended December 31,
(In millions)	2019		2018		2017
Unrealized mark-to-market results
Reversal of previously recognized unrealized (gains)/losses on settled positions related to economic hedges	$	(68)	$	(73)	$	47
Reversal of acquired loss/(gain) positions related to economic hedges	6		(10)		—
Net unrealized gains on open positions related to economic hedges	42		97		159
Total unrealized mark-to-market (losses)/gains for economic hedging activities	(20)		14		206
Reversal of previously recognized unrealized (gains) on settled positions related to trading activity	(11)		(12)		(25)

Net unrealized gains on open positions related to trading activity	31		29		14
Total unrealized mark-to-market gains/(losses) for trading activity	20		17		(11)
Total unrealized gains	$	—	$	31	$	195


	Year Ended December 31,
(In millions)	2019		2018		2017
Unrealized gains/(losses) included in operating revenues	$	53	$	(113)	$	241
Unrealized (losses)/gains included in cost of operations	(53)		144		(46)
Total impact to statement of operations — energy commodities	$	—	$	31	$	195
Total impact to statement of operations — interest rate contracts	$	(38)	$	—	$	4

Nuclear Decommissioning Trust Fund (Tables)

12 Months Ended

Dec. 31, 2019

Regulated Operations [Abstract]

Summary of Aggregate Fair Values and Unrealized Gains And Losses (Including Other-Than-Temporary Impairments) for the Securities Held in The Nuclear Decommissioning Trust Fund


	As of December 31, 2019													As of December 31, 2018
(In millions, except otherwise noted)	Fair Value		Unrealized Gains		Unrealized Losses		Weighted- average maturities (in years)	Fair Value		Unrealized Gains		Unrealized Losses		Weighted- average maturities (in years)
Cash and cash equivalents	$	17	$	—	$	—	—	$	19	$	—	$	—	—
U.S. government and federal agency obligations	68		4		—		11	46		1		—		12
Federal agency mortgage-backed securities	100		3		—		24	100		1		2		23
Commercial mortgage-backed securities	29		1		1		24	22		—		1		22
Corporate debt securities	109		6		—		11	96		1		2		11
Equity securities	466		324		—		—	376		231		1		—
Foreign government fixed income securities	5		—		—		10	4		—		—		9
Total	$	794	$	338	$	1		$	663	$	234	$	6

Summary of Proceeds From Sales of Available-For-Sale securities and the related realized gains and losses


	Year Ended December 31,
(In millions)	2019		2018		2017
Realized gains	$	18	$	17	$	22
Realized (losses)	(9)		(13)		(8)
Proceeds from sale of securities	381		513		501

Inventory (Tables)

12 Months Ended

Dec. 31, 2019

Inventory Disclosure [Abstract]

Schedule of Inventory

Inventory consisted of:


	As of December 31,
(In millions)	2019		2018
Fuel oil	$	73	$	74
Coal	93		97
Natural gas	21		28
Spare parts	196		213

Total Inventory	$	383	$	412

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

NRG's major classes of property, plant and equipment

The Company's major classes of property, plant, and equipment were as follows:


	As of December 31,					Depreciable
(In millions)	2019		2018		Lives
Facilities and equipment	$	3,262	$	3,763	1-40 years
Land and improvements	324		347
Nuclear fuel	235		212		5 years
Hardware and office equipment and furnishings	422		431		2-10 years
Construction in progress	102		106
Total property, plant, and equipment	4,345		4,859
Accumulated depreciation	(1,752)		(1,811)
Net property, plant, and equipment	$	2,593	$	3,048

Leases (Tables)

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Lease Cost

Lease Cost:


(In millions)	For the Year Ended December 31, 2019
Finance lease cost:	$	—
Amortization of right-of-use assets	—
Shares issued under ESPP	—
Interest on lease liabilities	—
Operating lease cost	$	109
Short-term lease cost	3
Variable lease cost	6
Sublease income	(17)
Total lease cost	$	101

Other information:


(In millions)	For the Year Ended December 31, 2019

Cash paid for amounts included in the measurement of lease liabilities:


Operating cash flows from operating leases	$	104


Right-of-use assets obtained in exchange for new operating lease liabilities	215

Lease Term and Discount Rate for operating leases:


	December 31, 2019

Weighted average remaining lease term (in years)	7.8



Weighted average discount rate	5.72	%

Schedule of Annual Payments Based on Maturities of Leases

As of December 31, 2019, annual payments based on the maturities of NRG's leases are expected to be as follows:


	(In millions)
2020	$	96
2021	87
2022	87
2023	85
2024	75
Thereafter	296
Total undiscounted lease payments	$	726
Less: present value adjustment	(170)
Total discounted lease payments	$	556

Future minimum lease commitments under operating leases

Future minimum lease commitments under the Powerton and Joliet operating leases as of December 31, 2018 were as follows:


Period	(In millions)
2019	$	1
2020	1
2021	3
2022	6
2023	6
Thereafter	222
Total ^(a)	$	239

^(a) Termination of leases could be at a significant premium to the remaining lease payments

Future minimum lease commitments under operating leases, other than Powerton and Joliet, as of December 31, 2018 were as follows:


Period^(a)	(In millions)
2019	$	60
2020	55
2021	43
2022	40
2023	39
Thereafter	95
Total	$	332

^(a) Amounts in the table exclude future sublease income of $29 million associated with long-term leases for office locations

Goodwill and Other Intangibles (Tables)

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Summary of the Components of Intangible Assets Subject to Amortization

The following tables summarize the components of NRG's intangible assets subject to amortization:


(In millions)
Year Ended December 31, 2019	Emission Allowances		Fuel Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other		Total
January 1, 2019	$	659	$	49	$	478	$	131	$	345	$	80	$	1,742
Purchases	13		—		—		—		—		29		42
Acquisition of businesses ^(a)	—		—		110		154		28		26		318
Usage	(4)		—		—		—		—		(17)		(21)
Write-off of fully amortized balances	(8)		—		(13)		—		—		(9)		(30)
Impairment	—		—		(2)		—		—		—		(2)
Other	2		—		—		—		—		—		2
December 31, 2019	662		49		573		285		373		109		2,051
Less accumulated amortization	(539)		(45)		(345)		(75)		(220)		(38)		(1,262)
Net carrying amount	$	123	$	4	$	228	$	210	$	153	$	71	$	789

(a)The weighted average life of acquired intangibles was: customer relationships 7 years, marketing partnerships 9 years, trade names 12 years, and energy supply contracts 2 years


(In millions)
Year Ended December 31, 2018	Emission Allowances		Fuel Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other		Total
January 1, 2018	$	755	$	49	$	768	$	88	$	342	$	78	$	2,080
Purchases	33		—		—		—		—		28		61
Acquisition of businesses^(a)	—		—		122		43		13		—		178
Usage	(1)		—		—		—		—		(26)		(27)
Write-off of fully amortized balances	(107)		—		(411)		—		(10)		—		(528)
Impairment	(5)		—		(1)		—		—		—		(6)
Other	(16)		—		—		—		—		—		(16)
December 31, 2018	659		49		478		131		345		80		1,742
Less accumulated amortization	(515)		(45)		(314)		(61)		(195)		(21)		(1,151)
Net carrying amount	$	144	$	4	$	164	$	70	$	150	$	59	$	591

(a)The weighted average life of acquired intangibles was: customer relationships 6 years, trade names 7 years, and marketing partnerships 14 years

Schedule of Amortization of Intangible Expense

The following table presents NRG's amortization of intangible assets for each of the past three years:


	Years Ended December 31,
(In millions)	2019		2018		2017
Emission allowances	$	32	$	39	$	71


Customer relationships	44		32		34
Marketing partnerships	15		9		5
Trade names	25		23		23
Other	35		30		33
Total amortization	$	151	$	133	$	166

Schedule of Estimated Amortization of Intangible Assets for Next Five Years

The following table presents estimated amortization of NRG's intangible assets as of December 31, 2019 for each of the next five years:


(In millions)
Year Ended December 31,	Emission Allowances		Fuel Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other		Total
2020	$	36	$	1	$	68	$	24	$	27	$	33	$	189
2021	35		—		52		24		27		3		141
2022	38		—		36		23		27		3		127
2023	40		1		35		23		26		3		128
2024	35		—		15		23		17		3		93

Debt and Finance Leases (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Long-term Debt and Capital Leases

Long-term debt and finance leases consisted of the following:


(In millions, except rates)	December 31, 2019		December 31, 2018		December 31, 2019 Interest rate %

Recourse debt:
Senior Notes, due 2024	$	—	$	733	6.250
Senior Notes, due 2026	1,000		1,000		7.250
Senior Notes, due 2027	1,230		1,230		6.625
Senior Notes, due 2028	821		821		5.750
Senior Notes, due 2029	733		—		5.250
Convertible Senior Notes, due 2048^(a)	575		575		2.750
Senior Secured First Lien Notes, due 2024	600		—		3.750
Senior Secured First Lien Notes, due 2029	500		—		4.450
2023 Term Loan Facility ^(b)	—		1,698		L+ 1.75
Revolving Credit Facility ^(c)	83		—		L+ 1.75
Tax-exempt bonds	466		466		4.125 - 6.00
Subtotal recourse debt	6,008		6,523
Non-recourse debt:
Agua Caliente Borrower 1, due 2038	—		86		5.430
Midwest Generation, due 2019	—		48		4.390
Other	34		34		various
Subtotal all non-recourse debt	34		168
Subtotal long-term debt (including current maturities)	6,042		6,691
Finance leases	—		1		various


Subtotal long-term debt and finance leases (including current maturities)	6,042		6,692
Less current maturities	(88)		(72)
Less debt issuance costs	(65)		(70)
Discounts	(86)		(101)
Total long-term debt and finance leases	$	5,803	$	6,449

(a) The effective interest rate was 5.05% and 5.02% for the years ended December 31, 2019 and 2018, respectively

(b) As of December 31, 2018, the interest rate was 1-month LIBOR plus 1.75%

Debt includes the following discounts:


	As of December 31,
(In millions)	2019		2018
Term loan facility, due 2023	$	—	$	(4)
Midwest Generation, due 2019	—		(1)
Senior Secured First Lien Notes, due 2024 and 2029	(1)		—
Convertible Senior Notes, due 2048	(85)		(96)
Total discounts	$	(86)	$	(101)

Annual Payments Based On the Maturities of NRG's Debt

As of December 31, 2019, annual payments based on the maturities of NRG's debt are expected to be as follows:


	(In millions)
2020^(a)	$	88
2021	6
2022	5
2023	4
2024	604
Thereafter	5,335
Total	$	6,042

(a) Includes $83 million of Revolving Credit Facility balance outstanding as of December 31, 2019

Debt Redemption


(In millions, except percentages)	Principal Repurchased		Cash Paid^(a)		Average Early Redemption Percentage
5.750% senior notes due 2028	$	29	$	30	99.24	%
6.250% senior notes due 2022	14		15		103.25	%
Total at June 30, 2018	$	43	$	45
6.250% senior notes due 2022	493		512		103.13	%
5.750% senior notes due 2028	20		20		99.13	%
6.625% senior notes due 2027	20		21		103.06	%
Total at September 30, 2018	$	576	$	598
6.250% senior notes due 2022	485		508		103.13	%
Total at December 31, 2018	$	1,061	$	1,106

(a) Includes accrued interest of $14 million

In addition, on or after May 15, 2021, NRG may redeem some or all of the notes at redemption prices expressed as percentages of principal amount as set forth in the following table, plus accrued and unpaid interest on the notes redeemed to the first applicable redemption date:


Redemption Period	Redemption Percentage
May 15, 2021 to May 14, 2022	103.625	%
May 15, 2022 to May 14, 2023	102.417	%
May 15, 2023 to May 14, 2024	101.208	%
May 15, 2024 and thereafter	100.000	%

In addition, on or after July 15, 2021, NRG may redeem some or all of the notes at redemption prices expressed as percentages of principal amount as set forth in the following table, plus accrued and unpaid interest on the notes redeemed to the first applicable redemption date:


Redemption Period	Redemption Percentage
July 15, 2021 to July14, 2022	103.313	%
July 15, 2022 to July 14, 2023	102.208	%
July 15, 2023 to July 14, 2024	101.104	%
July 15, 2024 and thereafter	100.000	%

In addition, on or after January 15, 2023, NRG may redeem some or all of the notes at redemption prices expressed as percentages of principal amount as set forth in the following table, plus accrued and unpaid interest on the notes redeemed to the first applicable redemption date:


Redemption Period	Redemption Percentage
January 15, 2023 to January 14, 2024	102.875	%
January 15, 2024 to January 14, 2025	101.917	%
January 15, 2025 to January 14, 2026	100.958	%
January 15, 2026 and thereafter	100.000	%

In addition, on or after June 15, 2024, NRG may redeem some or all of the notes at redemption prices expressed as percentages of principal amount as set forth in the following table, plus accrued and unpaid interest on the notes redeemed to the first applicable redemption date:


Redemption Period	Redemption Percentage
June 15, 2024 to June 14, 2025	102.625	%
June 15, 2025 to June 14, 2026	101.750	%
June 15, 2026 to June 14, 2027	100.875	%
June 15, 2027 and thereafter	100.000	%

Schedule of Tax Exempt Bonds

Tax Exempt Bonds


	As of December 31,
(In millions, except rates)	2019		2018		Interest Rate %
Indian River Power, tax exempt bonds, due 2040	$	57	$	57	6.000
Indian River Power LLC, tax exempt bonds, due 2045	190		190		5.375
Dunkirk Power LLC, tax exempt bonds, due 2042	59		59		5.875
City of Texas City, tax exempt bonds, due 2045	33		33		4.125
Fort Bend County, tax exempt bonds, due 2038	54		54		4.750
Fort Bend County, tax exempt bonds, due 2042	73		73		4.750
Total	$	466	$	466

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Schedule of Company's ARO Obligations and Related Additions, reductions and Accretion


(In millions)	Nuclear Decommission		Other		Total
Balance as of December 31, 2018	$	282	$	397	$	679
Revisions in estimates for current obligations^(a)	—		27		27
Additions	—		9		9
Spending for current obligations	—		(33)		(33)
Accretion ^(a)	16		30		46
Balance as of December 31, 2019	$	298	$	430	$	728

(a) Total ARO accretion expense includes non-Nuclear Decommissioning Trust accretion and revised asset retirement liabilities on non-operating plants

Benefit Plans and Other Postretirement Benefits (Tables)

12 Months Ended

Dec. 31, 2019

Retirement Benefits [Abstract]

Schedule of Net Benefit Cost (Credit) Related to Pension and Other Postretirement Benefit Plans Components

The annual net periodic benefit cost/(credit) related to NRG's pension and other postretirement benefit plans include the following components:


	Year Ended December 31,
	Pension Benefits
(In millions)	2019		2018		2017
Service cost benefits earned	$	10	$	23	$	26
Interest cost on benefit obligation	46		44		43
Expected return on plan assets	(59)		(62)		(58)
Amortization of unrecognized net loss	3		—		4
Settlement/curtailment expense	—		7		—
Net periodic benefit cost	$	—	$	12	$	15


	Year Ended December 31,
	Other Postretirement Benefits
(In millions)	2019		2018		2017
Service cost benefits earned	$	1	$	1	$	1
Interest cost on benefit obligation	3		4		4
Amortization of unrecognized prior service credit	(13)		(10)		(9)
Amortization of unrecognized net (gain)/loss	—		—		(1)
Curtailment gain	—		(10)		—
Net periodic benefit (credit)	$	(9)	$	(15)	$	(5)

Schedule of Comparison of Pension Benefit obligation, Other Postretirement Benefit Obligations and Related Plan Assets on a Combined Basis

A comparison of the pension benefit obligation, other postretirement benefit obligations and related plan assets for NRG's plans on a combined basis is as follows:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Benefit obligation at January 1	$	1,222	$	1,329	$	83	$	128
Service cost	10		23		1		1
Interest cost	46		44		3		4
Plan amendments	—		17		(2)		(28)
Actuarial (gain)/loss	207		(95)		16		(6)
Employee and retiree contributions	—		—		4		3
Curtailment gain	—		(20)		—		(7)
Benefit payments	(88)		(76)		(12)		(12)
Benefit obligation at December 31	1,397		1,222		93		83
Fair value of plan assets at January 1	981		1,104		—		—
Actual return on plan assets	216		(80)		—		—
Employee and retiree contributions	—		—		4		3
Employer contributions	41		33		7		9
Benefit payments	(88)		(76)		(11)		(12)
Fair value of plan assets at December 31	1,150		981		—		—
Funded status at December 31 — excess of obligation over assets	$	(247)	$	(241)	$	(93)	$	(83)

Schedule of Amounts Recognized in Balance Sheet

Amounts recognized in NRG's balance sheets were as follows:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Other current liabilities	$	—	$	—	$	7	$	7
Other non-current liabilities	247		241		86		76

Schedule of Amounts Recognized in OCI Not Yet Recognized as Components of Net Periodic Benefit Costs

Amounts recognized in NRG's accumulated OCI that have not yet been recognized as components of net periodic benefit cost were as follows:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Net loss/(gain)	$	138	$	90	$	7	$	(9)
Prior service cost/(credit)	2		3		(43)		(53)
Total accumulated OCI	$	140	$	93	$	(36)	$	(62)

Net accumulated OCI	$	140	$	93	$	(36)	$	(62)

Schedule of Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income

Other changes in plan assets and benefit obligations recognized in OCI were as follows:


	Year Ended December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Net actuarial loss/(gain)	$	50	$	47	$	16	$	(5)
Amortization of net actuarial (gain)/loss	(3)		—		—		—
Curtailment	—		(27)		—		2
Prior service credit	—		17		(2)		(28)
Amortization of prior service cost	—		—		12		10
Total recognized in OCI	$	47	$	37	$	26	$	(21)
Net periodic benefit cost/(credit)	—		12		(9)		(15)
Net recognized in net periodic pension cost/(credit) and OCI	$	47	$	49	$	17	$	(36)

Schedule of Benefit Obligations Significant Components

The following table presents the balances of significant components of NRG's pension plan:


	As of December 31,
	Pension Benefits
(In millions)	2019		2018
Projected benefit obligation	$	1,397	$	1,222
Accumulated benefit obligation	1,362		1,188
Fair value of plan assets	1,150		981

Schedule of Fair Value of Pension Plan Assets by Asset Category and Level within the Fair Value Hierarchy


	Fair Value Measurements as of December 31, 2019
(In millions)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Total
Common/collective trust investment — U.S. equity	$	—	$	233	$	233
Common/collective trust investment — non-U.S. equity	—		73		73
Common/collective trust investment — non-core assets	—		143		143
Common/collective trust investment — fixed income	—		272		272
Short-term investment fund	12		—		12
Subtotal fair value	$	12	$	721	$	733
Measured at net asset value practical expedient:
Common/collective trust investment — non-U.S. equity					84
Common/collective trust investment — fixed income					279
Common/collective trust investment — non-core assets					24
Partnerships/joint ventures					30
Total fair value					$	1,150


	Fair Value Measurements as of December 31, 2018
(In millions)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Total
Common/collective trust investment — U.S. equity	$	—	$	183	$	183
Common/collective trust investment — non-U.S. equity	—		53		53
Common/collective trust investment — non-core assets	—		117		117
Common/collective trust investment — fixed income	—		256		256
Short-term investment fund	12		—		12
Subtotal fair value	$	12	$	609	$	621
Measured at net asset value practical expedient:
Common/collective trust investment — non-U.S. equity					70
Common/collective trust investment — fixed income					249
Common/collective trust investment — non-core assets					16
Partnerships/joint ventures					25
Total fair value					$	981

Schedule of Assumptions Used to Calculate Benefit Expense

The following table presents the significant assumptions used to calculate NRG's benefit obligations:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
Weighted-Average Assumptions	2019		2018		2019		2018
Discount rate	3.26	%	4.38	%	3.26	%	4.37	%
Rate of compensation increase	3.00	%	3.00	%	—	%	—	%
Health care trend rate	—		—		7.5% grading to 4.5% in 2028		7.8% grading to 4.5% in 2025

The following table presents the significant assumptions used to calculate NRG's benefit expense:


	As of December 31,
	Pension Benefits								Other Postretirement Benefits
Weighted-Average Assumptions	2019		2018		2017		2019	2018	2017
Discount rate	4.38%/4.2%		3.71%/4.04%		4.26	%	4.37%	3.71% /4.08%	4.29	%
Expected return on plan assets	6.35	%	6.17	%	6.85	%	—	—	—
Rate of compensation increase	3.00	%	3.00	%	3.00	%	—	—	—
Health care trend rate	—		—		—		7.8% grading to 4.5% in 2025	8.2% grading to 4.5% in 2025	7.0% grading to 5.0% in 2025

Schedule of Target Allocation of Pension Plan Assets

The target allocations of NRG's pension plan assets were as follows for the year ended December 31, 2019:


U.S. equity	20	%
Non-U.S. equity	13	%
Non-core assets	17	%
U.S. fixed income	50	%

Schedule of Performance Benchmarks

Performance benchmarks are composed of the following indices:


Asset Class						Index
U.S. equities						Dow Jones U.S. Total Stock Market Index
Non-U.S. equities						MSCI All Country World Ex-U.S. IMI Index
Non-core assets^(a)						Various (per underlying asset class)
Fixed income securities						Barclays Capital Long Term Government/Credit Index & Barclays Strips 20+ Index

Schedule of Expected Benefit Payments

NRG's expected future benefit payments for each of the next five years, and in the aggregate for the five years thereafter, are as follows:


			Other Postretirement Benefit
(In millions)	Pension Benefit Payments		Benefit Payments		Medicare Prescription Drug Reimbursements
2020	$	84	$	7	$	—
2021	86		6		—
2022	86		6		—
2023	86		6		—
2024	86		6		—
2025-2029	402		19		2

Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates


(In millions)	1-Percentage- Point Increase		1-Percentage- Point Decrease

Effect on postretirement benefit obligation	$	7	$	(5)

Schedule of Benefit Costs and Other Changes Recognized in the Financial Statements Related to its Interest in STP

The Company has recognized the following in its statement of financial position, statement of operations and accumulated OCI related to its 44% interest in STP:


	As of December 31,
	Pension Benefits						Other Postretirement Benefits
(In millions)	2019		2018		2019		2018
Funded status — STPNOC benefit plans	$	(77)	$	(78)	$	(20)	$	(19)
Net periodic benefit cost/(credit)	9		8		(4)		(7)
Other changes in plan assets and benefit obligations recognized in other comprehensive (loss)/income	(13)		(7)		6		2

Defined Contribution Plan Contributions

The Company's contributions to these plans were as follows:


	Year Ended December 31,
(In millions)	2019		2018		2017
Company contributions to defined contribution plans	$	22	$	28	$	56

Capital Structure (Tables)

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

Changes in NRG's common shares issued and outstanding

The following table reflects the changes in NRG's common shares issued and outstanding for each period presented:


	Common
	Issued	Treasury	Outstanding
Balance as of December 31, 2016	417,583,825	(102,140,814)	315,443,011
Shares issued under ESPP	—	560,769	560,769
Shares issued under LTIPs	739,309	—	739,309

Balance as of December 31, 2017	418,323,134	(101,580,045)	316,743,089
Shares issued under ESPP	—	175,862	175,862
Shares issued under LTIPs	1,965,752	—	1,965,752
Share repurchases	—	(35,234,664)	(35,234,664)
Balance as of December 31, 2018	420,288,886	(136,638,847)	283,650,039
Shares issued under ESPP	—	46,128	46,128
Shares issued under LTIPs	1,601,904	—	1,601,904
Share repurchases	—	(36,301,882)	(36,301,882)
Balance as of December 31, 2019	421,890,790	(172,894,601)	248,996,189

Summary of shares repurchased

The following table summarizes the shares repurchases made from 2018 through February 27, 2020:


	Total number of shares and share equivalents purchased	Average price paid per share and share equivalent		Amounts paid for shares and share equivalents purchased (in millions)
2018 repurchases:
Shares repurchased under May 24, 2018 Accelerated Repurchase Agreement	10,829,903			354
Shares repurchased under September 5, 2018 Accelerated Repurchase Agreement	13,307,130			500
Other repurchases	11,097,631			396
Total Share Repurchases during 2018	35,234,664	$35.48		$	1,250


2019 repurchases:
Repurchases under February 28, 2019 Accelerated Share Repurchase Agreement	9,438,671			400
Other repurchases	26,863,211			1,008
Equivalent shares purchased in lieu of tax withholdings on equity compensation issuances^(a)	936,928			36
Total Share Repurchases during 2019	37,238,810	$	38.79	$	1,444
2020 repurchases:
Repurchases made subsequent to December 31, 2019	2,428,545			92
Equivalent shares purchased in lieu of tax withholdings on equity compensation issuances^(a)	709,536			27
Total share repurchases January 1, 2020 through February 27, 2020	3,138,081	$	37.87	$	119

Investments Accounted for by the Equity Method and Variable Interest Entities (Tables)

12 Months Ended

Dec. 31, 2019

Equity Method Investments and Joint Ventures [Abstract]

Summary NRG's equity method investments

The following table summarizes NRG's equity method investments as of December 31, 2019:


(In millions, except percentages)
Name	Economic Interest		Investment Balance
Agua Caliente	35.0	%	213
Gladstone	37.5	%	124
Ivanpah Master Holdings, LLC	54.5	%	20
Watson Cogeneration Company	49.0	%	15
Midway-Sunset Cogeneration Company	50.0	%	9
Other^(a)	Various		7
Total equity investments in affiliates			$	388

(a) Refer to Note 11, Asset Impairments, for discussion of NRG's investment in Petra Nova Parish Holdings, LLC

Undistributed earnings by equity investment


	As of December 31,
(In millions)	2019		2018
Undistributed earnings from equity investments	$	42	$	34

Summary of Financial Information for Consolidated VIEs

The summarized financial information for the Company's consolidated VIEs consisted of the following:


(In millions)	December 31, 2019		December 31, 2018
Current assets	$	3	$	3
Net property, plant and equipment	71		76
Other long-term assets	27		28
Total assets	101		107
Current liabilities	4		2
Long-term debt	24		29
Other long-term liabilities	8		7
Total liabilities	36		38
Redeemable noncontrolling interests	20		19
Net assets less noncontrolling interests	$	45	$	50

Earnings /Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Reconciliation of NRG's basic and diluted earnings per share

The reconciliation of NRG's basic income/(loss) per share to diluted income/(loss) per share is shown in the following table:


	Year Ended December 31,
(In millions, except per share amounts)	2019		2018		2017
Basic income/(loss) per share attributable to NRG, Inc;
Net income/(loss) attributable to NRG Energy, Inc. common stockholders	$	4,438	$	268	$	(2,153)



Weighted average number of common shares outstanding-basic	262		304		317
Income/(Loss) per weighted average common share — basic	$	16.94	$	0.88	$	(6.79)
Diluted income/(loss) per share attributable to NRG, Inc;
Net income/(loss) attributable to NRG Energy, Inc. common stockholders	$	4,438	$	268	$	(2,153)
Weighted average number of common shares outstanding-basic	262		304		317
Incremental shares attributable to the issuance of equity compensation (treasury stock method)	2		4		—
Weighted average number of common shares outstanding-diluted	264		308		317
Income/(Loss) per weighted average common share — diluted	$	16.81	$	0.87	$	(6.79)

Summary of NRG's outstanding equity instruments that are anti-dilutive and were not included in the computation of the Company's diluted earnings per share

The following table summarizes NRG's outstanding equity instruments that are anti-dilutive and were not included in the computation of the Company's diluted income/(loss) per share:


	Year Ended December 31,
(In millions)	2019	2018	2017
Equity compensation plans	—	—	5

Segment Reporting (Tables)

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Segment Reporting


	For the Year Ended December 31, 2019
(In millions)	Texas		East		West/Other		Corporate^(a)		Eliminations		Total
Operating revenues^(a)	$	7,069	$	2,319	$	440	$	—	$	(7)	$	9,821
Operating expenses	5,818		1,895		397		50		(7)		8,153
Depreciation and amortization	188		121		33		31		—		373
Impairment losses	1		—		4		—		—		5
Development costs	3		3		1		—		—		7
Total operating cost and expenses	6,010		2,019		435		81		(7)		8,538

Gain on sale of assets	—		1		—		6		—		7
Operating income/(loss)	1,059		301		5		(75)		—		1,290
Equity in (losses)/earnings of unconsolidated affiliates	(4)		—		6		—		—		2
Impairment losses on investments	(103)		—		—		(5)		—		(108)
Other income, net	20		6		10		30		—		66
Loss on debt extinguishment	—		—		(3)		(48)		—		(51)
Interest expense	—		(18)		(10)		(385)		—		(413)
Income/(loss) from continuing operations before income taxes	972		289		8		(483)		—		786
Income tax expense/(benefit)	—		2		1		(3,337)		—		(3,334)
Net income from continuing operations	972		287		7		2,854		—		4,120
Gain from discontinued operations, net of income tax	—		—		—		321		—		321
Net Income	972		287		7		3,175		—		4,441
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests	—		—		3		—		—		3
Net income attributable to NRG Energy, Inc.	$	972	$	287	$	4	$	3,175	$	—	$	4,438

Balance sheet
Equity investments in affiliates	$	6	$	—	$	382	$	—	$	—	$	388
Capital expenditures	136		30		25		37		—		228
Goodwill^(b)	325		254		—		—		—		579
Total assets	$	5,711	$	2,160	$	1,190	$	8,342	$	(4,872)	$	12,531


(a) Inter-segment sales and inter-segment net derivative gains and losses included in operating revenues	$	1	$	8	$	(2)	$	—	$	—	$	7
(b) Goodwill was allocated based on the regions in which the business operates and are expected to benefit using a relative fair value approach


	For the Year Ended December 31, 2018
(In millions)	Texas		East		West/Other		Corporate^(a)		Eliminations		Total
Operating revenues^(a)	$	6,401	$	2,371	$	724	$	—	$	(18)	$	9,478
Operating expenses	5,399		2,024		467		125		(18)		7,997
Depreciation and amortization	156		105		127		33		—		421
Impairment losses	5		82		12		—		—		99
Development costs	3		3		3		2		—		11
Total operating cost and expenses	5,563		2,214		609		160		(18)		8,528

Gain on sale of assets	4		—		(2)		30		—		32
Operating income/(loss)	842		157		113		(130)		—		982
Equity in (losses)/earnings of unconsolidated affiliates	(3)		—		13		(1)		—		9
Impairment losses on investments	(15)		—		—		—		—		(15)
Other income/(loss), net	13		2		4		(1)		—		18
Loss on debt extinguishment	—		—		—		(44)		—		(44)
Interest expense	—		(22)		(39)		(422)		—		(483)
Income/(loss) from continuing operations before income taxes	837		137		91		(598)		—		467
Income tax expense	—		1		—		6		—		7
Net income/(loss) from continuing operations	837		136		91		(604)		—		460
Loss from discontinued operations, net of income tax	—		—		—		(192)		—		(192)
Net Income/(loss)	837		136		91		(796)		—		268
Less: Net income/(loss) attributable to noncontrolling interests and redeemable noncontrolling interests	—		—		5		(5)		—		—
Net income/(loss) attributable to NRG Energy, Inc.	$	837	$	136	$	86	$	(791)	$	—	$	268

Balance sheet
Equity investments in affiliates	$	6	$	—	406		$	—	$	—	$	412
Capital expenditures	143		171		29		45		—		388
Goodwill^(b)	320		253		—		—		—		573
Total assets	$	5,357	$	2,187	$	1,548	$	6,631	$	(5,095)	$	10,628


(a) Inter-segment sales and inter-segment net derivative gains and losses included in operating revenues	$	19	$	(5)	4	$	—	$	—	$	18
(b) Goodwill was allocated based on the regions in which the business operates and are expected to benefit using a relative fair value approach


	For the Year Ended December 31, 2017
(In millions)	Texas		East		West/Other		Corporate^(a)		Eliminations		Total
Operating revenues^(a)	$	6,318	$	2,009	$	788	$	6	$	(47)	$	9,074
Operating expenses	5,393		1,684		498		239		(48)		7,766
Depreciation and amortization	258		112		194		35		(3)		596
Impairment losses	1,317		106		111		—		—		1,534
Development costs	4		6		6		6		—		22
Total operating costs and expenses	6,972		1,908		809		280		(51)		9,918
Other income - affiliate	—		—		—		87		—		87
Gain/(loss) on sale of assets	5		15		(5)		1		—		16
Operating (loss)/income	(649)		116		(26)		(186)		4		(741)
Equity in (losses)/earnings of unconsolidated affiliates	(22)		—		10		(2)		—		(14)
Impairment losses on investments	(69)		—		(6)		(4)		—		(79)
Other (expense)/income, net	(2)		4		22		27		—		51
Loss on debt extinguishment	—		—		—		(49)		—		(49)
Interest expense	—		(29)		(77)		(451)		—		(557)
(Loss)/income from continuing operations before income taxes	(742)		91		(77)		(665)		4		(1,389)
Income tax benefit	—		—		(6)		(38)		—		(44)
Net (loss)/income from continuing operations	(742)		91		(71)		(627)		4		(1,345)
Loss from discontinued operations, net of income tax	—		—		—		(992)		—		(992)
Net (loss)/income	(742)		91		(71)		(1,619)		4		(2,337)
Less: Net income/(loss) attributable to noncontrolling interests and redeemable noncontrolling interests	—		—		1		(189)		4		(184)
Net (loss)/income attributable to NRG Energy, Inc.	$	(742)	$	91	$	(72)	$	(1,430)	$	—	$	(2,153)


(a) Inter-segment sales and inter-segment net derivative gains and losses included in operating revenues			$	41					$	1					(4)						$	9					$	—					$	47

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Income tax provision from continuing operations

The income tax provision from continuing operations consisted of the following amounts:


	Year Ended December 31,
(In millions, except effective income tax rate)	2019			2018			2017
Current

State	$	2		$	6		$	19
Foreign	4			—			—
Total — current	6			6			19
Deferred
U.S. Federal	(3,000)			(16)			(60)
State	(340)			16			(5)
Foreign	—			1			2
Total — deferred	(3,340)			1			(63)
Total income tax (benefit)/expense	$	(3,334)		$	7		$	(44)
Effective income tax rate	(424.2)		%	1.5		%	3.2		%

Domestic and foreign components of income/(loss) before income tax (benefit)/expense

The following represented the domestic and foreign components of income/(loss) from continuing operations before income taxes:


	Year Ended December 31,
(In millions)	2019		2018		2017
U.S.	$	771	$	468	$	(1,406)
Foreign	15		(1)		17
Total	$	786	$	467	$	(1,389)

Reconciliation of the U.S. federal statutory rate to NRG's effective rate

Reconciliations of the U.S. federal statutory tax rate to NRG's effective tax rate were as follows:


	Year Ended December 31,
(In millions, except effective income tax rate)	2019			2018			2017
Income/(loss) from continuing operations before income taxes	$	786		$	467		$	(1,389)
Tax at federal statutory tax rate	165			98			(486)
State taxes	13			18			19
Foreign operations	—			—			2
Permanent differences	(9)			7			—
Valuation allowance - current period activities	(3,492)			(106)			455

Book goodwill impairment	—			—			30
Deferred impact of state tax rate changes	12			—			—
Production tax credits ("PTC")	—			(7)			(8)
Recognition of uncertain tax benefits	(10)			1			(5)


Alternative minimum tax ("AMT") refundable credit	—			(4)			(64)
Tax Act - corporate income tax rate change	—			—			665
Valuation allowance due to corporate income tax rate change	—			—			(660)
Other	(13)			—			8
Income tax (benefit)/expense	$	(3,334)		$	7		$	(44)
Effective income tax rate	(424.2)		%	1.5		%	3.2		%

Company's deferred tax assets and liabilities

The temporary differences, which gave rise to the Company's deferred tax assets and liabilities consisted of the following:


	As of December 31,
(In millions)	2019		2018
Deferred tax assets:
Deferred compensation, accrued vacation and other reserves	$	81	$	134
Difference between book and tax basis of property	548		554
Goodwill	—		11
Differences between book and tax basis of contracts	—		38
Pension and other postretirement benefits	86		87
Equity compensation	11		9
Bad debt reserve	13		14

U.S. Federal net operating loss carryforwards	2,116		2,241
Foreign net operating loss carryforwards	105		63
State net operating loss carryforwards	360		379

Federal and state tax credit carryforwards	384		381
Federal benefit on state uncertain tax positions	4		6
Intangibles amortization (excluding goodwill)	—		21
Interest disallowance carryforward per §163(j) of the Tax Act	82		102
Inventory obsolescence	7		7
Other	3		—
Discontinued operations	—		17
Total deferred tax assets	3,800		4,064
Deferred tax liabilities:
Emissions allowances	19		15

Derivatives, net	27		37
Goodwill	8		—
Intangibles amortization (excluding goodwill)	15		—
Equity method investments	201		180

Convertible Debt	19		21
Other	—		1
Discontinued operations	—		36
Total deferred tax liabilities	289		290
Total deferred tax assets less deferred tax liabilities	3,511		3,774
Valuation allowance	(242)		(3,812)
Discontinued operations	—		19
Total deferred tax assets/(liabilities), net of valuation allowance	$	3,269	$	(19)

Summary of NRG's net deferred tax position

The following table summarizes NRG's net deferred tax position as presented in the consolidated balance sheets:


	As of December 31,
(In millions)	2019		2018
Deferred tax asset	$	3,286	$	46

Deferred tax liability	(17)		(65)
Net deferred tax asset/(liability)	$	3,269	$	(19)

Reconciliation of total amounts of uncertain tax benefits

The following table summarizes uncertain tax benefits activity:


	As of December 31,
(In millions)	2019		2018
Balance as of January 1	$	26	$	30
Increase due to current year positions	2		4

Settlements, payments and statute closure	(13)		(8)
Uncertain tax benefits as of December 31	$	15	$	26

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement, Noncash Expense [Abstract]

Summary of Company's non-vested RSU awards and changes during the year

The following table summarizes the Company's non-vested RSU awards and changes during the year:


	Units	Weighted Average Grant Date Fair Value per Unit
Non-vested at December 31, 2018	1,458,082	$	16.16
Granted	266,938	37.37
Forfeited	(73,905)	24.73
Vested	(933,876)	14.20

Non-vested at December 31, 2019	717,239	25.56

Summary of Company's Non-vested DSU awards and changes during the year

The following table summarizes the Company's outstanding DSU awards and changes during the year:


	Units	Weighted Average Grant Date Fair Value per Unit
Outstanding at December 31, 2018	331,915	$	22.94
Granted	57,630	34.84

Converted to Common Stock	(58,322)	28.93

Outstanding at December 31, 2019	331,223	23.98

The following table summarizes the Company's non-vested PSU awards and changes during the year:


	Units	Weighted Average Grant-Date Fair Value per Unit
Non-vested at December 31, 2018	1,710,634	$	19.12
Granted^(a)	936,889	22.50
Forfeited	(37,526)	23.04
Vested^(b)	(1,409,456)	14.72
Non-vested at December 31, 2019^(c)	1,200,541	26.65

(b) MSUs granted during 2016 vested during 2019 at 200%

Summary of Company's PSU awards and changes during the year

The following table summarizes the Company's outstanding DSU awards and changes during the year:


	Units	Weighted Average Grant Date Fair Value per Unit
Outstanding at December 31, 2018	331,915	$	22.94
Granted	57,630	34.84

Converted to Common Stock	(58,322)	28.93

Outstanding at December 31, 2019	331,223	23.98

The following table summarizes the Company's non-vested PSU awards and changes during the year:


	Units	Weighted Average Grant-Date Fair Value per Unit
Non-vested at December 31, 2018	1,710,634	$	19.12
Granted^(a)	936,889	22.50
Forfeited	(37,526)	23.04
Vested^(b)	(1,409,456)	14.72
Non-vested at December 31, 2019^(c)	1,200,541	26.65

(b) MSUs granted during 2016 vested during 2019 at 200%

Schedule of Assumptions used in Fair Value Model

Significant assumptions used in the fair value model with respect to the Company's PSUs are summarized below:


	2019		2018		2017		2016
	RPSUs		RPSUs		RPSUs		MSUs
Expected volatility	40.72	%	47.52	%	43.96	%	34.33	%
Expected term (in years)	3		3		3		3
Risk free rate	2.45	%	2.01	%	1.5	%	1.31	%

Summary of Company's NQSO activity, and changes during the year

The following table summarizes the Company's NQSO activity and changes during the year:


	Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2018	279,934	$	25.04	2	$	4
Expired	(8,254)	26.76
Exercised	(137,282)	24.67
Outstanding at December 31, 2019	134,398	25.31		1	2
Exercisable at December 31, 2019	134,398	25.31		1	2

Summary of the total intrinsic value of options exercised and the cash received from the exercises of options

The following table summarizes the total intrinsic value of options exercised and the cash received from the exercises of options:


	Year Ended December 31,
(In millions)	2019		2018		2017

Total intrinsic value of options exercised	$	2	$	10	$	1
Cash received from options exercised	3		24		4

Summary of NRG's total compensation expense recognized and total non-vested compensation costs not yet recognized and the period over which this expense is expected to be recognized


							Non-vested Compensation Cost
(In millions, except weighted average data)	Compensation Expense									Unrecognized Total Cost	Weighted Average Recognition Period Remaining (In years)
	Year Ended December 31,									As of December 31,
Award	2019		2018		2017		2019		2019

RSUs	9		12		15		8		1.06
DSUs	2		2		2		—		0.00
MSUs	—		4		5		—		0.50
RPSUs	10		7		3		9		0.71
PRSUs^(a)	11		16		13		10		1.05
Total^(b)	$	32	$	41	$	38	$	27
Tax detriment recognized	$	(12)	$	(4)	$	(5)

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2019

Summary of NRG's material related-party transactions with affiliates

The following table summarizes NRG's material related party transactions with third party affiliates:


	Year Ended December 31,
(In millions)	2019		2018		2017
Revenues from Related Parties Included in Operating Revenues
Gladstone	$	4	$	3	$	3
GenConn^(a)	—		4		5
Ivanpah^(b)	35		20		—
Midway-Sunset	5		5		—
Total	$	44	$	32	$	8

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2019

Commitments and Contingencies Disclosure [Abstract]

Commitments under coal, gas and transportation contractual agreements

As of December 31, 2019, the Company's minimum commitments under such outstanding agreements are estimated as follows:


Period	(In millions)
2020	$	124
2021	125
2022	73
2023	53
2024	62
Thereafter	139
Total^(a)	$	576

(a) Actual coal, gas and transportation purchases are significantly higher than these estimated minimum unconditional long- term firm commitments

Minimum purchase commitment obligations under purchased power agreements

These contracts are not included in the consolidated balance sheet as of December 31, 2019. Minimum purchase commitment obligations are as follows as of December 31, 2019:


Period	(In millions)
2020	$	35
2021	49
2022	68
2023	56
2024	56
Thereafter	349
Total	$	613

Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2019

Supplemental Cash Flow Information [Abstract]

Details of supplemental disclosures of cash flow and non-cash investing and financing information


	Year Ended December 31,
(In millions)	2019		2018		2017
Cash and cash equivalents	$	345	$	563	$	770
Funds deposited by counterparties	32		33		37
Restricted cash	8		17		279
Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statements of cash flows	$	385	$	613	$	1,086

Detail of supplemental disclosures of cash flow and non-cash investing and financing information was:


	Year Ended December 31,
(In millions)	2019		2018		2017
Interest paid, net of amount capitalized	$	372	$	436	$	543
Income taxes paid, net of refunds	8		9		9
Non-cash investing activities:
Additions to fixed assets for accrued capital expenditures	1		20		19

Guarantees (Tables)

12 Months Ended

Dec. 31, 2019

Guarantees [Abstract]

Summary of NRG's estimated guarantees, indemnity, and other contingent liability

The following table summarizes the maximum potential exposures that can be estimated for NRG's guarantees, indemnities, and other contingent liabilities by maturity:


	By Remaining Maturity at December 31,
(In millions)	2019
Guarantees	Under 1 Year		1-3 Years		3-5 Years		Over 5 Years		Total		2018 Total
Letters of credit and surety bonds^(a)	$	878	$	115	$	31	$	—	$	1,024	$	1,253
Asset sales guarantee obligations	4		490		—		204		698		793
Other guarantees	77		5		—		206		288		721
Total guarantees	$	959	$	610	$	31	$	410	$	2,010	$	2,767

(a)December 31, 2019 includes $14 million of letter of credit and surety bonds for the benefit of GenOn where NRG holds cash or letter of credit to back stop the liability

Jointly Owned Plants (Tables)

12 Months Ended

Dec. 31, 2019

Jointly Owned Plants Disclosure [Abstract]

Summary of NRG's proportionate ownership interest in the company's jointly-owned facilities

The following table summarizes NRG's proportionate ownership interest in the Company's jointly-owned facilities:


(In millions unless otherwise stated)
As of December 31, 2019	Ownership Interest		Property, Plant & Equipment		Accumulated Depreciation		Construction in Progress
South Texas Project Units 1 and 2, Bay City, TX	44.00	%	$	413	$	(206)	$	8
Cedar Bayou Unit 4, Baytown, TX	50.00	%	218		(93)		7

Unaudited Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Summary of Unaudited Quarterly Financial Data

Summarized unaudited quarterly financial data is as follows:


	Quarter Ended
	2019
(In millions, except per share data)	December 31		September 30		June 30		March 31
Operating revenues	$	2,195	$	2,996	$	2,465	$	2,165
Operating income	209		540		320		221
Net income from continuing operations	3,463		374		189		94
(Loss)/income from discontinued operations	(78)		(2)		13		388
Net income	3,385		372		202		482
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests	2		—		1		—

Income available to Common Stockholders	$	3,383	$	372	$	201	$	482
Weighted average number of common shares outstanding — basic	251		254		265		278
(Loss)/income from discontinued operations per weighted average common share — basic	$	(0.31)	$	(0.01)	$	0.05	$	1.39
Net Income per weighted average common share — basic	$	13.48	$	1.46	$	0.76	$	1.73
Weighted average number of common shares outstanding — diluted	253		256		267		280
(Loss)/income from discontinued operations per weighted average common share — diluted	$	(0.31)	$	(0.01)	$	0.05	$	1.38
Net income per weighted average common share — diluted	$	13.37	$	1.45	$	0.75	$	1.72


	Quarter Ended
	2018
(In millions, except per share data)	December 31		September 30		June 30		March 31
Operating revenues	$	1,992	$	2,960	$	2,461	$	2,065
Operating income	49		398		174		361
Net (loss)/income from continuing operations	(93)		287		27		238
Income/(loss) from discontinued operations	80		(336)		69		(5)
Net (loss)/income	(13)		(49)		96		233
Less: Net (loss)/income attributable to noncontrolling interests and redeemable noncontrolling interests	(2)		23		24		(46)

(Loss)/income available to Common Stockholders	$	(11)	$	(72)	$	72	$	279
Weighted average number of common shares outstanding — basic	289		299		310		318
Income/(loss) from discontinued operations per weighted average common share — basic	$	0.28	$	(1.12)	$	0.22	$	(0.02)
Net (loss)/income per weighted average common share — basic	$	(0.04)	$	(0.24)	$	0.23	$	0.88
Weighted average number of common shares outstanding — diluted	289		299		314		322
Income/(loss) from discontinued operations per weighted average common share — diluted	$	0.28	$	(1.12)	$	0.22	$	(0.02)
Net (loss)/income per weighted average common share — diluted	$	(0.04)	$	(0.24)	$	0.23	$	0.87

Condensed Consolidating Financial Information (Tables)

12 Months Ended

Dec. 31, 2019

Condensed Financial Information Disclosure [Abstract]

Schedule of Guarantor Subsidiaries

Unless otherwise noted below, each of the following guarantor subsidiaries fully and unconditionally guaranteed the Senior Notes and Senior Secured First Lien Notes as of December 31, 2019:


Ace Energy, Inc.	NRG Astoria Gas Turbine Operations Inc.	NRG Oswego Harbor Power Operations Inc.
Allied Home Warranty GP LLC	NRG Business Services LLC	NRG PacGen Inc.
Allied Warranty LLC	NRG Cabrillo Power Operations Inc.	NRG Portable Power LLC
Arthur Kill Power LLC	NRG California Peaker Operations LLC	NRG Power Marketing LLC
Astoria Gas Turbine Power LLC	NRG Cedar Bayou Development Company, LLC	NRG Reliability Solutions LLC
BidURenergy, Inc.	NRG Connected Home LLC	NRG Renter's Protection LLC
Cabrillo Power I LLC	NRG Connecticut Affiliate Services Inc.	NRG Retail LLC
Cabrillo Power II LLC	NRG Construction LLC	NRG Retail Northeast LLC
Carbon Management Solutions LLC	NRG Curtailment Solutions, Inc	NRG Rockford Acquisition LLC
Cirro Group, Inc.	NRG Development Company Inc.	NRG Saguaro Operations Inc.
Cirro Energy Services, Inc.	NRG Devon Operations Inc.	NRG Security LLC
Connecticut Jet Power LLC	NRG Dispatch Services LLC	NRG Services Corporation
Devon Power LLC	NRG Distributed Energy Resources Holdings LLC	NRG SimplySmart Solutions LLC
Dunkirk Power LLC	NRG Distributed Generation PR LLC	NRG South Central Affiliate Services Inc.
Eastern Sierra Energy Company LLC	NRG Dunkirk Operations Inc.	NRG South Central Operations Inc.
El Segundo Power, LLC	NRG ECOKAP Holdings LLC	NRG South Texas LP
El Segundo Power II LLC	NRG El Segundo Operations Inc.	NRG Texas Gregory LLC
Energy Alternatives Wholesale, LLC	NRG Energy Labor Services LLC	NRG Texas Holding Inc.
Energy Choice Solutions LLC	NRG Energy Services Group LLC	NRG Texas LLC
Energy Plus Holdings LLC	NRG Energy Services International Inc.	NRG Texas Power LLC
Energy Plus Natural Gas LLC	NRG Energy Services LLC	NRG Warranty Services LLC
Energy Protection Insurance Company	NRG Generation Holdings, Inc.	NRG West Coast LLC
Everything Energy LLC	NRG Greenco LLC	NRG Western Affiliate Services Inc.
Forward Home Security, LLC	NRG Home & Business Solutions LLC	O'Brien Cogeneration, Inc. II
GCP Funding Company, LLC	NRG Home Services LLC	Oswego Harbor Power LLC
Green Mountain Energy Company	NRG Home Solutions LLC	Reliant Energy Northeast LLC
Gregory Partners, LLC	NRG Home Solutions Product LLC	Reliant Energy Power Supply, LLC
Gregory Power Partners LLC	NRG Homer City Services LLC	Reliant Energy Retail Holdings, LLC
Huntley Power LLC	NRG HQ DG LLC	Reliant Energy Retail Services, LLC
Independence Energy Alliance LLC	NRG Huntley Operations Inc.	RERH Holdings, LLC
Independence Energy Group LLC	NRG Identity Protect LLC	Saguaro Power LLC
Independence Energy Natural Gas LLC	NRG Ilion Limited Partnership	Somerset Operations Inc.
Indian River Operations Inc.	NRG Ilion LP LLC	Somerset Power LLC
Indian River Power LLC	NRG International LLC	Texas Genco GP, LLC
Meriden Gas Turbines LLC	NRG Maintenance Services LLC	Texas Genco Holdings, Inc.
Middletown Power LLC	NRG Mextrans Inc.	Texas Genco LP, LLC
Montville Power LLC	NRG MidAtlantic Affiliate Services Inc.	Texas Genco Services, LP
NEO Corporation	NRG Middletown Operations Inc.	US Retailers LLC
New Genco GP, LLC	NRG Montville Operations Inc.	Vienna Operations Inc.
Norwalk Power LLC	NRG North Central Operations Inc.	Vienna Power LLC
NRG Advisory Services LLC	NRG Northeast Affiliate Services Inc.	WCP (Generation) Holdings LLC
NRG Affiliate Services Inc.	NRG Norwalk Harbor Operations Inc.	West Coast Power LLC
NRG Arthur Kill Operations Inc.	NRG Operating Services, Inc.

Condensed Consolidating Statement of Operations

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS

For the Year Ended December 31, 2019


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Operating Revenues
Total operating revenues	$	8,041	$	1,791	$	—	$	(11)	$	9,821
Operating Costs and Expenses
Cost of operations	5,936		1,351		27		(11)		7,303
Depreciation and amortization	212		130		31		—		373
Impairment losses	1		4		—		—		5
Selling, general and administrative	466		83		278		—		827
Reorganization costs	—		—		23		—		23
Development costs	—		—		7		—		7
Total operating costs and expenses	6,615		1,568		366		(11)		8,538

Gain on sale of assets	1		—		6		—		7
Operating Income/(Loss)	1,427		223		(360)		—		1,290
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	48		—		1,562		(1,610)		—
Equity in earnings of unconsolidated affiliates	—		2		—		—		2
Impairment losses on investments	—		(101)		(7)		—		(108)
Other income, net	23		12		31		—		66

Loss on debt extinguishment, net	—		(3)		(48)		—		(51)
Interest expense	(14)		(14)		(385)		—		(413)
Total other income/(expense)	57		(104)		1,153		(1,610)		(504)
Income from Continuing Operations Before Income Taxes	1,484		119		793		(1,610)		786
Income tax expense/(benefit)	—		4		(3,338)		—		(3,334)
Income from Continuing Operations	1,484		115		4,131		(1,610)		4,120
Income from discontinued operations, net of income tax	9		5		307		—		321
Net Income	1,493		120		4,438		(1,610)		4,441
Less: Net income attributable to redeemable noncontrolling interests	—		3		—		—		3
Net Income Attributable to NRG Energy, Inc.	$	1,493	$	117	$	4,438	$	(1,610)	$	4,438

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS

For the Year Ended December 31, 2018


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Operating Revenues
Total operating revenues	$	8,119	$	1,385	$	—	$	(26)	$	9,478
Operating Costs and Expenses
Cost of operations	6,147		959		28		(26)		7,108
Depreciation and amortization	238		150		33		—		421
Impairment losses	6		93		—		—		99
Selling, general and administrative	462		63		348		(74)		799
Reorganization costs	4		—		86		—		90
Development costs	—		1		11		(1)		11
Total operating costs and expenses	6,857		1,266		506		(101)		8,528

Gain on sale of assets	4		28		—		—		32
Operating Income/(Loss)	1,266		147		(506)		75		982
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	23		—		1,291		(1,314)		—
Equity in earnings/(losses) of unconsolidated affiliates	—		10		(1)		—		9
Impairment losses on investments	—		(15)		—		—		(15)
Other income/(expense), net	32		(13)		(1)		—		18

Loss on debt extinguishment, net	—		—		(44)		—		(44)
Interest expense	(14)		(49)		(420)		—		(483)
Total other income/(expense)	41		(67)		825		(1,314)		(515)
Income from Continuing Operations Before Income Taxes	1,307		80		319		(1,239)		467
Income tax expense/(benefit)	372		19		(384)		—		7
Income from Continuing Operations	935		61		703		(1,239)		460
Income/(loss) from discontinued operations, net of income tax	62		75		(329)		—		(192)
Net Income	997		136		374		(1,239)		268
Less: Net (loss)/income attributable to noncontrolling interests and redeemable noncontrolling interests	—		(181)		106		75		—
Net Income Attributable to NRG Energy, Inc.	$	997	$	317	$	268	$	(1,314)	$	268

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS

For the Year Ended December 31, 2017


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc.		Eliminations^(a)		Consolidated Balance
Operating Revenues
Total operating revenues	$	7,818	$	1,304	$	—	$	(48)	$	9,074
Operating Costs and Expenses
Cost of operations	5,998		862		72		(46)		6,886
Depreciation and amortization	343		221		32		—		596
Impairment losses	1,346		188		—		—		1,534
Selling, general and administrative	410		64		364		(2)		836
Reorganization costs	6		—		38		—		44
Development costs	—		4		18		—		22
Total operating costs and expenses	8,103		1,339		524		(48)		9,918
Other income - affiliate	—		—		87		—		87
Gain on sale of assets	4		12		—		—		16
Operating Loss	(281)		(23)		(437)		—		(741)
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	18		—		28		(46)		—
Equity in losses of unconsolidated affiliates	—		(10)		(4)		—		(14)
Impairment losses on investments	—		(75)		(4)		—		(79)
Other income, net	9		14		28		—		51

Loss on debt extinguishment, net	—		—		(49)		—		(49)
Interest expense	(14)		(91)		(452)		—		(557)
Total other income/(expense)	13		(162)		(453)		(46)		(648)
Loss from Continuing Operations Before Income Taxes	(268)		(185)		(890)		(46)		(1,389)
Income tax (benefit)/expense	(598)		(62)		616		—		(44)
Income/(Loss) from Continuing Operations	330		(123)		(1,506)		(46)		(1,345)
Income/(loss) from discontinued operations, net of income tax	91		(420)		(663)		—		(992)
Net Income/(Loss)	421		(543)		(2,169)		(46)		(2,337)
Less: Net loss attributable to noncontrolling interests and redeemable noncontrolling interests	—		(168)		(16)		—		(184)
Net Income/(Loss) Attributable to NRG Energy, Inc.	$	421	$	(375)	$	(2,153)	$	(46)	$	(2,153)

(a)All significant intercompany transactions have been eliminated in consolidation

Condensed Consolidating Statements of Comprehensive Income

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME

For the Year Ended December 31, 2019


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Net Income	$	1,493	$	120	$	4,438	$	(1,610)	$	4,441
Other Comprehensive Loss, net of tax

Foreign currency translation adjustments, net	—		(1)		(1)		1		(1)
Available-for-sale securities, net	—		—		(19)		—		(19)
Defined benefit plan, net	(17)		—		(78)		17		(78)
Other comprehensive loss	(17)		(1)		(98)		18		(98)
Comprehensive Income	1,476		119		4,340		(1,592)		4,343
Less: Comprehensive income attributable to redeemable noncontrolling interests	—		3		—		—		3
Comprehensive Income Attributable to NRG Energy, Inc.	$	1,476	$	116	$	4,340	$	(1,592)	$	4,340

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME

For the Year Ended December 31, 2018


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Net Income	$	997	$	136	$	374	$	(1,239)	$	268
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net	—		29		9		(15)		23
Foreign currency translation adjustments, net	(10)		(10)		(13)		22		(11)
Available-for-sale securities, net	—		—		1		—		1
Defined benefit plan, net	(9)		—		(35)		9		(35)
Other comprehensive (loss)/income	(19)		19		(38)		16		(22)
Comprehensive Income	978		155		336		(1,223)		246
Less: Comprehensive (loss)/income attributable to noncontrolling interests and redeemable noncontrolling interests	—		(166)		104		76		14
Comprehensive Income Attributable to NRG Energy, Inc.	$	978	$	321	$	232	$	(1,299)	$	232

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS)

For the Year Ended December 31, 2017


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Net Income/(Loss)	$	421	$	(543)	$	(2,169)	$	(46)	$	(2,337)
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net	1		13		25		(26)		13
Foreign currency translation adjustments, net	6		7		—		(1)		12
Available-for-sale securities, net	—		—		(8)		—		(8)
Defined benefit plan, net	(13)		30		46		(17)		46
Other comprehensive (loss)/income	(6)		50		63		(44)		63
Comprehensive Income/(Loss)	415		(493)		(2,106)		(90)		(2,274)
Less: Comprehensive loss attributable to noncontrolling interest and redeemable noncontrolling interests	—		(103)		(16)		(60)		(179)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	$	415	$	(390)	$	(2,090)	$	(30)	$	(2,095)

(a)All significant intercompany transactions have been eliminated in consolidation

Condensed Consolidating Balance Sheets

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING BALANCE SHEETS

December 31, 2019


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc.		Eliminations^(a)		Consolidated Balance
ASSETS
Current Assets
Cash and cash equivalents	$	—	$	20	$	325	$	—	$	345
Funds deposited by counterparties	32		—		—		—		32
Restricted cash	5		1		2		—		8
Accounts receivable, net	1,293		239		233		(740)		1,025
Inventory	272		111		—		—		383
Derivative instruments	856		45		—		(41)		860
Cash collateral posted in support of energy risk management activities	182		8		—		—		190

Prepayments and other current assets	170		8		67		—		245


Total current assets	2,810		432		627		(781)		3,088
Property, plant and equipment, net	1,483		952		158		—		2,593
Other Assets
Investment in subsidiaries	710		—		4,785		(5,495)		—
Equity investments in affiliates	—		388		—		—		388
Operating lease right-of-use assets, net	81		261		122		—		464

Goodwill	359		220		—		—		579
Intangible assets, net	375		414		—		—		789
Nuclear decommissioning trust fund	794		—		—		—		794
Derivative instruments	308		15		—		(13)		310
Deferred income taxes	421		(19)		2,884		—		3,286
Other non-current assets	145		30		65		—		240


Total other assets	3,193		1,309		7,856		(5,508)		6,850
Total Assets	$	7,486	$	2,693	$	8,641	$	(6,289)	$	12,531
LIABILITIES AND STOCKHOLDERS' EQUITY
Current Liabilities
Current portion of long-term debt	$	—	$	5	$	83	$	—	$	88
Current portion of operating lease liabilities	20		32		21		—		73
Accounts payable	918		141		403		(740)		722

Derivative instruments	797		25		—		(41)		781
Cash collateral received in support of energy risk management activities	32		—		—		—		32

Accrued expenses and other current liabilities	280		44		339		—		663



Total current liabilities	2,047		247		846		(781)		2,359
Other Liabilities
Long-term debt	302		28		5,473		—		5,803
Non-current operating lease liabilities	64		301		118		—		483
Nuclear decommissioning reserve	298		—		—		—		298
Nuclear decommissioning trust liability	487		—		—		—		487

Derivative instruments	334		1		—		(13)		322
Deferred income taxes	—		17		—		—		17

Other non-current liabilities	399		153		532		—		1,084


Total other liabilities	1,884		500		6,123		(13)		8,494
Total Liabilities	3,931		747		6,969		(794)		10,853
Redeemable noncontrolling interest in subsidiaries	—		20		—		—		20
Stockholders' Equity	3,555		1,926		1,672		(5,495)		1,658
Total Liabilities and Stockholders' Equity	$	7,486	$	2,693	$	8,641	$	(6,289)	$	12,531

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING BALANCE SHEETS

December 31, 2018


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc.		Eliminations^(a)		Consolidated Balance
ASSETS
Current Assets
Cash and cash equivalents	$	55	$	28	$	480	$	—	$	563
Funds deposited by counterparties	33		—		—		—		33
Restricted cash	7		10		—		—		17
Accounts receivable. net	1,354		115		309		(754)		1,024
Inventory	278		134		—		—		412
Derivative instruments	779		50		16		(81)		764
Cash collateral posted in support of energy risk management activities	275		12		—		—		287

Prepayments and other current assets	180		32		90		—		302
Current assets - held-for-sale	—		1		—		—		1
Current assets - discontinued operations	177		20		—		—		197
Total current assets	3,138		402		895		(835)		3,600
Property, plant and equipment, net	1,938		957		153		—		3,048
Other Assets
Investment in subsidiaries	446		—		4,707		(5,153)		—
Equity investments in affiliates	—		412		—		—		412


Goodwill	359		214		—		—		573
Intangible assets, net	422		169		—		—		591
Nuclear decommissioning trust fund	663		—		—		—		663
Derivative instruments	296		4		22		(5)		317
Deferred income taxes	6		(143)		183		—		46
Other non-current assets	133		71		97		(12)		289
Non-current assets - held-for-sale	—		77		—		—		77
Non-current assets - discontinued operations	405		607		—		—		1,012
Total other assets	2,730		1,411		5,009		(5,170)		3,980
Total Assets	$	7,806	$	2,770	$	6,057	$	(6,005)	$	10,628
LIABILITIES AND STOCKHOLDERS' EQUITY
Current Liabilities
Current portion of long-term debt and finance leases	$	—	$	55	$	17	$	—	$	72

Accounts payable	1,368		(185)		434		(754)		863

Derivative instruments	713		41		—		(81)		673
Cash collateral received in support of energy risk management activities	33		—		—		—		33

Accrued expenses and other current liabilities	291		36		353		—		680

Current liabilities - held-for-sale	—		5		—		—		5
Current liabilities - discontinued operations	24		48		—		—		72
Total current liabilities	2,429		—		804		(835)		2,398
Other Liabilities
Long-term debt and finance leases	244		192		6,025		(12)		6,449

Nuclear decommissioning reserve	282		—		—		—		282
Nuclear decommissioning trust liability	371		—		—		—		371

Derivative instruments	306		3		—		(5)		304
Deferred income taxes	112		61		(108)		—		65

Other non-current liabilities	402		320		552		—		1,274
Non-current liabilities - held-for-sale	—		65		—		—		65
Non-current liabilities - discontinued operations	58		577		—		—		635
Total other liabilities	1,775		1,218		6,469		(17)		9,445
Total Liabilities	4,204		1,218		7,273		(852)		11,843
Redeemable noncontrolling interest in subsidiaries	—		19		—		—		19
Stockholders' Equity	3,602		1,533		(1,216)		(5,153)		(1,234)
Total Liabilities and Stockholders' Equity	$	7,806	$	2,770	$	6,057	$	(6,005)	$	10,628

(a)All significant intercompany transactions have been eliminated in consolidation

Condensed Consolidating Statements of Cash Flows

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS

For the Year Ended December 31, 2019


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Cash Flows from Operating Activities
Net income	$	1,493	$	120	$	4,438	$	(1,610)	$	4,441
Income from discontinued operations	9		5		307		—		321
Net income from continuing operations	1,484		115		4,131		(1,610)		4,120
Adjustments to reconcile net income to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries	(48)		14		(1,562)		1,610		14
Depreciation and amortization	212		130		31		—		373
Accretion of asset retirement obligations	43		8		—		—		51
Provision for bad debts	78		17		—		—		95
Amortization of nuclear fuel	52		—		—		—		52
Amortization of financing costs and debt discount/premiums	—		—		26		—		26
Adjustment for debt extinguishment	—		3		48		—		51
Amortization of emission allowances	24		14		—		—		38
Amortization of unearned equity compensation	—		—		20		—		20
Net gain on sale and disposal of assets	(20)		—		(3)		—		(23)
Impairment losses	1		105		7		—		113
Changes in derivative instruments	20		(24)		38		—		34
Changes in deferred income taxes and liability for uncertain tax benefits	(525)		(168)		(2,660)		—		(3,353)
Changes in collateral deposits in support of energy risk management activities	101		4		—		—		105

Changes in nuclear decommissioning trust liability	37		—		—		—		37


Changes in other working capital	(220)		(118)		(10)		—		(348)
Cash provided by continuing operations	1,239		100		66		—		1,405
Cash provided/(used) by discontinued operations	17		(9)		—		—		8
Net Cash Provided by Operating Activities	1,256		91		66		—		1,413
Cash Flows from Investing Activities


Intercompany dividends	—		—		2,513		(2,513)		—
Payments for acquisitions of businesses	(355)		—		—		—		(355)
Capital expenditures	(164)		(27)		(37)		—		(228)


Net proceeds from sale of emission allowances	11		—		—		—		11
Investments in nuclear decommissioning trust fund securities	(416)		—		—		—		(416)
Proceeds from sales of nuclear decommissioning trust fund securities	381		—		—		—		381
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	1		400		893		—		1,294

Changes in investments in unconsolidated affiliates	—		(91)		—		—		(91)
Net contributions to discontinued operations	—		(44)		—		—		(44)
Other	—		—		6		—		6
Cash (used)/provided by continuing operations	(542)		238		3,375		(2,513)		558
Cash used by discontinued operations	—		(2)		—		—		(2)
Net Cash (Used)/Provided by Investing Activities	(542)		236		3,375		(2,513)		556
Cash Flows from Financing Activities



Intercompany dividends and transfers	(751)		(214)		(1,548)		2,513		—
Payments of dividends to common stockholders	—		—		(32)		—		(32)
Payments for share repurchase activity	—		—		(1,440)		—		(1,440)

Payments for debt extinguishment costs	—		—		(26)		—		(26)
Net distributions to redeemable noncontrolling interests from subsidiaries	—		(2)		—		—		(2)
Proceeds from issuance of common stock	—		—		3		—		3
Proceeds from issuance of long-term debt	—		—		1,916		—		1,916
Payments of debt issuance costs	—		—		(35)		—		(35)
Payments for short and long-term debt	—		(139)		(2,432)		—		(2,571)

Other	(4)		—		—		—		(4)
Cash used by continuing operations	(755)		(355)		(3,594)		2,513		(2,191)
Cash provided by discontinued operations	—		43		—		—		43
Net Cash Used by Financing Activities	(755)		(312)		(3,594)		2,513		(2,148)

Change in cash from discontinued operations	17		32		—		—		49
Net Decrease in Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties	(58)		(17)		(153)		—		(228)
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at Beginning of Period	95		38		480		—		613
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at End of Period	$	37	$	21	$	327	$	—	$	385

(a)All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS

For the Year Ended December 31, 2018


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Cash Flows from Operating Activities
Net income	$	997	$	136	$	374	$	(1,239)	$	268
Income/(loss) from discontinued operations	62		75		(329)		—		(192)
Net income from continuing operations	935		61		703		(1,239)		460
Adjustments to reconcile net income to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries	(23)		47		(1,231)		1,253		46
Depreciation and amortization	238		150		33		—		421
Accretion of asset retirement obligations	28		10		—		—		38
Provision for bad debts	79		6		—		—		85
Amortization of nuclear fuel	48		—		—		—		48
Amortization of financing costs and debt discount/premiums	—		6		23		—		29
Adjustment for debt extinguishment	—		—		44		—		44
Amortization of emission allowances and out-of-market contracts	36		9		—		—		45
Amortization of unearned equity compensation	—		—		25		—		25
Net (gain)/loss on sale and disposal of assets	(30)		(20)		1		—		(49)
Impairment losses	5		109		—		—		114
Changes in derivative instruments	25		15		11		(14)		37
Changes in deferred income taxes and liability for uncertain tax benefits	372		5		(372)		—		5
Changes in collateral deposits in support of energy risk management activities	(94)		(11)		—		—		(105)

Changes in nuclear decommissioning trust liability	60		—		—		—		60
GenOn settlement, net of insurance proceeds	—		—		(63)		—		(63)
Net loss on deconsolidation of Agua Caliente and Ivanpah projects	—		13		—		—		13
Changes in other working capital	(100)		(166)		16		—		(250)
Cash provided/(used) by continuing operations	1,579		234		(810)		—		1,003
Cash provided by discontinued operations	89		285		—		—		374
Net Cash Provided/(Used) by Operating Activities	1,668		519		(810)		—		1,377
Cash Flows from Investing Activities


Intercompany dividends	—		—		2,006		(2,006)		—
Payments for acquisitions of businesses	(40)		(203)		—		—		(243)
Capital expenditures	(192)		(151)		(45)		—		(388)


Net proceeds from sale of emission allowances	19		—		—		—		19
Investments in nuclear decommissioning trust fund securities	(572)		—		—		—		(572)
Proceeds from sales of nuclear decommissioning trust fund securities	513		—		—		—		513
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	14		8		1,542		—		1,564
Deconsolidation of Agua Caliente and Ivanpah projects	—		(268)		—		—		(268)
Changes in investments in unconsolidated affiliates	—		(39)		—		—		(39)
Net contributions to discontinued operations	—		(60)		—		—		(60)
Other	—		—		(6)		—		(6)
Cash (used)/provided by continuing operations	(258)		(713)		3,497		(2,006)		520
Cash used by discontinued operations	—		(725)		—		—		(725)
Net Cash (Used)/Provided by Investing Activities	(258)		(1,438)		3,497		(2,006)		(205)
Cash Flows from Financing Activities



Intercompany dividends and transfers	(1,267)		86		(825)		2,006		—
Payments of dividends to common stockholders	—		—		(37)		—		(37)
Payments for treasury stock	—		—		(1,250)		—		(1,250)

Payments for debt extinguishment costs	—		—		(32)		—		(32)
Net distributions to noncontrolling interests from subsidiaries	—		(16)		—		—		(16)
Proceeds from issuance of common stock	—		—		21		—		21
Proceeds from issuance of long-term debt	—		163		937		—		1,100
Payments of debt issuance costs	—		—		(19)		—		(19)
Payments for short and long-term debt	—		(138)		(1,596)		—		(1,734)
Receivable from affiliate	—		—		(26)		—		(26)
Other	—		(4)		—		—		(4)
Cash (used)/provided by continuing operations	(1,267)		91		(2,827)		2,006		(1,997)
Cash provided by discontinued operations	—		471		—		—		471
Net Cash (Used)/Provided by Financing Activities	(1,267)		562		(2,827)		2,006		(1,526)
Effect of exchange rate changes on cash and cash equivalents	—		1		—		—		1
Change in cash from discontinued operations	89		31		—		—		120
Net Increase/(Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties	54		(387)		(140)		—		(473)
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at Beginning of Period	41		425		620		—		1,086
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at End of Period	$	95	$	38	$	480	$	—	$	613

(a) All significant intercompany transactions have been eliminated in consolidation

NRG ENERGY, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS

For the Year Ended December 31, 2017


(In millions)	Guarantor Subsidiaries		Non-Guarantor Subsidiaries		NRG Energy, Inc. (Note Issuer)		Eliminations^(a)		Consolidated Balance
Cash Flows from Operating Activities
Net income/(loss)	$	421	$	(543)	$	(2,169)	$	(46)	$	(2,337)
Income/(loss) from discontinued operations	91		(420)		(663)		—		(992)
Net income/(loss) from continuing operations	330		(123)		(1,506)		(46)		(1,345)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries	(18)		12		60		48		102
Depreciation and amortization	343		221		32		—		596
Accretion of asset retirement obligations	37		7		—		—		44
Provision for bad debts	56		—		12		—		68
Amortization of nuclear fuel	51		—		—		—		51
Amortization of financing costs and debt discount/premiums	—		13		16		—		29
Adjustment for debt extinguishment	—		—		49		—		49
Amortization of emission allowances and out-of-market contracts	42		12		—		—		54
Amortization of unearned equity compensation	—		—		35		—		35
Net loss/(gain) on sale and disposal of assets	2		(11)		—		—		(9)
Impairment losses	1,346		264		4		—		1,614
Changes in derivative instruments	(214)		50		(4)		(2)		(170)
Changes in deferred income taxes and liability for uncertain tax benefits	(300)		(9)		322		—		13
Changes in collateral deposits in support of energy risk management activities	(98)		18		—		—		(80)

Changes in nuclear decommissioning trust liability	11		—		—		—		11


Changes in other working capital	(15)		(396)		205		—		(206)
Cash provided/(used) by continuing operations	1,573		58		(775)		—		856
Cash provided by discontinued operations	116		638		—		—		754
Net Cash Provided/(Used) by Operating Activities	1,689		696		(775)		—		1,610
Cash Flows from Investing Activities

Intercompany dividends	—		—		1,665		(1,665)		—

Payments for acquisitions of businesses	(14)		—		—		—		(14)
Capital expenditures	(180)		(43)		(31)		—		(254)


Net proceeds from sale of emission allowances	66		—		—		—		66
Investments in nuclear decommissioning trust fund securities	(512)		—		—		—		(512)
Proceeds from sales of nuclear decommissioning trust fund securities	501		—		—		—		501
Proceeds from sale of assets, net of cash disposed	33		54		343		—		430
Changes in investments in unconsolidated affiliates	—		(57)		—		—		(57)
Net distributions from discontinued operations	—		—		150		—		150
Other	18		12		—		—		30
Cash (used)/provided by continuing operations	(88)		(34)		2,127		(1,665)		340
Cash used by discontinued operations	(13)		(966)		—		—		(979)
Net Cash (Used)/Provided by Investing Activities	(101)		(1,000)		2,127		(1,665)		(639)
Cash Flows from Financing Activities

Intercompany dividends and transfers	(1,447)		(4)		(214)		1,665		—


Payment of dividends to common stockholders	—		—		(38)		—		(38)



Payments for debt extinguishment costs	—		—		(42)		—		(42)
Net distributions to noncontrolling interests from subsidiaries	—		(30)		—		—		(30)
Payments for issuance of common stock	—		—		(2)		—		(2)
Proceeds from issuance of long-term debt	—		94		1,084		—		1,178
Payment of debt issuance costs	—		(2)		(16)		—		(18)
Payments for short and long-term debt	—		(183)		(1,701)		—		(1,884)
Receivable from affiliate	—		—		(125)		—		(125)
Other	—		(8)		—		—		(8)
Cash used by continuing operations	(1,447)		(133)		(1,054)		1,665		(969)
Cash used by discontinued operations	(109)		(60)		—		—		(169)
Net Cash Used by Financing Activities	(1,556)		(193)		(1,054)		1,665		(1,138)
Effect of exchange rate changes on cash and cash equivalents	—		(1)		—		—		(1)
Change in cash from discontinued operations	(6)		(388)		—		—		(394)
Net Increase/(Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties	38		(110)		298		—		226
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at Beginning of Period	3		535		322		—		860
Cash and Cash Equivalents, Restricted Cash, and Funds Deposited by Counterparties at End of Period	$	41	$	425	$	620	$	—	$	1,086

(a) All significant intercompany transactions have been eliminated in consolidation

Nature of Business (Details) MW in Thousands	Dec. 31, 2019 MW
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Generation capacity (in MW)	23

Summary of Significant Accounting Policies - Net Income/(Loss) Attributable to Continuing and Discontinued Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Income/(loss) from continuing operations, net of income tax	$ 4,117	$ 465	$ (977)
Income/(loss) from discontinued operations, net of income tax	321	(197)	(1,176)
Net Income/(Loss) Attributable to NRG Energy, Inc.	$ 4,438	$ 268	$ (2,153)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Summary of Significant Accounting Policies - Additional (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Funds Deposited by Counterparties
Number of months beyond which company can not predict the holding of collateral (in months)	12 months
Accounts Receivable, Net [Abstract]
Allowance for doubtful accounts	$ 43	$ 32
Project Development Costs and Capitalized Interest
Amount of interest capitalized	3	7	$ 20
Finite-Lived Intangible Assets, Net [Abstract]
Intangible assets, accumulated amortization	$ 1,262	1,151
Lease Revenue
Lease term	20 years
Lessor Accounting
Operating lease income	$ 20	21
Contingent rental income	5	104	253
Gross Receipts and Sales Taxes
Gross Receipts Tax	109	99	92
Cost of Energy for Retail Operations
Transmission and distribution charges not yet billed	103	105	107
Foreign Currency Translation and Transaction Gains and Losses
Cumulative translation adjustment	(13)	(13)	(2)
Marketing and Advertising Expense
Advertising expense	66	73	66
Reorganization Costs
Reorganization costs	23	$ 90	$ 44
Operating lease right-of-use assets, net	464			$ 404
Operating lease liability	$ 556			$ 321
South Texas Project
Property, Plant and Equipment
Ownership Interest (as a percent)	44.00%

Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 345	$ 563	$ 770
Funds deposited by counterparties	32	33	37
Restricted cash	8	17	279
Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statements of cash flows	$ 385	$ 613	$ 1,086	$ 860

Summary of Significant Accounting Policies - Redeemable Non Controlling Interest (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 19	$ 78	$ 46
Distributions to redeemable noncontrolling interest		(43)	(65)
Contributions from redeemable noncontrolling interest		26	99
Comprehensive loss attributable to redeemable noncontrolling interest	3	1	(72)
Net loss attributable to redeemable noncontrolling interest - discontinued operations		(27)
Sale of NRG Yield and the Renewables Platform		(2,548)
Balance at end of period	20	19	78
NRG Yield Inc. And Zephyr Renewables
Noncontrolling Interest [Roll Forward]
Sale of NRG Yield and the Renewables Platform		(48)
Redeemable noncontrolling interest
Noncontrolling Interest [Roll Forward]
Distributions to redeemable noncontrolling interest	$ (2)	(3)	(2)
Non-cash adjustments to redeemable noncontrolling interest		$ (8)	$ 7

Revenue Recognition - Adoption of ASC 606 (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ (1,616)	$ (6,022)
ASU 2014-09 \| Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit			$ 15

Revenue Recognition - Capacity Revenue (Details) $ in Millions	Dec. 31, 2019 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Estimated future fixed fee performance obligation	$ 564
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Estimated future fixed fee performance obligation	$ 604
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Estimated future fixed fee performance obligation	$ 303
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from Contract with Customer [Abstract]
Estimated future fixed fee performance obligation	$ 42
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue from Contract with Customer [Abstract]
Estimated future fixed fee performance obligation	$ 8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period	1 year

Revenue Recognition - Disaggregated Revenues (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									$ 7,991	$ 8,148
Mark-to-market for economic hedging activities									(20)	14	$ 206
Revenues	$ 2,195	$ 2,996	$ 2,465	$ 2,165	$ 1,992	$ 2,960	$ 2,461	$ 2,065	9,821	9,478	9,074
Less: Lease revenue									20	21
Derivative revenue									0	31	195
Retail Revenue \| Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									6,254	5,591
Retail Revenue \| Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									1,279	1,303
Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									7,533	6,894
Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									1,169	1,496
Derivative revenue									1,595	1,233
Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									700	825
Derivative revenue									109	137
Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities									33	(130)
Derivative revenue									1,810	1,309
Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									386	393
Total operating revenues
Disaggregation of Revenue [Line Items]
Revenues									9,821	9,478
Other derivative revenue
Disaggregation of Revenue [Line Items]
Derivative revenue									73	69
Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									(5)	(19)
Revenues									(7)	(18)	(47)
Less: Lease revenue									0	0
Corporate/Eliminations \| Retail Revenue \| Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									(3)	(1)
Corporate/Eliminations \| Retail Revenue \| Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									0	0
Corporate/Eliminations \| Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									(3)	(1)
Corporate/Eliminations \| Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									0	13
Derivative revenue									(1)	14
Corporate/Eliminations \| Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									0	0
Derivative revenue									0	0
Corporate/Eliminations \| Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities									(1)	(13)
Derivative revenue									(2)	1
Corporate/Eliminations \| Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									(3)	(17)
Corporate/Eliminations \| Total operating revenues
Disaggregation of Revenue [Line Items]
Revenues									(7)	(18)
Corporate/Eliminations \| Other derivative revenue
Disaggregation of Revenue [Line Items]
Derivative revenue									0	1
Texas \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									5,507	5,304
Revenues									7,069	6,401	6,318
Less: Lease revenue									0	1
Texas \| Operating Segments \| Retail Revenue \| Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									5,027	4,618
Texas \| Operating Segments \| Retail Revenue \| Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									1,205	1,238
Texas \| Operating Segments \| Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									6,232	5,856
Texas \| Operating Segments \| Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									529	371
Derivative revenue									1,459	1,131
Texas \| Operating Segments \| Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									0	0
Derivative revenue									0	0
Texas \| Operating Segments \| Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities									47	(77)
Derivative revenue									1,562	1,096
Texas \| Operating Segments \| Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									261	251
Texas \| Operating Segments \| Total operating revenues
Disaggregation of Revenue [Line Items]
Revenues									7,069	6,401
Texas \| Operating Segments \| Other derivative revenue
Disaggregation of Revenue [Line Items]
Derivative revenue									56	42
Texas \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenues									(1)	(19)	(41)
East \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									2,135	2,160
Revenues									2,319	2,371	2,009
Less: Lease revenue									1	1
East \| Operating Segments \| Retail Revenue \| Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									1,230	974
East \| Operating Segments \| Retail Revenue \| Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									74	65
East \| Operating Segments \| Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									1,304	1,039
East \| Operating Segments \| Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									322	546
Derivative revenue									98	90
East \| Operating Segments \| Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									664	746
Derivative revenue									109	137
East \| Operating Segments \| Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities									(29)	(35)
Derivative revenue									183	210
East \| Operating Segments \| Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									58	75
East \| Operating Segments \| Total operating revenues
Disaggregation of Revenue [Line Items]
Revenues									2,319	2,371
East \| Operating Segments \| Other derivative revenue
Disaggregation of Revenue [Line Items]
Derivative revenue									5	17
East \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenues									(8)	5	(1)
West/Other \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									354	703
Revenues									440	724	788
Less: Lease revenue									19	19
West/Other \| Operating Segments \| Retail Revenue \| Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									0	0
West/Other \| Operating Segments \| Retail Revenue \| Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									0	0
West/Other \| Operating Segments \| Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									0	0
West/Other \| Operating Segments \| Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									318	566
Derivative revenue									39	(2)
West/Other \| Operating Segments \| Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									36	79
Derivative revenue									0	0
West/Other \| Operating Segments \| Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities									16	(5)
Derivative revenue									67	2
West/Other \| Operating Segments \| Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer									70	84
West/Other \| Operating Segments \| Total operating revenues
Disaggregation of Revenue [Line Items]
Revenues									440	724
West/Other \| Operating Segments \| Other derivative revenue
Disaggregation of Revenue [Line Items]
Derivative revenue									12	9
West/Other \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenues									$ 2	$ (4)	$ 4

Revenue Recognition - Contract Balances (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Contract Assets And Liabilities [Line Items]
Deferred customer acquisition costs	$ 133	$ 111
Accounts receivable, net	1,025	1,024
Unbilled revenues (included within Accounts receivable, net - Contracts with customers)	402	392
Deferred revenue	82	67
Deferred revenue from contract with customers	24	19
Revenue recognized	13	16
Accounts receivable, net - Contracts with customers
Schedule Of Contract Assets And Liabilities [Line Items]
Accounts receivable, net	1,002	999
Accounts receivable, net - Derivative instruments
Schedule Of Contract Assets And Liabilities [Line Items]
Accounts receivable, net	18	20
Accounts receivable, net - Affiliate
Schedule Of Contract Assets And Liabilities [Line Items]
Accounts receivable, net	$ 5	$ 5

Acquisitions, Discontinued Operations and Dispositions - Acquisitions (Details) customer in Thousands, $ in Millions			12 Months Ended
	Aug. 01, 2019 USD ($) state customer	Jun. 01, 2018 USD ($) state customer	Dec. 31, 2019 USD ($) customer	Dec. 31, 2018 USD ($) customer	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Goodwill			$ 579	$ 573
Stream Energy
Business Acquisition [Line Items]
Number of states in which the entity operates \| state	9
Purchase price	$ 329
Working capital adjustments	$ 29
Residential customer equivalents acquired \| customer	600
Customers acquired \| customer	450
Account receivable	$ 98
Accounts payable	(73)
Other net current and non-current working capital	5
Goodwill	6
Stream Energy \| Texas
Business Acquisition [Line Items]
Goodwill	5
Stream Energy \| East
Business Acquisition [Line Items]
Goodwill	1
Stream Energy \| Marketing Partnerships
Business Acquisition [Line Items]
Intangible assets	154
Stream Energy \| Customer Relationships
Business Acquisition [Line Items]
Intangible assets	85
Stream Energy \| Trade Names
Business Acquisition [Line Items]
Intangible assets	28
Stream Energy \| Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets	$ 26
XOOM Energy, LLC
Business Acquisition [Line Items]
Number of states in which the entity operates \| state		19
Purchase price		$ 213
Working capital adjustments		$ 48
Residential customer equivalents acquired \| customer		395
Customers acquired \| customer		300
Other net current and non-current working capital		$ 46
Intangible assets		133
Goodwill		34
XOOM Energy, LLC \| Texas
Business Acquisition [Line Items]
Goodwill		28
XOOM Energy, LLC \| East
Business Acquisition [Line Items]
Goodwill		$ 6
Small Book Acquisitions 2019
Business Acquisition [Line Items]
Purchase price			$ 17
Customers acquired \| customer			72
Cash paid to acquire business			$ 13		$ 2
Small Book Acquisitions 2018
Business Acquisition [Line Items]
Purchase price				$ 44
Customers acquired \| customer				115
Cash paid to acquire business			$ 2	$ 40

Acquisitions, Discontinued Operations and Dispositions - Discontinued Operations (Details) $ in Millions	Feb. 06, 2018 USD ($) extension	Dec. 31, 2019 USD ($) MW	Feb. 04, 2019 USD ($) MW	Dec. 31, 2018 USD ($)	Aug. 31, 2018 USD ($)	Mar. 30, 2018 USD ($) MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Generation capacity (in MW) \| MW		23,000
Buckthorn Renewables, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration						$ 42
Generation capacity (in MW) \| MW						154
Discontinued Operations \| South Central Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration			$ 1,000
Generation capacity (in MW) \| MW			1,153
Discontinued Operations \| NRG Yield Inc. And Zephyr Renewables
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration					$ 1,348
Discontinued Operations \| NRG Yield Inc. And Zephyr Renewables \| Cost To Complete Construction
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other commitment		$ 15
Discontinued Operations \| NRG Yield Inc. And Zephyr Renewables \| Property Taxes For Solar Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other commitment		22
Discontinued Operations \| Carlsbad Energy Holdings LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration	$ 385
Other commitment		$ 23		$ 23
Membership percentage	100.00%
Lease and easement agreement, number of extensions \| extension	2
Renewal term	10 years

Acquisitions, Discontinued Operations and Dispositions - Major Classes of Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets - discontinued operations	$ 0	$ 197
Non-current assets - discontinued operations	0	1,012
Current liabilities - discontinued operations	0	72
Other non-current liabilities		65
Non-current liabilities - discontinued operations	$ 0	635
South Central Portfolio \| Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents		89
Accounts receivable, net		49
Inventory		35
Other current assets		5
Current assets - discontinued operations		178
Property, plant and equipment, net		408
Other non-current assets		1
Non-current assets - discontinued operations		409
Accounts payable		19
Other current liabilities		5
Current liabilities - discontinued operations		24
Out-of-market contracts, net		50
Other non-current liabilities		11
Non-current liabilities - discontinued operations		61
Carlsbad Energy Holdings LLC \| Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restricted Cash		4
Accounts receivable, net		10
Other current assets		5
Current assets - discontinued operations		19
Property, plant and equipment, net		590
Intangible assets, net		9
Other non-current assets		4
Non-current assets - discontinued operations		603
Current portion of long term debt and capital leases		20
Accounts payable		27
Other current liabilities		1
Current liabilities - discontinued operations		48
Long-term debt and capital leases		572
Other non-current liabilities		2
Non-current liabilities - discontinued operations		$ 574

Acquisitions, Discontinued Operations and Dispositions - Summary of Results (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(loss) on disposal of discontinued operations, net of tax									$ 0	$ (13)	$ 0
Income/(loss) from discontinued operations, net of income tax	$ (78)	$ (2)	$ 13	$ 388	$ 80	$ (336)	$ 69	$ (5)	321	(192)	(992)
Discontinued Operations \| South Central Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenue									31	410	422
Operating costs and expenses									(23)	(346)	(335)
Other income									0	2	0
(Loss)/gain from operations of discontinued components, before tax									8	66	87
(Loss)/income on disposal of discontinued operations, net of tax									20	0	0
Income/(loss) from discontinued operations, net of income tax									28	66	87
Discontinued Operations \| Carlsbad Energy Holdings LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenue									19	909	1,164
Operating costs and expenses									(9)	(661)	(1,114)
Other expenses									(5)	(174)	(288)
(Loss)/gain from operations of discontinued components, before tax									5	74	(238)
Income tax expense									0	4	52
Income/(loss) from discontinued operations, net of tax									5	70	(290)
Gain/(loss) on disposal of discontinued operations, net of tax									265	(134)	0
Income/(expense) from California property tax indemnification									22	(153)	0
Income/(expense) from other commitments, indemnification and fees									4	(75)	0
(Loss)/income on disposal of discontinued operations, net of tax									291	(362)	0
Income/(loss) from discontinued operations, net of income tax									296	(292)	(290)
Discontinued Operations \| GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenue									0	0	646
Operating costs and expenses									0	0	(702)
Other expenses									0	0	(98)
(Loss)/gain from operations of discontinued components, before tax									0	0	(154)
Income tax expense									0	0	9
(Loss)/gain from discontinued operations									0	0	(163)
Interest income-affiliate									0	3	8
Income/(loss) from discontinued operations, net of tax									0	3	(155)
Gain/(loss) on disposal of discontinued operations, net of tax									0	0	(208)
Settlement consideration, insurance and services credit									0	63	(289)
Pension and post-retirement liability assumptions									0	21	(131)
Income/(expense) from other commitments, indemnification and fees									(3)	(53)	(6)
(Loss)/income on disposal of discontinued operations, net of tax									(3)	31	(634)
Income/(loss) from discontinued operations, net of income tax									$ (3)	$ 34	$ (789)

Acquisitions, Discontinued Operations and Dispositions - Sale of Assets Prior to Discontinued (Details) $ in Millions	Dec. 31, 2019 MW	Jan. 11, 2019 USD ($)	Jun. 19, 2018 USD ($)	Mar. 30, 2018 USD ($) MW	Mar. 27, 2017 USD ($) utility_scale_solar_project MW
Business Acquisition [Line Items]
Generation capacity (in MW) \| MW	23,000
UPMC Thermal Project
Business Acquisition [Line Items]
Cash consideration		$ 3	$ 84
Buckthorn Renewables, LLC
Business Acquisition [Line Items]
Cash consideration				$ 42
Percentage of ownership sold				10000.00%
Generation capacity (in MW) \| MW				154
Debt assumed				$ 183
Agua Caliente Solar Project
Business Acquisition [Line Items]
Cash consideration					$ 130
Debt assumed					328
Working capital adjustments					$ 1
Agua Caliente Solar Project \| Agua Caliente
Business Acquisition [Line Items]
Percentage of ownership sold					16.00%
Generation capacity (in MW) \| MW					46
Agua Caliente Solar Project \| Utah Portfolio
Business Acquisition [Line Items]
Generation capacity (in MW) \| MW					265
Number Of utility scale solar projects \| utility_scale_solar_project					7

Acquisitions, Discontinued Operations and Dispositions - GenOn Settlement and Plan Confirmation (Details) - USD ($) $ in Millions			1 Months Ended
	Jul. 16, 2018	Apr. 27, 2018	Dec. 31, 2017	Dec. 14, 2018
GenOn Mid-Atlantic \| Restructuring Support Agreement \| Letter of Credit \| Intercompany Credit Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Letters of credit facility		$ 38
Services Agreement \| GenOn \| Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Collateral posted	$ 15
GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Settlement consideration	261
Deduction for GenOn tax losses				$ 9,500
Professional fees		$ 6
GenOn \| Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Settlement payment	125
GenOn \| Services Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Credit applied			$ 28
GenOn \| Services Agreement \| Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Credit applied	28
Remaining payments and other balances due under settlement agreement	10
GenOn \| Revolving Credit Facility Borrowings \| Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Intercompany secured revolving credit facility and accrued interest and fees	151
GenOn \| Accrued Interest On Borrowings \| Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Intercompany secured revolving credit facility and accrued interest and fees	12
GenOn \| Reduction Of Settlement Payment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Remaining payments and other balances due under settlement agreement	4
GenOn \| Assignment Of Historical Claims Against REMA
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Remaining payments and other balances due under settlement agreement	8
GenOn \| Other \| Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Remaining payments and other balances due under settlement agreement	$ 2

Acquisitions, Discontinued Operations and Dispositions - Dispositions (Details) - USD ($) $ in Millions				12 Months Ended
	Aug. 01, 2018	Jun. 29, 2018	Jun. 28, 2018	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Parent guarantee				$ 2,010	$ 2,767
Other guarantees
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Parent guarantee				288	721
BETM \| Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of ownership sold	100.00%
Proceeds from sale of businesses, net of working capital adjustments	$ 71
Gain on sale of business	15
Cash collateral	4
BETM \| Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations \| Letter of Credit
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Parent guarantee	119
BETM \| Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations \| Other guarantees
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Parent guarantee	$ 32
Canal Three \| Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business		$ 17
Cash received		$ 16
Cash proceeds			$ 167
Proceeds distributed to Company			$ 151
Other \| Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash received				$ 22	$ 28

Fair Value of Financial Instruments - Estimated Carrying Amounts of Fair Value of Financial Instruments not Carried at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Liabilities
Long-term Debt	$ 6,042	$ 6,691
Level 2
Debt, Long-term and Short-term, Combined Amount [Abstract]
Long-term debt, including current portion	6,388	6,528
Level 3
Debt, Long-term and Short-term, Combined Amount [Abstract]
Long-term debt, including current portion	116	169
Carrying Amount
Assets
Notes receivable	11	17
Liabilities
Long-term Debt	5,956	6,591
Fair Value
Assets
Notes receivable	8	14
Liabilities
Long-term Debt	$ 6,504	$ 6,697

Fair Value of Financial Instruments - Assets and Liabilities Measured and Recorded at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in securities (classified within other current and non-current assets)	$ 20	$ 39
Other trust fund investments:
Other trust fund investments	1	1
Measured using net asset value practical expedient:
Total assets	1,993	1,792
Derivative liabilities:
Total liabilities	1,103	977
Commodity contracts
Derivative assets:
Derivative assets	1,170	1,042
Derivative liabilities:
Commodity contracts	1,103	977
Interest rate contracts
Derivative assets:
Derivative assets		39
Cash and cash equivalents
Nuclear trust fund investments:
Nuclear trust fund investments	17	19
U.S. government and federal agency obligations
Nuclear trust fund investments:
Nuclear trust fund investments	68	46
Federal agency mortgage-backed securities
Nuclear trust fund investments:
Nuclear trust fund investments	100	100
Commercial mortgage-backed securities
Nuclear trust fund investments:
Nuclear trust fund investments	29	22
Corporate debt securities
Nuclear trust fund investments:
Nuclear trust fund investments	109	96
Equity securities
Nuclear trust fund investments:
Nuclear trust fund investments	388	312
Measured using net asset value practical expedient:
Equity contracts	8	8
Foreign government fixed income securities
Nuclear trust fund investments:
Nuclear trust fund investments	5	4
Equity securities-nuclear trust fund investments
Measured using net asset value practical expedient:
Equity contracts	78	64
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in securities (classified within other current and non-current assets)	0	2
Other trust fund investments:
Other trust fund investments	1	1
Measured using net asset value practical expedient:
Total assets	558	517
Derivative liabilities:
Total liabilities	143	224
Level 1 \| Commodity contracts
Derivative assets:
Derivative assets	84	137
Derivative liabilities:
Commodity contracts	143	224
Level 1 \| Interest rate contracts
Derivative assets:
Derivative assets		0
Level 1 \| Cash and cash equivalents
Nuclear trust fund investments:
Nuclear trust fund investments	17	19
Level 1 \| U.S. government and federal agency obligations
Nuclear trust fund investments:
Nuclear trust fund investments	68	46
Level 1 \| Federal agency mortgage-backed securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 1 \| Commercial mortgage-backed securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 1 \| Corporate debt securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 1 \| Equity securities
Nuclear trust fund investments:
Nuclear trust fund investments	388	312
Measured using net asset value practical expedient:
Equity contracts	0	0
Level 1 \| Foreign government fixed income securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 1 \| Equity securities-nuclear trust fund investments
Measured using net asset value practical expedient:
Equity contracts	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in securities (classified within other current and non-current assets)	20	18
Other trust fund investments:
Other trust fund investments	0	0
Measured using net asset value practical expedient:
Total assets	1,156	1,075
Derivative liabilities:
Total liabilities	805	664
Level 2 \| Commodity contracts
Derivative assets:
Derivative assets	893	796
Derivative liabilities:
Commodity contracts	805	664
Level 2 \| Interest rate contracts
Derivative assets:
Derivative assets		39
Level 2 \| Cash and cash equivalents
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 2 \| U.S. government and federal agency obligations
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 2 \| Federal agency mortgage-backed securities
Nuclear trust fund investments:
Nuclear trust fund investments	100	100
Level 2 \| Commercial mortgage-backed securities
Nuclear trust fund investments:
Nuclear trust fund investments	29	22
Level 2 \| Corporate debt securities
Nuclear trust fund investments:
Nuclear trust fund investments	109	96
Level 2 \| Equity securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Measured using net asset value practical expedient:
Equity contracts	0	0
Level 2 \| Foreign government fixed income securities
Nuclear trust fund investments:
Nuclear trust fund investments	5	4
Level 2 \| Equity securities-nuclear trust fund investments
Measured using net asset value practical expedient:
Equity contracts	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in securities (classified within other current and non-current assets)	0	19
Other trust fund investments:
Other trust fund investments	0	0
Measured using net asset value practical expedient:
Total assets	193	128
Derivative liabilities:
Total liabilities	155	89
Level 3 \| Commodity contracts
Derivative assets:
Derivative assets	193	109
Derivative liabilities:
Commodity contracts	155	89
Level 3 \| Interest rate contracts
Derivative assets:
Derivative assets		0
Level 3 \| Cash and cash equivalents
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 3 \| U.S. government and federal agency obligations
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 3 \| Federal agency mortgage-backed securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 3 \| Commercial mortgage-backed securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 3 \| Corporate debt securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 3 \| Equity securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Measured using net asset value practical expedient:
Equity contracts	0	0
Level 3 \| Foreign government fixed income securities
Nuclear trust fund investments:
Nuclear trust fund investments	0	0
Level 3 \| Equity securities-nuclear trust fund investments
Measured using net asset value practical expedient:
Equity contracts	$ 0	$ 0

Fair Value of Financial Instruments - Reconciliation of Level 3 Financial Instruments (Details) - Level 3 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 39	$ 4
Contracts added from acquisitions	(3)	12
Included in earnings
Included in earnings	(26)	(21)
Included in OCI	0
Purchases	40	41
Sale	(19)
Transfers into Level 3	2	5
Transfers out of Level 3	5	(2)
Ending balance	38	39
Gains (Losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held at the end of period	17	(17)
Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	19	19
Contracts added from acquisitions	0	0
Included in earnings
Included in earnings	0	0
Included in OCI	0
Purchases	0	0
Sale	(19)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	0	19
Gains (Losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held at the end of period	0	0
Derivative
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	20	(15)
Contracts added from acquisitions	(3)	12
Included in earnings
Included in earnings	(26)	(21)
Included in OCI	0
Purchases	40	41
Sale	0
Transfers into Level 3	2	5
Transfers out of Level 3	5	(2)
Ending balance	38	20
Gains (Losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held at the end of period	$ 17	$ (17)

Fair Value of Financial Instruments - Derivative Fair Value Measurements Narrative (Details)	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Total derivative assets valued with prices provided by models and other valuation techniques percentage	16.00%
Total derivative liabilities valued with prices provided by models and other valuation techniques, percentage	14.00%

Fair Value of Financial Instruments - Derivative Fair Value Measurement (Details) $ in Millions	Dec. 31, 2019 USD ($) $ / MWh	Dec. 31, 2018 USD ($) $ / MWh
Fair Value Measurement Inputs and Valuation Techniques [Abstract
Cash collateral posted in support of energy risk management activities	$ 190	$ 287
Cash collateral received in support of energy risk management activities	32	33
Commodity contracts
Assets
Derivative assets	1,170	1,042
Liabilities
Commodity contracts	1,103	977
Fair Value Measurement Inputs and Valuation Techniques [Abstract
Cash collateral posted in support of energy risk management activities	73	114
Cash collateral received in support of energy risk management activities	7	31
Commodity contracts \| Level 3
Assets
Derivative assets	193	109
Liabilities
Commodity contracts	155	89
Commodity contracts \| Fair Value, Measurements, Recurring \| Level 3
Assets
Derivative assets	193	109
Liabilities
Commodity contracts	155	89
Commodity contracts \| Fair Value, Measurements, Recurring \| Power Contracts \| Level 3
Assets
Derivative assets	151	89
Liabilities
Commodity contracts	$ 139	$ 75
Commodity contracts \| Fair Value, Measurements, Recurring \| Power Contracts \| Level 3 \| Low
Fair Value Measurement Inputs and Valuation Techniques [Abstract
Forward Market Price (USD per MWh) \| $ / MWh	8	1
Commodity contracts \| Fair Value, Measurements, Recurring \| Power Contracts \| Level 3 \| High
Fair Value Measurement Inputs and Valuation Techniques [Abstract
Forward Market Price (USD per MWh) \| $ / MWh	218	214
Commodity contracts \| Fair Value, Measurements, Recurring \| Power Contracts \| Level 3 \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Abstract
Forward Market Price (USD per MWh) \| $ / MWh	24	31
Commodity contracts \| Fair Value, Measurements, Recurring \| Financial Transmission Rights \| Level 3
Assets
Derivative assets	$ 42	$ 20
Liabilities
Commodity contracts	$ 16	$ 14
Commodity contracts \| Fair Value, Measurements, Recurring \| Financial Transmission Rights \| Level 3 \| Low
Fair Value Measurement Inputs and Valuation Techniques [Abstract
Auction Prices (USD per MWh) \| $ / MWh	(105)	(90)
Commodity contracts \| Fair Value, Measurements, Recurring \| Financial Transmission Rights \| Level 3 \| High
Fair Value Measurement Inputs and Valuation Techniques [Abstract
Auction Prices (USD per MWh) \| $ / MWh	213	34
Commodity contracts \| Fair Value, Measurements, Recurring \| Financial Transmission Rights \| Level 3 \| Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Abstract
Auction Prices (USD per MWh) \| $ / MWh	0	0

Fair Value of Financial Instruments - Counterparty Credit Risk (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) counterparty	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Derivative Fair Value Meaurements and Concentration of Credit Risk
Counterparty credit exposure, excluding credit risk exposure under certain long term agreements	$ 239
Counterparty credit exposure, collateral held (cash and letters of credit) against positions	51
Counterparty credit exposure, net	$ 233
Company's exposure before collateral expected to roll off (as a percent)	67.00%
Net exposure (as a percent)	100.00%
Wholesale counterparties with net exposure \| counterparty	33,000,000
Counterparty credit risk exposure to certain counterparties, threshold (as a percent)	10.00%
Estimated counterparty credit risk exposure under certain long term agreements, including California tolling agreements, South Central load obligations and solar power purchase agreements for the next 5 years	$ 548
Period of estimated counterparty credit risk exposure under certain long term agreements, including California tolling agreements, South Central load obligations and solar power purchase agreements (in years)	5 years
Provision for bad debts	$ 95	$ 85	$ 68
Investment grade
Derivative Fair Value Meaurements and Concentration of Credit Risk
Net exposure (as a percent)	56.00%
Non-Investment grade/Non-Rated
Derivative Fair Value Meaurements and Concentration of Credit Risk
Net exposure (as a percent)	44.00%
Utilities, energy merchants, marketers and other
Derivative Fair Value Meaurements and Concentration of Credit Risk
Net exposure (as a percent)	84.00%
Financial Institutions
Derivative Fair Value Meaurements and Concentration of Credit Risk
Net exposure (as a percent)	16.00%

Accounting for Derivative Instruments and Hedging Activities - Net Notional Volume Buy/Sell of Open Derivative Transactions (Details) shares in Millions, bbl in Millions, T in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) MMBTU MWh T shares bbl	Dec. 31, 2018 USD ($) MMBTU MWh T shares bbl
Long \| Emissions
Derivative [Line Items]
Derivative, nonmonetary notional amount, mass (ton)	3
Long \| Renewables Energy Certificates
Derivative [Line Items]
Derivative, non-monetary notional amount (in shares) \| shares	1	1
Long \| Coal
Derivative [Line Items]
Derivative, nonmonetary notional amount, mass (ton)	10	13
Long \| Oil
Derivative [Line Items]
Derivative, nonmonetary notional amount, volume (in barrels) \| bbl	0	1
Long \| Power
Derivative [Line Items]
Derivative, nonmonetary notional amount, energy measure in (millions of btu) and (megawatt hours) \| MWh	38	1
Long \| Interest
Derivative [Line Items]
Derivative, Notional Amount (in usd) \| $	$ 0	$ 1,000
Short \| Emissions
Derivative [Line Items]
Derivative, nonmonetary notional amount, mass (ton)		2
Short \| Natural Gas
Derivative [Line Items]
Derivative, nonmonetary notional amount, energy measure in (millions of btu) and (megawatt hours) \| MMBTU	181	330
Short \| Capacity
Derivative [Line Items]
Derivative, nonmonetary notional amount, energy measure in (millions of btu) and (megawatt hours) \| MWh	1	1

Accounting for Derivative Instruments and Hedging Activities - Fair Value Within the Derivative Instrument Valuation (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative assets	$ 1,170	$ 1,081
Commodity contracts	1,103	977
Interest rate contracts current
Derivative [Line Items]
Derivative assets	0	17
Commodity contracts	0	0
Interest rate contracts long-term
Derivative [Line Items]
Derivative assets	0	22
Commodity contracts	0	0
Commodity contracts current
Derivative [Line Items]
Derivative assets	860	747
Commodity contracts	781	673
Commodity contracts long-term
Derivative [Line Items]
Derivative assets	310	295
Commodity contracts	$ 322	$ 304

Accounting for Derivative Instruments and Hedging Activities - Offsetting of Derivatives by Counterparty Master Agreement level and Collateral Received (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Cash Collateral (Held)/Posted	$ (32)	$ (33)
Cash Collateral (Held)/Posted	190	287
Gross Amounts of Recognized Assets / Liabilities		104
Derivative Instruments		0
Cash Collateral (Held) / Posted		83
Net Amount		187
Commodity contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative assets	1,170	1,042
Derivative Instruments	(909)	(778)
Cash Collateral (Held)/Posted	(7)	(31)
Net Amount	254	233
Derivative liabilities	(1,103)	(977)
Derivative Instruments	909	778
Cash Collateral (Held)/Posted	73	114
Net Amount	(121)	(85)
Gross Amounts of Recognized Assets / Liabilities	67	65
Derivative Instruments	0	0
Cash Collateral (Held) / Posted	66	83
Net Amount	$ 133	148
Interest rate contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative assets		39
Derivative Instruments		0
Cash Collateral (Held)/Posted		0
Net Amount		39
Gross Amounts of Recognized Assets / Liabilities		39
Derivative Instruments		0
Cash Collateral (Held) / Posted		0
Net Amount		$ 39

Accounting for Derivative Instruments and Hedging Activities - Effect on the Company's of Accumulated OCI Balance Attributable to Cash Flow Hedge Derivatives, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Beginning balance	$ (1,234)	$ 1,968	$ 4,446
Reclassified from accumulated OCI to income:
Sale of NRG Yield and Renewables		25	0
Ending balance	1,658	(1,234)	1,968
Interest rate contracts \| AOCI Including Portion Attributable to Noncontrolling Interest
Derivative [Line Items]
Beginning balance	0	(54)	(66)
Reclassified from accumulated OCI to income:
Ending balance		0	(54)
Interest rate contracts \| Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Reclassified from accumulated OCI to income:
Due to realization of previously deferred amounts	$ 8		12
Interest rate contracts \| Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
Reclassified from accumulated OCI to income:
Mark-to-market of cash flow hedge accounting contracts		$ 21	$ 0

Accounting for Derivative Instruments and Hedging Activities - Pre-tax Effects of Economic Hedges not Designated as Cash Flow Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unrealized Mark To Market Results [Abstract]
Reversal of previously recognized unrealized (gains)/losses on settled positions related to economic hedges	$ (68)	$ (73)	$ 47
Reversal of acquired loss/(gain) positions related to economic hedges	6	(10)	0
Net unrealized gains on open positions related to economic hedges	42	97	159
Total unrealized mark-to-market (losses)/gains for economic hedging activities	(20)	14	206
Reversal of previously recognized unrealized (gains) on settled positions related to trading activity	(11)	(12)	(25)
Net unrealized gains on open positions related to trading activity	31	29	14
Total unrealized mark-to-market gains/(losses) for trading activity	20	17	(11)
Total unrealized gains	0	31	195
Credit Risk Related Contingent Features [Abstract]
Collateral required contracts with credit rating contingent features in a net liability position	3
Adequate Assurance Clauses
Credit Risk Related Contingent Features [Abstract]
Collateral required for contracts in net liability positions that have adequate assurance clauses	14
Credit Rating Contingent Features
Credit Risk Related Contingent Features [Abstract]
Collateral required for contracts in net liability positions that have adequate assurance clauses	24
Commodity contracts
Unrealized Mark To Market Results [Abstract]
Total unrealized gains	0	31	195
Commodity contracts \| Operating revenue
Unrealized Mark To Market Results [Abstract]
Total unrealized gains	53	(113)	241
Commodity contracts \| Cost of operations
Unrealized Mark To Market Results [Abstract]
Total unrealized gains	(53)	144	(46)
Interest rate contracts
Unrealized Mark To Market Results [Abstract]
Total unrealized gains	$ (38)	$ 0	$ 4

Nuclear Decommissioning Trust Fund - Summary of Aggregate Fair Values and Realized Gains and Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Nuclear decommissioning trust fund disclosure
Fair Value	$ 794	$ 663
Unrealized Gains	338	234
Unrealized Losses	1	6
Cash and cash equivalents
Nuclear decommissioning trust fund disclosure
Fair Value	17	19
Unrealized Gains	0	0
Unrealized Losses	0	0
U.S. government and federal agency obligations
Nuclear decommissioning trust fund disclosure
Fair Value	68	46
Unrealized Gains	4	1
Unrealized Losses	$ 0	$ 0
Weighted- average maturities (in years)	11 years	12 years
Federal agency mortgage-backed securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 100	$ 100
Unrealized Gains	3	1
Unrealized Losses	$ 0	$ 2
Weighted- average maturities (in years)	24 years	23 years
Commercial mortgage-backed securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 29	$ 22
Unrealized Gains	1	0
Unrealized Losses	$ 1	$ 1
Weighted- average maturities (in years)	24 years	22 years
Corporate debt securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 109	$ 96
Unrealized Gains	6	1
Unrealized Losses	$ 0	$ 2
Weighted- average maturities (in years)	11 years	11 years
Equity securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 466	$ 376
Unrealized Gains	324	231
Unrealized Losses	0	1
Foreign government fixed income securities
Nuclear decommissioning trust fund disclosure
Fair Value	5	4
Unrealized Gains	0	0
Unrealized Losses	$ 0	$ 0
Weighted- average maturities (in years)	10 years	9 years
South Texas Project
Nuclear decommissioning trust fund disclosure
Ownership Interest (as a percent)	44.00%

Nuclear Decommissioning Trust Fund - Summary of Proceeds from Sale of Available -for-sale Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Regulated Operations [Abstract]
Realized gains	$ 18	$ 17	$ 22
Realized (losses)	(9)	(13)	(8)
Proceeds from sales of nuclear decommissioning trust fund securities	$ 381	$ 513	$ 501

Inventory (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Fuel oil	$ 73	$ 74
Coal	93	97
Natural gas	21	28
Spare parts	196	213
Total Inventory	$ 383	$ 412

Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment
Total property, plant, and equipment	$ 4,345	$ 4,859
Accumulated depreciation	(1,752)	(1,811)
Net property, plant, and equipment	2,593	3,048
Facilities and equipment
Property, Plant and Equipment
Total property, plant, and equipment	$ 3,262	3,763
Facilities and equipment \| Minimum
Property, Plant and Equipment
Depreciable lives (in years)	1 year
Facilities and equipment \| Maximum
Property, Plant and Equipment
Depreciable lives (in years)	40 years
Land and improvements
Property, Plant and Equipment
Total property, plant, and equipment	$ 324	347
Nuclear fuel
Property, Plant and Equipment
Total property, plant, and equipment	$ 235	212
Depreciable lives (in years)	5 years
Hardware and office equipment and furnishings
Property, Plant and Equipment
Total property, plant, and equipment	$ 422	431
Hardware and office equipment and furnishings \| Minimum
Property, Plant and Equipment
Depreciable lives (in years)	2 years
Hardware and office equipment and furnishings \| Maximum
Property, Plant and Equipment
Depreciable lives (in years)	10 years
Construction in progress
Property, Plant and Equipment
Total property, plant, and equipment	$ 102	$ 106

Leases - Lease Cost and Other Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Lease, Cost [Abstract]
Operating lease cost	$ 109
Short-term lease cost	3
Variable lease cost	6
Sublease income	17
Total lease cost	101
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	104
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 215
Leases, Weighted Average Discount Rate [Abstract]
Weighted average remaining lease term (in years)	7 years 9 months 18 days
Weighted average discount rate	5.72%

Leases - Annual Payments Based on the Maturities of Leases (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019
Leases [Abstract]
2020	$ 96
2021	87
2022	87
2023	85
2024	75
Thereafter	296
Total undiscounted lease payments	726
Less present value adjustment	(170)
Operating lease liability	$ 556	$ 321

Leases - 2018 Operating Lease Commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Other Operating Leases
Long-term Purchase Commitment [Line Items]
Lease expense	$ 66	$ 69
Midwest Generation, LLC
Long-term Purchase Commitment [Line Items]
Leased interest	100.00%
Out-of-market contracts, net			$ 159
Lease expense	$ 14

Leases - Future Minimum Lease Commitments Before Adoption of ASU 2016-02 (Details) $ in Millions	Dec. 31, 2018 USD ($)
Operating Leased Assets [Line Items]
Future sublease income	$ 29
Powerton and Joliet
Operating Leased Assets [Line Items]
2019	1
2020	1
2021	3
2022	6
2023	6
Thereafter	222
Total (a)	239
Other Leased Property
Operating Leased Assets [Line Items]
2019	60
2020	55
2021	43
2022	40
2023	39
Thereafter	95
Total (a)	$ 332

Asset Impairments (Details) - USD ($)		3 Months Ended					12 Months Ended
Asset Impairments (Details) - USD ($)	Sep. 05, 2018	Sep. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Feb. 20, 2019	Dec. 31, 2014
Asset Impairments
Impairment losses, other assets							$ 12,000,000
Impairment losses							5,000,000	$ 99,000,000	$ 1,534,000,000
Equity method investments			$ 412,000,000				388,000,000	412,000,000
Impairment losses on investments							$ 108,000,000	15,000,000	79,000,000
Emission Allowances
Asset Impairments
Impairment losses									20,000,000
Renewables
Asset Impairments
Impairment losses									29,000,000
Construction in Progress
Asset Impairments
Impairment losses						$ 41,000,000
Construction in progress						$ 0
Held-for-sale \| NRG Solar Guam, LLC
Asset Impairments
Impairment losses			$ 12,000,000
Cash consideration										$ 8,000,000
Petra Nova
Asset Impairments
Contribution in cash		$ 95,000,000
Letter of credit		12,000,000
Guarantee (up to)		124,000,000
Impairment losses on equity method investments		$ 101,000,000
Keystone
Asset Impairments
Impairment losses on equity method investments	$ 14,000,000
Ownership percentage											3.70%
Impairment losses on investments									35,000,000
Conemaugh
Asset Impairments
Impairment losses on equity method investments	$ 14,000,000
Impairment losses on investments									35,000,000
Dunkirk
Asset Impairments
Impairment losses on equity method investments				$ 46,000,000
Equity method investments				$ 0
Other Investments
Asset Impairments
Impairment losses on equity method investments								15,000,000
Impairment losses on investments								$ 13,000,000	10,000,000
South Texas Project
Asset Impairments
Impairment losses on investments									1,248,000,000
Indian River
Asset Impairments
Impairment losses on investments									$ 36,000,000
Petra Nova Parish Holdings
Asset Impairments
Ownership percentage					50.00%				50.00%
Impairment losses on investments					$ 69,000,000

Goodwill and Other Intangibles - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Other Intangibles
Goodwill	$ 579,000,000	$ 579,000,000	$ 573,000,000
Impairment		2,000,000	6,000,000
Emission allowances held-for-sale	6,000,000	6,000,000	12,000,000
Emission Allowances
Goodwill and Other Intangibles
Impairment		0	5,000,000
Impairment related to power purchase agreements			0
BETM \| Held-for-sale
Goodwill and Other Intangibles
Goodwill	21,000,000	21,000,000
Goodwill, Impairment Loss	90,000,000
Midwest Generation
Goodwill and Other Intangibles
Goodwill	165,000,000	165,000,000
Midwest Generation \| Lease Agreements
Goodwill and Other Intangibles
Out of market contracts			$ 121,000,000
Texas
Goodwill and Other Intangibles
Goodwill	$ 414,000,000	$ 414,000,000

Goodwill and Other Intangibles - Components of Intangible Assets Subject to Amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	$ 1,742	$ 2,080
Purchases	42	61
Acquisition of businesses	318	178
Usage	(21)	(27)
Write-off of fully amortized balances	(30)	(528)
Impairment	(2)	(6)
Other	2	(16)
Balance at end of period	2,051	1,742
Less accumulated amortization	(1,262)	(1,151)
Net carrying amount	789	591
Emission Allowances
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	659	755
Purchases	13	33
Acquisition of businesses	0	0
Usage	(4)	(1)
Write-off of fully amortized balances	(8)	(107)
Impairment	0	(5)
Other	2	(16)
Balance at end of period	662	659
Less accumulated amortization	(539)	(515)
Net carrying amount	123	144
Fuel Contracts
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	49	49
Purchases	0	0
Acquisition of businesses	0	0
Usage	0	0
Write-off of fully amortized balances	0	0
Impairment	0	0
Other	0	0
Balance at end of period	49	49
Less accumulated amortization	(45)	(45)
Net carrying amount	$ 4	4
Customer Contracts
Finite-lived Intangible Assets [Roll Forward]
Weighted average useful life, years	2 years
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	$ 478	768
Purchases	0	0
Acquisition of businesses	110	122
Usage	0	0
Write-off of fully amortized balances	(13)	(411)
Impairment	(2)	(1)
Other	0	0
Balance at end of period	573	478
Less accumulated amortization	(345)	(314)
Net carrying amount	$ 228	$ 164
Weighted average useful life, years	7 years	6 years
Marketing Partnerships
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	$ 131	$ 88
Purchases	0	0
Acquisition of businesses	154	43
Usage	0	0
Write-off of fully amortized balances	0	0
Impairment	0	0
Other	0	0
Balance at end of period	285	131
Less accumulated amortization	(75)	(61)
Net carrying amount	$ 210	$ 70
Weighted average useful life, years	9 years	14 years
Trade Names
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	$ 345	$ 342
Purchases	0	0
Acquisition of businesses	28	13
Usage	0	0
Write-off of fully amortized balances	0	(10)
Impairment	0	0
Other	0	0
Balance at end of period	373	345
Less accumulated amortization	(220)	(195)
Net carrying amount	$ 153	$ 150
Weighted average useful life, years	12 years	7 years
Other
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	$ 80	$ 78
Purchases	29	28
Acquisition of businesses	26	0
Usage	(17)	(26)
Write-off of fully amortized balances	(9)	0
Impairment	0	0
Other	0	0
Balance at end of period	109	80
Less accumulated amortization	(38)	(21)
Net carrying amount	$ 71	$ 59

Goodwill and Other Intangibles - Schedule of Amortization Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Total amortization	$ 151	$ 133	$ 166
Emission Allowances
Finite-Lived Intangible Assets [Line Items]
Total amortization	32	39	71
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Total amortization	44	32	34
Marketing Partnerships
Finite-Lived Intangible Assets [Line Items]
Total amortization	15	9	5
Trade Names
Finite-Lived Intangible Assets [Line Items]
Total amortization	25	23	23
Other
Finite-Lived Intangible Assets [Line Items]
Total amortization	$ 35	$ 30	$ 33

Goodwill and Other Intangibles - Schedule of Estimated Amortization of Intangible Asset for the Next Five Years (Details) $ in Millions	Dec. 31, 2019 USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	$ 189
2021	141
2022	127
2023	128
2024	93
Emission Allowances
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	36
2021	35
2022	38
2023	40
2024	35
Fuel Contracts
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	1
2021	0
2022	0
2023	1
2024	0
Customer Relationships
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	68
2021	52
2022	36
2023	35
2024	15
Marketing Partnerships
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	24
2021	24
2022	23
2023	23
2024	23
Trade Names
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	27
2021	27
2022	27
2023	26
2024	17
Other
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	33
2021	3
2022	3
2023	3
2024	$ 3

Debt and Finance Leases - Schedule of Long-term Debt and Finance Leases (Details) - USD ($) $ in Millions				12 Months Ended
	Mar. 21, 2018	Jan. 24, 2017	Jun. 30, 2016	Dec. 31, 2019	Dec. 31, 2018	May 28, 2019	May 24, 2019	May 14, 2019	Nov. 05, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 07, 2017	Aug. 02, 2016	May 23, 2016
Debt Instrument [Line Items]
Long-term debt				$ 6,042	$ 6,691
Finance leases					1
Subtotal long-term debt and finance leases (including current maturities)				6,042	6,692
Less current maturities				(88)	(72)
Less debt issuance costs				(65)	(70)
Discounts				(86)	(101)
Total long-term debt and finance leases				5,803	6,449
Debt Instrument, Unamortized Discount [Abstract]
Total discounts				(86)	(101)
Recourse Debt
Debt Instrument [Line Items]
Long-term debt				6,008	6,523
Recourse Debt \| Senior Notes, due 2024
Debt Instrument [Line Items]
Long-term debt				$ 0	733
Interest rate, stated percentage				6.25%
Recourse Debt \| Senior Notes, due 2026
Debt Instrument [Line Items]
Long-term debt				$ 1,000	1,000
Interest rate, stated percentage				7.25%										7.25%
Recourse Debt \| Senior Notes, due 2027
Debt Instrument [Line Items]
Long-term debt				$ 1,230	1,230
Interest rate, stated percentage				6.625%						6.625%			6.625%
Recourse Debt \| Senior Notes, due 2028
Debt Instrument [Line Items]
Long-term debt				$ 821	821
Interest rate, stated percentage				5.75%						5.75%	5.75%	5.75%
Recourse Debt \| Senior Notes due 2029
Debt Instrument [Line Items]
Long-term debt				$ 733	0
Interest rate, stated percentage				5.25%			5.25%	5.25%
Recourse Debt \| Convertible Senior Notes Due 2048
Debt Instrument [Line Items]
Long-term debt				$ 575	575
Discounts				$ 85	$ 96
Interest rate, stated percentage				2.75%
Effective rate				5.05%	5.02%
Debt Instrument, Unamortized Discount [Abstract]
Total discounts				$ 85	$ 96
Recourse Debt \| Senior Secured First Lien Notes, due 2024
Debt Instrument [Line Items]
Long-term debt				$ 600	0
Interest rate, stated percentage				3.75%		3.75%
Recourse Debt \| Senior Secured First Lien Notes, due 2029
Debt Instrument [Line Items]
Long-term debt				$ 500	0
Interest rate, stated percentage				4.45%		4.45%
Recourse Debt \| Term Loan Facility
Debt Instrument [Line Items]
Long-term debt			$ 1,900	$ 0	1,698				$ 260
Discounts				0	4
Debt Instrument, Unamortized Discount [Abstract]
Total discounts				$ 0	$ 4
Recourse Debt \| Term Loan Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.75%	2.25%	2.75%	1.75%	1.75%
Recourse Debt \| Tax-exempt bonds
Debt Instrument [Line Items]
Long-term debt				$ 466	$ 466
Recourse Debt \| Tax-exempt bonds \| Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage				4.125%
Recourse Debt \| Tax-exempt bonds \| Maximum
Debt Instrument [Line Items]
Interest rate, stated percentage				6.00%
Recourse Debt \| Senior Secured First Lien Notes, due 2024 and 2029
Debt Instrument [Line Items]
Discounts				$ 1	0
Debt Instrument, Unamortized Discount [Abstract]
Total discounts				1	0
Line of Credit \| Revolver Facility \| Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt				$ 83	0
Line of Credit \| Revolver Facility \| Revolving Credit Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				1.75%
Non Recourse Debt
Debt Instrument [Line Items]
Long-term debt				$ 34	168
Non Recourse Debt \| Agua Caliente Borrower 1, due 2038
Debt Instrument [Line Items]
Long-term debt				$ 0	86
Interest rate, stated percentage				5.43%
Non Recourse Debt \| Midwest Generation, due 2019
Debt Instrument [Line Items]
Long-term debt				$ 0	48
Discounts				$ 0	1
Interest rate, stated percentage				4.39%
Debt Instrument, Unamortized Discount [Abstract]
Total discounts				$ 0	1
Non Recourse Debt \| Other
Debt Instrument [Line Items]
Long-term debt				$ 34	$ 34

Debt and Finance Leases - Annual Payments Based on the Maturities of Debt and Capital Leases (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
2020	$ 88
2021	6
2022	5
2023	4
2024	604
Thereafter	5,335
Subtotal long-term debt and finance leases (including current maturities)	6,042	$ 6,692
Revolving Credit Facility \| Revolver Facility \| Line of Credit
Debt Instrument [Line Items]
2020	$ 83

Debt and Finance Leases - Issuance of Senior Notes (Details) - Recourse Debt - USD ($)	Dec. 31, 2019	May 28, 2019	May 24, 2019	May 14, 2019
Senior Notes due 2029
Debt Instrument [Line Items]
Aggregate principal amount				$ 733,000,000
Interest rate, stated percentage	5.25%		5.25%	5.25%
Senior Notes 2024
Debt Instrument [Line Items]
Interest rate, stated percentage	6.25%
Senior Secured First Lien Notes, Due 2024 and 2029
Debt Instrument [Line Items]
Aggregate principal amount		$ 1,100,000,000
Senior Secured First Lien Notes, Due 2024
Debt Instrument [Line Items]
Aggregate principal amount		$ 600,000,000
Interest rate, stated percentage	3.75%	3.75%
Senior Secured First Lien Notes, Due 2029
Debt Instrument [Line Items]
Aggregate principal amount		$ 500,000,000
Interest rate, stated percentage	4.45%	4.45%

Debt and Finance Leases - Issuance of Convertible Senior Notes (Details)	3 Months Ended
	Jun. 30, 2018 USD ($) $ / shares
Debt Instrument [Line Items]
Debt issuance transaction costs	$ 12,000,000
Convertible Senior Notes Due 2048 \| Convertible Debt
Debt Instrument [Line Items]
Aggregate principal amount	$ 575,000,000
Interest rate, stated percentage	2.75%
Conversion price per common share (in usd per share) \| $ / shares	$ 47.74
Conversion ratio	20.9479
Debt, estimated fair value	$ 472,000,000
Carrying amount of equity component	$ 103,000,000
Debt discount amortization period	7 years
Debt deferred financing costs amortization period	7 years
Convertible Senior Notes Due 2048 \| Convertible Debt \| Additional Paid-in Capita
Debt Instrument [Line Items]
Debt issuance transaction costs	$ 2,000,000
Convertible Senior Notes Due 2048 \| Convertible Debt \| Deferred Financing Costs
Debt Instrument [Line Items]
Debt issuance transaction costs	$ 10,000,000

Debt and Finance Leases - Senior Notes Redemption and Repurchases (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018	Jun. 30, 2018	Dec. 07, 2017	Aug. 02, 2016
Debt Instrument [Line Items]
Loss on debt extinguishment		$ 51	$ 44	$ 49
Senior Notes
Debt Instrument [Line Items]
Loss on debt extinguishment			38
Write off of deferred debt issuance cost			7
Recourse Debt \| Senior Notes, due 2024
Debt Instrument [Line Items]
Principal amount redeemed		$ 733
Interest rate, stated percentage		6.25%
Loss on debt extinguishment		$ 29
Write off of deferred debt issuance cost		$ 5
Recourse Debt \| Senior Notes
Debt Instrument [Line Items]
Principal Repurchased	$ 1,061		1,061		$ 576	$ 43
Cash Paid	1,106		1,106		$ 598	$ 45
Redemption percentage of principal		25.00%
Accrued interest	14		14
Recourse Debt \| Senior Notes, due 2028
Debt Instrument [Line Items]
Interest rate, stated percentage		5.75%			5.75%	5.75%	5.75%
Principal Repurchased					$ 20
Recourse Debt \| Senior Notes Due In 2022 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage		6.25%			6.25%	6.25%
Principal Repurchased	485		485		$ 493
Cash Paid	$ 508		$ 508
Redemption percentage of principal	103.13%
Recourse Debt \| Senior Notes, due 2027
Debt Instrument [Line Items]
Interest rate, stated percentage		6.625%			6.625%			6.625%
Principal Repurchased					$ 20

Debt and Finance Leases - Senior Notes Outstanding with Early Redemption Features (Details) - Recourse Debt	Dec. 31, 2019	May 24, 2019	May 14, 2019	Sep. 30, 2018	Jun. 30, 2018	Dec. 07, 2017	Aug. 02, 2016	May 23, 2016
Senior Notes due 2026
Debt Instrument [Line Items]
Interest rate, stated percentage	7.25%							7.25%
Senior Notes due 2027
Debt Instrument [Line Items]
Interest rate, stated percentage	6.625%			6.625%			6.625%
Senior Notes due 2028
Debt Instrument [Line Items]
Interest rate, stated percentage	5.75%			5.75%	5.75%	5.75%
Senior Notes due 2029
Debt Instrument [Line Items]
Interest rate, stated percentage	5.25%	5.25%	5.25%

Debt and Finance Leases - Recourse Debt Redemption Period (Details) - Recourse Debt	12 Months Ended
	Dec. 31, 2019
Senior Notes
Debt Instrument [Line Items]
Average Early Redemption Percentage	25.00%
Senior Notes due 2026 \| Treasury Rate
Debt Instrument [Line Items]
Premium percentage of principal amount of note discount factor (as percent)	1.00%
Treasury rate redemption (as percentage)	0.50%
Senior Notes due 2027 \| Treasury Rate
Debt Instrument [Line Items]
Premium percentage of principal amount of note discount factor (as percent)	1.00%
Treasury rate redemption (as percentage)	50.00%
Senior Notes due 2028
Debt Instrument [Line Items]
Redemption percentage	35.00%
Senior Notes due 2028 \| Treasury Rate
Debt Instrument [Line Items]
Premium percentage of principal amount of note discount factor (as percent)	1.00%
Treasury rate redemption (as percentage)	50.00%
Senior Notes due 2029
Debt Instrument [Line Items]
Redemption percentage	40.00%
Senior Notes due 2029 \| Treasury Rate
Debt Instrument [Line Items]
Treasury rate redemption (as percentage)	0.50%
Redemption Period Prior To 15 May 2021 \| Senior Notes due 2026
Debt Instrument [Line Items]
Redemption percentage	100.00%
Present value of note (as percentage)	1.03625
May 15, 2021 to May 14, 2022 \| Senior Notes due 2026
Debt Instrument [Line Items]
Redemption percentage	103.625%
May 15, 2022 to May 14, 2023 \| Senior Notes due 2026
Debt Instrument [Line Items]
Redemption percentage	102.417%
May 15, 2023 to May 14, 2024 \| Senior Notes due 2026
Debt Instrument [Line Items]
Redemption percentage	101.208%
May 15, 2024 and thereafter \| Senior Notes due 2026
Debt Instrument [Line Items]
Redemption percentage	100.00%
Redemption Period Prior To 15 July 2021 \| Senior Notes due 2027
Debt Instrument [Line Items]
Redemption percentage	100.00%
Present value of note (as percentage)	1.03313
July 15, 2021 to July14, 2022 \| Senior Notes due 2027
Debt Instrument [Line Items]
Redemption percentage	103.313%
July 15, 2022 to July 14, 2023 \| Senior Notes due 2027
Debt Instrument [Line Items]
Redemption percentage	102.208%
July 15, 2023 to July 14, 2024 \| Senior Notes due 2027
Debt Instrument [Line Items]
Redemption percentage	101.104%
July 15, 2024 and thereafter \| Senior Notes due 2027
Debt Instrument [Line Items]
Redemption percentage	100.00%
Redemption Period Prior to January 15, 2021 \| Senior Notes due 2028
Debt Instrument [Line Items]
Redemption percentage	105.75%
Redemption Period Prior to January 15, 2023 \| Senior Notes due 2028
Debt Instrument [Line Items]
Redemption percentage	100.00%
Present value of note (as percentage)	1.02875
January 15, 2023 to January 14, 2024 \| Senior Notes due 2028
Debt Instrument [Line Items]
Redemption percentage	102.875%
January 15, 2024 to January 14, 2025 \| Senior Notes due 2028
Debt Instrument [Line Items]
Redemption percentage	101.917%
January 15, 2025 to January 14, 2026 \| Senior Notes due 2028
Debt Instrument [Line Items]
Redemption percentage	100.958%
January 15, 2026 and thereafter \| Senior Notes due 2028
Debt Instrument [Line Items]
Redemption percentage	100.00%
Redemption Period Prior to June 15, 2022 \| Senior Notes due 2029
Debt Instrument [Line Items]
Redemption percentage	105.25%
Outstanding principal after redemption, percentage (at least)	50.00%
Redemption Period Prior to June 15, 2024 \| Senior Notes due 2029
Debt Instrument [Line Items]
Redemption percentage	100.00%
Premium percentage of principal amount of note discount factor (as percent)	1.00%
Present value of note (as percentage)	1.02625
June 15, 2024 to June 14, 2025 \| Senior Notes due 2029
Debt Instrument [Line Items]
Redemption percentage	102.625%
June 15, 2025 to June 14, 2026 \| Senior Notes due 2029
Debt Instrument [Line Items]
Redemption percentage	101.75%
June 15, 2026 to June 14, 2027 \| Senior Notes due 2029
Debt Instrument [Line Items]
Redemption percentage	100.875%
June 15, 2027 and thereafter \| Senior Notes due 2029
Debt Instrument [Line Items]
Redemption percentage	100.00%

Debt and Finance Leases - Senior Credit Facility and Tax Exempt Bonds (Details) - USD ($)						12 Months Ended
	May 28, 2019	Nov. 05, 2018	Mar. 21, 2018	Jan. 24, 2017	Jun. 30, 2016	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt						$ 6,042,000,000	$ 6,691,000,000
Loss on debt extinguishment						51,000,000	44,000,000	$ 49,000,000
Decrease to long-term debt outstanding	$ 594,000,000
Credit Agreement \| Adjusted Base Rate \| Revolving Credit Facility \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.25%
Credit Agreement \| Adjusted Base Rate \| Revolving Credit Facility \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	0.75%
Credit Agreement \| Eurodollar \| Revolving Credit Facility \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	2.25%
Credit Agreement \| Eurodollar \| Revolving Credit Facility \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.75%
Recourse Debt
Debt Instrument [Line Items]
Long-term debt						6,008,000,000	6,523,000,000
Recourse Debt \| Term Loan Facility
Debt Instrument [Line Items]
Long-term debt		$ 260,000,000			$ 1,900,000,000	$ 0	$ 1,698,000,000
Percent of face value					99.50%
Periodic payment, percentage of principal					0.0025
Payment amount		155,000,000
Loss on debt extinguishment	$ 17,000,000	3,000,000
Write off of deferred debt issuance cost	13,000,000	2,000,000
Repayment of debt	(1,700,000,000)
Recourse Debt \| Term Loan Facility \| Interest Rate Swap
Debt Instrument [Line Items]
Reduction to interest expense	(25,000,000)
Recourse Debt \| Term Loan Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			1.75%	2.25%	2.75%	1.75%	1.75%
Decrease in interest rate margin			0.50%	0.50%
Recourse Debt \| Term Loan Facility \| LIBOR floor
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			0.00%	0.75%	0.75%
Recourse Debt \| Indian River Power, tax exempt bonds, due 2040
Debt Instrument [Line Items]
Long-term debt						$ 57,000,000	$ 57,000,000
Interest rate, stated percentage						6.00%
Recourse Debt \| Indian River Power LLC, tax exempt bonds, due 2045
Debt Instrument [Line Items]
Long-term debt						$ 190,000,000	190,000,000
Interest rate, stated percentage						5.375%
Recourse Debt \| Dunkirk Power LLC, tax exempt bonds, due 2042
Debt Instrument [Line Items]
Long-term debt						$ 59,000,000	59,000,000
Interest rate, stated percentage						5.875%
Recourse Debt \| City of Texas City, tax exempt bonds, due 2045
Debt Instrument [Line Items]
Long-term debt						$ 33,000,000	33,000,000
Interest rate, stated percentage						4.125%
Recourse Debt \| Fort Bend County, tax exempt bonds, due 2038
Debt Instrument [Line Items]
Long-term debt						$ 54,000,000	54,000,000
Interest rate, stated percentage						4.75%
Recourse Debt \| Fort Bend County, tax exempt bonds, due 2042
Debt Instrument [Line Items]
Long-term debt						$ 73,000,000	73,000,000
Interest rate, stated percentage						4.75%
Recourse Debt \| Tax-exempt bonds
Debt Instrument [Line Items]
Long-term debt						$ 466,000,000	466,000,000
Recourse Debt \| Tax-exempt bonds \| Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage						4.125%
Recourse Debt \| Tax-exempt bonds \| Maximum
Debt Instrument [Line Items]
Interest rate, stated percentage						6.00%
Revolving Credit Facility \| 2016 Tranche A Revolving Credit Facility due 2018
Debt Instrument [Line Items]
Revolving credit facility					$ 289,000,000
Revolving Credit Facility \| 2016 Tranche B Revolving Credit Facility due 2021
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)					2.25%
Revolving credit facility					$ 2,200,000,000
Senior Credit Facility \| Term Loan Facility
Debt Instrument [Line Items]
Long-term debt		$ 105,000,000
Line of Credit \| Credit Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt						$ 83,000,000	$ 0
Revolving credit facility	2,600,000,000
Increase in revolving commitments	$ 184,000,000
Line of Credit \| Credit Agreement \| LIBOR \| Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)						1.75%

Debt and Finance Leases - Non-Recourse Debt (Details) - USD ($)	Oct. 21, 2019	Jan. 04, 2019	Apr. 07, 2016	Dec. 31, 2019
Agua Caliente Borrower 1, due 2038
Debt Instrument [Line Items]
Redemption percentage of principal	102.00%
Non Recourse Debt \| Agua Caliente Borrower 1, due 2038
Debt Instrument [Line Items]
Interest rate, stated percentage				5.43%
Non Recourse Debt \| Credit Agreement 2019 \| Letter of Credit
Debt Instrument [Line Items]
Credit facility		$ 80,000,000
Annual facility fees, percentage		1.33%
Letter of credit				$ 80,000,000
Midwest Generation \| Non Recourse Debt
Debt Instrument [Line Items]
Proceeds from sale of unforced capacity			$ 253,000,000
Interest rate, stated percentage			4.39%

Asset Retirement Obligations (Details) $ in Millions	12 Months Ended
Asset Retirement Obligations (Details) $ in Millions	Dec. 31, 2019 USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance as of December 31, 2018	$ 679
Revisions in estimates for current obligations(a)	27
Additions	9
Spending for current obligations	(33)
Accretion	46
Balance as of December 31, 2019	728
Nuclear Decommission
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance as of December 31, 2018	282
Revisions in estimates for current obligations(a)	0
Additions	0
Spending for current obligations	0
Accretion	16
Balance as of December 31, 2019	298
Other
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance as of December 31, 2018	397
Revisions in estimates for current obligations(a)	27
Additions	9
Spending for current obligations	(33)
Accretion	30
Balance as of December 31, 2019	$ 430

Benefit Plans and Other Postretirement Benefits - Narrative (Details) $ in Millions	Dec. 31, 2019 USD ($) numberOfBenefitPlans	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Benefit Plans and Other Postretirement Benefits
Number of qualified pension plans \| numberOfBenefitPlans	2
Pension Benefits
Benefit Plans and Other Postretirement Benefits
Expects to contribute to the pension plans	$ 56
GenOn
Benefit Plans and Other Postretirement Benefits
Pension liability retained			$ 92
Liability retained other post-employment and retiree health and welfare benefits		$ 23
GenOn \| Restructuring Support Agreement
Benefit Plans and Other Postretirement Benefits
Amount of pension liability future contributions			$ 13
Expects to contribute to the pension plans	$ 21

Benefit Plans and Other Postretirement Benefits - Net Benefit Costs and Funded Status (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Annual periodic pension cost
Curtailment gain	$ (8)
Pension and other post retirement benefit obligations
Curtailment gain	$ (32)
Pension Benefits
Annual periodic pension cost
Service cost benefits earned		$ 10	$ 23	$ 26
Interest cost on benefit obligation		46	44	43
Expected return on plan assets		(59)	(62)	(58)
Amortization of unrecognized net loss		3	0	4
Curtailment gain		0	7	0
Net periodic benefit cost		0	12	15
Pension and other post retirement benefit obligations
Benefit obligation at January 1		1,222	1,329
Service cost		10	23	26
Interest cost		46	44	43
Plan amendments		0	17
Actuarial (gain)/loss		207	(95)
Employee and retiree contributions		0	0
Curtailment gain		0	(20)
Benefit payments		(88)	(76)
Benefit obligation at December 31		1,397	1,222	1,329
Fair value of plan assets for pension and other post retirement benefit
Fair value of plan assets at January 1		981	1,104
Actual return on plan assets		216	(80)
Employee and retiree contributions		0	0
Employer contributions		41	33
Benefit payments		(88)	(76)
Fair value of plan assets at December 31		1,150	981	1,104
Funded status at December 31 — excess of obligation over assets		(247)	(241)
Other Postretirement Benefits Plan
Annual periodic pension cost
Service cost benefits earned		1	1	1
Interest cost on benefit obligation		3	4	4
Amortization of unrecognized prior service credit		(13)	(10)	(9)
Amortization of unrecognized net loss		0	0	(1)
Curtailment gain		0	(10)	0
Net periodic benefit cost		(9)	(15)	(5)
Pension and other post retirement benefit obligations
Benefit obligation at January 1		83	128
Service cost		1	1	1
Interest cost		3	4	4
Plan amendments		(2)	(28)
Actuarial (gain)/loss		16	(6)
Employee and retiree contributions		4	3
Curtailment gain		0	(7)
Benefit payments		(12)	(12)
Benefit obligation at December 31		93	83	128
Fair value of plan assets for pension and other post retirement benefit
Fair value of plan assets at January 1		0	0
Actual return on plan assets		0	0
Employee and retiree contributions		4	3
Employer contributions		7	9
Benefit payments		(11)	(12)
Fair value of plan assets at December 31		0	0	$ 0
Funded status at December 31 — excess of obligation over assets		$ (93)	$ (83)

Benefit Plans and Other Postretirement Benefits - Amounts Recognized in the Balance Sheets and OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Amounts recognized in balance sheet
Other current liabilities	$ 0	$ 0
Other non-current liabilities	247	241
Amounts recognized in accumulated OCI
Net loss/(gain)	138	90
Prior service cost/(credit)	2	3
Total/Net accumulated OCI	140	93
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss/(gain)	50	47
Amortization of net actuarial (gain)/loss	(3)	0	$ (4)
Curtailment	0	(27)
Prior service credit	0	17
Amortization of prior service cost	0	0
Total recognized in OCI	47	37
Net periodic benefit cost (credit)	0	12	15
Net recognized in net periodic pension cost/(credit) and OCI	47	49
Expected unrecognized gain that will be amortized from accumulated OCI to net periodic cost over the next fiscal year	5
Significant components of NRG's domestic pension plan
Projected benefit obligation	1,397	1,222	1,329
Accumulated benefit obligation	1,362	1,188
Fair value of plan assets	1,150	981	1,104
Other Postretirement Benefits Plan
Amounts recognized in balance sheet
Other current liabilities	7	7
Other non-current liabilities	86	76
Amounts recognized in accumulated OCI
Net loss/(gain)	7	(9)
Prior service cost/(credit)	(43)	(53)
Total/Net accumulated OCI	(36)	(62)
Other changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss/(gain)	16	(5)
Amortization of net actuarial (gain)/loss	0	0	1
Curtailment	0	2
Prior service credit	(2)	(28)
Amortization of prior service cost	12	10
Total recognized in OCI	26	(21)
Net periodic benefit cost (credit)	(9)	(15)	(5)
Net recognized in net periodic pension cost/(credit) and OCI	17	(36)
Expected unrecognized gain that will be amortized from accumulated OCI to net periodic cost over the next fiscal year	1
Expected amortization of unrecognized prior service credit over the next fiscal Year		14
Significant components of NRG's domestic pension plan
Projected benefit obligation	93	83	128
Fair value of plan assets	$ 0	$ 0	$ 0

Benefit Plans and Other Postretirement Benefits - Fair Values of Pension Assets By Asset Category and Level Within the Fair Value Hierarchy (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Minimum
Significant assumptions used to calculate NRG's benefit expense
Aon Hewitt above median yield curve discount rate (in years)	6 months
Maximum
Significant assumptions used to calculate NRG's benefit expense
Aon Hewitt above median yield curve discount rate (in years)	99 years
Pension Benefits
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	$ 1,150	$ 981	$ 1,104
Significant assumptions used to calculate NRG's benefit obligations
Discount rate	3.26%	4.38%
Rate of compensation increase	3.00%	3.00%
Significant assumptions used to calculate NRG's benefit expense
Discount rate			4.26%
Expected return on plan assets	6.35%	6.17%	6.85%
Rate of compensation increase	3.00%	3.00%	3.00%
Pension Benefits \| Minimum
Significant assumptions used to calculate NRG's benefit expense
Discount rate	4.38%	3.71%
Pension Benefits \| Maximum
Significant assumptions used to calculate NRG's benefit expense
Discount rate	4.20%	4.04%
Pension Benefits \| Common/collective trust investment — U.S. equity
Target allocations
Target allocation of pension plan assets (as percent)	20.00%
Pension Benefits \| Common/collective trust investment — non-U.S. equity
Target allocations
Target allocation of pension plan assets (as percent)	13.00%
Pension Benefits \| Common/collective trust investment — non-core assets
Target allocations
Target allocation of pension plan assets (as percent)	17.00%
Pension Benefits \| Common/collective trust investment — fixed income
Target allocations
Target allocation of pension plan assets (as percent)	50.00%
Pension Benefits \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	$ 12	$ 12
Pension Benefits \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Common/collective trust investment — U.S. equity
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	0	0
Pension Benefits \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Common/collective trust investment — non-U.S. equity
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	0	0
Pension Benefits \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Common/collective trust investment — non-core assets
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	0	0
Pension Benefits \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Common/collective trust investment — fixed income
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	0	0
Pension Benefits \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Short-term investment fund
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	12	12
Pension Benefits \| Significant Observable Inputs (Level 2)
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	721	609
Pension Benefits \| Significant Observable Inputs (Level 2) \| Common/collective trust investment — U.S. equity
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	233	183
Pension Benefits \| Significant Observable Inputs (Level 2) \| Common/collective trust investment — non-U.S. equity
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	73	53
Pension Benefits \| Significant Observable Inputs (Level 2) \| Common/collective trust investment — non-core assets
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	143	117
Pension Benefits \| Significant Observable Inputs (Level 2) \| Common/collective trust investment — fixed income
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	272	256
Pension Benefits \| Significant Observable Inputs (Level 2) \| Short-term investment fund
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	0	0
Pension Benefits \| Total
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	733	621
Pension Benefits \| Total \| Common/collective trust investment — U.S. equity
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	233	183
Pension Benefits \| Total \| Common/collective trust investment — non-U.S. equity
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	73	53
Pension Benefits \| Total \| Common/collective trust investment — non-core assets
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	143	117
Pension Benefits \| Total \| Common/collective trust investment — fixed income
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	272	256
Pension Benefits \| Total \| Short-term investment fund
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	12	12
Pension Benefits \| Fair Value Measured at Net Asset Value Per Share
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	1,150	981
Pension Benefits \| Fair Value Measured at Net Asset Value Per Share \| Common/collective trust investment — non-U.S. equity
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	84	70
Pension Benefits \| Fair Value Measured at Net Asset Value Per Share \| Common/collective trust investment — non-core assets
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	24	16
Pension Benefits \| Fair Value Measured at Net Asset Value Per Share \| Common/collective trust investment — fixed income
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	279	249
Pension Benefits \| Fair Value Measured at Net Asset Value Per Share \| Partnerships/joint ventures
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	30	25
Other Postretirement Benefits Plan
Benefit Plans and Other Postretirement Benefits
Fair value of plan assets	$ 0	$ 0	$ 0
Significant assumptions used to calculate NRG's benefit obligations
Discount rate	3.26%	4.37%
Rate of compensation increase	0.00%	0.00%
Significant assumptions used to calculate NRG's benefit expense
Discount rate			4.29%
Expected return on plan assets	0.00%	0.00%	0.00%
Rate of compensation increase	0.00%	0.00%	0.00%
Other Postretirement Benefits Plan \| Minimum
Significant assumptions used to calculate NRG's benefit expense
Discount rate	4.37%	3.71%
Other Postretirement Benefits Plan \| Maximum
Significant assumptions used to calculate NRG's benefit expense
Discount rate		4.08%
Other Postretirement Benefits Plan \| Postretirement Benefit Obligation
Significant assumptions used to calculate NRG's benefit obligations
Year Health care cost trend rate reaches ultimate trend rate	2028	2025
Other Postretirement Benefits Plan \| Postretirement Benefit Obligation \| Before age 65
Significant assumptions used to calculate NRG's benefit obligations
Health care trend rate	7.50%	7.80%	7.00%
Other Postretirement Benefits Plan \| Postretirement Benefit Obligation \| Age 65 and after
Significant assumptions used to calculate NRG's benefit obligations
Health care trend rate	4.50%	4.50%
Other Postretirement Benefits Plan \| Net Period Benefit Cost/Credit
Significant assumptions used to calculate NRG's benefit obligations
Year Health care cost trend rate reaches ultimate trend rate	2025	2025	2025
Other Postretirement Benefits Plan \| Net Period Benefit Cost/Credit \| Before age 65
Significant assumptions used to calculate NRG's benefit obligations
Health care trend rate	7.80%	8.20%
Other Postretirement Benefits Plan \| Net Period Benefit Cost/Credit \| Age 65 and after
Significant assumptions used to calculate NRG's benefit obligations
Health care trend rate	4.50%	4.50%	5.00%

Benefit Plans and Other Postretirement Benefits - Expected Future Benefit Payments For the Next Five Years and Other (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
One-percentage-point change in assumed health care cost trend rates
Effect on postretirement benefit obligation, 1-Percentage-Point Increase		$ 7
Effect on postretirement benefit obligation, 1-Percentage-Point Decrease		(5)
STP Defined Benefit Plans
Curtailment gain	$ 8
Increase to pension liability	$ (32)
Company's contributions to 401(k) plans
Company contributions to defined contribution plans		22	$ 28	$ 56
South Texas Project
STP Defined Benefit Plans
Amount reimbursed to STPNOC towards defined benefit plans		24	13
Expected reimbursement of contribution to retirement plan obligations to STPNOC in 2014		7
Pension Benefit Payments
NRG's expected future benefit payments
2020		84
2021		86
2022		86
2023		86
2024		86
2025-2029		402
STP Defined Benefit Plans
Curtailment gain		0	(7)	0
Increase to pension liability		0	(20)
Recognized amount in statement of financial position, statement of operations and accumulated OCI related to STP
Funded status — STPNOC benefit plans		(247)	(241)
Net periodic benefit cost (credit)		0	12	15
Total recognized in other comprehensive loss		(47)	(37)
Pension Benefit Payments \| South Texas Project
Recognized amount in statement of financial position, statement of operations and accumulated OCI related to STP
Funded status — STPNOC benefit plans		(77)	(78)
Net periodic benefit cost (credit)		9	8
Total recognized in other comprehensive loss		(13)	(7)
Other Postretirement Benefits Plan
NRG's expected future benefit payments
2020		7
2021		6
2022		6
2023		6
2024		6
2025-2029		19
Medicare prescription drug reimbursements
2020		0
2021		0
2022		0
2023		0
2024		0
2025-2029		2
STP Defined Benefit Plans
Curtailment gain		0	10	0
Increase to pension liability		0	(7)
Recognized amount in statement of financial position, statement of operations and accumulated OCI related to STP
Funded status — STPNOC benefit plans		(93)	(83)
Net periodic benefit cost (credit)		(9)	(15)	$ (5)
Total recognized in other comprehensive loss		(26)	21
Other Postretirement Benefits Plan \| South Texas Project
Recognized amount in statement of financial position, statement of operations and accumulated OCI related to STP
Funded status — STPNOC benefit plans		(20)	(19)
Net periodic benefit cost (credit)		(4)	(7)
Total recognized in other comprehensive loss		$ 6	$ 2
South Texas Project
STP Defined Benefit Plans
Ownership interest in STP (as a percent)		44.00%
Percentage of contribution to the retirement plan obligation reimbursed		44.00%

Capital Structure - Changes in Common Shares issued and Outstanding (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Capital Structure
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000	10,000,000	10,000,000
Common stock, shares authorized (in shares)	500,000,000	500,000,000	500,000,000	500,000,000
Increase (Decrease) in Stockholders' Equity (in shares)
Beginning balance, common shares issued (in shares)	420,288,886
Beginning balance, treasury shares(in shares)	(136,638,847)
Beginning balance, common shares outstanding (in shares)	283,650,039
Share repurchases (in shares)	(36,301,882)	(35,234,664)
Ending balance, common shares issued (in shares)	421,890,790	420,288,886
Ending balance, treasury shares (in shares)	(172,894,601)	(136,638,847)
Ending balance, common shares outstanding (in shares)	248,996,189	283,650,039
Common Stock
Increase (Decrease) in Stockholders' Equity (in shares)
Beginning balance, common shares issued (in shares)	420,288,886	418,323,134	417,583,825
Beginning balance, common shares outstanding (in shares)	283,650,039	316,743,089	315,443,011
Shares issued under ESPP (in shares)	46,128	175,862	560,769
Shares issued from LTIP (in shares)	1,601,904	1,965,752	739,309
Ending balance, common shares issued (in shares)	421,890,790	420,288,886	418,323,134
Ending balance, common shares outstanding (in shares)	248,996,189	283,650,039	316,743,089
Treasury Stock
Increase (Decrease) in Stockholders' Equity (in shares)
Beginning balance, treasury shares(in shares)	(136,638,847)	(101,580,045)	(102,140,814)
Shares issued under ESPP (in shares)	46,128	175,862	560,769
Shares issued from LTIP (in shares)	0	0	0
Share repurchases (in shares)	(36,301,882)	(35,234,664)
Ending balance, treasury shares (in shares)	(172,894,601)	(136,638,847)	(101,580,045)

Capital Structure - Common Stock (Details) - USD ($)		1 Months Ended	2 Months Ended	3 Months Ended			12 Months Ended
Capital Structure - Common Stock (Details) - USD ($)	Jan. 21, 2020	Mar. 31, 2019	Feb. 27, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Quarterly dividends per share (usd per share)							$ 0.03	$ 0.03	$ 0.03
Dividends paid per share (in usd per share)							$ 0.12	$ 0.12	$ 0.12
Eligible compensation withholding, minimum, percentage		1.00%
Eligible compensation withholding, maximum, percentage		10.00%					10.00%
Exercise price as a percentage of fair value (as a percent)		95.00%					85.00%
Treasury stock reserved for issuance under the ESPP (in shares)					2,885,060		2,885,060
Shares repurchased (in shares)							36,301,882	35,234,664
Long-term capital allocation policy, target allocation of cash generated allocated to growth investments, percentage					50.00%
Long-term capital allocation, target allocation, cash generated allocated returned to shareholders, percentage					50.00%
Capital Allocation Plan
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Stock repurchase program, authorized amount					$ 1,250,000,000		$ 1,250,000,000	$ 1,500,000,000
Shares repurchased (in shares)							37,238,810	35,234,664
2018 Capital Allocation Plan
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Shares repurchased (in shares)						250,000,000		1,250,000,000
2019 Capital Allocation Plan
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Shares repurchased (in shares)							1,194,000,000
Subsequent Event
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Dividends per common share (in usd per share)	$ 0.30
Subsequent Event \| Capital Allocation Plan
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Shares repurchased (in shares)			3,138,081
Subsequent Event \| 2019 Capital Allocation Plan
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Shares repurchased (in shares)			56,000,000
Scenario, Forecast
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Common stock, dividends, proposed annual amount, per share (usd per share)				$ 1.20
Scenario, Forecast \| Minimum
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Annual dividend growth rate, percentage				700.00%
Scenario, Forecast \| Maximum
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Annual dividend growth rate, percentage				9.00%
Scenario, Plan \| Subsequent Event
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Common stock, dividends, proposed annual amount, per share (usd per share)	$ 1.20
Long-term incentive plans
Common Stock, Employee Stock Purchase Plan and Share Repurchases
Long-term incentive plans (in shares)					16,029,127		16,029,127

Capital Structure - Summary of Changes in Shares Repurchased (Details) - USD ($) $ / shares in Units, $ in Millions	2 Months Ended		12 Months Ended
	Feb. 27, 2020	Apr. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)				36,301,882	35,234,664
Shares repurchased under May 24, 2018 Accelerated Repurchase Agreement
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)					10,829,903
Amounts paid for shares and share equivalents purchased (in millions)					$ 354
Shares repurchased under September 5, 2018 Accelerated Repurchase Agreement
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)					13,307,130
Amounts paid for shares and share equivalents purchased (in millions)					$ 500
Other repurchases
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)				26,863,211	11,097,631
Amounts paid for shares and share equivalents purchased (in millions)				$ 1,008	$ 396
Repurchases under February 28, 2019 Accelerated Share Repurchase Agreement
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)		9,438,671
Amounts paid for shares and share equivalents purchased (in millions)		$ 400
Equivalent shares purchased in lieu of tax withholding on equity compensation issuances
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)				936,928
Average price paid per share (in shares)				$ 38.78
Amounts paid for shares and share equivalents purchased (in millions)				$ 36
Capital Allocation Plan
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)				37,238,810	35,234,664
Average price paid per share (in shares)				$ 38.79	$ 35.48
Amounts paid for shares and share equivalents purchased (in millions)				$ 1,444	$ 1,250
Subsequent Event \| Other repurchases
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)	2,428,545
Amounts paid for shares and share equivalents purchased (in millions)	$ 92
Subsequent Event \| Equivalent shares purchased in lieu of tax withholding on equity compensation issuances
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)	709,536
Average price paid per share (in shares)			$ 38.24
Amounts paid for shares and share equivalents purchased (in millions)	$ 27
Subsequent Event \| Capital Allocation Plan
Capital Allocation Plan [Line Items]
Total number of shares purchased (in shares)	3,138,081
Average price paid per share (in shares)	$ 37.87
Amounts paid for shares and share equivalents purchased (in millions)	$ 119

Investments Accounted for by the Equity Method and Variable Interest Entities - Summary of Equity Method Investments (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Investments Accounted for by the Equity Method
Equity investments in affiliates	$ 388	$ 412
Undistributed earnings by equity investment	$ 42	$ 34
Agua Caliente
Investments Accounted for by the Equity Method
Economic interest in equity method investments (as a percent)	35.00%
Equity investments in affiliates	$ 213
Gladstone
Investments Accounted for by the Equity Method
Economic interest in equity method investments (as a percent)	37.50%
Equity investments in affiliates	$ 124
Ivanpah Master Holdings, LLC
Investments Accounted for by the Equity Method
Economic interest in equity method investments (as a percent)	54.50%
Equity investments in affiliates	$ 20
Watson Cogeneration Company
Investments Accounted for by the Equity Method
Economic interest in equity method investments (as a percent)	49.00%
Equity investments in affiliates	$ 15
Midway-Sunset Cogeneration Company
Investments Accounted for by the Equity Method
Economic interest in equity method investments (as a percent)	50.00%
Equity investments in affiliates	$ 9
Other
Investments Accounted for by the Equity Method
Equity investments in affiliates	$ 7

Investments Accounted for by the Equity Method and Variable Interest Entities - PG&E Bankruptcy (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Investments Accounted for by the Equity Method
Equity investments in affiliates	$ 388	$ 412
Agua Caliente
Investments Accounted for by the Equity Method
Equity investments in affiliates	213
Ivanpah Master Holdings, LLC
Investments Accounted for by the Equity Method
Equity investments in affiliates	$ 20

Investments Accounted for by the Equity Method and Variable Interest Entities - Variable Interest Entities (Details) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2018 USD ($)	Dec. 31, 2019 project MW	Dec. 31, 2018 USD ($)
Schedule of Equity Method Investments [Line Items]
Generation capacity (in MW) \| MW		23,000
Ivanpah Master Holdings LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage		54.50%
Number of solar electric generating projects \| project		3
Generation capacity (in MW) \| MW		393
Release of reserves to fund equity distributions	$ 95
Loss on deconsolidation			$ 22
Reduction of assets due to deconsolidation			1,300
Reduction of liabilities due to deconsolidation			$ 1,200
Gladstone
Schedule of Equity Method Investments [Line Items]
Ownership percentage		37.50%
Generation capacity (in MW) \| MW		1,613

Investments Accounted for by the Equity Method and Variable Interest Entities - Other Equity Investments (Details) $ in Millions	Dec. 31, 2019 USD ($) MW	Dec. 31, 2018 USD ($)
Schedule of Equity Method Investments [Line Items]
Generation capacity (in MW) \| MW	23,000
Equity investments in affiliates \| $	$ 388	$ 412
Gladstone
Schedule of Equity Method Investments [Line Items]
Ownership percentage	37.50%
Generation capacity (in MW) \| MW	1,613
Equity investments in affiliates \| $	$ 124

Investments Accounted For by the Equity Method and Variable Interest Entities - Entities that are Consolidated (Details) - Variable Interest Entity - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Current assets	$ 3	$ 3
Net property, plant and equipment	71	76
Other long-term assets	27	28
Total assets	101	107
Current liabilities	4	2
Long-term debt	24	29
Other long-term liabilities	8	7
Total liabilities	36	38
Redeemable noncontrolling interests	20	19
Net assets less noncontrolling interests	$ 45	$ 50

Earnings /Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic income/(loss) per share attributable to NRG, Inc;
Net Income/(Loss) Attributable to NRG Energy, Inc.									$ 4,438	$ 268	$ (2,153)
Weighted average number of common shares outstanding — basic (in shares)	251,000,000	254,000,000	265,000,000	278,000,000	289,000,000	299,000,000	310,000,000	318,000,000	262,000,000	304,000,000	317,000,000
Income/(Loss) per weighted average common share — basic (in usd per share)	$ 13.48	$ 1.46	$ 0.76	$ 1.73	$ (0.04)	$ (0.24)	$ 0.23	$ 0.88	$ 16.94	$ 0.88	$ (6.79)
Incremental shares attributable to the issuance of equity compensation (treasury stock method) (in shares)									2,000,000	4,000,000	0
Weighted average number of common shares outstanding — diluted (in shares)	253,000,000	256,000,000	267,000,000	280,000,000	289,000,000	299,000,000	314,000,000	322,000,000	264,000,000	308,000,000	317,000,000
Income (Loss) per weighted average common share — diluted (in usd per share)	$ 13.37	$ 1.45	$ 0.75	$ 1.72	$ (0.04)	$ (0.24)	$ 0.23	$ 0.87	$ 16.81	$ 0.87	$ (6.79)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

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+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Earnings /Loss Per Share - Summary of Outstanding Equity Instruments that are Anti-dilutive and Excluded from Computation of Loss Per Share (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Compensation Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	0	5

Segment Reporting (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
Segment Reporting (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement
Revenues		$ 2,195	$ 2,996	$ 2,465	$ 2,165	$ 1,992	$ 2,960	$ 2,461	$ 2,065	$ 9,821	$ 9,478	$ 9,074
Operating expenses										8,153	7,997	7,766
Depreciation and amortization										373	421	596
Impairment losses										5	99	1,534
Development costs										7	11	22
Total operating costs and expenses										8,538	8,528	9,918
Other income - affiliate	$ 84									0	0	87
(Loss)/Gain on sale of assets										7	32	16
Operating (loss)/income		209	540	320	221	49	398	174	361	1,290	982	(741)
Equity in earnings/(losses) of unconsolidated affiliates										2	9	(14)
Impairment losses on investments										(108)	(15)	(79)
Other income, net										66	18	51
Loss on debt extinguishment										(51)	(44)	(49)
Interest expense										(413)	(483)	(557)
Income/(Loss) from Continuing Operations Before Income Taxes										786	467	(1,389)
Income tax (benefit)/expense										(3,334)	7	(44)
Income/(Loss) from Continuing Operations		3,463	374	189	94	(93)	287	27	238	4,120	460	(1,345)
Income/(loss) from discontinued operations, net of income tax		(78)	(2)	13	388	80	(336)	69	(5)	321	(192)	(992)
Net Income/(Loss)		3,385	372	202	482	(13)	(49)	96	233	4,441	268	(2,337)
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests		2	$ 0	$ 1	$ 0	(2)	$ 23	$ 24	$ (46)	3	0	(184)
Net Income/(Loss) Attributable to NRG Energy, Inc.										4,438	268	(2,153)
Balance sheet
Equity investments in affiliates		388				412				388	412
Capital expenditures		228				388				228	388
Goodwill		579				573				579	573
Total assets		12,531				10,628				12,531	10,628
Eliminations
Income Statement
Revenues										(7)	(18)	(47)
Operating expenses										(7)	(18)	(48)
Depreciation and amortization										0	0	(3)
Impairment losses										0	0	0
Development costs										0	0	0
Total operating costs and expenses										(7)	(18)	(51)
Other income - affiliate												0
(Loss)/Gain on sale of assets										0	0	0
Operating (loss)/income										0	0	4
Equity in earnings/(losses) of unconsolidated affiliates										0	0	0
Impairment losses on investments										0	0	0
Other income, net										0	0	0
Loss on debt extinguishment										0	0	0
Interest expense										0	0	0
Income/(Loss) from Continuing Operations Before Income Taxes										0	0	4
Income tax (benefit)/expense										0	0	0
Income/(Loss) from Continuing Operations										0	0	4
Income/(loss) from discontinued operations, net of income tax										0	0	0
Net Income/(Loss)										0	0	4
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests										0	0	4
Net Income/(Loss) Attributable to NRG Energy, Inc.										0	0	0
Balance sheet
Equity investments in affiliates		0				0				0	0
Capital expenditures		0				0				0	0
Goodwill		0				0				0	0
Total assets		(4,872)				(5,095)				(4,872)	(5,095)
Texas \| Operating Segments
Income Statement
Revenues										7,069	6,401	6,318
Operating expenses										5,818	5,399	5,393
Depreciation and amortization										188	156	258
Impairment losses										1	5	1,317
Development costs										3	3	4
Total operating costs and expenses										6,010	5,563	6,972
Other income - affiliate												0
(Loss)/Gain on sale of assets										0	4	5
Operating (loss)/income										1,059	842	(649)
Equity in earnings/(losses) of unconsolidated affiliates										(4)	(3)	(22)
Impairment losses on investments										(103)	(15)	(69)
Other income, net										20	13	(2)
Loss on debt extinguishment										0	0	0
Interest expense										0	0	0
Income/(Loss) from Continuing Operations Before Income Taxes										972	837	(742)
Income tax (benefit)/expense										0	0	0
Income/(Loss) from Continuing Operations										972	837	(742)
Income/(loss) from discontinued operations, net of income tax										0	0	0
Net Income/(Loss)										972	837	(742)
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests										0	0	0
Net Income/(Loss) Attributable to NRG Energy, Inc.										972	837	(742)
Balance sheet
Equity investments in affiliates		6				6				6	6
Capital expenditures		136				143				136	143
Goodwill		325				320				325	320
Total assets		5,711				5,357				5,711	5,357
Texas \| Eliminations
Income Statement
Revenues										(1)	(19)	(41)
East \| Operating Segments
Income Statement
Revenues										2,319	2,371	2,009
Operating expenses										1,895	2,024	1,684
Depreciation and amortization										121	105	112
Impairment losses										0	82	106
Development costs										3	3	6
Total operating costs and expenses										2,019	2,214	1,908
Other income - affiliate												0
(Loss)/Gain on sale of assets										1	0	15
Operating (loss)/income										301	157	116
Equity in earnings/(losses) of unconsolidated affiliates										0	0	0
Impairment losses on investments										0	0	0
Other income, net										6	2	4
Loss on debt extinguishment										0	0	0
Interest expense										(18)	(22)	(29)
Income/(Loss) from Continuing Operations Before Income Taxes										289	137	91
Income tax (benefit)/expense										2	1	0
Income/(Loss) from Continuing Operations										287	136	91
Income/(loss) from discontinued operations, net of income tax										0	0	0
Net Income/(Loss)										287	136	91
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests										0	0	0
Net Income/(Loss) Attributable to NRG Energy, Inc.										287	136	91
Balance sheet
Equity investments in affiliates		0				0				0	0
Capital expenditures		30				171				30	171
Goodwill		254				253				254	253
Total assets		2,160				2,187				2,160	2,187
East \| Eliminations
Income Statement
Revenues										(8)	5	(1)
West/Other \| Operating Segments
Income Statement
Revenues										440	724	788
Operating expenses										397	467	498
Depreciation and amortization										33	127	194
Impairment losses										4	12	111
Development costs										1	3	6
Total operating costs and expenses										435	609	809
Other income - affiliate												0
(Loss)/Gain on sale of assets										0	(2)	(5)
Operating (loss)/income										5	113	(26)
Equity in earnings/(losses) of unconsolidated affiliates										6	13	10
Impairment losses on investments										0	0	(6)
Other income, net										10	4	22
Loss on debt extinguishment										(3)	0	0
Interest expense										(10)	(39)	(77)
Income/(Loss) from Continuing Operations Before Income Taxes										8	91	(77)
Income tax (benefit)/expense										1	0	(6)
Income/(Loss) from Continuing Operations										7	91	(71)
Income/(loss) from discontinued operations, net of income tax										0	0	0
Net Income/(Loss)										7	91	(71)
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests										3	5	1
Net Income/(Loss) Attributable to NRG Energy, Inc.										4	86	(72)
Balance sheet
Equity investments in affiliates		382				406				382	406
Capital expenditures		25				29				25	29
Goodwill		0				0				0	0
Total assets		1,190				1,548				1,190	1,548
West/Other \| Eliminations
Income Statement
Revenues										2	(4)	4
Corporate \| Operating Segments
Income Statement
Revenues										0	0	6
Operating expenses										50	125	239
Depreciation and amortization										31	33	35
Impairment losses										0	0	0
Development costs										0	2	6
Total operating costs and expenses										81	160	280
Other income - affiliate												87
(Loss)/Gain on sale of assets										6	30	1
Operating (loss)/income										(75)	(130)	(186)
Equity in earnings/(losses) of unconsolidated affiliates										0	(1)	(2)
Impairment losses on investments										(5)	0	(4)
Other income, net										30	(1)	27
Loss on debt extinguishment										(48)	(44)	(49)
Interest expense										(385)	(422)	(451)
Income/(Loss) from Continuing Operations Before Income Taxes										(483)	(598)	(665)
Income tax (benefit)/expense										(3,337)	6	(38)
Income/(Loss) from Continuing Operations										2,854	(604)	(627)
Income/(loss) from discontinued operations, net of income tax										321	(192)	(992)
Net Income/(Loss)										3,175	(796)	(1,619)
Less: Net income attributable to noncontrolling interests and redeemable noncontrolling interests										0	(5)	(189)
Net Income/(Loss) Attributable to NRG Energy, Inc.										3,175	(791)	(1,430)
Balance sheet
Equity investments in affiliates		0				0				0	0
Capital expenditures		37				45				37	45
Goodwill		0				0				0	0
Total assets		$ 8,342				$ 6,631				8,342	6,631
Corporate \| Eliminations
Income Statement
Revenues										$ 0	$ 0	$ (9)
Customer Concentration Risk \| Texas
Segment Reporting Information
Concentration risk, percentage										10.00%	11.00%

Income Taxes - Income Tax Provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
State	$ 2	$ 6	$ 19
Foreign	4	0	0
Total — current	6	6	19
Deferred
U.S. Federal	(3,000)	(16)	(60)
State	(340)	16	(5)
Foreign	0	1	2
Total — deferred	(3,340)	1	(63)
Income tax expense/(benefit)	(3,334)	7	(44)
Domestic and foreign components of income from continuing operations before income tax expense
U.S.	771	468	(1,406)
Foreign	15	(1)	17
Income/(Loss) from Continuing Operations Before Income Taxes	786	467	(1,389)
Reconciliation of the U.S. federal statutory rate to NRG's effective rate from continuing operations
Income/(loss) from continuing operations before income taxes	786	467	(1,389)
Tax at federal statutory tax rate	165	98	(486)
State taxes	13	18	19
Foreign operations	0	0	2
Permanent differences	(9)	7	0
Valuation allowance - current period activities	(3,492)	(106)	455
Book goodwill impairment	0	0	30
Deferred impact of state tax rate changes	12	0	0
Production tax credits ("PTC")	0	(7)	(8)
Recognition of uncertain tax benefits	(10)	1	(5)
Alternative minimum tax ("AMT") refundable credit	0	(4)	(64)
Tax Act - corporate income tax rate change	0	0	665
Valuation allowance due to corporate income tax rate change	0	0	(660)
Other	(13)	0	8
Income tax expense/(benefit)	$ (3,334)	$ 7	$ (44)
Effective income tax rate (as a percent)	(424.20%)	1.50%	3.20%

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Deferred compensation, accrued vacation and other reserves	$ 81	$ 134
Difference between book and tax basis of property	548	554
Goodwill	0	11
Differences between book and tax basis of contracts	0	38
Pension and other postretirement benefits	86	87
Equity compensation	11	9
Bad debt reserve	13	14
U.S. Federal net operating loss carryforwards	2,116	2,241
Foreign net operating loss carryforwards	105	63
State net operating loss carryforwards	360	379
Federal and state tax credit carryforwards	384	381
Federal benefit on state uncertain tax positions	4	6
Intangibles amortization (excluding goodwill)	0	21
Interest disallowance carryforward per §163(j) of the Tax Act	82	102
Inventory obsolescence	7	7
Other	3	0
Discontinued operations	0	17
Total deferred tax assets	3,800	4,064
Net deferred tax liability		(19)
Deferred Tax Liabilities, Gross [Abstract]
Emissions allowances	19	15
Derivatives, net	27	37
Goodwill	8	0
Intangibles amortization (excluding goodwill)	15	0
Equity method investments	201	180
Convertible Debt	19	21
Deferred Tax Liabilities, Other	0	1
Discontinued operations	0	36
Deferred Tax Liabilities, Gross, Total	289	290
Total deferred tax assets less deferred tax liabilities	3,511	3,774
Valuation allowance	(242)	(3,812)
Discontinued operations	0	19
Net deferred tax asset	3,269
Net deferred tax liability		(19)
NRG's net deferred tax position
Deferred tax asset	3,286	46
Deferred tax liability	(17)	(65)
Deferred tax asset	$ 3,269
Net deferred tax liability		$ (19)

Income Taxes - Deferred Tax Assets and Valuation Allowance, Taxes Receivable and Payable (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Taxes receivable and payable
Valuation allowance - current period activities	$ 3,492	$ 106	$ (455)
NOLs untilized	593
Deferred tax liability		19
Deferred tax asset	3,269
Net deferred tax asset	3,500	3,800
Valuation allowance	242	$ 3,812
Current taxes payable	13
Current taxes receivable	1
Federal Tax Authority
Taxes receivable and payable
Operating loss carryforwards	2,100
State and Local Jurisdiction
Taxes receivable and payable
Operating loss carryforwards	360
Foreign Tax Authority
Taxes receivable and payable
Operating loss carryforwards	$ 105

Income Taxes - Reconciliation of Uncertain Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Uncertain tax benefits
Uncertain tax benefits	$ 26	$ 30	$ 15	$ 26
Liability for uncertainty in income taxes, noncurrent			17	30
Unrecognized tax benefits, income tax penalties expense	1
Accrued interest and penalties related to unrecognized tax benefits			$ 2	$ 4
Uncertain tax benefits reconciliation
Balance as of January 1	26	30
Increase due to current year positions	2	4
Settlements, payments and statute closure	(13)	(8)
Uncertain tax benefits as of December 31	$ 15	$ 26

Stock-Based Compensation - Long-Term Incentive Plan (Details) - shares	Apr. 27, 2017	Dec. 31, 2019	Dec. 31, 2018
NRG LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in the number of shares available for issuance (in shares)	3,000,000
Number of shares authorized for issuance under plan (in shares)		25,000,000	25,000,000
Number of shares available for grant under plan (in shares)		9,935,750	8,564,611
NRG GenOn LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance under plan (in shares)	0
Number of shares available for grant under plan (in shares)		319,264	520,182

Stock-Based Compensation - Restricted Stock Units (RSUs (Details) - RSUs - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Award vesting period	3 years
Units
Non-vested at beginning of period (in shares)	1,458,082
Granted (in shares)	266,938
Forfeited (in shares)	(73,905)
Vested (in shares)	(933,876)
Non-vested at end of period (in shares)	717,239	1,458,082
Weighted Average Grant Date Fair Value per Unit
Non-vested at beginning of period (in usd per share)	$ 16.16
Granted (in usd per share)	37.37	$ 28.90	$ 12.44
Forfeited (in usd per share)	24.73
Vested (in usd per share)	14.20
Non-vested at end of period (in usd per share)	$ 25.56	$ 16.16
Vested in period, fair value	$ 36	$ 42	$ 19
Weighted average grant date fair value (in usd per share)	$ 37.37	$ 28.90	$ 12.44

Stock-Based Compensation - Deferred Stock Units, DSUs (Details) - DSUs - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Units
Balance outstanding at the beginning of the period (in shares)	331,915
Granted (in shares)	57,630
Converted to Common Stock (in shares)	(58,322)
Balance outstanding at the end of the period (in shares)	331,223	331,915
Weighted Average Grant Date Fair Value per Unit
Balance outstanding at the beginning of the period, (in usd per share)	$ 22.94
Granted (in usd per share)	34.84	$ 33.43	$ 16.76
Vested (in usd per share)	28.93
Balance outstanding at the end of the period (in usd per share)	$ 23.98	$ 22.94
Aggregate intrinsic value for DSUs outstanding	$ 13,000,000	$ 13,000,000	$ 12,000,000
Aggregate intrinsic values for DSUs converted to common stock during the period	$ 2,000,000	$ 6,000,000	$ 4,000,000
Weighted average grant date fair value (in usd per share)	$ 34.84	$ 33.43	$ 16.76

Stock -Based Compensation - Performance Stock Units, RPSUs and MSUs Plan description (Details)	12 Months Ended
	Dec. 31, 2019 shares
RPSUs
Stock-Based Compensation
Award vesting period	3 years
Award vesting right, percentage	200.00%
RPSUs \| Share-based Payment Arrangement, Tranche One
Stock-Based Compensation
Award vesting right, percentage	0.00%
RPSUs \| Share-based Payment Arrangement, Tranche Two
Stock-Based Compensation
Award vesting right, percentage	25.00%
RPSUs \| Share-based Payment Arrangement, Tranche Three
Stock-Based Compensation
Award vesting right, percentage	100.00%
RPSUs \| Share-based Payment Arrangement, Tranche Four
Stock-Based Compensation
Award vesting right, percentage	15.00%
RPSUs \| Share-based Payment Arrangement, Tranche Five
Stock-Based Compensation
Award vesting right, percentage	200.00%
MSUs
Stock-Based Compensation
Award vesting right, percentage	200.00%
MSUs \| Share-based Payment Arrangement, Tranche One
Stock-Based Compensation
Award vesting right, percentage	25.00%
Vested (in shares)	0
MSUs \| Share-based Payment Arrangement, Tranche Two
Stock-Based Compensation
Award vesting right, percentage	25.00%
MSUs \| Share-based Payment Arrangement, Tranche Three
Stock-Based Compensation
Award vesting right, percentage	25.00%
MSUs \| Share-based Payment Arrangement, Tranche Four
Stock-Based Compensation
Award vesting right, percentage	100.00%
MSUs \| Share-based Payment Arrangement, Tranche Five
Stock-Based Compensation
Award vesting right, percentage	100.00%

Stock-Based Compensation - Performance Stock Units (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
PSUs
Units
Non-vested at beginning of period (in shares)	1,710,634
Granted (in shares)	936,889
Forfeited (in shares)	(37,526)
Vested (in shares)	(1,409,456)
Non-vested at end of period (in shares)	1,200,541	1,710,634
Weighted Average Grant-Date Fair Value per Unit
Non-vested at beginning of period (in usd per share)	$ 19.12
Granted (in usd per share)	22.50	$ 35.36	$ 15.91
Forfeited (in usd per share)	23.04
Vested (in usd per share)	14.72
Non-vested at end of period (in usd per share)	26.65	$ 19.12
RPSUs
Weighted Average Grant-Date Fair Value per Unit
Granted (in usd per share)	$ 45.77
Award vesting, percentage	200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected volatility	40.72%	47.52%	43.96%
Expected term (in years)	3 years	3 years	3 years
Risk free rate	2.45%	2.01%	1.50%
MSUs
Units
Non-vested at end of period (in shares)	8,645
Weighted Average Grant-Date Fair Value per Unit
Granted (in usd per share)	$ 14.72
Award vesting, percentage	200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected volatility				34.33%
Expected term (in years)				3 years
Risk free rate				1.31%

Stock-Based Compensation - Non-Qualified Stock Options (Details) - NQSOs - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Shares granted during the period (in shares)	0	0	0
Maximum contractual term for outstanding options (in years)	10 years
NQSO activity and changes
Outstanding at the beginning of the period (in shares)	279,934
Forfeited (in shares)	(8,254)
Exercised (in shares)	(137,282)
Outstanding at the end of the period (in shares)	134,398	279,934
Exercisable at the end of the period (in shares)	134,398
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding (in usd per share)	$ 25.04
Forfeited (in usd per share)	26.76
Exercised (in usd per share)	24.67
Outstanding (in usd per share)	25.31	$ 25.04
Exercisable (in usd per share)	$ 25.31
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures
Weighted Average Remaining Contractual Term, Outstanding (in years)	1 year	2 years
Weighted Average Remaining Contractual Term, Exercisable (in years)	1 year
Aggregate Intrinsic Value	$ 2	$ 4
Aggregate Intrinsic Value, Exercisable	$ 2

Stock-Based Compensation - Intrinsic Value of Options Exercised and Cash Received (Details) - NQSOs - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised	$ 2	$ 10	$ 1
Cash received from options exercised	$ 3	$ 24	$ 4

Stock-Based Compensation - Supplemental Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-Based Compensation
Minimum tax withholdings	$ 36	$ 19	$ 5
Compensation Expense	32	41	38
Tax detriment recognized	(12)	(4)	(5)
Unrecognized Total Cost	27
GenOn
Stock-Based Compensation
Compensation Expense		1	6
RSUs
Stock-Based Compensation
Compensation Expense	9	12	15
Unrecognized Total Cost	$ 8
Weighted Average Recognition Period Remaining (In years)	1 year 21 days
Award vesting period	3 years
DSUs
Stock-Based Compensation
Compensation Expense	$ 2	2	2
Unrecognized Total Cost	$ 0
Weighted Average Recognition Period Remaining (In years)	0 years
MSUs
Stock-Based Compensation
Compensation Expense	$ 0	4	5
Unrecognized Total Cost	$ 0
Weighted Average Recognition Period Remaining (In years)	6 months
RPSUs
Stock-Based Compensation
Compensation Expense	$ 10	7	3
Unrecognized Total Cost	$ 9
Weighted Average Recognition Period Remaining (In years)	8 months 15 days
Award vesting period	3 years
PRSUs
Stock-Based Compensation
Compensation Expense	$ 11	$ 16	$ 13
Unrecognized Total Cost	$ 10
Weighted Average Recognition Period Remaining (In years)	1 year 18 days
Award vesting period	3 years

Related Party Transactions - Summary of Material Related Party Transactions With Third Party Affiliates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Revenues from Related Parties Included in Operating Revenues	$ 44	$ 32	$ 8
Gladstone
Related Party Transaction [Line Items]
Revenues from Related Parties Included in Operating Revenues	4	3	3
GenConn(a)
Related Party Transaction [Line Items]
Revenues from Related Parties Included in Operating Revenues	0	4	5
Ivanpah(b)
Related Party Transaction [Line Items]
Revenues from Related Parties Included in Operating Revenues	35	20	0
Midway-Sunset
Related Party Transaction [Line Items]
Revenues from Related Parties Included in Operating Revenues	$ 5	$ 5	$ 0

Related Party Transactions - Service Agreement and Transition Service Agreement with GeOn (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Jul. 16, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 12, 2017
Related Party Transaction [Line Items]
Service fees			$ 44	$ 32	$ 8
Other income - affiliate		$ 84	0	0	87
Services Agreement \| GenOn
Related Party Transaction [Line Items]
Credit applied		$ 28
Services Agreement \| Restructuring Support Agreement
Related Party Transaction [Line Items]
Shared services annualized rate						$ 84
Services Agreement \| Restructuring Support Agreement \| GenOn
Related Party Transaction [Line Items]
Credit applied	$ 28
Transition Services Agreement \| Restructuring Support Agreement \| GenOn
Related Party Transaction [Line Items]
Other income - affiliate					87
Shared service, selling, general and administrative				$ 53	$ 42
Management Service \| Services Agreement \| GenOn
Related Party Transaction [Line Items]
Service fees			$ 193

Related Party Transactions - Credit Agreement with GenOn and Commercial Operations Agreement (Details) - Revolving Credit Facility - Intercompany Credit Agreement - GenOn - USD ($)	Dec. 31, 2019	Dec. 31, 2017
Related Party Transaction [Line Items]
Revolving credit facility	$ 500,000,000
Letters of credit outstanding under revolver	$ 14,000,000	$ 92,000,000

Commitments and Contingencies - Transportation and Purchased Power Commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Coal, Gas and Transportation Commitments
Commitments and Contingencies
Purchases	$ 1,200	$ 1,200	$ 1,100
Minimum purchase commitment
2020	124
2021	125
2022	73
2023	53
2024	62
Thereafter	139
Total	576
Purchases	1,200	$ 1,200	$ 1,100
Renewable Purchased Power Agreements
Minimum purchase commitment
2020	35
2021	49
2022	68
2023	56
2024	56
Thereafter	349
Total	$ 613

Commitments and Contingencies - Narrative (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2019 USD ($) facility	Dec. 31, 2019 USD ($) case	Dec. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Nuclear insurance liability limit per incident		$ 13,900,000
Required nuclear liability insurance		450,000
Nuclear financial protection pool mandated by the Price-Anderson Act		13,500,000
Maximum assessment mandated by Price-Anderson Act per nuclear reactor for a nuclear incident		$ 138,000
Maximum assessment, administrative fee (as percent)		5.00%
Maximum assessment payment mandated by Price-Anderson Act for a nuclear incident		$ 21,000
Maximum assessment		44.00%
Nuclear operator maximum annual assessment		$ 9,000
Maximum liability per nuclear incident		61,000
Mutual property insurance additional blanket policy property coverage		1,250,000
Nuclear property insurance coverage limit per individual insured		1,500,000
Lost revenue insurance maximum weekly recovery		2,500
Accidental outage weekly recovery limit for loss revenues from a nuclear industry mutual insurance company in the event of insurable loss		$ 1,980
The number of months a nuclear industry mutual insurance company will respond to retrospective premium adjustments		24 months
Number of years board of directors of industry mutual insurance company can adjust policy after policy expires		6 years
Sierra Club Et Al V. Midwest Generation L L C
Loss Contingencies [Line Items]
Number of facilities \| facility	4
Commonwealth Edison Company And Exelon Generation Company LLC
Loss Contingencies [Line Items]
Financial obligations under agreement	$ 26,000
XOOM Energy Litigation
Loss Contingencies [Line Items]
Number of class action lawsuits \| case		2
High
Loss Contingencies [Line Items]
Multiplier that the industry mutual insurance company may assess against insureds premium		10
Low
Loss Contingencies [Line Items]
Multiplier that the industry mutual insurance company may assess against insureds premium		6
Nuclear Event
Loss Contingencies [Line Items]
Total nuclear property insurance coverage		$ 2,750,000
Lost revenue insurance maximum weekly recovery		274,000
Accidental outage weekly recovery limit for loss revenues from a nuclear industry mutual insurance company in the event of insurable loss		216,000
Non-nuclear Event
Loss Contingencies [Line Items]
Total nuclear property insurance coverage		1,000,000
Lost revenue insurance maximum weekly recovery		184,000
Accidental outage weekly recovery limit for loss revenues from a nuclear industry mutual insurance company in the event of insurable loss		$ 144,000
Lignite Contract with Texas Westmoreland Coal Co.
Loss Contingencies [Line Items]
Bond obligation			$ 99,000

Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
Cash Flow Information (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Information [Abstract]
Interest paid, net of amount capitalized	$ 372	$ 436	$ 543
Income taxes paid, net of refunds	8	9	9
Additions to fixed assets for accrued capital expenditures	$ 1	$ 20	$ 19

Guarantees (Details) - USD ($) $ in Millions	12 Months Ended
Guarantees (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Guarantor Obligations
Under 1 Year	$ 959
1-3 Years	610
3-5 Years	31
Over 5 Years	410
Guarantees by Remaining Maturity, Total	2,010	$ 2,767
Letters of credit and surety bonds
Guarantor Obligations
Under 1 Year	878
1-3 Years	115
3-5 Years	31
Over 5 Years	0
Guarantees by Remaining Maturity, Total	$ 1,024	1,253
Letters of credit and surety bonds, maximum expiration period (in years)	1 year
Asset sales guarantee obligations
Guarantor Obligations
Under 1 Year	$ 4
1-3 Years	490
3-5 Years	0
Over 5 Years	204
Guarantees by Remaining Maturity, Total	698	793
Other guarantees
Guarantor Obligations
Under 1 Year	77
1-3 Years	5
3-5 Years	0
Over 5 Years	206
Guarantees by Remaining Maturity, Total	288	$ 721
GenOn \| Letters of credit and surety bonds
Guarantor Obligations
Guarantees by Remaining Maturity, Total	$ 14

Jointly Owned Plants (Details) $ in Millions	Dec. 31, 2019 USD ($)
South Texas Project Units 1 and 2, Bay City, TX
Jointly Owned Utility Plant Interests
Ownership Interest (as a percent)	44.00%
Property, Plant & Equipment	$ 413
Accumulated Depreciation	(206)
Construction in Progress	$ 8
Cedar Bayou Unit 4, Baytown, TX
Jointly Owned Utility Plant Interests
Ownership Interest (as a percent)	50.00%
Property, Plant & Equipment	$ 218
Accumulated Depreciation	(93)
Construction in Progress	$ 7

Unaudited Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 2,195	$ 2,996	$ 2,465	$ 2,165	$ 1,992	$ 2,960	$ 2,461	$ 2,065	$ 9,821	$ 9,478	$ 9,074
Operating income	209	540	320	221	49	398	174	361	1,290	982	(741)
Net income from continuing operations	3,463	374	189	94	(93)	287	27	238	4,120	460	(1,345)
Income/(loss) from discontinued operations, net of income tax	(78)	(2)	13	388	80	(336)	69	(5)	321	(192)	(992)
Net Income/(Loss)	3,385	372	202	482	(13)	(49)	96	233	4,441	268	(2,337)
Less: Net income/(loss) attributable to noncontrolling interest and redeemable interests	2	0	1	0	(2)	23	24	(46)	$ 3	$ 0	$ (184)
Income/(Loss) Available to Common Stockholders	$ 3,383	$ 372	$ 201	$ 482	$ (11)	$ (72)	$ 72	$ 279
Weighted average number of common shares outstanding — basic (in shares)	251,000,000	254,000,000	265,000,000	278,000,000	289,000,000	299,000,000	310,000,000	318,000,000	262,000,000	304,000,000	317,000,000
Income/(loss) from discontinued operations per weighted average common share — basic (in usd per share)	$ (0.31)	$ (0.01)	$ 0.05	$ 1.39	$ 0.28	$ (1.12)	$ 0.22	$ (0.02)	$ 1.23	$ (0.63)	$ (3.13)
Income/(Loss) per weighted average common share — basic (in usd per share)	$ 13.48	$ 1.46	$ 0.76	$ 1.73	$ (0.04)	$ (0.24)	$ 0.23	$ 0.88	$ 16.94	$ 0.88	$ (6.79)
Weighted average number of common shares outstanding — diluted (in shares)	253,000,000	256,000,000	267,000,000	280,000,000	289,000,000	299,000,000	314,000,000	322,000,000	264,000,000	308,000,000	317,000,000
Income/(loss) from discontinued operations per weighted average common share — diluted (in usd per share)	$ (0.31)	$ (0.01)	$ 0.05	$ 1.38	$ 0.28	$ (1.12)	$ 0.22	$ (0.02)	$ 1.22	$ (0.62)	$ (3.13)
Net (loss)/income per weighted average common share — diluted (in usd per share)	$ 13.37	$ 1.45	$ 0.75	$ 1.72	$ (0.04)	$ (0.24)	$ 0.23	$ 0.87	$ 16.81	$ 0.87	$ (6.79)

Condensed Consolidating Financial Information (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument
Long-term debt	$ 6,042	$ 6,691
Recourse Debt
Debt Instrument
Long-term debt	6,008	$ 6,523
Senior Notes due 2026 To 2048 \| Recourse Debt
Debt Instrument
Long-term debt	4,400
Senior Secured First Lien Notes due 2024 to 2029 \| Recourse Debt
Debt Instrument
Long-term debt	$ 1,100

Condensed Consolidating Financial Information - Statements of Operations (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Revenues
Total operating revenues		$ 2,195	$ 2,996	$ 2,465	$ 2,165	$ 1,992	$ 2,960	$ 2,461	$ 2,065	$ 9,821	$ 9,478	$ 9,074
Operating Costs and Expenses
Cost of operations										7,303	7,108	6,886
Depreciation and amortization										373	421	596
Impairment losses										5	99	1,534
Selling, general and administrative										827	799	836
Reorganization costs										23	90	44
Development costs										7	11	22
Total operating costs and expenses										8,538	8,528	9,918
Other income - affiliate	$ 84									0	0	87
(Loss)/Gain on sale of assets										7	32	16
Operating Income/(Loss)		209	540	320	221	49	398	174	361	1,290	982	(741)
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries										0	0	0
Equity in earnings/(losses) of unconsolidated affiliates										2	9	(14)
Impairment losses on investments										(108)	(15)	(79)
Other income, net										66	18	51
Loss on debt extinguishment, net										(51)	(44)	(49)
Interest expense										(413)	(483)	(557)
Total other expense										(504)	(515)	(648)
Income/(Loss) from Continuing Operations Before Income Taxes										786	467	(1,389)
Income/(Loss) from Continuing Operations										(3,334)	7	(44)
Income/(Loss) from Continuing Operations		3,463	374	189	94	(93)	287	27	238	4,120	460	(1,345)
Income/(loss) from discontinued operations, net of income tax		(78)	(2)	13	388	80	(336)	69	(5)	321	(192)	(992)
Net Income/(Loss)		3,385	372	202	482	(13)	(49)	96	233	4,441	268	(2,337)
Less: Net income/(loss) attributable to noncontrolling interest and redeemable interests		$ 2	$ 0	$ 1	$ 0	$ (2)	$ 23	$ 24	$ (46)	3	0	(184)
Net Income/(Loss) Attributable to NRG Energy, Inc.										4,438	268	(2,153)
Eliminations
Operating Revenues
Total operating revenues										(11)	(26)	(48)
Operating Costs and Expenses
Cost of operations										(11)	(26)	(46)
Depreciation and amortization										0	0	0
Impairment losses										0	0	0
Selling, general and administrative										0	(74)	(2)
Reorganization costs										0	0	0
Development costs										0	(1)	0
Total operating costs and expenses										(11)	(101)	(48)
Other income - affiliate												0
(Loss)/Gain on sale of assets										0	0	0
Operating Income/(Loss)										0	75	0
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries										(1,610)	(1,314)	(46)
Equity in earnings/(losses) of unconsolidated affiliates										0	0	0
Impairment losses on investments										0	0	0
Other income, net										0	0	0
Loss on debt extinguishment, net										0	0	0
Interest expense										0	0	0
Total other expense										(1,610)	(1,314)	(46)
Income/(Loss) from Continuing Operations Before Income Taxes										(1,610)	(1,239)	(46)
Income/(Loss) from Continuing Operations										0	0	0
Income/(Loss) from Continuing Operations										(1,610)	(1,239)	(46)
Income/(loss) from discontinued operations, net of income tax										0	0	0
Net Income/(Loss)										(1,610)	(1,239)	(46)
Less: Net income/(loss) attributable to noncontrolling interest and redeemable interests										0	75	0
Net Income/(Loss) Attributable to NRG Energy, Inc.										(1,610)	(1,314)	(46)
Guarantor Subsidiaries
Operating Revenues
Total operating revenues										8,041	8,119	7,818
Operating Costs and Expenses
Cost of operations										5,936	6,147	5,998
Depreciation and amortization										212	238	343
Impairment losses										1	6	1,346
Selling, general and administrative										466	462	410
Reorganization costs										0	4	6
Development costs										0	0	0
Total operating costs and expenses										6,615	6,857	8,103
Other income - affiliate												0
(Loss)/Gain on sale of assets										1	4	4
Operating Income/(Loss)										1,427	1,266	(281)
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries										48	23	18
Equity in earnings/(losses) of unconsolidated affiliates										0	0	0
Impairment losses on investments										0	0	0
Other income, net										23	32	9
Loss on debt extinguishment, net										0	0	0
Interest expense										(14)	(14)	(14)
Total other expense										57	41	13
Income/(Loss) from Continuing Operations Before Income Taxes										1,484	1,307	(268)
Income/(Loss) from Continuing Operations										0	372	(598)
Income/(Loss) from Continuing Operations										1,484	935	330
Income/(loss) from discontinued operations, net of income tax										9	62	91
Net Income/(Loss)										1,493	997	421
Less: Net income/(loss) attributable to noncontrolling interest and redeemable interests										0	0	0
Net Income/(Loss) Attributable to NRG Energy, Inc.										1,493	997	421
Non-Guarantor Subsidiaries
Operating Revenues
Total operating revenues										1,791	1,385	1,304
Operating Costs and Expenses
Cost of operations										1,351	959	862
Depreciation and amortization										130	150	221
Impairment losses										4	93	188
Selling, general and administrative										83	63	64
Reorganization costs										0	0	0
Development costs										0	1	4
Total operating costs and expenses										1,568	1,266	1,339
Other income - affiliate												0
(Loss)/Gain on sale of assets										0	28	12
Operating Income/(Loss)										223	147	(23)
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries										0	0	0
Equity in earnings/(losses) of unconsolidated affiliates										2	10	(10)
Impairment losses on investments										(101)	(15)	(75)
Other income, net										12	(13)	14
Loss on debt extinguishment, net										(3)	0	0
Interest expense										(14)	(49)	(91)
Total other expense										(104)	(67)	(162)
Income/(Loss) from Continuing Operations Before Income Taxes										119	80	(185)
Income/(Loss) from Continuing Operations										4	19	(62)
Income/(Loss) from Continuing Operations										115	61	(123)
Income/(loss) from discontinued operations, net of income tax										5	75	(420)
Net Income/(Loss)										120	136	(543)
Less: Net income/(loss) attributable to noncontrolling interest and redeemable interests										3	(181)	(168)
Net Income/(Loss) Attributable to NRG Energy, Inc.										117	317	(375)
NRG Energy, Inc. (Note Issuer)
Operating Revenues
Total operating revenues										0	0	0
Operating Costs and Expenses
Cost of operations										27	28	72
Depreciation and amortization										31	33	32
Impairment losses										0	0	0
Selling, general and administrative										278	348	364
Reorganization costs										23	86	38
Development costs										7	11	18
Total operating costs and expenses										366	506	524
Other income - affiliate												87
(Loss)/Gain on sale of assets										6	0	0
Operating Income/(Loss)										(360)	(506)	(437)
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries										1,562	1,291	28
Equity in earnings/(losses) of unconsolidated affiliates										0	(1)	(4)
Impairment losses on investments										(7)	0	(4)
Other income, net										31	(1)	28
Loss on debt extinguishment, net										(48)	(44)	(49)
Interest expense										(385)	(420)	(452)
Total other expense										1,153	825	(453)
Income/(Loss) from Continuing Operations Before Income Taxes										793	319	(890)
Income/(Loss) from Continuing Operations										(3,338)	(384)	616
Income/(Loss) from Continuing Operations										4,131	703	(1,506)
Income/(loss) from discontinued operations, net of income tax										307	(329)	(663)
Net Income/(Loss)										4,438	374	(2,169)
Less: Net income/(loss) attributable to noncontrolling interest and redeemable interests										0	106	(16)
Net Income/(Loss) Attributable to NRG Energy, Inc.										$ 4,438	$ 268	$ (2,153)

Condensed Consolidating Financial Information - Statements of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income	$ 3,385	$ 372	$ 202	$ 482	$ (13)	$ (49)	$ 96	$ 233	$ 4,441	$ 268	$ (2,337)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gain on derivatives, net									0	23	13
Foreign currency translation adjustments, net									(1)	(11)	12
Available-for-sale securities, net									(19)	1	(8)
Defined benefit plan, net									(78)	(35)	46
Other comprehensive (loss)/income									(98)	(22)	63
Comprehensive Income/(Loss)									4,343	246	(2,274)
Less: Comprehensive income attributable to redeemable noncontrolling interests									3	14	(179)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.									4,340	232	(2,095)
Eliminations
Net income									(1,610)	(1,239)	(46)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gain on derivatives, net										(15)	(26)
Foreign currency translation adjustments, net									1	22	(1)
Available-for-sale securities, net									0	0	0
Defined benefit plan, net									17	9	(17)
Other comprehensive (loss)/income									18	16	(44)
Comprehensive Income/(Loss)									(1,592)	(1,223)	(90)
Less: Comprehensive income attributable to redeemable noncontrolling interests									0	76	(60)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.									(1,592)	(1,299)	(30)
Guarantor Subsidiaries
Net income									1,493	997	421
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gain on derivatives, net										0	1
Foreign currency translation adjustments, net									0	(10)	6
Available-for-sale securities, net									0	0	0
Defined benefit plan, net									(17)	(9)	(13)
Other comprehensive (loss)/income									(17)	(19)	(6)
Comprehensive Income/(Loss)									1,476	978	415
Less: Comprehensive income attributable to redeemable noncontrolling interests									0	0	0
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.									1,476	978	415
Non-Guarantor Subsidiaries
Net income									120	136	(543)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gain on derivatives, net										29	13
Foreign currency translation adjustments, net									(1)	(10)	7
Available-for-sale securities, net									0	0	0
Defined benefit plan, net									0	0	30
Other comprehensive (loss)/income									(1)	19	50
Comprehensive Income/(Loss)									119	155	(493)
Less: Comprehensive income attributable to redeemable noncontrolling interests									3	(166)	(103)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.									116	321	(390)
NRG Energy, Inc. (Note Issuer)
Net income									4,438	374	(2,169)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gain on derivatives, net										9	25
Foreign currency translation adjustments, net									(1)	(13)	0
Available-for-sale securities, net									(19)	1	(8)
Defined benefit plan, net									(78)	(35)	46
Other comprehensive (loss)/income									(98)	(38)	63
Comprehensive Income/(Loss)									4,340	336	(2,106)
Less: Comprehensive income attributable to redeemable noncontrolling interests									0	104	(16)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.									$ 4,340	$ 232	$ (2,090)

Condensed Consolidating Financial Information - Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 345		$ 563	$ 770
Funds deposited by counterparties	32		33	37
Restricted cash	8		17	279
Accounts receivable, net	1,025		1,024
Inventory	383		412
Derivative instruments	860		764
Cash collateral posted in support of energy risk management activities	190		287
Prepayments and other current assets	245		302
Current assets - held-for-sale	0		1
Current assets - discontinued operations	0		197
Total current assets	3,088		3,600
Property, plant and equipment, net	2,593		3,048
Other Assets
Investment in subsidiaries	0		0
Equity investments in affiliates	388		412
Operating lease right-of-use assets, net	464	$ 404
Goodwill	579		573
Intangible assets, net	789		591
Nuclear decommissioning trust fund	794		663
Derivative instruments	310		317
Deferred income taxes	3,286		46
Other non-current assets	240		289
Non-current assets - held-for-sale	0		77
Non-current assets - discontinued operations	0		1,012
Total other assets	6,850		3,980
Total Assets	12,531		10,628
Current Liabilities
Current portion of long-term debt and finance leases	88		72
Current portion of operating lease liabilities	73
Accounts payable	722		863
Derivative instruments	781		673
Cash collateral received in support of energy risk management activities	32		33
Accrued expenses and other current liabilities	663		680
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current			5
Current liabilities - discontinued operations	0		72
Total current liabilities	2,359		2,398
Other Liabilities
Long-term debt and finance leases	5,803		6,449
Non-current operating lease liabilities	483
Nuclear decommissioning reserve	298		282
Nuclear decommissioning trust liability	487		371
Derivative instruments	322		304
Deferred income taxes	17		65
Other non-current liabilities	1,084		1,274
Non-current liabilities - held-for-sale			65
Non-current liabilities - discontinued operations	0		635
Total other liabilities	8,494		9,445
Total Liabilities	10,853		11,843
Redeemable noncontrolling interest in subsidiaries	20		19	78	$ 46
Total Stockholders' Equity	1,658		(1,234)	$ 1,968	$ 4,446
Total Liabilities and Stockholders' Equity	12,531		10,628
Eliminations
Current Assets
Cash and cash equivalents	0		0
Funds deposited by counterparties	0		0
Restricted cash	0		0
Accounts receivable, net	(740)		(754)
Inventory	0		0
Derivative instruments	(41)		(81)
Cash collateral posted in support of energy risk management activities	0		0
Prepayments and other current assets	0		0
Current assets - held-for-sale			0
Current assets - discontinued operations			0
Total current assets	(781)		(835)
Property, plant and equipment, net	0		0
Other Assets
Investment in subsidiaries	(5,495)		(5,153)
Equity investments in affiliates	0		0
Operating lease right-of-use assets, net	0
Goodwill	0		0
Intangible assets, net	0		0
Nuclear decommissioning trust fund	0		0
Derivative instruments	(13)		(5)
Deferred income taxes	0		0
Other non-current assets	0		(12)
Non-current assets - held-for-sale			0
Non-current assets - discontinued operations			0
Total other assets	(5,508)		(5,170)
Total Assets	(6,289)		(6,005)
Current Liabilities
Current portion of long-term debt and finance leases	0		0
Current portion of operating lease liabilities	0
Accounts payable	(740)		(754)
Derivative instruments	(41)		(81)
Cash collateral received in support of energy risk management activities	0		0
Accrued expenses and other current liabilities	0		0
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current			0
Current liabilities - discontinued operations			0
Total current liabilities	(781)		(835)
Other Liabilities
Long-term debt and finance leases	0		(12)
Non-current operating lease liabilities	0
Nuclear decommissioning reserve	0		0
Nuclear decommissioning trust liability	0		0
Derivative instruments	(13)		(5)
Deferred income taxes	0		0
Other non-current liabilities	0		0
Non-current liabilities - held-for-sale			0
Non-current liabilities - discontinued operations			0
Total other liabilities	(13)		(17)
Total Liabilities	(794)		(852)
Redeemable noncontrolling interest in subsidiaries	0		0
Total Stockholders' Equity	(5,495)		(5,153)
Total Liabilities and Stockholders' Equity	(6,289)		(6,005)
Guarantor Subsidiaries
Current Assets
Cash and cash equivalents	0		55
Funds deposited by counterparties	32		33
Restricted cash	5		7
Accounts receivable, net	1,293		1,354
Inventory	272		278
Derivative instruments	856		779
Cash collateral posted in support of energy risk management activities	182		275
Prepayments and other current assets	170		180
Current assets - held-for-sale			0
Current assets - discontinued operations			177
Total current assets	2,810		3,138
Property, plant and equipment, net	1,483		1,938
Other Assets
Investment in subsidiaries	710		446
Equity investments in affiliates	0		0
Operating lease right-of-use assets, net	81
Goodwill	359		359
Intangible assets, net	375		422
Nuclear decommissioning trust fund	794		663
Derivative instruments	308		296
Deferred income taxes	421		6
Other non-current assets	145		133
Non-current assets - held-for-sale			0
Non-current assets - discontinued operations			405
Total other assets	3,193		2,730
Total Assets	7,486		7,806
Current Liabilities
Current portion of long-term debt and finance leases	0		0
Current portion of operating lease liabilities	20
Accounts payable	918		1,368
Derivative instruments	797		713
Cash collateral received in support of energy risk management activities	32		33
Accrued expenses and other current liabilities	280		291
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current			0
Current liabilities - discontinued operations			24
Total current liabilities	2,047		2,429
Other Liabilities
Long-term debt and finance leases	302		244
Non-current operating lease liabilities	64
Nuclear decommissioning reserve	298		282
Nuclear decommissioning trust liability	487		371
Derivative instruments	334		306
Deferred income taxes	0		112
Other non-current liabilities	399		402
Non-current liabilities - held-for-sale			0
Non-current liabilities - discontinued operations			58
Total other liabilities	1,884		1,775
Total Liabilities	3,931		4,204
Redeemable noncontrolling interest in subsidiaries	0		0
Total Stockholders' Equity	3,555		3,602
Total Liabilities and Stockholders' Equity	7,486		7,806
Non-Guarantor Subsidiaries
Current Assets
Cash and cash equivalents	20		28
Funds deposited by counterparties	0		0
Restricted cash	1		10
Accounts receivable, net	239		115
Inventory	111		134
Derivative instruments	45		50
Cash collateral posted in support of energy risk management activities	8		12
Prepayments and other current assets	8		32
Current assets - held-for-sale			1
Current assets - discontinued operations			20
Total current assets	432		402
Property, plant and equipment, net	952		957
Other Assets
Investment in subsidiaries	0		0
Equity investments in affiliates	388		412
Operating lease right-of-use assets, net	261
Goodwill	220		214
Intangible assets, net	414		169
Nuclear decommissioning trust fund	0		0
Derivative instruments	15		4
Deferred income taxes	(19)		(143)
Other non-current assets	30		71
Non-current assets - held-for-sale			77
Non-current assets - discontinued operations			607
Total other assets	1,309		1,411
Total Assets	2,693		2,770
Current Liabilities
Current portion of long-term debt and finance leases	5		55
Current portion of operating lease liabilities	32
Accounts payable	141		(185)
Derivative instruments	25		41
Cash collateral received in support of energy risk management activities	0		0
Accrued expenses and other current liabilities	44		36
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current			5
Current liabilities - discontinued operations			48
Total current liabilities	247		0
Other Liabilities
Long-term debt and finance leases	28		192
Non-current operating lease liabilities	301
Nuclear decommissioning reserve	0		0
Nuclear decommissioning trust liability	0		0
Derivative instruments	1		3
Deferred income taxes	17		61
Other non-current liabilities	153		320
Non-current liabilities - held-for-sale			65
Non-current liabilities - discontinued operations			577
Total other liabilities	500		1,218
Total Liabilities	747		1,218
Redeemable noncontrolling interest in subsidiaries	20		19
Total Stockholders' Equity	1,926		1,533
Total Liabilities and Stockholders' Equity	2,693		2,770
NRG Energy, Inc.
Current Assets
Cash and cash equivalents	325		480
Funds deposited by counterparties	0		0
Restricted cash	2		0
Accounts receivable, net	233		309
Inventory	0		0
Derivative instruments	0		16
Cash collateral posted in support of energy risk management activities	0		0
Prepayments and other current assets	67		90
Current assets - held-for-sale			0
Current assets - discontinued operations			0
Total current assets	627		895
Property, plant and equipment, net	158		153
Other Assets
Investment in subsidiaries	4,785		4,707
Equity investments in affiliates	0		0
Operating lease right-of-use assets, net	122
Goodwill	0		0
Intangible assets, net	0		0
Nuclear decommissioning trust fund	0		0
Derivative instruments	0		22
Deferred income taxes	2,884		183
Other non-current assets	65		97
Non-current assets - held-for-sale			0
Non-current assets - discontinued operations			0
Total other assets	7,856		5,009
Total Assets	8,641		6,057
Current Liabilities
Current portion of long-term debt and finance leases	83		17
Current portion of operating lease liabilities	21
Accounts payable	403		434
Derivative instruments	0		0
Cash collateral received in support of energy risk management activities	0		0
Accrued expenses and other current liabilities	339		353
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current			0
Current liabilities - discontinued operations			0
Total current liabilities	846		804
Other Liabilities
Long-term debt and finance leases	5,473		6,025
Non-current operating lease liabilities	118
Nuclear decommissioning reserve	0		0
Nuclear decommissioning trust liability	0		0
Derivative instruments	0		0
Deferred income taxes	0		(108)
Other non-current liabilities	532		552
Non-current liabilities - held-for-sale			0
Non-current liabilities - discontinued operations			0
Total other liabilities	6,123		6,469
Total Liabilities	6,969		7,273
Redeemable noncontrolling interest in subsidiaries	0		0
Total Stockholders' Equity	1,672		(1,216)
Total Liabilities and Stockholders' Equity	$ 8,641		$ 6,057

Condensed Consolidating Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net Income/(Loss)	$ 3,385	$ 372	$ 202	$ 482	$ (13)	$ (49)	$ 96	$ 233	$ 4,441	$ 268	$ (2,337)
Income/(loss) from discontinued operations, net of income tax	(78)	(2)	13	388	80	(336)	69	(5)	321	(192)	(992)
Income/(loss) from continuing operations	3,463	$ 374	$ 189	94	(93)	$ 287	$ 27	238	4,120	460	(1,345)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries									14	46	102
Depreciation and amortization									373	421	596
Accretion of asset retirement obligations									51	38	44
Provision for bad debts									95	85	68
Amortization of nuclear fuel									52	48	51
Amortization of financing costs and debt discount/premiums									26	29	29
Adjustment for debt extinguishment									51	44	49
Amortization of emission allowances									38	45	54
Amortization of unearned equity compensation									20	25	35
Net gain on sale of assets and disposal of assets									(23)	(49)	(9)
Impairment losses									113	114	1,614
Changes in derivative instruments									34	37	(170)
Changes in deferred income taxes and liability for uncertain tax benefits									(3,353)	5	13
Changes in collateral deposits in support of risk management activities									105	(105)	(80)
Changes in nuclear decommissioning trust liability									37	60	11
GenOn settlement, net of insurance proceeds									0	(63)	0
Net loss on deconsolidation of Agua Caliente and Ivanpah projects									0	13	0
Changes in other working capital									(348)	(250)	(206)
Cash provided by continuing operations									1,405	1,003	856
Cash provided/(used) by discontinued operations									8	374	754
Net Cash Provided by Operating Activities									1,413	1,377	1,610
Cash Flows from Investing Activities
Intercompany dividends									0	0	0
Payments for acquisitions of businesses									(355)	(243)	(14)
Capital expenditures									(228)	(388)	(254)
Net proceeds from sale of emission allowances									11	19	66
Investments in nuclear decommissioning trust fund securities									(416)	(572)	(512)
Proceeds from sales of nuclear decommissioning trust fund securities									381	513	501
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees									1,294	1,564	430
Deconsolidation of Agua Caliente and Ivanpah projects									0	(268)	0
Changes in investments in unconsolidated affiliates									(91)	(39)	(57)
Net contributions to discontinued operations									(44)	(60)	150
Other									6	(6)	30
Cash provided by continuing operations									558	520	340
Cash used by discontinued operations									(2)	(725)	(979)
Net Cash Provided/(Used) by Investing Activities									556	(205)	(639)
Cash Flows from Financing Activities
Intercompany dividends and transfers									0	0	0
Payments of dividends to common stockholders									(32)	(37)	(38)
Payment for preferred shares									(1,440)	(1,250)
Payments for debt extinguishment costs									(26)	(32)	(42)
Net distributions to redeemable noncontrolling interests from subsidiaries									(2)	(16)	(30)
Proceeds/(payments) from issuance of common stock									3	21	(2)
Proceeds from issuance of long-term debt									1,916	1,100	1,178
Payments of debt issuance costs									(35)	(19)	(18)
Payments for short and long-term debt									(2,571)	(1,734)	(1,884)
Receivable from affiliate									0	(26)	(125)
Other									(4)	(4)	(8)
Cash used by continuing operations									(2,191)	(1,997)	(969)
Cash provided/(used) by discontinued operations									43	471	(169)
Net Cash (Used)/Provided by Financing Activities									(2,148)	(1,526)	(1,138)
Effect of exchange rate changes on cash and cash equivalents									0	1	(1)
Change in Cash from discontinued operations									49	120	(394)
Net (Decrease)/Increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash									(228)	(473)	226
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	385				613				385	613	1,086
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period				613				1,086	613	1,086	860
Eliminations
Cash Flows from Operating Activities
Net Income/(Loss)									(1,610)	(1,239)	(46)
Income/(loss) from discontinued operations, net of income tax									0	0	0
Income/(loss) from continuing operations									(1,610)	(1,239)	(46)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries									1,610	1,253	48
Depreciation and amortization									0	0	0
Accretion of asset retirement obligations									0	0	0
Provision for bad debts									0	0	0
Amortization of nuclear fuel									0	0	0
Amortization of financing costs and debt discount/premiums									0	0	0
Adjustment for debt extinguishment									0	0	0
Amortization of emission allowances									0	0	0
Amortization of unearned equity compensation									0	0	0
Net gain on sale of assets and disposal of assets									0	0	0
Impairment losses									0	0	0
Changes in derivative instruments									0	(14)	(2)
Changes in deferred income taxes and liability for uncertain tax benefits									0	0	0
Changes in collateral deposits in support of risk management activities									0	0	0
Changes in nuclear decommissioning trust liability									0	0	0
GenOn settlement, net of insurance proceeds										0
Net loss on deconsolidation of Agua Caliente and Ivanpah projects										0
Changes in other working capital									0	0	0
Cash provided by continuing operations									0	0	0
Cash provided/(used) by discontinued operations									0	0	0
Net Cash Provided by Operating Activities									0	0	0
Cash Flows from Investing Activities
Intercompany dividends									(2,513)	(2,006)	(1,665)
Payments for acquisitions of businesses									0	0	0
Capital expenditures									0	0	0
Net proceeds from sale of emission allowances									0	0	0
Investments in nuclear decommissioning trust fund securities									0	0	0
Proceeds from sales of nuclear decommissioning trust fund securities									0	0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees									0	0	0
Deconsolidation of Agua Caliente and Ivanpah projects										0
Changes in investments in unconsolidated affiliates									0	0	0
Net contributions to discontinued operations									0	0	0
Other									0	0	0
Cash provided by continuing operations									(2,513)	(2,006)	(1,665)
Cash used by discontinued operations									0	0	0
Net Cash Provided/(Used) by Investing Activities									(2,513)	(2,006)	(1,665)
Cash Flows from Financing Activities
Intercompany dividends and transfers									2,513	2,006	1,665
Payments of dividends to common stockholders									0	0	0
Payment for preferred shares									0	0
Payments for debt extinguishment costs									0	0	0
Net distributions to redeemable noncontrolling interests from subsidiaries									0	0	0
Proceeds/(payments) from issuance of common stock									0	0	0
Proceeds from issuance of long-term debt									0	0	0
Payments of debt issuance costs									0	0	0
Payments for short and long-term debt									0	0	0
Receivable from affiliate										0	0
Other									0	0	0
Cash used by continuing operations									2,513	2,006	1,665
Cash provided/(used) by discontinued operations									0	0	0
Net Cash (Used)/Provided by Financing Activities									2,513	2,006	1,665
Effect of exchange rate changes on cash and cash equivalents										0	0
Change in Cash from discontinued operations									0	0	0
Net (Decrease)/Increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash									0	0	0
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	0				0				0	0	0
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period				0				0	0	0	0
Guarantor Subsidiaries
Cash Flows from Operating Activities
Net Income/(Loss)									1,493	997	421
Income/(loss) from discontinued operations, net of income tax									9	62	91
Income/(loss) from continuing operations									1,484	935	330
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries									(48)	(23)	(18)
Depreciation and amortization									212	238	343
Accretion of asset retirement obligations									43	28	37
Provision for bad debts									78	79	56
Amortization of nuclear fuel									52	48	51
Amortization of financing costs and debt discount/premiums									0	0	0
Adjustment for debt extinguishment									0	0	0
Amortization of emission allowances									24	36	42
Amortization of unearned equity compensation									0	0	0
Net gain on sale of assets and disposal of assets									(20)	(30)	2
Impairment losses									1	5	1,346
Changes in derivative instruments									20	25	(214)
Changes in deferred income taxes and liability for uncertain tax benefits									(525)	372	(300)
Changes in collateral deposits in support of risk management activities									101	(94)	(98)
Changes in nuclear decommissioning trust liability									37	60	11
GenOn settlement, net of insurance proceeds										0
Net loss on deconsolidation of Agua Caliente and Ivanpah projects										0
Changes in other working capital									(220)	(100)	(15)
Cash provided by continuing operations									1,239	1,579	1,573
Cash provided/(used) by discontinued operations									17	89	116
Net Cash Provided by Operating Activities									1,256	1,668	1,689
Cash Flows from Investing Activities
Intercompany dividends									0	0	0
Payments for acquisitions of businesses									(355)	(40)	(14)
Capital expenditures									(164)	(192)	(180)
Net proceeds from sale of emission allowances									11	19	66
Investments in nuclear decommissioning trust fund securities									(416)	(572)
Proceeds from sales of nuclear decommissioning trust fund securities									381	513	501
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees									1	14	33
Deconsolidation of Agua Caliente and Ivanpah projects										0
Changes in investments in unconsolidated affiliates									0	0	0
Net contributions to discontinued operations									0	0	0
Other									0	0	18
Cash provided by continuing operations									(542)	(258)	(88)
Cash used by discontinued operations									0	0	(13)
Net Cash Provided/(Used) by Investing Activities									(542)	(258)	(101)
Cash Flows from Financing Activities
Intercompany dividends and transfers									(751)	(1,267)	(1,447)
Payments of dividends to common stockholders									0	0	0
Payment for preferred shares									0	0
Payments for debt extinguishment costs									0	0	0
Net distributions to redeemable noncontrolling interests from subsidiaries									0	0	0
Proceeds/(payments) from issuance of common stock									0	0	0
Proceeds from issuance of long-term debt									0	0	0
Payments of debt issuance costs									0	0	0
Payments for short and long-term debt									0	0	0
Receivable from affiliate										0	0
Other									(4)	0	0
Cash used by continuing operations									(755)	(1,267)	(1,447)
Cash provided/(used) by discontinued operations									0	0	(109)
Net Cash (Used)/Provided by Financing Activities									(755)	(1,267)	(1,556)
Effect of exchange rate changes on cash and cash equivalents										0	0
Change in Cash from discontinued operations									17	89	(6)
Net (Decrease)/Increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash									(58)	54	38
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	37				95				37	95	41
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period				95				41	95	41	3
Non-Guarantor Subsidiaries
Cash Flows from Operating Activities
Net Income/(Loss)									120	136	(543)
Income/(loss) from discontinued operations, net of income tax									5	75	(420)
Income/(loss) from continuing operations									115	61	(123)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries									14	47	12
Depreciation and amortization									130	150	221
Accretion of asset retirement obligations									8	10	7
Provision for bad debts									17	6	0
Amortization of nuclear fuel									0	0	0
Amortization of financing costs and debt discount/premiums									0	6	13
Adjustment for debt extinguishment									3	0	0
Amortization of emission allowances									14	9	12
Amortization of unearned equity compensation									0	0	0
Net gain on sale of assets and disposal of assets									0	(20)	(11)
Impairment losses									105	109	264
Changes in derivative instruments									(24)	15	50
Changes in deferred income taxes and liability for uncertain tax benefits									(168)	5	(9)
Changes in collateral deposits in support of risk management activities									4	(11)	18
Changes in nuclear decommissioning trust liability									0	0	0
GenOn settlement, net of insurance proceeds										0
Net loss on deconsolidation of Agua Caliente and Ivanpah projects										13
Changes in other working capital									(118)	(166)	(396)
Cash provided by continuing operations									100	234	58
Cash provided/(used) by discontinued operations									(9)	285	638
Net Cash Provided by Operating Activities									91	519	696
Cash Flows from Investing Activities
Intercompany dividends									0	0	0
Payments for acquisitions of businesses									0	(203)	0
Capital expenditures									(27)	(151)	(43)
Net proceeds from sale of emission allowances									0	0	0
Investments in nuclear decommissioning trust fund securities									0	0	0
Proceeds from sales of nuclear decommissioning trust fund securities									0	0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees									400	8	54
Deconsolidation of Agua Caliente and Ivanpah projects										(268)
Changes in investments in unconsolidated affiliates									(91)	(39)	(57)
Net contributions to discontinued operations									(44)	(60)	0
Other									0	0	12
Cash provided by continuing operations									238	(713)	(34)
Cash used by discontinued operations									(2)	(725)	(966)
Net Cash Provided/(Used) by Investing Activities									236	(1,438)	(1,000)
Cash Flows from Financing Activities
Intercompany dividends and transfers									(214)	86	(4)
Payments of dividends to common stockholders									0	0	0
Payment for preferred shares									0	0
Payments for debt extinguishment costs									0	0	0
Net distributions to redeemable noncontrolling interests from subsidiaries									(2)	(16)	(30)
Proceeds/(payments) from issuance of common stock									0	0	0
Proceeds from issuance of long-term debt									0	163	94
Payments of debt issuance costs									0	0	(2)
Payments for short and long-term debt									(139)	(138)	(183)
Receivable from affiliate										0	0
Other									0	(4)	(8)
Cash used by continuing operations									(355)	91	(133)
Cash provided/(used) by discontinued operations									43	471	(60)
Net Cash (Used)/Provided by Financing Activities									(312)	562	(193)
Effect of exchange rate changes on cash and cash equivalents										1	(1)
Change in Cash from discontinued operations									32	31	(388)
Net (Decrease)/Increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash									(17)	(387)	(110)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	21				38				21	38	425
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period				38				425	38	425	535
NRG Energy, Inc. (Note Issuer)
Cash Flows from Operating Activities
Net Income/(Loss)									4,438	374	(2,169)
Income/(loss) from discontinued operations, net of income tax									307	(329)	(663)
Income/(loss) from continuing operations									4,131	703	(1,506)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates and consolidated subsidiaries									(1,562)	(1,231)	60
Depreciation and amortization									31	33	32
Accretion of asset retirement obligations									0	0	0
Provision for bad debts									0	0	12
Amortization of nuclear fuel									0	0	0
Amortization of financing costs and debt discount/premiums									26	23	16
Adjustment for debt extinguishment									48	44	49
Amortization of emission allowances									0	0	0
Amortization of unearned equity compensation									20	25	35
Net gain on sale of assets and disposal of assets									(3)	1	0
Impairment losses									7	0	4
Changes in derivative instruments									38	11	(4)
Changes in deferred income taxes and liability for uncertain tax benefits									(2,660)	(372)	322
Changes in collateral deposits in support of risk management activities									0	0	0
Changes in nuclear decommissioning trust liability									0	0	0
GenOn settlement, net of insurance proceeds										(63)
Net loss on deconsolidation of Agua Caliente and Ivanpah projects										0
Changes in other working capital									(10)	16	205
Cash provided by continuing operations									66	(810)	(775)
Cash provided/(used) by discontinued operations									0	0	0
Net Cash Provided by Operating Activities									66	(810)	(775)
Cash Flows from Investing Activities
Intercompany dividends									2,513	2,006	1,665
Payments for acquisitions of businesses									0	0	0
Capital expenditures									(37)	(45)	(31)
Net proceeds from sale of emission allowances									0	0	0
Investments in nuclear decommissioning trust fund securities									0	0	0
Proceeds from sales of nuclear decommissioning trust fund securities									0	0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees									893	1,542	343
Deconsolidation of Agua Caliente and Ivanpah projects										0
Changes in investments in unconsolidated affiliates									0	0	0
Net contributions to discontinued operations									0	0	150
Other									6	(6)	0
Cash provided by continuing operations									3,375	3,497	2,127
Cash used by discontinued operations									0	0	0
Net Cash Provided/(Used) by Investing Activities									3,375	3,497	2,127
Cash Flows from Financing Activities
Intercompany dividends and transfers									(1,548)	(825)	(214)
Payments of dividends to common stockholders									(32)	(37)	(38)
Payment for preferred shares									(1,440)	(1,250)
Payments for debt extinguishment costs									(26)	(32)	(42)
Net distributions to redeemable noncontrolling interests from subsidiaries									0	0	0
Proceeds/(payments) from issuance of common stock									3	21	(2)
Proceeds from issuance of long-term debt									1,916	937	1,084
Payments of debt issuance costs									(35)	(19)	(16)
Payments for short and long-term debt									(2,432)	(1,596)	(1,701)
Receivable from affiliate										(26)	(125)
Other									0	0	0
Cash used by continuing operations									(3,594)	(2,827)	(1,054)
Cash provided/(used) by discontinued operations									0	0	0
Net Cash (Used)/Provided by Financing Activities									(3,594)	(2,827)	(1,054)
Effect of exchange rate changes on cash and cash equivalents										0	0
Change in Cash from discontinued operations									0	0	0
Net (Decrease)/Increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash									(153)	(140)	298
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 327				$ 480				327	480	620
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period				$ 480				$ 620	$ 480	$ 620	$ 322

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts, deducted from accounts receivable
Income tax valuation allowance, deducted from deferred tax assets
Balance at Beginning of Period	$ 32	$ 28	$ 28
Charged to Costs and Expenses	95	83	57
Charged to Other Accounts	0	0	0
Deductions	(84)	(79)	(57)
Balance at End of Period	43	32	28
Income tax valuation allowance, deducted from deferred tax assets
Income tax valuation allowance, deducted from deferred tax assets
Balance at Beginning of Period	3,794	1,863	4,116
Charged to Costs and Expenses	(3,543)	1,934	(151)
Charged to Other Accounts	(9)	(128)	(15)
Deductions	0	125	(2,087)
Balance at End of Period	$ 242	$ 3,794	$ 1,863