NRG Energy (NRG) 10-Q 7 Aug 19 2019 Q2 Quarterly report Financial data

Cover

Cover - shares	6 Months Ended
	Jun. 30, 2019	Aug. 07, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	001-15891
Entity Registrant Name	NRG Energy, Inc
Entity Incorporation, State or Country Code	DE
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
Title of 12(b) Security	Common Stock, par value $0.01
Trading Symbol	NRG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		252,987,889
Entity Central Index Key	0001013871
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating Revenues
Total operating revenues	$ 2,465	$ 2,461	$ 4,630	$ 4,526
Operating Costs and Expenses
Cost of operations	1,845	1,889	3,496	3,274
Depreciation and amortization	85	112	170	232
Impairment losses	1	74	1	74
Selling, general and administrative	211	200	405	376
Reorganization costs	2	23	15	43
Development costs	2	3	4	8
Total operating costs and expenses	2,146	2,301	4,091	4,007
Gain on sale of assets	1	14	2	16
Operating Income/(Loss)	320	174	541	535
Other Income/(Expense)
Equity in earnings/(losses) of unconsolidated affiliates	0	5	(21)	6
Other income/(expense), net	20	(23)	32	(23)
Loss on debt extinguishment, net	(47)	(1)	(47)	(3)
Interest expense	(105)	(123)	(219)	(239)
Total other income/(expense)	(132)	(142)	(255)	(259)
Income from Continuing Operations Before Income Taxes	188	32	286	276
Income tax expense/(benefit)	(1)	5	3	11
Income from Continuing Operations	189	27	283	265
Income/(loss) from discontinued operations	13	69	401	64
Net (loss)/income	202	96	684	329
Less: Net income/(loss) attributable to noncontrolling interest and redeemable interests	1	24	1	(22)
Net income attributable to NRG Energy, Inc.	$ 201	$ 72	$ 683	$ 351
Earnings per Share Attributable to NRG Energy, Inc.
Weighted average number of common shares outstanding — basic (in shares)	265	310	272	314
Income from continuing operations per weighted average common share — basic (in usd per share)	$ 0.71	$ 0.01	$ 1.04	$ 0.92
Income/(loss) from discontinued operations per weighted average common share — basic (in usd per share))	0.05	0.22	1.47	0.20
Earnings per Weighted Average Common Share — Basic (in usd per share)	$ 0.76	$ 0.23	$ 2.51	$ 1.12
Weighted average number of common shares outstanding — diluted (in shares)	267	314	274	318
Income from continuing operations per weighted average common share — diluted (in usd per share)	$ 0.70	$ 0.01	$ 1.03	$ 0.90
income from discontinued operations per weighted average common share — diluted (in usd per share)	0.05	0.22	1.46	0.20
Earnings per Weighted Average Common Share — Diluted (in usd per share)	0.75	0.23	2.49	1.10
Dividends Per Common Share (in usd per share)	$ 0.03	$ 0.03	$ 0.06	$ 0.06

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 202	$ 96	$ 684	$ 329
Other Comprehensive (Loss)/Income
Unrealized gain on derivatives	0	5	0	19
Foreign currency translation adjustments	(1)	(4)	0	(6)
Available-for-sale securities	1	1	1	1
Defined benefit plans	(3)	(1)	(6)	(2)
Other comprehensive (loss)/income	(3)	1	(5)	12
Comprehensive Income	199	97	679	341
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest	1	26	1	(12)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	$ 198	$ 71	$ 678	$ 353

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 294	$ 563
Funds deposited by counterparties	31	33
Restricted cash	11	17
Accounts receivable, net	1,049	1,024
Inventory	370	412
Derivative instruments	850	764
Cash collateral paid in support of energy risk management activities	163	287
Prepayments and other current assets	277	302
Current assets - held-for-sale	0	1
Current assets - discontinued operations	0	197
Total current assets	3,045	3,600
Property, plant and equipment, net	2,610	3,048
Other Assets
Equity investments in affiliates	383	412
Operating lease right-of-use assets, net	499
Goodwill	573	573
Intangible assets, net	561	591
Nuclear decommissioning trust fund	748	663
Derivative instruments	426	317
Deferred income taxes	55	46
Other non-current assets	271	289
Non-current assets - held-for-sale	0	77
Non-current assets - discontinued operations	0	1,012
Total other assets	3,516	3,980
Total Assets	9,171	10,628
Current Liabilities
Current portion of long-term debt and capital leases	87	72
Current portion of operating lease liabilities	74
Accounts payable	723	863
Derivative instruments	778	673
Cash collateral received in support of energy risk management activities	31	33
Accrued expenses and other current liabilities	601	680
Current liabilities - held-for-sale	0	5
Current liabilities - discontinued operations	0	72
Total current liabilities	2,294	2,398
Other Liabilities
Long-term debt and capital leases	5,794	6,449
Non-current operating lease liabilities	513
Nuclear decommissioning reserve	290	282
Nuclear decommissioning trust liability	448	371
Derivative instruments	374	304
Deferred income taxes	71	65
Other non-current liabilities	1,016	1,274
Non-current liabilities - held-for-sale	0	65
Non-current liabilities - discontinued operations	0	635
Total other liabilities	8,506	9,445
Total Liabilities	10,800	11,843
Redeemable noncontrolling interest in subsidiaries	19	19
Commitments and Contingencies
Stockholders' Equity
Common stock; $0.01 par value; 500,000,000 shares authorized; 421,830,474 and 420,288,886 shares issued and 258,570,598 and 283,650,039 shares outstanding at June 30, 2019 and December 31, 2018, respectively	4	4
Additional paid-in-capital	8,488	8,510
Accumulated deficit	(5,355)	(6,022)
Less treasury stock, at cost - 163,259,876 and 136,638,847 shares at June 30, 2019 and December 31, 2018, respectively	(4,686)	(3,632)
Accumulated other comprehensive loss	(99)	(94)
Total Stockholders' Equity	(1,648)	(1,234)
Total Liabilities and Stockholders' Equity	$ 9,171	$ 10,628

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par or 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)	421,830,474	420,288,886
Common stock, shares outstanding (in shares)	258,570,598	283,650,039
Treasury stock, shares (in shares)	163,259,876	136,638,847

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows from Operating Activities
Net (loss)/income	$ 684	$ 329
Income from discontinued operations, net of income tax	401	64
(Loss)/income from continuing operations	283	265
Adjustments to reconcile net income to cash provided by operating activities:
Distributions and equity earnings of unconsolidated affiliates	22	12
Depreciation, amortization and accretion	184	252
Provision for bad debts	52	30
Amortization of nuclear fuel	27	24
Amortization of financing costs and debt discount/premiums	13	13
Loss on debt extinguishment, net	47	3
Amortization of intangibles and out-of-market contracts	14	20
Amortization of unearned equity compensation	10	15
Loss/(gain) on sale and disposal of assets	1	(16)
Impairment losses	1	88
Changes in derivative instruments	(22)	(145)
Changes in deferred income taxes and liability for uncertain tax benefits	(5)	(2)
Changes in collateral deposits in support of energy risk management activities	125	(9)
Changes in nuclear decommissioning trust liability	17	41
Loss on deconsolidation of Ivanpah project	0	22
Changes in other working capital	(388)	(349)
Cash provided/(used) by continuing operations	381	264
Cash provided by discontinued operations	8	249
Net Cash Provided/(Used) by Operating Activities	389	513
Cash Flows from Investing Activities
Payments for acquisitions of businesses	(21)	(211)
Capital expenditures	(107)	(282)
Net proceeds from sale of emission allowances	(1)	3
Investments in nuclear decommissioning trust fund securities	(209)	(346)
Proceeds from the sale of nuclear decommissioning trust fund securities	191	303
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	1,289	146
Deconsolidation of Ivanpah project	0	(160)
Changes in investments in unconsolidated affiliates	7	(15)
Contributions to discontinued operations	(44)	(16)
Cash (used)/provided by continuing operations	1,105	(578)
Cash used by discontinued operations	(2)	(584)
Net Cash (Used)/Provided by Investing Activities	1,103	(1,162)
Cash Flows from Financing Activities
Payments of dividends to common stockholders	(16)	(19)
Payments for treasury stock	(1,039)	(500)
Payments for debt extinguishment costs	(24)	0
Distributions to noncontrolling interests from subsidiaries	(1)	(14)
Proceeds from issuance of common stock	2	11
Proceeds from issuance of short and long-term debt	1,833	994
Payment of debt issuance costs	(33)	(19)
Payments for short and long-term debt	2,485	348
Cash (used)/provided by continuing operations	(1,763)	105
Cash provided by discontinued operations	43	345
Net Cash (Used)/Provided by Financing Activities	(1,720)	450
Change in Cash from discontinued operations	49	10
Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash	(277)	(209)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period	613	1,086
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 336	$ 877

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	NRG Yield, Inc.	Common Stock	Additional Paid-In Capital	Additional Paid-In CapitalNRG Yield, Inc.	Accumulated Deficit	Treasury Stock	Accumulated Other Comprehensive Loss	Noncontrolling Interest	Noncontrolling InterestNRG Yield, Inc.
Balance at Dec. 31, 2017	$ 1,968		$ 4	$ 8,376		$ (6,268)	$ (2,386)	$ (72)	$ 2,314
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	249					279			(30)
Other comprehensive (loss) income	11							11
Sale of assets to NRG Yield, Inc.		$ 12			$ 8					$ 4
ESPP share purchases	3			(2)			5
Share repurchases	(93)						(93)
Equity-based compensation	(10)			(10)
Issuance of common stock	7			7
Common stock dividends	(10)					(10)
Distributions to noncontrolling interest and dividends paid	(19)	(30)							(19)	(30)
Contributions from noncontrolling interests	153								153
Adoption of new accounting standards	17					17
Balance at Mar. 31, 2018	2,258		4	8,379		(5,982)	(2,474)	(61)	2,392
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	104					72			32
Other comprehensive (loss) income	1							1
Sale of assets to NRG Yield, Inc.		(2)								(2)
ESPP share purchases	(1)						(1)
Share repurchases	(407)			(11)			(396)
Equity-based compensation	8			8
Issuance of common stock	4			4
Common stock dividends	(9)					(9)
Distributions to noncontrolling interest and dividends paid	(15)	$ (31)							(15)	$ (31)
Contributions from noncontrolling interests	150								150
Adoption of new accounting standards	(1)					(1)
Deconsolidation of Business	(89)								(89)
Equity component of convertible senior notes	101			101
Balance at Jun. 30, 2018	2,071		4	8,481		(5,920)	(2,871)	(60)	$ 2,437
Balance at Dec. 31, 2018	(1,234)		4	8,510		(6,022)	(3,632)	(94)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	482					482
Other comprehensive (loss) income	(2)							(2)
Share repurchases	(749)			(10)			(739)
Equity-based compensation	(32)			(32)
Issuance of common stock	5			5
Common stock dividends	(8)					(8)
Balance at Mar. 31, 2019	(1,538)		4	8,473		(5,548)	(4,371)	(96)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	201					201
Other comprehensive (loss) income	(3)							(3)
Share repurchases	(305)			10			(315)
Equity-based compensation	5			5
Common stock dividends	(8)					(8)
Balance at Jun. 30, 2019	$ (1,648)		$ 4	$ 8,488		$ (5,355)	$ (4,686)	$ (99)

Nature of Business and Basis of

Nature of Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	Nature of Business and Basis of Presentation General NRG Energy, Inc., or NRG or the Company, is an energy company built on dynamic retail brands with diverse generation assets. NRG brings the power of energy to consumers by producing, selling and delivering electricity and related products and services in major competitive power markets in the U.S. in a manner that delivers value to all of NRG's stakeholders. NRG is perfecting the integrated model by balancing retail load with generation supply within its deregulated markets, while evolving to a customer-driven business. The Company sells energy, services, and innovative, sustainable products and services directly to retail customers under the names "NRG", "Reliant" and other brand names owned by NRG, supported by approximately 23,000 MW of generation as of June 30, 2019 . The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with the SEC's regulations for interim financial information and with the instructions to Form 10-Q. Accordingly, they do not include all of the information and notes required by generally accepted accounting principles for complete financial statements. The following notes should be read in conjunction with the accounting policies and other disclosures as set forth in the notes to the consolidated financial statements in the Company's 2018 Form 10-K. Interim results are not necessarily indicative of results for a full year. In the opinion of management, the accompanying unaudited interim condensed consolidated financial statements contain all material adjustments consisting of normal and recurring accruals necessary to present fairly the Company's consolidated financial position as of June 30, 2019 , and the results of operations, comprehensive income, cash flows and statements of stockholders' equity for the three and six months ended June 30, 2019 and 2018 . Discontinued Operations During the fourth quarter of 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 discontinued operations, as the sale, which closed on February 4, 2019, represented a strategic shift in the business in which NRG operates. The financial information for all historical periods has been recast to reflect the presentation of these entities as discontinued operations. On August 31, 2018, as described in Note 4 , Acquisitions, Discontinued Operations and Dispositions , NRG deconsolidated NRG Yield, Inc. and its Renewables Platform for financial reporting purposes. The financial information for all historical periods has been recast 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 also deconsolidated the Agua Caliente project from its financial results and began accounting for the project as an equity method investment. Use of Estimates The preparation of financial statements in conformity with GAAP 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. Reclassifications Certain prior year amounts have been reclassified for comparative purposes.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Net Income attributable to NRG Energy, Inc. The following table reflects the net income attributable to NRG Energy, Inc. after removing the net income/(loss) attributable to the noncontrolling interest and redeemable noncontrolling interest: Three months ended June 30, Six months ended June 30, 2019 2018 2019 2018 (In millions) Income from continuing operations, net of income tax $ 188 $ 27 $ 282 $ 272 Income from discontinued operations, net of income tax 13 45 401 79 Net income attributable to NRG Energy, Inc. $ 201 $ 72 $ 683 $ 351 Other Balance Sheet Information The following table presents the allowance for doubtful accounts included in accounts receivable, net; accumulated depreciation included in property, plant and equipment, net; accumulated amortization included in intangible assets, net and accumulated amortization included in out-of-market contracts, net: June 30, 2019 December 31, 2018 (In millions) Accounts receivable allowance for doubtful accounts $ 28 $ 32 Property, plant and equipment accumulated depreciation 1,684 1,811 Intangible assets accumulated amortization 1,182 1,149 Out-of-market contracts accumulated amortization — 37 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. June 30, 2019 December 31, 2018 (In millions) Cash and cash equivalents $ 294 $ 563 Funds deposited by counterparties 31 33 Restricted cash 11 17 Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statement of cash flows $ 336 $ 613 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 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. 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 under the modified retrospective approach by applying the provisions of the new leases guidance at the effective date without adjusting the comparative periods presented. The Company assessed its leasing arrangements, evaluated the impact of applying practical expedients and accounting policy elections, and implemented lease accounting software to meet the reporting requirements of the standard. The Company established operating lease liabilities of $404 million and right-of-use assets of $321 million upon adoption, before considering deferred taxes. The adoption of Topic 842 did not have a material impact on the statements of operations or cash flows. See Note 8 , Leases , for further discussion. Recent Accounting Developments - Guidance Not Yet Adopted 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 , in response to stakeholders’ observations that Topic 810, Consolidations , could be improved thereby improving general purpose financial reporting. Specifically, ASC 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 retained earnings at the beginning of the earliest period presented. The Company is evaluating the impact of adopting this guidance on the consolidated financial statements and disclosures. 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 guidance in ASU No. 2018-13 eliminates such disclosures as the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. The amendments in ASU No. 2018-13 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, with early adoption permitted for any eliminated or modified disclosures. Certain disclosures in ASU No. 2018-13 are required to be applied on a retrospective basis and others on a prospective basis. As the amendment contemplates changes in disclosures only, it will have no material impact on the Company's results of operations, cash flows, or statement of financial position.

Revenue Recognition

Revenue Recognition	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition Performance Obligations As of June 30, 2019 , estimated future fixed fee performance obligations are $315 million for the remaining six months of fiscal year 2019 , and $512 million , $542 million , $284 million and $29 million for the entirety of fiscal years 2020 , 2021 , 2022 and 2023 , 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. Disaggregated Revenues The following tables represent the Company’s disaggregation of revenue from contracts with customers for the three and six months ended June 30, 2019 and 2018 along with the reportable segment for each category: Three months ended June 30, 2019 Generation (In millions) Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue (a)(c) $ — $ 497 $ 117 $ 614 $ (365 ) $ 249 Capacity revenue (c) — — 154 154 1 155 Retail revenue Mass customers 1,401 — — — (1 ) 1,400 Business Solutions customers 345 — — — — 345 Total retail revenue 1,746 — — — (1 ) 1,745 Mark-to-market for economic hedging activities (a)(b) 2 460 64 524 (285 ) 241 Other revenues (c) — 16 59 75 — 75 Total operating revenue 1,748 973 394 1,367 (650 ) 2,465 Less: Lease revenue 3 — 2 2 — 5 Less: Realized and unrealized ASC 815 revenue (a) 2 1,184 140 1,324 (649 ) 677 Total revenue from contracts with customers $ 1,743 $ (211 ) $ 252 $ 41 $ (1 ) $ 1,783 (a) Generation includes higher revenues due to the Company's large internal transfer of power based on average annualized market prices, which are offset by higher cost of operations within Retail (b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815 (c) The following table represents the realized revenues related to derivative instruments that are accounted for under ASC 815 which are included in the amounts above: Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue $ — $ 717 $ 42 $ 759 $ (365 ) $ 394 Capacity revenue — — 29 29 1 30 Other revenue — 7 5 12 — 12 Three months ended June 30, 2018 Generation (In millions) Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue (a)(c) $ — $ 402 $ 259 $ 661 $ (251 ) $ 410 Capacity revenue (c) — — 165 165 — 165 Retail revenue Mass customers 1,377 — — — (1 ) 1,376 Business Solutions customers 437 — — — — 437 Total retail revenue 1,814 — — — (1 ) 1,813 Mark-to-market for economic hedging activities (a)(b) — 296 (22 ) 274 (264 ) 10 Other revenues (c) — 10 57 67 (4 ) 63 Total operating revenue 1,814 708 459 1,167 (520 ) 2,461 Less: Lease revenue 3 — 2 2 — 5 Less: Realized and unrealized ASC 815 revenue (a) — 865 48 913 (511 ) 402 Total revenue from contracts with customers $ 1,811 $ (157 ) $ 409 $ 252 $ (9 ) $ 2,054 (a) Generation includes higher revenues due to the Company's large internal transfer of power based on average annualized market prices, which are offset by higher cost of operations within Retail (b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815 (c) The following table represents the realized revenues related to derivative instruments that are accounted for under ASC 815 which are included in the amounts above: Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue $ — $ 569 $ 26 $ 595 $ (247 ) $ 348 Capacity revenue — — 39 39 — 39 Other revenue — — 5 5 — 5 Six months ended June 30, 2019 Generation (In millions) Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue (a)(c) $ — $ 855 $ 341 $ 1,196 $ (641 ) $ 555 Capacity revenue (c) — — 309 309 — 309 Retail revenue Mass customers 2,722 — — — (2 ) 2,720 Business Solutions customers 631 — — — — 631 Total retail revenue 3,353 — — — (2 ) 3,351 Mark-to-market for economic hedging activities (a)(b) 2 473 56 529 (270 ) 261 Other revenues (c) — 45 111 156 (2 ) 154 Total operating revenue 3,355 1,373 817 2,190 (915 ) 4,630 Less: Lease revenue 6 — 4 4 — 10 Less: Realized and unrealized ASC 815 revenue (a) 2 1,730 237 1,967 (911 ) 1,058 Total revenue from contracts with customers $ 3,347 $ (357 ) $ 576 $ 219 $ (4 ) $ 3,562 (a) Generation includes higher revenues due to the Company's large internal transfer of power based on average annualized market prices, which are offset by higher cost of operations within Retail (b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815 (c) The following table represents the realized revenues related to derivative instruments that are accounted for under ASC 815 which are included in the amounts above: Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue $ — $ 1,242 $ 129 $ 1,371 $ (641 ) $ 730 Capacity revenue — — 48 48 — 48 Other revenue — 15 4 19 — 19 Six months ended June 30, 2018 Generation (In millions) Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue (a)(c) $ — $ 666 $ 598 $ 1,264 $ (411 ) $ 853 Capacity revenue (c) — — 308 308 (1 ) 307 Retail revenue Mass customers 2,553 — — — (2 ) 2,551 Business Solutions customers 747 — — — — 747 Total retail revenue 3,300 — — — (2 ) 3,298 Mark-to-market for economic hedging activities (a)(b) (6 ) (273 ) (27 ) (300 ) 220 (86 ) Other revenues (c) — 64 102 166 (12 ) 154 Total operating revenue 3,294 457 981 1,438 (206 ) 4,526 Less: Lease revenue 7 — 4 4 — 11 Less: Realized and unrealized ASC 815 revenue (a) (6 ) 714 132 846 (184 ) 656 Total revenue from contracts with customers $ 3,293 $ (257 ) $ 845 $ 588 $ (22 ) $ 3,859 (a) Generation includes higher revenues due to the Company's large internal transfer of power based on average annualized market prices, which are offset by higher cost of operations within Retail (b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815 (c) The following table represents the realized revenues related to derivative instruments that are accounted for under ASC 815 which are included in the amounts above: Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue $ — $ 982 $ 86 $ 1,068 $ (404 ) $ 664 Capacity revenue — — 65 65 — 65 Other revenue — 5 8 13 — 13 Contract Balances The following table reflects the contract assets and liabilities included in the Company’s balance sheet as of June 30, 2019 and December 31, 2018: (In millions) June 30, 2019 December 31, 2018 Deferred customer acquisition costs $ 123 $ 111 Accounts receivable, net - Contracts with customers 1,015 999 Accounts receivable, net - Derivative instruments 43 20 Accounts receivable, net - Affiliate 4 5 Total accounts receivable, net $ 1,062 $ 1,024 Unbilled revenues (included within Accounts receivable, net - Contracts with customers) $ 403 $ 392 Deferred revenues (a) 89 67 (a) Deferred revenues from contracts with customers for the six month period ended June 30, 2019 and the twelve month period ended December 31, 2018 were approximately $31 million and $19 million , respectively The revenue recognized during the six months ended June 30, 2019 and 2018, relating to the deferred revenue balance at the beginning of each period was $13 million and $16 million , respectively. The revenue recognized during the three months ended June 30, 2019 and 2018, relating to the deferred revenue balance at the beginning of each period was $19 million and $16 million

Acquisitions, Discontinued Oper

Acquisitions, Discontinued Operations and Dispositions	6 Months Ended
	Jun. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Acquisitions, Discontinued Operations and Dispositions	Acquisitions, Discontinued Operations and Dispositions Acquisitions Stream Energy Acquisition - On May 15, 2019 , the Company entered into an agreement to acquire Stream Energy's retail electricity and natural gas business operating in 9 states and Washington, D.C. for $300 million in cash and estimated transaction costs and working capital adjustments of approximately $25 million . The acquisition increased NRG's retail portfolio by approximately 600,000 RCEs or 450,000 customers. The acquisition closed on August 1, 2019 . XOOM Energy Acquisition - On June 1, 2018, the Company completed the acquisition of XOOM Energy, LLC, an electricity and natural gas retailer operating in 19 states, Washington, D.C. and Canada for $213 million in cash. 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 Discontinued Operations Sale of South Central Portfolio On February 4, 2019 , the Company completed the sale of the South Central Portfolio to Cleco for cash consideration of $1 billion excluding working capital and other adjustments. The Company concluded that the divested business met the criteria for discontinued operations as of December 31, 2018, as the disposition represented a strategic shift in the business in which NRG operates and the criteria for held-for-sale were met. As such, all current and prior period results for the operations of the South Central Portfolio, except for the Cottonwood facility as discussed below, were reclassified as discontinued operations. In connection with the transaction, NRG also entered into a transition services agreement to provide certain corporate services to the divested business. The South Central Portfolio includes the 1,153 MW Cottonwood natural gas generating facility. Upon the closing of the sale of the South Central Portfolio, NRG entered into an agreement with Cleco to leaseback the Cottonwood facility through May 2025. Due to its continuing involvement with the Cottonwood facility, NRG did not use discontinued operations treatment in accounting for historical and ongoing activity with Cottonwood. Summarized results of the South Central Portfolio discontinued operations were as follows: Three months ended Six months ended (In millions) June 30, 2019 June 30, 2018 June 30, 2019 June 30, 2018 Operating revenues $ — $ 107 $ 31 $ 209 Operating costs and expenses — (91 ) (23 ) (177 ) Gain from discontinued operations, net of tax — 16 8 32 Gain on disposal of discontinued operations, net of tax 1 — 28 — Gain from discontinued operations, including disposal, net of tax $ 1 $ 16 $ 36 $ 32 The following table summarizes the major classes of assets and liabilities classified as discontinued operations of the South Central Portfolio: (In millions) December 31, 2018 Cash and cash equivalents $ 89 Accounts receivable - trade, 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 Sale of Ownership in NRG Yield, Inc. and the Renewables Platform On August 31, 2018, the Company completed the sale of its ownership interests in NRG Yield, Inc. and the Renewables Platform to GIP for total cash consideration of $1.348 billion . The Company concluded that the divested businesses met the criteria for discontinued operations, as the dispositions represent a strategic shift in the markets in which NRG operates. As such, all prior period results for NRG Yield, Inc. and the Renewables Platform were reclassified as discontinued operations. In connection with the transaction, NRG entered into a transition services agreement to provide certain corporate services to the divested businesses. During the six months ended June 30, 2019 , the Company recorded an adjustment to reduce the purchase price by $17 million in connection with the completion of the Patriot Wind project. The Company expects to recover a portion of this adjustment in the future. During the six months ended June 30, 2019 , the Company reduced the liability related to the indemnification of NRG Yield for any increase in property taxes for certain solar properties by $22 million due to updated estimates. Carlsbad On February 6, 2018, NRG entered into an agreement with NRG Yield and GIP to sell 100% of its membership interests in Carlsbad Energy Holdings LLC, which owns the Carlsbad project, for $385 million of cash consideration, excluding working capital adjustments. The primary condition to close the Carlsbad transaction was the completion of the sale of NRG Yield and the Renewables Platform. At the time of the sale of NRG Yield and the Renewables Platform in August 2018, the Company concluded that the Carlsbad project met the criteria for discontinued operations and accordingly, all current and prior period results for Carlsbad were reclassified as discontinued operations. The transaction closed on February 27, 2019. Carlsbad continues to have a ground lease and easement agreement with NRG with an initial term ending in 2039 and two ten year extensions. As a result of the transaction, additional commitments related to the project totaled approximately $23 million as of December 31, 2018 and June 30, 2019. Summarized results of NRG Yield, Inc. and the Renewables Platform and Carlsbad discontinued operations were as follows: Three months ended Six months ended (In millions) June 30, 2019 June 30, 2018 June 30, 2019 June 30, 2018 Operating revenues $ — $ 368 $ 19 $ 628 Operating costs and expenses — (223 ) (9 ) (453 ) Other expenses — (65 ) (5 ) (123 ) Gain from operations of discontinued components, before tax — 80 5 52 Income tax expense/(benefit) — 2 — (5 ) Gain from discontinued operations, net of tax — 78 5 57 Gain on disposal of discontinued operations, net of tax (17 ) — 331 — Other Commitments, Indemnification and Fees 27 — 27 — Gain on disposal of discontinued operations, net of tax 10 — 358 — Gain from discontinued operations, including disposal, net of tax $ 10 $ 78 $ 363 $ 57 The following table summarizes the major classes of assets and liabilities classified as discontinued operations of Carlsbad: (In millions) December 31, 2018 Restricted cash $ 4 Accounts receivable - trade, 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 Sale of Assets to NRG Yield, Inc. Prior to Discontinued Operations On June 19, 2018, the Company completed the UPMC Thermal Project and received cash consideration from NRG Yield of $84 million , plus an additional $3 million received at final completion in January 2019. On March 30, 2018, the Company sold to NRG Yield, Inc. 100 % of NRG's interests in Buckthorn Renewables, LLC, which owns a 154 MW construction-stage utility-scale solar generation project located in Texas. NRG Yield, Inc. paid cash consideration of $42 million, excluding working capital adjustments, and assumed non-recourse debt of $183 million. GenOn On June 14, 2017, the GenOn Entities filed voluntary petitions for relief under Chapter 11 of the Bankruptcy Code in the Bankruptcy Court. As a result of the bankruptcy filings, NRG concluded that it no longer controlled GenOn as it was subject to the control of the Bankruptcy Court; and, accordingly, NRG deconsolidated GenOn for financial reporting purposes as of June 14, 2017. By eliminating a large portion of its operations in the PJM market with the deconsolidation of GenOn, NRG concluded that GenOn met the criteria for discontinued operations, as this represented a strategic shift in the business in which NRG operates. As such, all prior period results for GenOn were reclassified as discontinued operations. GenOn's plan of reorganization was confirmed on December 14, 2018. Summarized results of GenOn discontinued operations were as follows: Three months ended Six months ended (In millions) June 30, 2019 June 30, 2018 June 30, 2019 June 30, 2018 Interest income - affiliate $ — $ 2 $ — $ 3 Pension and post-retirement liability assumption — 1 — 1 Advisory and consulting fees — (1 ) — (2 ) Other 2 (27 ) 2 (27 ) Gain/(loss) from discontinued operations, net of tax $ 2 $ (25 ) $ 2 $ (25 ) GenOn Settlement Effective July 16, 2018 , NRG and GenOn consummated the GenOn Settlement whereby the Company paid GenOn approximately $125 million, which included (i) the settlement consideration of $261 million, (ii) the transition services credit of $28 million and (iii) the return of $15 million of collateral posted to NRG; offset by the (i) $151 million in borrowings under the intercompany secured revolving credit facility, (ii) related accrued interest and fees of $12 million, (iii) remaining payments due under the transition services agreement of $10 million , (iv) $4 million reduction of the settlement payment related to NRG assigning to GenOn approximately $8 million of historical claims against REMA and (v) certain other balances due to NRG totaling $2 million . GenMA Settlement The Bankruptcy Court approved settlement terms agreed to among the GenOn Entities, NRG, the Consenting Holders, GenOn Mid-Atlantic, and certain of GenOn Mid-Atlantic's stakeholders, or the GenMA Settlement, and directed the settlement parties to cooperate in good faith to negotiate definitive documentation consistent with the GenMA Settlement term sheet in order to pursue consummation of the GenMA Settlement. The definitive documentation effectuating the GenMA Settlement was finalized as of April 27, 2018. Certain terms of the compromise with respect to NRG and GenOn Mid-Atlantic are as follows: • Settlement of all pending litigation and objections to the Plan (including with respect to releases and feasibility); • NRG provided $37.5 million in letters of credit as new qualifying credit support to GenOn Mid-Atlantic; and • NRG paid $6 million as reimbursement of professional fees incurred by certain of GenOn Mid- Atlantic's stakeholders in connection with the GenMA Settlement. Dispositions On June 29, 2018 , the Company completed the sale of Canal 3 to Stonepeak Kestrel for cash proceeds of $16 million and recorded a gain of $17 million . Prior to the sale, Canal 3 entered into a financing arrangement and received cash proceeds of $167 million , of which $151 million was distributed to the Company. The related debt was non-recourse to NRG and was transferred to Stonepeak Kestrel in connection with the sale of Canal 3. The Company entered into a project management agreement in 2018 to manage construction of Canal 3, and substantial completion was reached in June 2019. The Company completed other asset sales for cash proceeds of $18 million and $16 million during the six months ended June 30, 2019 and 2018, respectively.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	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 paid and received in support of energy risk management activities, the carrying amounts approximate fair values because of the short-term maturity of those instruments and are classified as Level 1 within the fair value hierarchy. The estimated carrying amounts and fair values of NRG's recorded financial instruments not carried at fair market value are as follows: As of June 30, 2019 As of December 31, 2018 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable $ 12 $ 8 $ 17 $ 14 Liabilities: Long-term debt, including current portion (a) 5,951 6,422 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 June 30, 2019 and December 31, 2018 : As of June 30, 2019 As of December 31, 2018 Level 2 Level 3 Level 2 Level 3 (In millions) Long-term debt, including current portion $ 6,305 $ 117 $ 6,528 $ 169 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 condensed consolidated balance sheets on a recurring basis and their level within the fair value hierarchy: As of June 30, 2019 (In millions) Total Level 1 Level 2 Level 3 Investments in securities (classified within other current and non-current assets) $ 38 $ — $ 19 $ 19 Nuclear trust fund investments: Cash and cash equivalents 25 25 — — U.S. government and federal agency obligations 57 57 — — Federal agency mortgage-backed securities 92 — 92 — Commercial mortgage-backed securities 29 — 29 — Corporate debt securities 102 — 102 — Equity securities 366 366 — — Foreign government fixed income securities 4 — 4 — Other trust fund investments: U.S. government and federal agency obligations 1 1 — — Derivative assets: Commodity contracts 1,276 131 770 375 Measured using net asset value practical expedient: Equity securities — nuclear trust fund investments 73 Equity securities 9 Total assets $ 2,072 $ 580 $ 1,016 $ 394 Derivative liabilities: Commodity contracts $ 1,152 $ 245 $ 629 $ 278 Total liabilities $ 1,152 $ 245 $ 629 $ 278 As of December 31, 2018 (In millions) Total Level 1 Level 2 Level 3 Investments in securities (classified within other current and 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 There were no transfers during the three and six months ended June 30, 2019 and 2018 between Levels 1 and 2. The following tables reconcile, for the three and six months ended June 30, 2019 and 2018 , the beginning and ending balances for financial instruments that are recognized at fair value in the condensed consolidated financial statements, at least annually, using significant unobservable inputs: Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Three months ended June 30, 2019 Six months ended June 30, 2019 (In millions) Debt Securities Derivatives (a) Total Debt Securities Derivatives (a) Total Beginning balance $ 18 $ (2 ) $ 16 $ 19 $ 20 $ 39 Contracts added from acquisitions — (1 ) (1 ) — (1 ) (1 ) Total gains/(losses) — realized/unrealized included in earnings 1 (17 ) (16 ) 1 (27 ) (26 ) Cash received — — — (1 ) — (1 ) Purchases — (10 ) (10 ) — (12 ) (12 ) Transfers into Level 3 (b) — 113 113 — 130 130 Transfers out of Level 3 (b) — 14 14 — (13 ) (13 ) Ending balance as of June 30, 2019 $ 19 $ 97 $ 116 $ 19 $ 97 $ 116 Gains/(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 June 30, 2019 $ 1 $ (19 ) $ (18 ) $ 1 $ (31 ) $ (30 ) (a) Consists of derivative 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 in/out are with Level 2 Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Three months ended June 30, 2018 Six months ended June 30, 2018 (In millions) Debt Securities Derivatives (a) Total Debt Securities Derivatives (a) Total Beginning balance $ 19 $ 5 $ 24 $ 19 $ (15 ) $ 4 Contracts added in XOOM acquisition — 12 12 — 12 12 Total (losses) — realized/unrealized included in earnings — (27 ) (27 ) — (16 ) (16 ) Purchases — (4 ) (4 ) — (3 ) (3 ) Transfers into Level 3 (b) — 193 193 — 197 197 Transfers out of Level 3 (b) — (5 ) (5 ) — (1 ) (1 ) Ending balance as of June 30, 2018 $ 19 $ 174 $ 193 $ 19 $ 174 $ 193 (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 June 30, 2018 $ — $ (27 ) $ (27 ) $ — $ (15 ) $ (15 ) (a) Consists of derivative 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 in/out are with Level 2 Derivative Fair Value Measurements A portion of NRG'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. The remainder of the assets and liabilities represent 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 the observable market data with similar characteristics. As of June 30, 2019 , contracts valued with prices provided by models and other valuation techniques make up 29% of derivative assets and 24% of derivative liabilities. 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 June 30, 2019 and December 31, 2018 : June 30, 2019 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 347 $ 261 Discounted Cash Flow Forward Market Price (per MWh) $ 4 $ 142 $ 25 FTRs 28 17 Discounted Cash Flow Auction Prices (per MWh) (134 ) 52 0 $ 375 $ 278 December 31, 2018 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) 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 June 30, 2019 and December 31, 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) 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 is calculated based on published default probabilities. As of June 30, 2019 the credit reserve resulted in a $2 million decrease in cost of operations. As of December 31, 2018 , the credit reserve did not result in a significant change in fair value in operating revenue and cost of operations. Concentration of Credit Risk In addition to the credit risk discussion as disclosed in Note 2 , Summary of Significant Accounting Policies , to the Company's 2018 Form 10-K, the following is a discussion of the concentration of credit risk for the Company's contractual obligations. 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. NRG is exposed to counterparty credit risk through various activities including wholesale sales, fuel purchases and retail supply arrangements, and retail customer credit risk through its retail load activities. Counterparty Credit Risk The Company's counterparty credit risk policies are disclosed in its 2018 Form 10-K. As of June 30, 2019 , counterparty credit exposure, excluding credit exposure from RTOs, ISOs, registered commodity exchanges and certain long-term agreements, was $273 million and NRG held collateral (cash and letters of credit) against those positions of $93 million , resulting in a net exposure of $226 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 60% of the Company's exposure before collateral is expected to roll off by the end of 2020 . 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. Net Exposure (a)(b) Category by Industry Sector (% of Total) Utilities, energy merchants, marketers and other 84 % Financial institutions 16 Total as of June 30, 2019 100 % Net Exposure (a) (b) Category by Counterparty Credit Quality (% of Total) Investment grade 53 % Non-investment grade/non-rated 47 Total as of June 30, 2019 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 in exposure to one wholesale counterparty in excess of 10% of total net exposure discussed above as of June 30, 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 its 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 the overall market and are excluded from the above exposures. Exchange Traded Transactions The Company enters into commodity transactions on registered exchanges, notably ICE, NYMEX and Nodal. 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 June 30, 2019 , aggregate credit risk exposure managed by NRG to these counterparties was approximately $524 million for the next five years , including exposure to PG&E as described below. NRG, through its unconsolidated affiliates Ivanpah and Agua Caliente, has exposure to PG&E of approximately $337 million for the next five years . As a result of the bankruptcy filing by PG&E on January 29, 2019, it is uncertain whether and to what extent the bankruptcy may have an effect on these contracts. For further discussion see Note 11 , Investments Accounted for Using the Equity Method and Variable Interest Entities, or VIEs . 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 June 30, 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.

Nuclear Decommissioning Trust F

Nuclear Decommissioning Trust Fund	6 Months Ended
	Jun. 30, 2019
Nuclear Decommissioning Trust Fund Disclosure [Abstract]
Nuclear Decommissioning Trust Fund	Nuclear Decommissioning Trust Fund NRG's Nuclear Decommissioning Trust Fund assets, which are for the decommissioning of its 44% interest in STP, are comprised of securities classified as available-for-sale and recorded at fair value based on actively quoted market prices. NRG accounts for the Nuclear Decommissioning Trust Fund in accordance with ASC 980, Regulated Operations , 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 OCI, 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 June 30, 2019 As of December 31, 2018 (In millions, except maturities) 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 $ 25 $ — $ — — $ 19 $ — $ — — U.S. government and federal agency obligations 57 4 — 12 46 1 — 12 Federal agency mortgage-backed securities 92 2 — 24 100 1 2 23 Commercial mortgage-backed securities 29 1 1 23 22 — 1 22 Corporate debt securities 102 5 — 11 96 1 2 11 Equity securities 439 291 — — 376 231 1 — Foreign government fixed income securities 4 — — 8 4 — — 9 Total $ 748 $ 303 $ 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 on the specific identification method. Six months ended June 30, 2019 2018 (In millions) Realized gains $ 5 $ 7 Realized losses (5 ) (6 ) Proceeds from sale of securities 191 303

Accounting for Derivative Instr

Accounting for Derivative Instruments and Hedging Activities	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Accounting for Derivative Instruments and Hedging Activities	Accounting for Derivative Instruments and Hedging Activities Energy-Related Commodities As of June 30, 2019 , NRG had energy-related derivative instruments extending through 2034 . The Company marks these derivatives to market through the statement of operations. NRG has executed power purchase agreements extending through 2033 that qualified for the NPNS exception and were therefore exempt from fair value accounting treatment. 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 June 30, 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 10 , Debt and Capital 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 category, excluding those derivatives that qualified for the NPNS exception, as of June 30, 2019 and December 31, 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. Total Volume June 30, 2019 December 31, 2018 Category Units (In millions) Emissions Short Ton 1 (2 ) Renewable Energy Certificates Certificates 1 1 Coal Short Ton 7 13 Natural Gas MMBtu (238 ) (330 ) Oil Barrels — 1 Power MWh 21 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 sheets: Fair Value Derivative Assets Derivative Liabilities June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 (In millions) Derivatives Not Designated as Cash Flow or Fair Value Hedges: Interest rate contracts current $ — $ 17 $ — $ — Interest rate contracts long-term — 22 — — Commodity contracts current 850 747 778 673 Commodity contracts long-term 426 295 374 304 Total Derivatives Not Designated as Cash Flow or Fair Value Hedges $ 1,276 $ 1,081 $ 1,152 $ 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 of derivatives by counterparty master agreement level and collateral received or paid: Gross Amounts Not Offset in the June 30, 2019 Balance Sheet Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount (In millions) Commodity contracts: Derivative assets $ 1,276 $ (1,029 ) $ (10 ) $ 237 Derivative liabilities (1,152 ) 1,029 58 (65 ) Total commodity contracts $ 124 $ — $ 48 $ 172 Gross Amounts Not Offset in the December 31, 2018 Balance Sheet Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount (In millions) 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 Loss The following table summarizes the effects on the Company's accumulated OCL balance attributable to cash flow hedge derivatives, net of tax: Interest Rate Contracts Three months ended June 30, 2018 Six months ended June 30, 2018 (In millions) Accumulated OCL beginning balance $ (31 ) $ (54 ) Reclassified from accumulated OCL to income: Due to realization of previously deferred amounts 3 7 Mark-to-market of cash flow hedge accounting contracts 5 24 Accumulated OCL ending balance, net of $5 tax $ (23 ) $ (23 ) Amounts reclassified from accumulated OCL into income are recorded in discontinued operations. Impact of Derivative Instruments on the Statements 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 results of operations. 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. Three months ended June 30, Six months ended June 30, 2019 2018 2019 2018 Unrealized mark-to-market results (In millions) Reversal of previously recognized unrealized losses/(gains) on settled positions related to economic hedges $ 11 $ (2 ) $ 30 $ (1 ) Reversal of acquired loss/(gain) positions related to economic hedges 1 (1 ) (1 ) (1 ) Net unrealized gains/(losses) on open positions related to economic hedges 9 (73 ) 12 132 Total unrealized mark-to-market gains/(losses) for economic hedging activities 21 (76 ) 41 130 Reversal of previously recognized unrealized gains on settled positions related to trading activity (1 ) (3 ) (7 ) (6 ) Net unrealized gains on open positions related to trading activity 13 8 26 19 Total unrealized mark-to-market gains for trading activity 12 5 19 13 Total unrealized gains/(losses) $ 33 $ (71 ) $ 60 $ 143 Three months ended June 30, Six months ended June 30, 2019 2018 2019 2018 (In millions) Unrealized gains/(losses) included in operating revenues $ 253 $ 15 $ 280 $ (73 ) Unrealized (losses)/gains included in cost of operations (220 ) (86 ) (220 ) 216 Total impact to statement of operations — energy commodities $ 33 $ (71 ) $ 60 $ 143 Total impact to statement of operations — interest rate contracts $ (29 ) $ 3 $ (38 ) $ 15 The reversals of acquired gain or loss positions were valued based upon the forward prices on the acquisition date. The roll-off amounts were offset by realized gains or losses at the settled prices and are reflected in operating revenue or cost of operations during the same period. For the six months ended June 30, 2019 , the $ 12 million unrealized gain from open economic hedge positions was primarily the result of an increase in value of forward power positions due to decreases in power prices. For the six months ended June 30, 2018 , the $132 million unrealized gain from open economic hedge positions was primarily the result of an increase in value of forward purchases of ERCOT heat rate and ERCOT electricity contracts due to ERCOT heat rate expansion and increases in ERCOT power prices. 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 with adequate assurance clauses that are in a net liability position as of June 30, 2019 was $19 million . The collateral required for contracts with credit rating contingent features that are in a net liability position as of June 30, 2019 was $13 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 $3 million as of June 30, 2019 . See Note 5 , Fair Value of Financial Instruments , for discussion regarding concentration of credit risk.

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	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 Topic 840 to the updated guidance in Topic 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 Topic 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 Topic 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 Topic 840. The Company elected the following practical expedients, which allow entities to: 1. not reassess whether any contracts that existed prior to the January 1, 2019 implementation date are or contain leases; 2. 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 Topic 840 will be classified as finance leases under Topic 842 and all commenced operating leases under Topic 840 will be classified as operating leases under Topic 842; 3. not reassess initial direct costs for any leases; 4. not reassess whether existing land easements, which were not previously accounted as leases under Topic 840, are or contain leases; and 5. 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) Three months ended June 30, 2019 Six months ended June 30, 2019 Operating lease cost 33 56 Short-term lease cost 1 1 Variable lease cost 2 3 Sublease income (5 ) (9 ) Total lease cost $ 31 $ 51 Other information: (In millions) Six months ended June 30, 2019 Cash paid for amounts included in the measurement of lease liabilities: $ 53 Operating cash flows from operating leases 53 Right-of-use assets obtained in exchange for new operating lease liabilities 214 Lease Term and Discount Rate: Weighted-average remaining lease term In Years Finance leases 2.5 Operating leases 8.1 Weighted-average discount rate % Finance leases 6.50 Operating leases 5.73 As of June 30, 2019 , annual payments based on the maturities of NRG's leases are expected to be as follows: (In millions) Remainder of 2019 $ 50 2020 95 2021 85 2022 85 2023 86 Thereafter 371 Total undiscounted lease payments $ 772 Less: present value adjustment (185 ) Total discounted lease payments $ 587

Impairments

Impairments	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Impairments	Impairments 2018 Impairment Losses Keystone and Conemaugh — On June 29, 2018, the Company entered into an agreement to sell 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. The transaction closed on September 5, 2018. 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 NYSPSC, 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 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, which would render the project impractical. Consequently, the Company recorded an impairment loss of $46 million during the second quarter of 2018, reducing the carrying amount of the related assets to $0

Debt and Capital Leases

Debt and Capital Leases	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt and Capital Leases	Debt and Capital Leases Long-term debt and capital leases consisted of the following: (In millions, except rates) June 30, 2019 December 31, 2018 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 575 575 2.750 Senior Secured First Lien Notes, due 2024 600 — 3.750 Senior Secured First Lien Notes, due 2029 500 — 4.450 Term Loan Facility (a) — 1,698 L+1.75 Tax-exempt bonds 466 466 4.125 - 6.00 Subtotal recourse debt 5,925 6,523 Non-recourse debt: Agua Caliente Borrower 1, due 2038 83 86 5.430 Midwest Generation — 48 4.390 Other 34 34 various Subtotal all non-recourse debt 117 168 Subtotal long-term debt (including current maturities) 6,042 6,691 Capital leases 1 1 various Subtotal long-term debt and capital leases (including current maturities) 6,043 6,692 Less current maturities (87 ) (72 ) Less debt issuance costs (71 ) (70 ) Discounts (91 ) (101 ) Total long-term debt and capital leases $ 5,794 $ 6,449 (a) As of December 31, 2018 , the interest rate was 1-month LIBOR plus 1.75% Recourse Debt Senior Notes Issuance of 2029 Senior Notes On May 14, 2019, NRG issued $733 million of aggregate principal amount at par of 5.25% senior unsecured notes due 2029, or the 2029 Senior Notes. The 2029 Senior Notes are senior unsecured obligations of NRG and are guaranteed by certain of its subsidiaries. Interest will be paid semi-annually beginning on December 15, 2019, until the maturity date of June 15, 2029. The proceeds from the issuance of the 2029 Senior Notes were utilized to redeem the Company's remaining 6.25% Senior Notes due 2024. Issuance of 2024 and 2029 Senior Secured First Lien Notes On May 28, 2019, NRG issued $1.1 billion of aggregate principal amount of senior secured first lien notes, consisting of $600 million 3.75% senior secured first lien notes due 2024 and $500 million 4.45% senior secured first lien notes due 2029, or the Senior Secured First Lien Notes, at a discount. The Senior Secured First Lien Notes are guaranteed on a first-priority basis by each of NRG’s current and future subsidiaries that guarantee indebtedness under its credit agreement. The Senior Secured First Lien Notes will be secured by a first priority security interest in the same collateral that is pledged for the benefit of the lenders under NRG’s credit agreement, which consists of a substantial portion of the property and assets owned by NRG and the guarantors. The collateral securing the Senior Secured First Lien Notes will be released if the Company obtains an investment grade rating from two out of the three rating agencies, subject to an obligation to reinstate the collateral if such rating agencies withdraw the Company's investment grade rating or downgrade its rating below investment grade. Interest will be paid semi-annually beginning on December 15, 2019, until the maturity dates of June 15, 2024 and June 15, 2029. The proceeds from the issuance of the Senior Secured First Lien Notes, together with cash on hand, were used to repay the Company's 2023 Term Loan Facility. 2024 Senior Notes Redemption During the three months ended June 30, 2019 , the Company redeemed $733 million of its 6.25% Senior Notes due 2024 and recorded a loss on debt extinguishment of $29 million , which included the write-off of previously deferred debt issuance costs of $5 million . Senior Credit Facility 2023 Term Loan Facility Repayment On May 28, 2019, the Company repaid its $1.7 billion 2023 Term Loan Facility using the proceeds from the issuance of the Senior Secured First Lien Notes, as well as cash on hand, resulting in a decrease of $594 million to long-term debt outstanding. The Company recorded a loss on debt extinguishment of $17 million , which included the write-off of previously deferred debt issuance costs of $13 million . As a result of the repayment of the outstanding 2023 Term Loan Facility, the Company terminated the related interest rate swap agreements, which were in-the-money, and received $25 million that was recorded as a reduction to interest expense. Revolving Credit Facility Modification On May 28, 2019, the Company amended its existing credit agreement to, among other things, (i) provide for a $184 million increase in revolving commitments, resulting in aggregate revolving commitments under the amended credit agreement equal to $2.6 billion , (ii) extend the maturity date of the revolving loans and commitments under the amended credit agreement to May 28, 2024, (iii) provide for a release of the collateral securing the amended credit agreement if NRG obtains an investment grade rating from two out of the three rating agencies, subject to an obligation to reinstate the collateral if such rating agencies withdraw NRG’s investment grade rating or downgrade NRG’s rating below investment grade, (iv) reduce the applicable margins for borrowings under (a) ABR Revolving Loans from 1.25% to 0.75% and (b) Eurodollar Revolving Loans from 2.25% to 1.75% , (v) add a sustainability-linked pricing metric that permits an interest rate adjustment tied to NRG meeting targets related to environmental sustainability and (vi) make certain other changes to the existing covenants. Non-Recourse Debt Agua Caliente Borrower 1 On January 22, 2019, the lenders of the Agua Caliente Borrower 1 debt notified Agua Caliente Borrower 1, a subsidiary of the Company, of certain defaults under the financing agreement as it relates to the bankruptcy filing made by PG&E on January 29, 2019. PG&E is the offtaker of the underlying contracts, which are material to the project. The financing was entered into along with Agua Caliente Borrower 2, LLC, a subsidiary of Clearway Energy Inc., which is joint and several to the parties. The Company is working with the lenders to determine a path forward. Cottonwood - Letters of Credit On January 4, 2019, the Company entered into an $80 million credit agreement to issue letters of credit, which is currently supporting the Cottonwood facility lease. Annual fees of 1.33% on the facility are paid quarterly in advance. As of June 30, 2019, the full $80 million was issued.

Investments Accounted for Using

Investments Accounted for Using the Equity Method and Variable Interest Entities, or VIEs	6 Months Ended
	Jun. 30, 2019
Variable Interest Entities Disclosure [Abstract]
Investments Accounted for Using the Equity Method and Variable Interest Entities, or VIEs	Investments Accounted for Using the Equity Method and Variable Interest Entities, or VIEs 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. 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. Under the current schedule set by the bankruptcy court, PG&E has the exclusive opportunity to propose a restructuring plan until September 26, 2019, although the ad hoc committee of senior unsecured noteholders filed a motion on June 25, 2019 to terminate PG&E's exclusivity period and to allow it to propose a plan that would include the assumption of all renewable contracts entered into by PG&E. The bankruptcy court has not yet ruled on that motion. The Company's subsidiaries are working with their partners on the projects and the loan counterparties. The Company believes that the Agua Caliente and Ivanpah PPAs with PG&E will not be rejected in the bankruptcy proceedings. NRG's maximum exposure to loss is limited to its equity investment, which was $206 million for Agua Caliente and $16 million for Ivanpah as of June 30, 2019. See Note 10 , Debt and Capital 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 and entered into a settlement during the second quarter of 2018. The settlement 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 during the six months ended June 30, 2018 . 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. Entities that are Consolidated The Company has a controlling financial interest in certain entities that have been identified as VIEs under ASC 810. These arrangements are primarily 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 to the Company's 2018 Form 10-K. The summarized financial information for the Company's consolidated VIEs consisted of the following: (In millions) June 30, 2019 December 31, 2018 Current assets $ 3 $ 3 Net property, plant and equipment 74 76 Other long-term assets 29 28 Total assets 106 107 Current liabilities 1 2 Long-term debt 28 29 Other long-term liabilities 8 7 Total liabilities 37 38 Redeemable noncontrolling interest 19 19 Net assets less noncontrolling interests $ 50 $ 50

Changes in Capital Structure

Changes in Capital Structure	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Changes in Capital Structure	Changes in Capital Structure As of June 30, 2019 and December 31, 2018 , the Company had 500,000,000 shares of common stock authorized. The following table reflects the changes in NRG's common stock issued and outstanding: Issued Treasury Outstanding Balance as of December 31, 2018 420,288,886 (136,638,847 ) 283,650,039 Shares issued under LTIPs 1,541,588 — 1,541,588 Shares repurchased — (26,621,029 ) (26,621,029 ) Balance as of June 30, 2019 421,830,474 (163,259,876 ) 258,570,598 Shares issued under LTIPs subsequent to June 30, 2019 3,827 — 3,827 Shares repurchased subsequent to June 30, 2019 — (5,586,536 ) (5,586,536 ) Balance as of August 7, 2019 421,834,301 (168,846,412 ) 252,987,889 Share Repurchases During January and February, the Company completed $250 million of share repurchases in connection with 2018 share repurchase program, at an average price of $40.61 per share. Through August 7, 2019, the Company completed additional share repurchases of $1.0 billion at an average price of $38.38 per share under the 2019 $1.0 billion program that was authorized in February 2019 by the Company's board of directors. In August 2019, the Company announced that the board of directors authorized an additional $250 million of share repurchases to be executed in the second half of 2019. On February 28, 2019, the Company executed an accelerated share repurchase agreement, or ASR Agreement, with a financial institution to repurchase a total of $400 million of outstanding common stock based on a volume weighted average price. The Company received initial shares of 9,086,903 , which were recorded in treasury stock at fair value based on the closing price on March 12, 2019, of $390 million , with the remaining $10 million recorded in additional paid in capital, representing the value of the forward contract to purchase additional shares. In April 2019, the financial institution delivered the remaining shares pursuant to the ASR agreement and the Company received 351,768 additional shares. The average price paid for all the shares delivered under the ASR Agreement was $42.38 per share. Upon receipt of the additional shares in April 2019, the Company transferred the $10 million from additional paid in capital to treasury stock. The following repurchases have been made during the six months ended June 30, 2019 and through August 7, 2019 under the 2018 and 2019 share repurchase programs: Total number of shares purchased Amounts paid for shares purchased (in millions) Board Authorized Share Repurchases 2018 program: Repurchases made during January-February to complete the 2018 program 6,153,415 $ 250 2019 program: Shares repurchased under February 28, 2019 Accelerated Share Repurchase Agreement 9,438,671 400 Other repurchases 11,028,943 404 Total Share Repurchases during the six months ended June 30, 2019 26,621,029 $ 1,054 Repurchases made subsequent to June 30, 2019 to complete the 2019 program 5,586,536 $ 196 Total Share Repurchases during the period ended August 7, 2019 32,207,565 $ 1,250 Employee Stock Purchase Plan In March 2019, the Company reopened participation in the ESPP, 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. NRG Common Stock Dividends A quarterly dividend of $0.03 per share was paid on the Company's common stock during the three months ended June 30, 2019 . On July 19, 2019 , NRG declared a quarterly dividend on the Company's common stock of $0.03 per share, payable August 15, 2019 , to stockholders of record as of August 1, 2019 , representing $0.12 per share on an annualized basis. The Company's common stock dividends are subject to available capital, market conditions, and compliance with associated laws, regulations and other contractual obligations.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per common share is computed by dividing net income 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 earnings per share is computed in a manner consistent with that of basic income per share while giving effect to all potentially dilutive common shares that were outstanding during the period. The outstanding non-qualified stock options, non-vested restricted stock units, market stock units, and relative performance stock units are not considered outstanding for purposes of computing basic income per share. However, these instruments are included in the denominator for purposes of computing diluted income 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 and diluted income per share is shown in the following table: Three months ended June 30, Six months ended June 30, In millions, except per share data 2019 2018 2019 2018 Basic income per share attributable to NRG Energy, Inc; Net income attributable to NRG Energy, Inc. common stockholders $ 201 $ 72 $ 683 $ 351 Weighted average number of common shares outstanding - basic 265 310 272 314 Income per weighted average common share — basic $ 0.76 $ 0.23 $ 2.51 $ 1.12 Diluted income per share attributable to NRG Energy, Inc; Net income attributable to NRG Energy, Inc. available to common shareholders $ 201 $ 72 $ 683 351 Weighted average number of common shares outstanding - basic 265 310 272 314 Incremental shares attributable to the issuance of equity compensation (treasury stock method) 2 4 2 4 Weighted average number of common shares outstanding - dilutive 267 314 274 318 Income per weighted average common share — diluted $ 0.75 $ 0.23 $ 2.49 $ 1.10 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 per share: Three months ended June 30, Six months ended June 30, In millions of shares 2019 2018 2019 2018 Equity compensation plans — — — 1

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company's segment structure reflects how management currently makes financial decisions and allocates resources. The Company's businesses are segregated into the Retail, Generation and corporate segments. Generation includes all power plant activities, domestic and international, as well as renewables. Retail includes Mass customers and Business Solutions, which includes C&I customers and other distributed and reliability products. Intersegment sales are accounted for at market.The financial information for the six months ended June 30, 2018 has been recast to reflect the current segment structure. On February 4, 2019, as described in Note 4 , Acquisitions, Discontinued Operations and Dispositions , the Company completed the sale of and deconsolidated the South Central Portfolio. On August 31, 2018, as described in Note 4 , Acquisitions, Discontinued Operations and Dispositions , NRG deconsolidated NRG Yield, Inc., its Renewables Platform and Carlsbad for financial reporting purposes. The financial information for the six months ended June 30, 2018 , has been recast to reflect the presentation of these entities as discontinued operations within the corporate segment. 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. Three months ended June 30, 2019 (a) Retail Generation Corporate Eliminations Total (In millions) Operating revenues (b) $ 1,748 $ 1,367 $ — $ (650 ) $ 2,465 Depreciation and amortization 32 45 8 — 85 Impairment losses 1 — — — 1 Reorganization costs 2 — — — 2 Gain on sale of assets — — 1 — 1 Loss on debt extinguishment, net — — (47 ) — (47 ) (Loss)/income from continuing operations before income taxes (280 ) 618 (151 ) 1 188 (Loss)/income from continuing operations (280 ) 618 (150 ) 1 189 Income from discontinued operations, net of tax — — 13 — 13 Net (loss)/income (280 ) 618 (137 ) 1 202 Net (loss)/income attributable to NRG Energy, Inc. $ (281 ) $ 618 $ (137 ) $ 1 $ 201 (a) Includes intersegment revenues and costs associated with the internal transfer of power, which is based on average annualized market prices and results in higher revenues in Generation and higher cost of operations in Retail that are eliminated in consolidation (b) Operating revenues include intersegment sales and net derivative gains and losses of: $ 2 $ 627 $ 21 $ — $ 650 Three months ended June 30, 2018 (a) Retail Generation Corporate Eliminations Total (In millions) Operating revenues (b) $ 1,814 $ 1,167 $ — $ (520 ) $ 2,461 Depreciation and amortization 30 74 9 (1 ) 112 Reorganization costs 1 3 19 — 23 Equity in earnings of unconsolidated affiliates — 5 2 (2 ) 5 (Loss)/income from continuing operations before income taxes (84 ) 252 (137 ) 1 32 (Loss)/income from continuing operations (84 ) 252 (142 ) 1 27 Income from discontinued operations, net of tax — — 69 — 69 Net (loss)/income (84 ) 252 (73 ) 1 96 Net (loss)/income attributable to NRG Energy, Inc. $ (84 ) $ 250 $ (97 ) $ 3 $ 72 (a) Includes intersegment revenues and costs associated with our internal transfer of power, which is based on average annualized market prices and results in higher revenues in Generation and higher cost of operations in Retail that are eliminated in consolidation (b) Operating revenues include intersegment sales and net derivative gains and losses of: $ 4 $ 514 $ 2 $ — $ 520 Six months ended June 30, 2019 (a) Retail Generation Corporate Eliminations Total (In millions) Operating revenues (b) $ 3,355 $ 2,190 $ — $ (915 ) $ 4,630 Depreciation and amortization 63 91 16 — 170 Impairment losses 1 — — — 1 Reorganization costs 3 1 11 — 15 Gain on sale of assets — 1 1 — 2 Equity in losses of unconsolidated affiliates — (21 ) — — (21 ) Loss on debt extinguishment, net — — (47 ) — (47 ) (Loss)/income from continuing operations before income taxes (169 ) 731 (275 ) (1 ) 286 (Loss)/income from continuing operations (170 ) 731 (277 ) (1 ) 283 Income from discontinued operations, net of tax — — 401 — 401 Net (loss)/income (170 ) 731 124 (1 ) 684 Net (loss)/income attributable to NRG Energy, Inc. common stockholders $ (171 ) $ 731 $ 124 $ (1 ) $ 683 (a) Includes intersegment revenues and costs associated with our internal transfer of power, which is based on average annualized market prices and results in higher revenues in Generation and higher cost of operations in Retail that are eliminated in consolidation (b) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 5 $ 862 $ 48 $ — $ 915 Six months ended June 30, 2018 (a) Retail Generation Corporate Eliminations Total Operating revenues (b) $ 3,294 $ 1,438 $ — $ (206 ) $ 4,526 Depreciation and amortization 56 160 18 (2 ) 232 Impairment losses — 74 — — 74 Reorganization costs 5 6 32 — 43 Gain on sale of assets — 2 14 — 16 Equity in earnings of unconsolidated affiliates — 7 1 (2 ) 6 Income/(loss) from continuing operations before income taxes 860 (319 ) (264 ) (1 ) 276 Income/(loss) from continuing operations 860 (319 ) (275 ) (1 ) 265 Income from discontinued operations, net of tax — — 64 — 64 Net income/(loss) 860 (319 ) (211 ) (1 ) 329 Net income/(loss) attributable to NRG Energy, Inc. common stockholders $ 859 $ (313 ) $ (196 ) $ 1 $ 351 (a) Includes intersegment revenues and costs associated with our internal transfer of power, which is based on average annualized market prices and results in higher revenues in Generation and higher cost of operations in Retail that are eliminated in consolidation (b) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 6 $ 205 $ (5 ) $ — $ 206

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Income Tax Rate The income tax provision consisted of the following: Three months ended June 30, Six months ended June 30, In millions, except rates 2019 2018 2019 2018 Income from continuing operations before income taxes $ 188 $ 32 $ 286 $ 276 Income tax (benefit)/expense from continuing operations (1 ) 5 3 11 Effective income tax rate (0.5 )% 15.6 % 1.0 % 4.0 % For the three and six months ended June 30, 2019 and 2018 , NRG's overall effective tax rate was lower than the statutory rate of 21% , primarily due to the tax benefit for the change in valuation allowance, partially offset by current state tax expense. Uncertain Tax Benefits As of June 30, 2019 , NRG has recorded a non-current tax liability of $28 million for uncertain tax benefits from positions taken on various state income tax returns, including accrued interest. For the six months ended June 30, 2019 , NRG accrued an immaterial amount of interest relating to the uncertain tax benefits. As of June 30, 2019 , NRG had cumulative interest and penalties related to these uncertain tax benefits of $4 million . The Company recognizes interest and penalties related to uncertain tax benefits in income tax expense. 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 2015. With few exceptions, state and local income tax examinations are no longer open for years before 2010.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The following table summarizes NRG's material related party transactions with third party affiliates: Three months ended June 30, Six months ended June 30, 2019 2018 2019 2018 (In millions) Revenues from Related Parties Included in Operating Revenues Gladstone $ 1 $ 1 $ 1 $ 1 GenConn — 1 — 3 Ivanpah 7 5 18 5 Midway-Sunset 1 — 2 — Revenues from Related Parties recorded against selling, general and administrative expenses GenOn — 21 — 42 Total $ 9 $ 28 $ 21 $ 51 Gladstone — NRG provides services to Gladstone, an equity method investment, under an operations and maintenance agreement. Fees for services under this contract primarily include recovery of NRG's costs of operating the plant, as approved in the annual budget, as well as a base monthly fee. GenConn — NRG provides services to GenConn under operations and maintenance agreements with GenConn Devon and GenConn Middletown that began in June 2010 and June 2011, respectively. NRG no longer has an ownership interest in GenConn as a result of the sale of its ownership interests in NRG Yield, Inc. and its Renewables Platform. Ivanpah — NRG provides services to Ivanpah, an equity method investment, under an operations and maintenance agreement and a project management agreement with each project company. Fees for the services under these contracts primarily include recovery of NRG's costs of operating the plant and providing administrative services, plus a profit margin. Ivanpah became a related party to NRG upon deconsolidation in the second quarter of 2018. Midway-Sunset — NRG provides services to Midway-Sunset, an equity method investment, under an operations and maintenance agreement. Fees for the services under this contract primarily include recovery of NRG's costs of operating the plant, as approved in the annual budget, as well as a base monthly fee and an annual incentive bonus. GenOn — NRG provided various management, personnel and other services to GenOn under the transition services agreement in conjunction with the confirmation of the GenOn Entities' plan of reorganization. GenOn provided notice to NRG of its intent to terminate the transition services agreement effective August 15, 2018 and all amounts owed and payable to NRG were settled.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments First Lien Structure NRG has granted first liens to certain counterparties on a substantial portion of the Company's assets, excluding NRG's assets that have project-level financing and the assets of certain non-guarantor subsidiaries, 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 MWh equivalents. The Company's lien counterparties may have a claim on NRG's assets to the extent market prices exceed the hedged price. As of June 30, 2019 , all 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 blended lignite obtained from the Jewett mine, which was operated by Texas Westmoreland Coal Co, or TWCC, and coal sourced from the Powder River Basin in Wyoming. On August 18, 2016, NRG gave notice to TWCC terminating the active mining of lignite under the contract, effective on December 31, 2016. Under the contract, TWCC remained responsible for reclamation activities. NRG is responsible for reclamation costs and 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 mine. Pursuant to the contract, NRG supports this obligation through surety bonds. Additionally, under the terms of the contract, NRG is obligated to provide additional performance assurance if required by the Railroad Commission of Texas. On October 9, 2018, TWCC and certain of its affiliates filed for protection under Chapter 11 of the U.S. Bankruptcy Code before the United States Bankruptcy Court for the Southern District of Texas. TWCC obtained authorization from the bankruptcy court to continue to perform its obligations under its contract with the Company and to maintain surety bonds programs throughout its operations. In addition, NRG has not received any indication from the Railroad Commission of Texas of an intent to draw on the surety bonds. TWCC and its debtor affiliates filed a plan of reorganization that the Bankruptcy Court confirmed on March 2, 2019. Pursuant to the plan, TWCC and its assets, including the Jewett mine and related agreements with NRG, were purchased by Westmoreland Mining LLC, an entity owned by Westmoreland Mining Holdings LLC, a new entity that is ultimately owned and controlled by certain holders of the pre-bankruptcy funded indebtedness of TWCC and certain of its affiliates. 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 18 , Regulatory Matters , and Note 19 , 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 certain of its subsidiaries, has 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, 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. California Department of Water Resources and San Diego Gas & Electric Company v. Sunrise Power Company LLC - On January 29, 2016, CDWR and SDG&E (plaintiffs) filed a lawsuit against Sunrise Power Company, along with NRG and Chevron Power Corporation (defendants). In June 2001, CDWR and Sunrise entered into a 10 -year PPA under which Sunrise would construct and operate a generating facility and provide power to CDWR. At the time the PPA was entered into, Sunrise had a transportation services agreement, or TSA, to purchase natural gas from Kern River through April 30, 2018. In August 2003, CDWR entered into an agreement with Sunrise and Kern River in which CDWR accepted assignment of the TSA through the term of the PPA. After the PPA expired, Kern River demanded that any reassignment be to a party which met certain creditworthiness standards which Sunrise did not. As such, the plaintiffs brought this lawsuit against the defendants alleging breach of contract, breach of covenant of good faith and fair dealing and improper distributions. Plaintiffs generally claim damages of $1.2 million per month for the remaining 70 months of the TSA. On April 20, 2016, the defendants filed objections in response to the plaintiffs' complaint. The objections were granted on June 14, 2016; however, the plaintiffs were allowed to file amended complaints on July 1, 2016. On July 27, 2016, defendants filed objections to the amended complaints. On November 18, 2016, the court sustained the objections and allowed plaintiffs another opportunity to file a second amended lawsuit which they did on January 13, 2017. On April 21, 2017, the court issued an order sustaining the objections without leave to amend. On July 14, 2017, plaintiffs filed a notice of appeal. On January 10, 2018, plaintiffs filed their opening appellate brief. Defendants filed their opposition brief on April 10, 2018. On May 30, 2018, plaintiffs filed their reply brief. The case is now waiting for the court of appeal to schedule oral argument. 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. On September 14, 2017, the court issued a scheduling order setting this case for trial on October 21, 2019. LaGen filed its answer and affirmative defenses on November 17, 2017. 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

Regulatory Matters

Regulatory Matters	6 Months Ended
	Jun. 30, 2019
Regulatory Matters Disclosure [Abstract]
Regulatory Matters	Regulatory Matters Environmental regulatory matters are discussed within Note 19 , Environmental Matters , to this Form 10-Q . 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. 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 2019. 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

Environmental Matters	6 Months Ended
	Jun. 30, 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 projects. 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, including migratory birds, eagles and threatened and endangered species. 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, EPA promulgated the ACE rule, which rescinded the CPP, which sought to broadly regulate CO 2 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. In February 2012, the EPA promulgated standards (the MATS rule) to control emissions of HAPs from coal and oil-fired electric generating units. The rule established limits for mercury, non-mercury metals, certain organics and acid gases, which had to be met beginning in April 2015. In December 2018, the EPA proposed a finding that regulating HAPs was not "appropriate and necessary" because the costs far exceed the benefits. Nonetheless, the EPA proposed keeping the substantive requirements of the MATS rule. While NRG cannot predict the final outcome of this rulemaking, NRG believes that because it has already invested in pollution controls and cleaner technologies, the fleet is well-positioned to comply with the MATS rule. Water Once Through Cooling Regulation — In August 2014, the EPA finalized the regulation regarding the use of water for once through cooling at existing facilities to address impingement and entrainment concerns. NRG anticipates that more stringent requirements will be incorporated into some of its water discharge permits over the next several years as NPDES permits are renewed. The Company anticipates the cost of complying with these requirements to be immaterial. 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, 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 released its opinion remanding portions of the rule to the EPA. Accordingly, 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 rule is revised. 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. Accordingly, we anticipate that the EPA will promulgate new regulations to address these issues (including compliance deadlines) as it reconsiders other aspects of the existing rule. The EPA has stated that it intends to further revise the rule. The Company will determine estimates of the cost of compliance after the rule is revised.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	6 Months Ended
	Jun. 30, 2019
Condensed Consolidating Financial Information Disclosure [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information As of June 30, 2019 , the Company had outstanding $4.4 billion of Senior Notes due from 2024 to 2048 and outstanding $1.1 billion of Senior Secured First Lien Notes due from 2024 to 2029, as shown in Note 10 , Debt and Capital 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 the Senior Secured First Lien Notes as of June 30, 2019 : Ace Energy, Inc. NRG Business Services LLC NRG PacGen Inc. Allied Home Warranty GP LLC NRG Cabrillo Power Operations Inc. NRG Portable Power LLC Allied Warranty LLC NRG California Peaker Operations LLC NRG Power Marketing LLC Arthur Kill Power LLC NRG Cedar Bayou Development Company, LLC NRG Reliability Solutions LLC Astoria Gas Turbine Power LLC NRG Connected Home LLC NRG Renter's Protection LLC BidURenergy, Inc. NRG Connecticut Affiliate Services Inc. NRG Retail LLC Cabrillo Power I LLC NRG Construction LLC NRG Retail Northeast LLC Cabrillo Power II LLC NRG Curtailment Solutions, Inc NRG Rockford Acquisition LLC Carbon Management Solutions LLC NRG Development Company Inc. NRG Saguaro Operations Inc. Cirro Group, Inc. NRG Devon Operations Inc. NRG Security LLC Cirro Energy Services, Inc. NRG Dispatch Services LLC NRG Services Corporation Connecticut Jet Power LLC NRG Distributed Energy Resources Holdings LLC NRG SimplySmart Solutions LLC Devon Power LLC NRG Distributed Generation PR LLC NRG South Central Affiliate Services Inc. Dunkirk Power LLC NRG Dunkirk Operations Inc. NRG South Central Operations Inc. Eastern Sierra Energy Company LLC NRG ECOKAP Holdings LLC NRG South Texas LP El Segundo Power, LLC NRG El Segundo Operations Inc. NRG Texas C&I Supply LLC El Segundo Power II LLC NRG Energy Labor Services LLC NRG Texas Gregory LLC Energy Alternatives Wholesale, LLC NRG Energy Services Group LLC NRG Texas Holding Inc. Energy Choice Solutions LLC NRG Energy Services International Inc. NRG Texas LLC Energy Plus Holdings LLC NRG Energy Services LLC NRG Texas Power LLC Energy Plus Natural Gas LLC NRG Generation Holdings, Inc. NRG Warranty Services LLC Energy Protection Insurance Company NRG Greenco LLC NRG West Coast LLC Everything Energy LLC NRG Home & Business Solutions LLC NRG Western Affiliate Services Inc. Forward Home Security, LLC NRG Home Services LLC O'Brien Cogeneration, Inc. II GCP Funding Company, LLC NRG Home Solutions LLC ONSITE Energy, Inc. Green Mountain Energy Company NRG Home Solutions Product LLC Oswego Harbor Power LLC Gregory Partners, LLC NRG Homer City Services LLC Reliant Energy Northeast LLC Gregory Power Partners LLC NRG Huntley Operations Inc. Reliant Energy Power Supply, LLC Huntley Power LLC NRG HQ DG LLC Reliant Energy Retail Holdings, LLC Independence Energy Alliance LLC NRG Identity Protect LLC Reliant Energy Retail Services, LLC Independence Energy Group LLC NRG Ilion Limited Partnership RERH Holdings, LLC Independence Energy Natural Gas LLC NRG Ilion LP LLC Saguaro Power LLC Indian River Operations Inc. NRG International LLC Somerset Operations Inc. Indian River Power LLC NRG Maintenance Services LLC Somerset Power LLC Meriden Gas Turbines LLC NRG Mextrans Inc. Texas Genco GP, LLC Middletown Power LLC NRG MidAtlantic Affiliate Services Inc. Texas Genco Holdings, Inc. Montville Power LLC NRG Middletown Operations Inc. Texas Genco LP, LLC NEO Corporation NRG Montville Operations Inc. Texas Genco Services, LP New Genco GP, LLC NRG North Central Operations Inc. US Retailers LLC Norwalk Power LLC NRG Northeast Affiliate Services Inc. Vienna Operations Inc. NRG Advisory Services LLC NRG Norwalk Harbor Operations Inc. Vienna Power LLC NRG Affiliate Services Inc. NRG Operating Services, Inc. WCP (Generation) Holdings LLC NRG Arthur Kill Operations Inc. NRG Oswego Harbor Power Operations Inc. West Coast Power LLC NRG Astoria Gas Turbine Operations 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. However, 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 of Regulation S-X of the Securities Act. 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. CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the three months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 2,140 $ 332 $ — $ (7 ) $ 2,465 Operating Costs and Expenses Cost of operations 1,590 252 10 (7 ) 1,845 Depreciation and amortization 51 26 8 — 85 Impairment losses 1 — — — 1 Selling, general and administrative 112 12 87 — 211 Reorganization costs — — 2 — 2 Development costs — 1 1 — 2 Total operating costs and expenses 1,754 291 108 (7 ) 2,146 Gain on sale of assets — 1 — — 1 Operating Income/(Loss) 386 42 (108 ) — 320 Other Income/(Expense) Equity in earnings of consolidated subsidiaries 2 — 430 (432 ) — Other income, net 4 8 8 — 20 Loss on debt extinguishment, net — — (47 ) — (47 ) Interest expense (3 ) (5 ) (97 ) — (105 ) Total other income/(expense) 3 3 294 (432 ) (132 ) Income from Continuing Operations Before Income Taxes 389 45 186 (432 ) 188 Income tax expense/(benefit) — 1 (2 ) — (1 ) Income from Continuing Operations 389 44 188 (432 ) 189 Income from discontinued operations, net of income tax — — 13 — 13 Net Income 389 44 201 (432 ) 202 Less: Net income attributable to noncontrolling interest and redeemable interests — 1 — — 1 Net Income Attributable to NRG Energy, Inc. $ 389 $ 43 $ 201 $ (432 ) $ 201 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the six months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,909 $ 727 $ — $ (6 ) $ 4,630 Operating Costs and Expenses Cost of operations 2,948 535 19 (6 ) 3,496 Depreciation and amortization 105 49 16 — 170 Impairment losses 1 — — — 1 Selling, general and administrative 234 28 143 — 405 Reorganization costs — — 15 — 15 Development costs — 1 3 — 4 Total operating costs and expenses 3,288 613 196 (6 ) 4,091 Gain on sale of assets 1 1 — — 2 Operating Income/(Loss) 622 115 (196 ) — 541 Other Income/(Expense) Equity in earnings of consolidated subsidiaries 12 — 729 (741 ) — Equity in losses of unconsolidated affiliates — (21 ) — — (21 ) Other income, net 8 9 15 — 32 Loss on debt extinguishment, net — — (47 ) — (47 ) Interest expense (7 ) (9 ) (203 ) — (219 ) Total other income/(expense) 13 (21 ) 494 (741 ) (255 ) Income from Continuing Operations Before Income Taxes 635 94 298 (741 ) 286 Income tax expense — 1 2 — 3 Income from Continuing Operations 635 93 296 (741 ) 283 Income from discontinued operations, net of income tax 9 5 387 — 401 Net Income 644 98 683 (741 ) 684 Less: Net income attributable to noncontrolling interest and redeemable interests — 1 — — 1 Net Income Attributable to NRG Energy, Inc. $ 644 $ 97 $ 683 $ (741 ) $ 683 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the three months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 389 $ 44 $ 201 $ (432 ) $ 202 Other Comprehensive Loss Foreign currency translation adjustments, net (1 ) (1 ) (1 ) 2 (1 ) Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — — (3 ) — (3 ) Other comprehensive loss (1 ) (1 ) (3 ) 2 (3 ) Comprehensive Income 388 43 198 (430 ) 199 Less: Comprehensive income attributable to noncontrolling redeemable interest — 1 — — 1 Comprehensive Income Attributable to NRG Energy, Inc. $ 388 $ 42 $ 198 $ (430 ) $ 198 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the six months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 644 $ 98 $ 683 $ (741 ) $ 684 Other Comprehensive Loss Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — — (6 ) — (6 ) Other comprehensive loss — — (5 ) — (5 ) Comprehensive Income 644 98 678 (741 ) 679 Less: Comprehensive income attributable to noncontrolling redeemable interest — 1 — — 1 Comprehensive Income Attributable to NRG Energy, Inc. $ 644 $ 97 $ 678 $ (741 ) $ 678 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ — $ 27 $ 267 $ — $ 294 Funds deposited by counterparties 31 — — — 31 Restricted cash 8 2 1 — 11 Accounts receivable, net 1,383 133 277 (744 ) 1,049 Inventory 254 116 — — 370 Derivative instruments 867 54 — (71 ) 850 Cash collateral paid in support of energy risk management activities 148 15 — — 163 Prepayments and other current assets 190 11 76 — 277 Total current assets 2,881 358 621 (815 ) 3,045 Property, plant and equipment, net 1,494 965 151 — 2,610 Other Assets Investment in subsidiaries 436 — 4,191 (4,627 ) — Equity investments in affiliates — 383 — — 383 Operating lease right-of-use assets, net 91 279 129 — 499 Goodwill 359 214 — — 573 Intangible assets, net 402 159 — — 561 Nuclear decommissioning trust fund 748 — — — 748 Derivative instruments 420 22 — (16 ) 426 Deferred income tax — 56 (1 ) — 55 Other non-current assets 148 30 96 (3 ) 271 Total other assets 2,604 1,143 4,415 (4,646 ) 3,516 Total Assets $ 6,979 $ 2,466 $ 5,187 $ (5,461 ) $ 9,171 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 87 $ — $ — $ 87 Current portion of operating lease liabilities 22 31 21 — 74 Accounts payable 937 107 423 (744 ) 723 Derivative instruments 817 32 — (71 ) 778 Cash collateral received in support of energy risk management activities 31 — — — 31 Accrued expenses and other current liabilities 258 42 301 — 601 Total current liabilities 2,065 299 745 (815 ) 2,294 Other Liabilities Long-term debt and capital leases 245 89 5,463 (3 ) 5,794 Non-current operating lease liabilities 73 313 127 — 513 Nuclear decommissioning reserve 290 — — — 290 Nuclear decommissioning trust liability 448 — — — 448 Derivative instruments 388 2 — (16 ) 374 Deferred income taxes (10 ) 68 13 — 71 Other non-current liabilities 399 148 469 — 1,016 Total other liabilities 1,833 620 6,072 (19 ) 8,506 Total Liabilities 3,898 919 6,817 (834 ) 10,800 Redeemable noncontrolling interest in subsidiaries — 19 — — 19 Stockholders’ Equity 3,081 1,528 (1,630 ) (4,627 ) (1,648 ) Total Liabilities and Stockholders’ Equity $ 6,979 $ 2,466 $ 5,187 $ (5,461 ) $ 9,171 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS For the six months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net income $ 644 $ 98 $ 683 $ (741 ) $ 684 Income from discontinued operations 9 5 387 — 401 Income from continuing operations 635 93 296 (741 ) 283 Adjustments to reconcile net income to net cash provided/(used) by operating activities: Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries (12 ) 22 (729 ) 741 22 Depreciation, amortization and accretion 115 53 16 — 184 Provision for bad debts 42 4 6 — 52 Amortization of nuclear fuel 27 — — — 27 Amortization of financing costs and debt discount/premiums — — 13 — 13 Loss on debt extinguishment, net — — 47 — 47 Amortization of intangibles 13 1 — — 14 Amortization of unearned equity compensation — — 10 — 10 (Loss)/gain on sale and disposal of assets (3 ) 1 3 — 1 Impairment losses 1 — — — 1 Changes in derivative instruments (28 ) (32 ) 38 — (22 ) Changes in deferred income taxes and liability for uncertain tax benefits — (3 ) (2 ) — (5 ) Changes in collateral deposits in support of energy risk management activities 128 (3 ) — — 125 Changes in nuclear decommissioning trust liability 17 — — — 17 Changes in other working capital (343 ) (64 ) 19 — (388 ) Cash provided/(used) by continuing operations 592 72 (283 ) — 381 Cash provided/(used) by discontinued operations 17 (9 ) — — 8 Net Cash Provided/(Used) by Operating Activities 609 63 (283 ) — 389 Cash Flows from Investing Activities Intercompany dividends — — 738 (738 ) — Payments for acquisitions of businesses (21 ) — — — (21 ) Capital expenditures (77 ) (15 ) (15 ) — (107 ) Net purchases of emission allowances (1 ) — — — (1 ) Investments in nuclear decommissioning trust fund securities (209 ) — — — (209 ) Proceeds from the sale of nuclear decommissioning trust fund securities 191 — — — 191 Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees 1 400 888 1,289 Net distributions from investments in unconsolidated affiliates — 7 — — 7 Contributions to discontinued operations — (44 ) — — (44 ) Cash (used)/provided by continuing operations (116 ) 348 1,611 (738 ) 1,105 Cash used by discontinued operations — (2 ) — — (2 ) Net Cash (Used)/Provided by Investing Activities (116 ) 346 1,611 (738 ) 1,103 Cash Flows from Financing Activities Payments from/(for) intercompany loans 206 (375 ) 169 — — Intercompany dividends (738 ) — — 738 — Payment of dividends to common stockholders — — (16 ) — (16 ) Payments for treasury stock — — (1,039 ) — (1,039 ) Payments for debt extinguishment — — (24 ) — (24 ) Distributions to noncontrolling interests from subsidiaries — (1 ) — — (1 ) Proceeds from issuance of common stock — — 2 — 2 Proceeds from issuance of long-term debt — — 1,833 — 1,833 Payment of debt issuance costs — — (33 ) — (33 ) Payments for long-term debt — (53 ) (2,432 ) — (2,485 ) Cash used by continuing operations (532 ) (429 ) (1,540 ) 738 (1,763 ) Cash provided by discontinued operations — 43 — — 43 Net Cash Used by Financing Activities (532 ) (386 ) (1,540 ) 738 (1,720 ) Change in cash from discontinued operations 17 32 — — 49 Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash (56 ) (9 ) (212 ) — (277 ) Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period 95 38 480 — 613 Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period $ 39 $ 29 $ 268 $ — $ 336 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the six months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,916 $ 620 $ — $ (10 ) $ 4,526 Operating Costs and Expenses Cost of operations 2,857 419 9 (11 ) 3,274 Depreciation and amortization 123 92 17 — 232 Impairment losses — 74 — — 74 Selling, general and administrative 212 27 137 — 376 Reorganization costs 3 — 40 — 43 Development costs — 2 7 (1 ) 8 Total operating costs and expenses 3,195 614 210 (12 ) 4,007 Gain on sale of assets 3 13 — — 16 Operating Income/(Loss) 724 19 (210 ) 2 535 Other Income/(Expense) Equity in earnings of consolidated subsidiaries 8 — 685 (693 ) — Equity in earnings/(losses) of unconsolidated affiliates — 7 (1 ) — 6 Other income/(loss), net 8 (36 ) 5 — (23 ) Loss on debt extinguishment, net — — (3 ) — (3 ) Interest expense (7 ) (34 ) (198 ) — (239 ) Total other income/(expense) 9 (63 ) 488 (693 ) (259 ) Income/(Loss) from Continuing Operations Before Income Taxes 733 (44 ) 278 (691 ) 276 Income tax expense/(benefit) 221 (16 ) (194 ) — 11 Income/(Loss) from Continuing Operations 512 (28 ) 472 (691 ) 265 Income/(loss) from discontinued operations, net of income tax 30 60 (26 ) — 64 Net Income 542 32 446 (691 ) 329 Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (119 ) 95 2 (22 ) Net Income Attributable to NRG Energy, Inc. $ 542 $ 151 $ 351 $ (693 ) $ 351 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the three months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 211 $ 93 $ 150 $ (358 ) $ 96 Other Comprehensive (Loss)/Income Unrealized gain on derivatives, net — 4 6 (5 ) 5 Foreign currency translation adjustments, net (4 ) (4 ) (5 ) 9 (4 ) Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — — (1 ) — (1 ) Other comprehensive (loss)/income (4 ) — 1 4 1 Comprehensive Income 207 93 151 (354 ) 97 Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests — (56 ) 80 2 26 Comprehensive Income Attributable to NRG Energy, Inc. $ 207 $ 149 $ 71 $ (356 ) $ 71 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the six months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income $ 542 $ 32 $ 446 $ (691 ) $ 329 Other Comprehensive (Loss)/Income Unrealized gain on derivatives, net — 20 21 (22 ) 19 Foreign currency translation adjustments, net (6 ) (6 ) (8 ) 14 (6 ) Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — — (2 ) — (2 ) Other comprehensive (loss)/income (6 ) 14 12 (8 ) 12 Comprehensive Income 536 46 458 (699 ) 341 Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests — (119 ) 105 2 (12 ) Comprehensive Income Attributable to NRG Energy, Inc. $ 536 $ 165 $ 353 $ (701 ) $ 353 (a) All significant intercompany transactions have been eliminated in consolidation CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2018 Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) 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 paid 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 capital 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 capital 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 six months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net income $ 542 $ 32 $ 446 $ (691 ) $ 329 Income/(loss) from discontinued operations 30 60 (26 ) — 64 Income/(loss) from continuing operations 512 (28 ) 472 (691 ) 265 Adjustments to reconcile net income to net cash provided/(used) by operating activities: Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries (8 ) 11 (682 ) 691 12 Depreciation, amortization and accretion 136 99 17 — 252 Provision for bad debts 30 — — — 30 Amortization of nuclear fuel 24 — — — 24 Amortization of financing costs and debt discount/premiums — 1 12 — 13 Loss on debt extinguishment, net — — 3 — 3 Amortization of intangibles and out-of-market contracts 16 4 — — 20 Amortization of unearned equity compensation — — 15 — 15 Loss on sale and disposal of assets (3 ) (13 ) — — (16 ) Impairment losses — 88 — — 88 Changes in derivative instruments (154 ) 19 (10 ) — (145 ) Changes in deferred income taxes and liability for uncertain tax benefits 221 (47 ) (176 ) — (2 ) Changes in collateral deposits in support of energy risk management activities (5 ) (4 ) — — (9 ) Changes in nuclear decommissioning trust liability 41 — — — 41 Loss on deconsolidation of Ivanpah project — 22 — — 22 Changes in other working capital 152 (56 ) (445 ) — (349 ) Cash provided/(used) by continuing operations 962 96 (794 ) — 264 Cash provided by discontinued operations 50 199 — — 249 Net Cash Provided/(Used) by Operating Activities 1,012 295 (794 ) — 513 Cash Flows from Investing Activities Intercompany dividends — — 157 (157 ) — Payments for acquisitions of businesses (2 ) (209 ) — — (211 ) Capital expenditures (103 ) (149 ) (30 ) — (282 ) Net proceeds from sale of emission allowances 3 — — — 3 Investments in nuclear decommissioning trust fund securities (346 ) — — — (346 ) Proceeds from the sale of nuclear decommissioning trust fund securities 303 — — — 303 Proceeds from sale of assets, net of cash disposed of 11 — 135 — 146 Deconsolidation of Ivanpah project — (160 ) — — (160 ) Net contributions for investments in unconsolidated affiliates — (15 ) — — (15 ) Contributions to discontinued operations — (16 ) — — (16 ) Cash (used)/provided by continuing operations (134 ) (549 ) 262 (157 ) (578 ) Cash provided/(used) by discontinued operations 2 (586 ) — — (584 ) Net Cash (Used)/Provided by Investing Activities (132 ) (1,135 ) 262 (157 ) (1,162 ) Cash Flows from Financing Activities Payments (for)/from intercompany loans (611 ) 204 407 — — Intercompany dividends (157 ) — — 157 — Payment of dividends to common stockholders — — (19 ) — (19 ) Payments for treasury stock — — (500 ) — (500 ) Distributions to noncontrolling interests from subsidiaries — (14 ) — — (14 ) Proceeds from issuance of common stock — — 11 — 11 Proceeds from issuance of short and long-term debt — 163 831 — 994 Payment of debt issuance costs — — (19 ) — (19 ) Payments for short and long-term debt — (63 ) (285 ) — (348 ) Cash (used)/provided by continuing operations (768 ) 290 426 157 105 Cash provided by discontinued operations — 345 — — 345 Net Cash (Used)/Provided by Financing Activities (768 ) 635 426 157 450 Change in cash from discontinued operations 52 (42 ) — — 10 Net Increase/(Decrease) in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash 60 (163 ) (106 ) — (209 ) Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period 41 425 620 — 1,086 Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period $ 101 $ 262 $ 514 $ — $ 877 (a) All significant intercompany transactions have been eliminated in consolidation

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP 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.
Reclassifications	Reclassifications Certain prior year amounts have been reclassified for comparative purposes.
Recent Accounting Developments	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 under the modified retrospective approach by applying the provisions of the new leases guidance at the effective date without adjusting the comparative periods presented. The Company assessed its leasing arrangements, evaluated the impact of applying practical expedients and accounting policy elections, and implemented lease accounting software to meet the reporting requirements of the standard. The Company established operating lease liabilities of $404 million and right-of-use assets of $321 million upon adoption, before considering deferred taxes. The adoption of Topic 842 did not have a material impact on the statements of operations or cash flows. See Note 8 , Leases , for further discussion. Recent Accounting Developments - Guidance Not Yet Adopted 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 , in response to stakeholders’ observations that Topic 810, Consolidations , could be improved thereby improving general purpose financial reporting. Specifically, ASC 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 retained earnings at the beginning of the earliest period presented. The Company is evaluating the impact of adopting this guidance on the consolidated financial statements and disclosures. 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 guidance in ASU No. 2018-13 eliminates such disclosures as the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy. The amendments in ASU No. 2018-13 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, with early adoption permitted for any eliminated or modified disclosures. Certain disclosures in ASU No. 2018-13 are required to be applied on a retrospective basis and others on a prospective basis. As the amendment contemplates changes in disclosures only, it will have no material impact on the Company's results of operations, cash flows, or statement of financial position.
Nuclear Decommissioning	NRG's Nuclear Decommissioning Trust Fund assets, which are for the decommissioning of its 44% interest in STP, are comprised of securities classified as available-for-sale and recorded at fair value based on actively quoted market prices. NRG accounts for the Nuclear Decommissioning Trust Fund in accordance with ASC 980, Regulated Operations , 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 OCI, consistent with regulatory treatment.
Segment Reporting	The Company's segment structure reflects how management currently makes financial decisions and allocates resources. The Company's businesses are segregated into the Retail, Generation and corporate segments. Generation includes all power plant activities, domestic and international, as well as renewables. Retail includes Mass customers and Business Solutions, which includes C&I customers and other distributed and reliability products. Intersegment sales are accounted for at market.The financial information for the six months ended June 30, 2018 has been recast to reflect the current segment structure. On February 4, 2019, as described in Note 4 , Acquisitions, Discontinued Operations and Dispositions , the Company completed the sale of and deconsolidated the South Central Portfolio. On August 31, 2018, as described in Note 4 , Acquisitions, Discontinued Operations and Dispositions , NRG deconsolidated NRG Yield, Inc., its Renewables Platform and Carlsbad for financial reporting purposes. The financial information for the six months ended June 30, 2018 , has been recast to reflect the presentation of these entities as discontinued operations within the corporate segment.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Net Income Attributable to NRG Energy, Inc. After Removing Net Loss from Noncontrolling Interest	The following table reflects the net income attributable to NRG Energy, Inc. after removing the net income/(loss) attributable to the noncontrolling interest and redeemable noncontrolling interest: Three months ended June 30, Six months ended June 30, 2019 2018 2019 2018 (In millions) Income from continuing operations, net of income tax $ 188 $ 27 $ 282 $ 272 Income from discontinued operations, net of income tax 13 45 401 79 Net income attributable to NRG Energy, Inc. $ 201 $ 72 $ 683 $ 351
Other Balance Sheet Information	The following table presents the allowance for doubtful accounts included in accounts receivable, net; accumulated depreciation included in property, plant and equipment, net; accumulated amortization included in intangible assets, net and accumulated amortization included in out-of-market contracts, net: June 30, 2019 December 31, 2018 (In millions) Accounts receivable allowance for doubtful accounts $ 28 $ 32 Property, plant and equipment accumulated depreciation 1,684 1,811 Intangible assets accumulated amortization 1,182 1,149 Out-of-market contracts accumulated amortization — 37
Reconciliation of Cash and Cash Equivalents, Restricted Cash and Funds Deposited by Counterparties	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. June 30, 2019 December 31, 2018 (In millions) Cash and cash equivalents $ 294 $ 563 Funds deposited by counterparties 31 33 Restricted cash 11 17 Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statement of cash flows $ 336 $ 613

Revenue Recognition (Tables)

Revenue Recognition (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue from Contracts with Customer	Disaggregated Revenues The following tables represent the Company’s disaggregation of revenue from contracts with customers for the three and six months ended June 30, 2019 and 2018 along with the reportable segment for each category: Three months ended June 30, 2019 Generation (In millions) Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue (a)(c) $ — $ 497 $ 117 $ 614 $ (365 ) $ 249 Capacity revenue (c) — — 154 154 1 155 Retail revenue Mass customers 1,401 — — — (1 ) 1,400 Business Solutions customers 345 — — — — 345 Total retail revenue 1,746 — — — (1 ) 1,745 Mark-to-market for economic hedging activities (a)(b) 2 460 64 524 (285 ) 241 Other revenues (c) — 16 59 75 — 75 Total operating revenue 1,748 973 394 1,367 (650 ) 2,465 Less: Lease revenue 3 — 2 2 — 5 Less: Realized and unrealized ASC 815 revenue (a) 2 1,184 140 1,324 (649 ) 677 Total revenue from contracts with customers $ 1,743 $ (211 ) $ 252 $ 41 $ (1 ) $ 1,783 (a) Generation includes higher revenues due to the Company's large internal transfer of power based on average annualized market prices, which are offset by higher cost of operations within Retail (b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815 (c) The following table represents the realized revenues related to derivative instruments that are accounted for under ASC 815 which are included in the amounts above: Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue $ — $ 717 $ 42 $ 759 $ (365 ) $ 394 Capacity revenue — — 29 29 1 30 Other revenue — 7 5 12 — 12 Three months ended June 30, 2018 Generation (In millions) Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue (a)(c) $ — $ 402 $ 259 $ 661 $ (251 ) $ 410 Capacity revenue (c) — — 165 165 — 165 Retail revenue Mass customers 1,377 — — — (1 ) 1,376 Business Solutions customers 437 — — — — 437 Total retail revenue 1,814 — — — (1 ) 1,813 Mark-to-market for economic hedging activities (a)(b) — 296 (22 ) 274 (264 ) 10 Other revenues (c) — 10 57 67 (4 ) 63 Total operating revenue 1,814 708 459 1,167 (520 ) 2,461 Less: Lease revenue 3 — 2 2 — 5 Less: Realized and unrealized ASC 815 revenue (a) — 865 48 913 (511 ) 402 Total revenue from contracts with customers $ 1,811 $ (157 ) $ 409 $ 252 $ (9 ) $ 2,054 (a) Generation includes higher revenues due to the Company's large internal transfer of power based on average annualized market prices, which are offset by higher cost of operations within Retail (b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815 (c) The following table represents the realized revenues related to derivative instruments that are accounted for under ASC 815 which are included in the amounts above: Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue $ — $ 569 $ 26 $ 595 $ (247 ) $ 348 Capacity revenue — — 39 39 — 39 Other revenue — — 5 5 — 5 Six months ended June 30, 2019 Generation (In millions) Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue (a)(c) $ — $ 855 $ 341 $ 1,196 $ (641 ) $ 555 Capacity revenue (c) — — 309 309 — 309 Retail revenue Mass customers 2,722 — — — (2 ) 2,720 Business Solutions customers 631 — — — — 631 Total retail revenue 3,353 — — — (2 ) 3,351 Mark-to-market for economic hedging activities (a)(b) 2 473 56 529 (270 ) 261 Other revenues (c) — 45 111 156 (2 ) 154 Total operating revenue 3,355 1,373 817 2,190 (915 ) 4,630 Less: Lease revenue 6 — 4 4 — 10 Less: Realized and unrealized ASC 815 revenue (a) 2 1,730 237 1,967 (911 ) 1,058 Total revenue from contracts with customers $ 3,347 $ (357 ) $ 576 $ 219 $ (4 ) $ 3,562 (a) Generation includes higher revenues due to the Company's large internal transfer of power based on average annualized market prices, which are offset by higher cost of operations within Retail (b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815 (c) The following table represents the realized revenues related to derivative instruments that are accounted for under ASC 815 which are included in the amounts above: Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue $ — $ 1,242 $ 129 $ 1,371 $ (641 ) $ 730 Capacity revenue — — 48 48 — 48 Other revenue — 15 4 19 — 19 Six months ended June 30, 2018 Generation (In millions) Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue (a)(c) $ — $ 666 $ 598 $ 1,264 $ (411 ) $ 853 Capacity revenue (c) — — 308 308 (1 ) 307 Retail revenue Mass customers 2,553 — — — (2 ) 2,551 Business Solutions customers 747 — — — — 747 Total retail revenue 3,300 — — — (2 ) 3,298 Mark-to-market for economic hedging activities (a)(b) (6 ) (273 ) (27 ) (300 ) 220 (86 ) Other revenues (c) — 64 102 166 (12 ) 154 Total operating revenue 3,294 457 981 1,438 (206 ) 4,526 Less: Lease revenue 7 — 4 4 — 11 Less: Realized and unrealized ASC 815 revenue (a) (6 ) 714 132 846 (184 ) 656 Total revenue from contracts with customers $ 3,293 $ (257 ) $ 845 $ 588 $ (22 ) $ 3,859 (a) Generation includes higher revenues due to the Company's large internal transfer of power based on average annualized market prices, which are offset by higher cost of operations within Retail (b) Revenue relates entirely to unrealized gains and losses on derivative instruments accounted for under ASC 815 (c) The following table represents the realized revenues related to derivative instruments that are accounted for under ASC 815 which are included in the amounts above: Retail Texas East/West/Other Subtotal Corporate/Eliminations Total Energy revenue $ — $ 982 $ 86 $ 1,068 $ (404 ) $ 664 Capacity revenue — — 65 65 — 65 Other revenue — 5 8 13 — 13
Contract Asset and Liabilities	The following table reflects the contract assets and liabilities included in the Company’s balance sheet as of June 30, 2019 and December 31, 2018: (In millions) June 30, 2019 December 31, 2018 Deferred customer acquisition costs $ 123 $ 111 Accounts receivable, net - Contracts with customers 1,015 999 Accounts receivable, net - Derivative instruments 43 20 Accounts receivable, net - Affiliate 4 5 Total accounts receivable, net $ 1,062 $ 1,024 Unbilled revenues (included within Accounts receivable, net - Contracts with customers) $ 403 $ 392 Deferred revenues (a) 89 67 (a) Deferred revenues from contracts with customers for the six month period ended June 30, 2019 and the twelve month period ended December 31, 2018 were approximately $31 million and $19 million , respectively The revenue recognized during the six months ended June 30, 2019 and 2018, relating to the deferred revenue balance at the beginning of each period was $13 million and $16 million , respectively. The revenue recognized during the three months ended June 30, 2019 and 2018, relating to the deferred revenue balance at the beginning of each period was $19 million and $16 million

Acquisitions, Discontinued Op_2

Acquisitions, Discontinued Operations and Dispositions (Tables)	6 Months Ended
	Jun. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Purchase Price Allocation	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 and Major Classes of Assets and Liabilities	The following table summarizes the major classes of assets and liabilities classified as discontinued operations of Carlsbad: (In millions) December 31, 2018 Restricted cash $ 4 Accounts receivable - trade, 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 GenOn discontinued operations were as follows: Three months ended Six months ended (In millions) June 30, 2019 June 30, 2018 June 30, 2019 June 30, 2018 Interest income - affiliate $ — $ 2 $ — $ 3 Pension and post-retirement liability assumption — 1 — 1 Advisory and consulting fees — (1 ) — (2 ) Other 2 (27 ) 2 (27 ) Gain/(loss) from discontinued operations, net of tax $ 2 $ (25 ) $ 2 $ (25 ) The following table summarizes the major classes of assets and liabilities classified as discontinued operations of the South Central Portfolio: (In millions) December 31, 2018 Cash and cash equivalents $ 89 Accounts receivable - trade, 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 the South Central Portfolio discontinued operations were as follows: Three months ended Six months ended (In millions) June 30, 2019 June 30, 2018 June 30, 2019 June 30, 2018 Operating revenues $ — $ 107 $ 31 $ 209 Operating costs and expenses — (91 ) (23 ) (177 ) Gain from discontinued operations, net of tax — 16 8 32 Gain on disposal of discontinued operations, net of tax 1 — 28 — Gain from discontinued operations, including disposal, net of tax $ 1 $ 16 $ 36 $ 32 Summarized results of NRG Yield, Inc. and the Renewables Platform and Carlsbad discontinued operations were as follows: Three months ended Six months ended (In millions) June 30, 2019 June 30, 2018 June 30, 2019 June 30, 2018 Operating revenues $ — $ 368 $ 19 $ 628 Operating costs and expenses — (223 ) (9 ) (453 ) Other expenses — (65 ) (5 ) (123 ) Gain from operations of discontinued components, before tax — 80 5 52 Income tax expense/(benefit) — 2 — (5 ) Gain from discontinued operations, net of tax — 78 5 57 Gain on disposal of discontinued operations, net of tax (17 ) — 331 — Other Commitments, Indemnification and Fees 27 — 27 — Gain on disposal of discontinued operations, net of tax 10 — 358 — Gain from discontinued operations, including disposal, net of tax $ 10 $ 78 $ 363 $ 57

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Estimated carrying amounts and fair values of NRG's recorded financial instruments not carried at fair market value	The estimated carrying amounts and fair values of NRG's recorded financial instruments not carried at fair market value are as follows: As of June 30, 2019 As of December 31, 2018 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable $ 12 $ 8 $ 17 $ 14 Liabilities: Long-term debt, including current portion (a) 5,951 6,422 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 June 30, 2019 and December 31, 2018 : As of June 30, 2019 As of December 31, 2018 Level 2 Level 3 Level 2 Level 3 (In millions) Long-term debt, including current portion $ 6,305 $ 117 $ 6,528 $ 169
Assets and liabilities measured and recorded at fair value on the consolidated balance sheets on a recurring basis	The following tables present assets and liabilities measured and recorded at fair value on the Company's condensed consolidated balance sheets on a recurring basis and their level within the fair value hierarchy: As of June 30, 2019 (In millions) Total Level 1 Level 2 Level 3 Investments in securities (classified within other current and non-current assets) $ 38 $ — $ 19 $ 19 Nuclear trust fund investments: Cash and cash equivalents 25 25 — — U.S. government and federal agency obligations 57 57 — — Federal agency mortgage-backed securities 92 — 92 — Commercial mortgage-backed securities 29 — 29 — Corporate debt securities 102 — 102 — Equity securities 366 366 — — Foreign government fixed income securities 4 — 4 — Other trust fund investments: U.S. government and federal agency obligations 1 1 — — Derivative assets: Commodity contracts 1,276 131 770 375 Measured using net asset value practical expedient: Equity securities — nuclear trust fund investments 73 Equity securities 9 Total assets $ 2,072 $ 580 $ 1,016 $ 394 Derivative liabilities: Commodity contracts $ 1,152 $ 245 $ 629 $ 278 Total liabilities $ 1,152 $ 245 $ 629 $ 278 As of December 31, 2018 (In millions) Total Level 1 Level 2 Level 3 Investments in securities (classified within other current and 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 in the consolidated financial statements at least annually using significant unobservable inputs	There were no transfers during the three and six months ended June 30, 2019 and 2018 between Levels 1 and 2. The following tables reconcile, for the three and six months ended June 30, 2019 and 2018 , the beginning and ending balances for financial instruments that are recognized at fair value in the condensed consolidated financial statements, at least annually, using significant unobservable inputs: Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Three months ended June 30, 2019 Six months ended June 30, 2019 (In millions) Debt Securities Derivatives (a) Total Debt Securities Derivatives (a) Total Beginning balance $ 18 $ (2 ) $ 16 $ 19 $ 20 $ 39 Contracts added from acquisitions — (1 ) (1 ) — (1 ) (1 ) Total gains/(losses) — realized/unrealized included in earnings 1 (17 ) (16 ) 1 (27 ) (26 ) Cash received — — — (1 ) — (1 ) Purchases — (10 ) (10 ) — (12 ) (12 ) Transfers into Level 3 (b) — 113 113 — 130 130 Transfers out of Level 3 (b) — 14 14 — (13 ) (13 ) Ending balance as of June 30, 2019 $ 19 $ 97 $ 116 $ 19 $ 97 $ 116 Gains/(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 June 30, 2019 $ 1 $ (19 ) $ (18 ) $ 1 $ (31 ) $ (30 ) (a) Consists of derivative 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 in/out are with Level 2 Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Three months ended June 30, 2018 Six months ended June 30, 2018 (In millions) Debt Securities Derivatives (a) Total Debt Securities Derivatives (a) Total Beginning balance $ 19 $ 5 $ 24 $ 19 $ (15 ) $ 4 Contracts added in XOOM acquisition — 12 12 — 12 12 Total (losses) — realized/unrealized included in earnings — (27 ) (27 ) — (16 ) (16 ) Purchases — (4 ) (4 ) — (3 ) (3 ) Transfers into Level 3 (b) — 193 193 — 197 197 Transfers out of Level 3 (b) — (5 ) (5 ) — (1 ) (1 ) Ending balance as of June 30, 2018 $ 19 $ 174 $ 193 $ 19 $ 174 $ 193 (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 June 30, 2018 $ — $ (27 ) $ (27 ) $ — $ (15 ) $ (15 ) (a) Consists of derivative 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 in/out are with Level 2
Significant unobservable inputs used developing fair values, Quantitative Information	The following tables quantify the significant unobservable inputs used in developing the fair value of the Company's Level 3 positions as of June 30, 2019 and December 31, 2018 : June 30, 2019 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 347 $ 261 Discounted Cash Flow Forward Market Price (per MWh) $ 4 $ 142 $ 25 FTRs 28 17 Discounted Cash Flow Auction Prices (per MWh) (134 ) 52 0 $ 375 $ 278 December 31, 2018 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) 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 June 30, 2019 and December 31, 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. Net Exposure (a)(b) Category by Industry Sector (% of Total) Utilities, energy merchants, marketers and other 84 % Financial institutions 16 Total as of June 30, 2019 100 % Net Exposure (a) (b) Category by Counterparty Credit Quality (% of Total) Investment grade 53 % Non-investment grade/non-rated 47 Total as of June 30, 2019 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

Nuclear Decommissioning Trust_2

Nuclear Decommissioning Trust Fund (Tables)	6 Months Ended
	Jun. 30, 2019
Nuclear Decommissioning Trust Fund Disclosure [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	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 June 30, 2019 As of December 31, 2018 (In millions, except maturities) 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 $ 25 $ — $ — — $ 19 $ — $ — — U.S. government and federal agency obligations 57 4 — 12 46 1 — 12 Federal agency mortgage-backed securities 92 2 — 24 100 1 2 23 Commercial mortgage-backed securities 29 1 1 23 22 — 1 22 Corporate debt securities 102 5 — 11 96 1 2 11 Equity securities 439 291 — — 376 231 1 — Foreign government fixed income securities 4 — — 8 4 — — 9 Total $ 748 $ 303 $ 1 $ 663 $ 234 $ 6
Summary of proceeds from sales of available-for-sale securities and the related realized gains and losses	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 on the specific identification method. Six months ended June 30, 2019 2018 (In millions) Realized gains $ 5 $ 7 Realized losses (5 ) (6 ) Proceeds from sale of securities 191 303

Accounting for Derivative Ins_2

Accounting for Derivative Instruments and Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net notional volume buy/(sell) of NRG's open derivative transactions broken out by commodity	The following table summarizes the net notional volume buy/(sell) of NRG's open derivative transactions broken out by category, excluding those derivatives that qualified for the NPNS exception, as of June 30, 2019 and December 31, 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. Total Volume June 30, 2019 December 31, 2018 Category Units (In millions) Emissions Short Ton 1 (2 ) Renewable Energy Certificates Certificates 1 1 Coal Short Ton 7 13 Natural Gas MMBtu (238 ) (330 ) Oil Barrels — 1 Power MWh 21 1 Capacity MW/Day (1 ) (1 ) Interest Dollars $ — $ 1,000
Fair value within the derivative instrument valuation on the balance sheets	The following table summarizes the fair value within the derivative instrument valuation on the balance sheets: Fair Value Derivative Assets Derivative Liabilities June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 (In millions) Derivatives Not Designated as Cash Flow or Fair Value Hedges: Interest rate contracts current $ — $ 17 $ — $ — Interest rate contracts long-term — 22 — — Commodity contracts current 850 747 778 673 Commodity contracts long-term 426 295 374 304 Total Derivatives Not Designated as Cash Flow or Fair Value Hedges $ 1,276 $ 1,081 $ 1,152 $ 977
Offsetting of derivatives by counterparty assets	The following table summarizes the offsetting of derivatives by counterparty master agreement level and collateral received or paid: Gross Amounts Not Offset in the June 30, 2019 Balance Sheet Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount (In millions) Commodity contracts: Derivative assets $ 1,276 $ (1,029 ) $ (10 ) $ 237 Derivative liabilities (1,152 ) 1,029 58 (65 ) Total commodity contracts $ 124 $ — $ 48 $ 172 Gross Amounts Not Offset in the December 31, 2018 Balance Sheet Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount (In millions) 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
Offsetting of derivatives by counterparty, liabilities	The following table summarizes the offsetting of derivatives by counterparty master agreement level and collateral received or paid: Gross Amounts Not Offset in the June 30, 2019 Balance Sheet Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount (In millions) Commodity contracts: Derivative assets $ 1,276 $ (1,029 ) $ (10 ) $ 237 Derivative liabilities (1,152 ) 1,029 58 (65 ) Total commodity contracts $ 124 $ — $ 48 $ 172 Gross Amounts Not Offset in the December 31, 2018 Balance Sheet Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount (In millions) 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 of ASC 815 on the Company's accumulated OCI balance attributable to cash flow hedge derivatives, net of tax	The following table summarizes the effects on the Company's accumulated OCL balance attributable to cash flow hedge derivatives, net of tax: Interest Rate Contracts Three months ended June 30, 2018 Six months ended June 30, 2018 (In millions) Accumulated OCL beginning balance $ (31 ) $ (54 ) Reclassified from accumulated OCL to income: Due to realization of previously deferred amounts 3 7 Mark-to-market of cash flow hedge accounting contracts 5 24 Accumulated OCL ending balance, net of $5 tax $ (23 ) $ (23 )
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	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. Three months ended June 30, Six months ended June 30, 2019 2018 2019 2018 Unrealized mark-to-market results (In millions) Reversal of previously recognized unrealized losses/(gains) on settled positions related to economic hedges $ 11 $ (2 ) $ 30 $ (1 ) Reversal of acquired loss/(gain) positions related to economic hedges 1 (1 ) (1 ) (1 ) Net unrealized gains/(losses) on open positions related to economic hedges 9 (73 ) 12 132 Total unrealized mark-to-market gains/(losses) for economic hedging activities 21 (76 ) 41 130 Reversal of previously recognized unrealized gains on settled positions related to trading activity (1 ) (3 ) (7 ) (6 ) Net unrealized gains on open positions related to trading activity 13 8 26 19 Total unrealized mark-to-market gains for trading activity 12 5 19 13 Total unrealized gains/(losses) $ 33 $ (71 ) $ 60 $ 143 Three months ended June 30, Six months ended June 30, 2019 2018 2019 2018 (In millions) Unrealized gains/(losses) included in operating revenues $ 253 $ 15 $ 280 $ (73 ) Unrealized (losses)/gains included in cost of operations (220 ) (86 ) (220 ) 216 Total impact to statement of operations — energy commodities $ 33 $ (71 ) $ 60 $ 143 Total impact to statement of operations — interest rate contracts $ (29 ) $ 3 $ (38 ) $ 15

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lease, Cost and Other Information	Lease Cost: (In millions) Three months ended June 30, 2019 Six months ended June 30, 2019 Operating lease cost 33 56 Short-term lease cost 1 1 Variable lease cost 2 3 Sublease income (5 ) (9 ) Total lease cost $ 31 $ 51 Other information: (In millions) Six months ended June 30, 2019 Cash paid for amounts included in the measurement of lease liabilities: $ 53 Operating cash flows from operating leases 53 Right-of-use assets obtained in exchange for new operating lease liabilities 214 Lease Term and Discount Rate: Weighted-average remaining lease term In Years Finance leases 2.5 Operating leases 8.1 Weighted-average discount rate % Finance leases 6.50 Operating leases 5.73
Schedule of Annual Payments Based on Maturities of Leases	As of June 30, 2019 , annual payments based on the maturities of NRG's leases are expected to be as follows: (In millions) Remainder of 2019 $ 50 2020 95 2021 85 2022 85 2023 86 Thereafter 371 Total undiscounted lease payments $ 772 Less: present value adjustment (185 ) Total discounted lease payments $ 587

Debt and Capital Leases (Tables

Debt and Capital Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Long-term debt and capital leases	Long-term debt and capital leases consisted of the following: (In millions, except rates) June 30, 2019 December 31, 2018 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 575 575 2.750 Senior Secured First Lien Notes, due 2024 600 — 3.750 Senior Secured First Lien Notes, due 2029 500 — 4.450 Term Loan Facility (a) — 1,698 L+1.75 Tax-exempt bonds 466 466 4.125 - 6.00 Subtotal recourse debt 5,925 6,523 Non-recourse debt: Agua Caliente Borrower 1, due 2038 83 86 5.430 Midwest Generation — 48 4.390 Other 34 34 various Subtotal all non-recourse debt 117 168 Subtotal long-term debt (including current maturities) 6,042 6,691 Capital leases 1 1 various Subtotal long-term debt and capital leases (including current maturities) 6,043 6,692 Less current maturities (87 ) (72 ) Less debt issuance costs (71 ) (70 ) Discounts (91 ) (101 ) Total long-term debt and capital leases $ 5,794 $ 6,449 (a) As of December 31, 2018 , the interest rate was 1-month LIBOR plus 1.75%

Investments Accounted for Usi_2

Investments Accounted for Using the Equity Method and Variable Interest Entities, or VIEs (Tables)	6 Months Ended
	Jun. 30, 2019
Variable Interest Entities Disclosure [Abstract]
Financial Information for Consolidated VIEs	The summarized financial information for the Company's consolidated VIEs consisted of the following: (In millions) June 30, 2019 December 31, 2018 Current assets $ 3 $ 3 Net property, plant and equipment 74 76 Other long-term assets 29 28 Total assets 106 107 Current liabilities 1 2 Long-term debt 28 29 Other long-term liabilities 8 7 Total liabilities 37 38 Redeemable noncontrolling interest 19 19 Net assets less noncontrolling interests $ 50 $ 50

Changes in Capital Structure (T

Changes in Capital Structure (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Changes in NRG's common shares issued and outstanding	The following table reflects the changes in NRG's common stock issued and outstanding: Issued Treasury Outstanding Balance as of December 31, 2018 420,288,886 (136,638,847 ) 283,650,039 Shares issued under LTIPs 1,541,588 — 1,541,588 Shares repurchased — (26,621,029 ) (26,621,029 ) Balance as of June 30, 2019 421,830,474 (163,259,876 ) 258,570,598 Shares issued under LTIPs subsequent to June 30, 2019 3,827 — 3,827 Shares repurchased subsequent to June 30, 2019 — (5,586,536 ) (5,586,536 ) Balance as of August 7, 2019 421,834,301 (168,846,412 ) 252,987,889
Shares Repurchased	The following repurchases have been made during the six months ended June 30, 2019 and through August 7, 2019 under the 2018 and 2019 share repurchase programs: Total number of shares purchased Amounts paid for shares purchased (in millions) Board Authorized Share Repurchases 2018 program: Repurchases made during January-February to complete the 2018 program 6,153,415 $ 250 2019 program: Shares repurchased under February 28, 2019 Accelerated Share Repurchase Agreement 9,438,671 400 Other repurchases 11,028,943 404 Total Share Repurchases during the six months ended June 30, 2019 26,621,029 $ 1,054 Repurchases made subsequent to June 30, 2019 to complete the 2019 program 5,586,536 $ 196 Total Share Repurchases during the period ended August 7, 2019 32,207,565 $ 1,250 Employee Stock Purchase Plan In March 2019, the Company reopened participation in the ESPP, 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.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Reconciliation of NRG's basic and diluted earnings per share	The reconciliation of NRG's basic and diluted income per share is shown in the following table: Three months ended June 30, Six months ended June 30, In millions, except per share data 2019 2018 2019 2018 Basic income per share attributable to NRG Energy, Inc; Net income attributable to NRG Energy, Inc. common stockholders $ 201 $ 72 $ 683 $ 351 Weighted average number of common shares outstanding - basic 265 310 272 314 Income per weighted average common share — basic $ 0.76 $ 0.23 $ 2.51 $ 1.12 Diluted income per share attributable to NRG Energy, Inc; Net income attributable to NRG Energy, Inc. available to common shareholders $ 201 $ 72 $ 683 351 Weighted average number of common shares outstanding - basic 265 310 272 314 Incremental shares attributable to the issuance of equity compensation (treasury stock method) 2 4 2 4 Weighted average number of common shares outstanding - dilutive 267 314 274 318 Income per weighted average common share — diluted $ 0.75 $ 0.23 $ 2.49 $ 1.10
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 per share: Three months ended June 30, Six months ended June 30, In millions of shares 2019 2018 2019 2018 Equity compensation plans — — — 1

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Schedule of segment reporting information, by segment	Three months ended June 30, 2019 (a) Retail Generation Corporate Eliminations Total (In millions) Operating revenues (b) $ 1,748 $ 1,367 $ — $ (650 ) $ 2,465 Depreciation and amortization 32 45 8 — 85 Impairment losses 1 — — — 1 Reorganization costs 2 — — — 2 Gain on sale of assets — — 1 — 1 Loss on debt extinguishment, net — — (47 ) — (47 ) (Loss)/income from continuing operations before income taxes (280 ) 618 (151 ) 1 188 (Loss)/income from continuing operations (280 ) 618 (150 ) 1 189 Income from discontinued operations, net of tax — — 13 — 13 Net (loss)/income (280 ) 618 (137 ) 1 202 Net (loss)/income attributable to NRG Energy, Inc. $ (281 ) $ 618 $ (137 ) $ 1 $ 201 (a) Includes intersegment revenues and costs associated with the internal transfer of power, which is based on average annualized market prices and results in higher revenues in Generation and higher cost of operations in Retail that are eliminated in consolidation (b) Operating revenues include intersegment sales and net derivative gains and losses of: $ 2 $ 627 $ 21 $ — $ 650 Three months ended June 30, 2018 (a) Retail Generation Corporate Eliminations Total (In millions) Operating revenues (b) $ 1,814 $ 1,167 $ — $ (520 ) $ 2,461 Depreciation and amortization 30 74 9 (1 ) 112 Reorganization costs 1 3 19 — 23 Equity in earnings of unconsolidated affiliates — 5 2 (2 ) 5 (Loss)/income from continuing operations before income taxes (84 ) 252 (137 ) 1 32 (Loss)/income from continuing operations (84 ) 252 (142 ) 1 27 Income from discontinued operations, net of tax — — 69 — 69 Net (loss)/income (84 ) 252 (73 ) 1 96 Net (loss)/income attributable to NRG Energy, Inc. $ (84 ) $ 250 $ (97 ) $ 3 $ 72 (a) Includes intersegment revenues and costs associated with our internal transfer of power, which is based on average annualized market prices and results in higher revenues in Generation and higher cost of operations in Retail that are eliminated in consolidation (b) Operating revenues include intersegment sales and net derivative gains and losses of: $ 4 $ 514 $ 2 $ — $ 520 Six months ended June 30, 2019 (a) Retail Generation Corporate Eliminations Total (In millions) Operating revenues (b) $ 3,355 $ 2,190 $ — $ (915 ) $ 4,630 Depreciation and amortization 63 91 16 — 170 Impairment losses 1 — — — 1 Reorganization costs 3 1 11 — 15 Gain on sale of assets — 1 1 — 2 Equity in losses of unconsolidated affiliates — (21 ) — — (21 ) Loss on debt extinguishment, net — — (47 ) — (47 ) (Loss)/income from continuing operations before income taxes (169 ) 731 (275 ) (1 ) 286 (Loss)/income from continuing operations (170 ) 731 (277 ) (1 ) 283 Income from discontinued operations, net of tax — — 401 — 401 Net (loss)/income (170 ) 731 124 (1 ) 684 Net (loss)/income attributable to NRG Energy, Inc. common stockholders $ (171 ) $ 731 $ 124 $ (1 ) $ 683 (a) Includes intersegment revenues and costs associated with our internal transfer of power, which is based on average annualized market prices and results in higher revenues in Generation and higher cost of operations in Retail that are eliminated in consolidation (b) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 5 $ 862 $ 48 $ — $ 915 Six months ended June 30, 2018 (a) Retail Generation Corporate Eliminations Total Operating revenues (b) $ 3,294 $ 1,438 $ — $ (206 ) $ 4,526 Depreciation and amortization 56 160 18 (2 ) 232 Impairment losses — 74 — — 74 Reorganization costs 5 6 32 — 43 Gain on sale of assets — 2 14 — 16 Equity in earnings of unconsolidated affiliates — 7 1 (2 ) 6 Income/(loss) from continuing operations before income taxes 860 (319 ) (264 ) (1 ) 276 Income/(loss) from continuing operations 860 (319 ) (275 ) (1 ) 265 Income from discontinued operations, net of tax — — 64 — 64 Net income/(loss) 860 (319 ) (211 ) (1 ) 329 Net income/(loss) attributable to NRG Energy, Inc. common stockholders $ 859 $ (313 ) $ (196 ) $ 1 $ 351 (a) Includes intersegment revenues and costs associated with our internal transfer of power, which is based on average annualized market prices and results in higher revenues in Generation and higher cost of operations in Retail that are eliminated in consolidation (b) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 6 $ 205 $ (5 ) $ — $ 206

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The income tax provision consisted of the following: Three months ended June 30, Six months ended June 30, In millions, except rates 2019 2018 2019 2018 Income from continuing operations before income taxes $ 188 $ 32 $ 286 $ 276 Income tax (benefit)/expense from continuing operations (1 ) 5 3 11 Effective income tax rate (0.5 )% 15.6 % 1.0 % 4.0 %

Related Party Transactions (Tab

Related Party Transactions (Tables)	6 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Summary of NRG's Material Related Party Transactions	The following table summarizes NRG's material related party transactions with third party affiliates: Three months ended June 30, Six months ended June 30, 2019 2018 2019 2018 (In millions) Revenues from Related Parties Included in Operating Revenues Gladstone $ 1 $ 1 $ 1 $ 1 GenConn — 1 — 3 Ivanpah 7 5 18 5 Midway-Sunset 1 — 2 — Revenues from Related Parties recorded against selling, general and administrative expenses GenOn — 21 — 42 Total $ 9 $ 28 $ 21 $ 51

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information (Tables)	6 Months Ended
	Jun. 30, 2019
Condensed Consolidating 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 the Senior Secured First Lien Notes as of June 30, 2019 : Ace Energy, Inc. NRG Business Services LLC NRG PacGen Inc. Allied Home Warranty GP LLC NRG Cabrillo Power Operations Inc. NRG Portable Power LLC Allied Warranty LLC NRG California Peaker Operations LLC NRG Power Marketing LLC Arthur Kill Power LLC NRG Cedar Bayou Development Company, LLC NRG Reliability Solutions LLC Astoria Gas Turbine Power LLC NRG Connected Home LLC NRG Renter's Protection LLC BidURenergy, Inc. NRG Connecticut Affiliate Services Inc. NRG Retail LLC Cabrillo Power I LLC NRG Construction LLC NRG Retail Northeast LLC Cabrillo Power II LLC NRG Curtailment Solutions, Inc NRG Rockford Acquisition LLC Carbon Management Solutions LLC NRG Development Company Inc. NRG Saguaro Operations Inc. Cirro Group, Inc. NRG Devon Operations Inc. NRG Security LLC Cirro Energy Services, Inc. NRG Dispatch Services LLC NRG Services Corporation Connecticut Jet Power LLC NRG Distributed Energy Resources Holdings LLC NRG SimplySmart Solutions LLC Devon Power LLC NRG Distributed Generation PR LLC NRG South Central Affiliate Services Inc. Dunkirk Power LLC NRG Dunkirk Operations Inc. NRG South Central Operations Inc. Eastern Sierra Energy Company LLC NRG ECOKAP Holdings LLC NRG South Texas LP El Segundo Power, LLC NRG El Segundo Operations Inc. NRG Texas C&I Supply LLC El Segundo Power II LLC NRG Energy Labor Services LLC NRG Texas Gregory LLC Energy Alternatives Wholesale, LLC NRG Energy Services Group LLC NRG Texas Holding Inc. Energy Choice Solutions LLC NRG Energy Services International Inc. NRG Texas LLC Energy Plus Holdings LLC NRG Energy Services LLC NRG Texas Power LLC Energy Plus Natural Gas LLC NRG Generation Holdings, Inc. NRG Warranty Services LLC Energy Protection Insurance Company NRG Greenco LLC NRG West Coast LLC Everything Energy LLC NRG Home & Business Solutions LLC NRG Western Affiliate Services Inc. Forward Home Security, LLC NRG Home Services LLC O'Brien Cogeneration, Inc. II GCP Funding Company, LLC NRG Home Solutions LLC ONSITE Energy, Inc. Green Mountain Energy Company NRG Home Solutions Product LLC Oswego Harbor Power LLC Gregory Partners, LLC NRG Homer City Services LLC Reliant Energy Northeast LLC Gregory Power Partners LLC NRG Huntley Operations Inc. Reliant Energy Power Supply, LLC Huntley Power LLC NRG HQ DG LLC Reliant Energy Retail Holdings, LLC Independence Energy Alliance LLC NRG Identity Protect LLC Reliant Energy Retail Services, LLC Independence Energy Group LLC NRG Ilion Limited Partnership RERH Holdings, LLC Independence Energy Natural Gas LLC NRG Ilion LP LLC Saguaro Power LLC Indian River Operations Inc. NRG International LLC Somerset Operations Inc. Indian River Power LLC NRG Maintenance Services LLC Somerset Power LLC Meriden Gas Turbines LLC NRG Mextrans Inc. Texas Genco GP, LLC Middletown Power LLC NRG MidAtlantic Affiliate Services Inc. Texas Genco Holdings, Inc. Montville Power LLC NRG Middletown Operations Inc. Texas Genco LP, LLC NEO Corporation NRG Montville Operations Inc. Texas Genco Services, LP New Genco GP, LLC NRG North Central Operations Inc. US Retailers LLC Norwalk Power LLC NRG Northeast Affiliate Services Inc. Vienna Operations Inc. NRG Advisory Services LLC NRG Norwalk Harbor Operations Inc. Vienna Power LLC NRG Affiliate Services Inc. NRG Operating Services, Inc. WCP (Generation) Holdings LLC NRG Arthur Kill Operations Inc. NRG Oswego Harbor Power Operations Inc. West Coast Power LLC NRG Astoria Gas Turbine Operations Inc.
CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS	NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the three months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 2,140 $ 332 $ — $ (7 ) $ 2,465 Operating Costs and Expenses Cost of operations 1,590 252 10 (7 ) 1,845 Depreciation and amortization 51 26 8 — 85 Impairment losses 1 — — — 1 Selling, general and administrative 112 12 87 — 211 Reorganization costs — — 2 — 2 Development costs — 1 1 — 2 Total operating costs and expenses 1,754 291 108 (7 ) 2,146 Gain on sale of assets — 1 — — 1 Operating Income/(Loss) 386 42 (108 ) — 320 Other Income/(Expense) Equity in earnings of consolidated subsidiaries 2 — 430 (432 ) — Other income, net 4 8 8 — 20 Loss on debt extinguishment, net — — (47 ) — (47 ) Interest expense (3 ) (5 ) (97 ) — (105 ) Total other income/(expense) 3 3 294 (432 ) (132 ) Income from Continuing Operations Before Income Taxes 389 45 186 (432 ) 188 Income tax expense/(benefit) — 1 (2 ) — (1 ) Income from Continuing Operations 389 44 188 (432 ) 189 Income from discontinued operations, net of income tax — — 13 — 13 Net Income 389 44 201 (432 ) 202 Less: Net income attributable to noncontrolling interest and redeemable interests — 1 — — 1 Net Income Attributable to NRG Energy, Inc. $ 389 $ 43 $ 201 $ (432 ) $ 201 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the six months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,909 $ 727 $ — $ (6 ) $ 4,630 Operating Costs and Expenses Cost of operations 2,948 535 19 (6 ) 3,496 Depreciation and amortization 105 49 16 — 170 Impairment losses 1 — — — 1 Selling, general and administrative 234 28 143 — 405 Reorganization costs — — 15 — 15 Development costs — 1 3 — 4 Total operating costs and expenses 3,288 613 196 (6 ) 4,091 Gain on sale of assets 1 1 — — 2 Operating Income/(Loss) 622 115 (196 ) — 541 Other Income/(Expense) Equity in earnings of consolidated subsidiaries 12 — 729 (741 ) — Equity in losses of unconsolidated affiliates — (21 ) — — (21 ) Other income, net 8 9 15 — 32 Loss on debt extinguishment, net — — (47 ) — (47 ) Interest expense (7 ) (9 ) (203 ) — (219 ) Total other income/(expense) 13 (21 ) 494 (741 ) (255 ) Income from Continuing Operations Before Income Taxes 635 94 298 (741 ) 286 Income tax expense — 1 2 — 3 Income from Continuing Operations 635 93 296 (741 ) 283 Income from discontinued operations, net of income tax 9 5 387 — 401 Net Income 644 98 683 (741 ) 684 Less: Net income attributable to noncontrolling interest and redeemable interests — 1 — — 1 Net Income Attributable to NRG Energy, Inc. $ 644 $ 97 $ 683 $ (741 ) $ 683 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the three months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 2,172 $ 291 $ — $ (2 ) $ 2,461 Operating Costs and Expenses Cost of operations 1,702 195 (5 ) (3 ) 1,889 Depreciation and amortization 63 40 9 — 112 Impairment losses — 74 — — 74 Selling, general and administrative 108 16 76 — 200 Reorganization costs 1 — 22 — 23 Development costs — 1 3 (1 ) 3 Total operating costs and expenses 1,874 326 105 (4 ) 2,301 Gain on sale of assets — 14 — — 14 Operating Income/(Loss) 298 (21 ) (105 ) 2 174 Other Income/(Expense) Equity in earnings of consolidated subsidiaries 7 — 353 (360 ) — Equity in earnings of unconsolidated affiliates — 5 — — 5 Other income/(loss), net 3 (29 ) 3 — (23 ) Loss on debt extinguishment, net — — (1 ) — (1 ) Interest expense (4 ) (13 ) (106 ) — (123 ) Total other income/(expense) 6 (37 ) 249 (360 ) (142 ) Income/(Loss) from Continuing Operations Before Income Taxes 304 (58 ) 144 (358 ) 32 Income tax expense/(benefit) 108 (71 ) (32 ) — 5 Income from Continuing Operations 196 13 176 (358 ) 27 Income/(loss) from discontinued operations, net of income tax 15 80 (26 ) — 69 Net Income 211 93 150 (358 ) 96 Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (56 ) 78 2 24 Net Income Attributable to NRG Energy, Inc. $ 211 $ 149 $ 72 $ (360 ) $ 72 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the six months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,916 $ 620 $ — $ (10 ) $ 4,526 Operating Costs and Expenses Cost of operations 2,857 419 9 (11 ) 3,274 Depreciation and amortization 123 92 17 — 232 Impairment losses — 74 — — 74 Selling, general and administrative 212 27 137 — 376 Reorganization costs 3 — 40 — 43 Development costs — 2 7 (1 ) 8 Total operating costs and expenses 3,195 614 210 (12 ) 4,007 Gain on sale of assets 3 13 — — 16 Operating Income/(Loss) 724 19 (210 ) 2 535 Other Income/(Expense) Equity in earnings of consolidated subsidiaries 8 — 685 (693 ) — Equity in earnings/(losses) of unconsolidated affiliates — 7 (1 ) — 6 Other income/(loss), net 8 (36 ) 5 — (23 ) Loss on debt extinguishment, net — — (3 ) — (3 ) Interest expense (7 ) (34 ) (198 ) — (239 ) Total other income/(expense) 9 (63 ) 488 (693 ) (259 ) Income/(Loss) from Continuing Operations Before Income Taxes 733 (44 ) 278 (691 ) 276 Income tax expense/(benefit) 221 (16 ) (194 ) — 11 Income/(Loss) from Continuing Operations 512 (28 ) 472 (691 ) 265 Income/(loss) from discontinued operations, net of income tax 30 60 (26 ) — 64 Net Income 542 32 446 (691 ) 329 Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (119 ) 95 2 (22 ) Net Income Attributable to NRG Energy, Inc. $ 542 $ 151 $ 351 $ (693 ) $ 351 (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 three months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 389 $ 44 $ 201 $ (432 ) $ 202 Other Comprehensive Loss Foreign currency translation adjustments, net (1 ) (1 ) (1 ) 2 (1 ) Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — — (3 ) — (3 ) Other comprehensive loss (1 ) (1 ) (3 ) 2 (3 ) Comprehensive Income 388 43 198 (430 ) 199 Less: Comprehensive income attributable to noncontrolling redeemable interest — 1 — — 1 Comprehensive Income Attributable to NRG Energy, Inc. $ 388 $ 42 $ 198 $ (430 ) $ 198 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the six months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 644 $ 98 $ 683 $ (741 ) $ 684 Other Comprehensive Loss Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — — (6 ) — (6 ) Other comprehensive loss — — (5 ) — (5 ) Comprehensive Income 644 98 678 (741 ) 679 Less: Comprehensive income attributable to noncontrolling redeemable interest — 1 — — 1 Comprehensive Income Attributable to NRG Energy, Inc. $ 644 $ 97 $ 678 $ (741 ) $ 678 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the three months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 211 $ 93 $ 150 $ (358 ) $ 96 Other Comprehensive (Loss)/Income Unrealized gain on derivatives, net — 4 6 (5 ) 5 Foreign currency translation adjustments, net (4 ) (4 ) (5 ) 9 (4 ) Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — — (1 ) — (1 ) Other comprehensive (loss)/income (4 ) — 1 4 1 Comprehensive Income 207 93 151 (354 ) 97 Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests — (56 ) 80 2 26 Comprehensive Income Attributable to NRG Energy, Inc. $ 207 $ 149 $ 71 $ (356 ) $ 71 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the six months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income $ 542 $ 32 $ 446 $ (691 ) $ 329 Other Comprehensive (Loss)/Income Unrealized gain on derivatives, net — 20 21 (22 ) 19 Foreign currency translation adjustments, net (6 ) (6 ) (8 ) 14 (6 ) Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — — (2 ) — (2 ) Other comprehensive (loss)/income (6 ) 14 12 (8 ) 12 Comprehensive Income 536 46 458 (699 ) 341 Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests — (119 ) 105 2 (12 ) Comprehensive Income Attributable to NRG Energy, Inc. $ 536 $ 165 $ 353 $ (701 ) $ 353 (a) All significant intercompany transactions have been eliminated in consolidation
CONDENSED CONSOLIDATING BALANCE SHEETS	NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ — $ 27 $ 267 $ — $ 294 Funds deposited by counterparties 31 — — — 31 Restricted cash 8 2 1 — 11 Accounts receivable, net 1,383 133 277 (744 ) 1,049 Inventory 254 116 — — 370 Derivative instruments 867 54 — (71 ) 850 Cash collateral paid in support of energy risk management activities 148 15 — — 163 Prepayments and other current assets 190 11 76 — 277 Total current assets 2,881 358 621 (815 ) 3,045 Property, plant and equipment, net 1,494 965 151 — 2,610 Other Assets Investment in subsidiaries 436 — 4,191 (4,627 ) — Equity investments in affiliates — 383 — — 383 Operating lease right-of-use assets, net 91 279 129 — 499 Goodwill 359 214 — — 573 Intangible assets, net 402 159 — — 561 Nuclear decommissioning trust fund 748 — — — 748 Derivative instruments 420 22 — (16 ) 426 Deferred income tax — 56 (1 ) — 55 Other non-current assets 148 30 96 (3 ) 271 Total other assets 2,604 1,143 4,415 (4,646 ) 3,516 Total Assets $ 6,979 $ 2,466 $ 5,187 $ (5,461 ) $ 9,171 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 87 $ — $ — $ 87 Current portion of operating lease liabilities 22 31 21 — 74 Accounts payable 937 107 423 (744 ) 723 Derivative instruments 817 32 — (71 ) 778 Cash collateral received in support of energy risk management activities 31 — — — 31 Accrued expenses and other current liabilities 258 42 301 — 601 Total current liabilities 2,065 299 745 (815 ) 2,294 Other Liabilities Long-term debt and capital leases 245 89 5,463 (3 ) 5,794 Non-current operating lease liabilities 73 313 127 — 513 Nuclear decommissioning reserve 290 — — — 290 Nuclear decommissioning trust liability 448 — — — 448 Derivative instruments 388 2 — (16 ) 374 Deferred income taxes (10 ) 68 13 — 71 Other non-current liabilities 399 148 469 — 1,016 Total other liabilities 1,833 620 6,072 (19 ) 8,506 Total Liabilities 3,898 919 6,817 (834 ) 10,800 Redeemable noncontrolling interest in subsidiaries — 19 — — 19 Stockholders’ Equity 3,081 1,528 (1,630 ) (4,627 ) (1,648 ) Total Liabilities and Stockholders’ Equity $ 6,979 $ 2,466 $ 5,187 $ (5,461 ) $ 9,171 (a) All significant intercompany transactions have been eliminated in consolidation CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2018 Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) 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 paid 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 capital 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 capital 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 six months ended June 30, 2019 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net income $ 644 $ 98 $ 683 $ (741 ) $ 684 Income from discontinued operations 9 5 387 — 401 Income from continuing operations 635 93 296 (741 ) 283 Adjustments to reconcile net income to net cash provided/(used) by operating activities: Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries (12 ) 22 (729 ) 741 22 Depreciation, amortization and accretion 115 53 16 — 184 Provision for bad debts 42 4 6 — 52 Amortization of nuclear fuel 27 — — — 27 Amortization of financing costs and debt discount/premiums — — 13 — 13 Loss on debt extinguishment, net — — 47 — 47 Amortization of intangibles 13 1 — — 14 Amortization of unearned equity compensation — — 10 — 10 (Loss)/gain on sale and disposal of assets (3 ) 1 3 — 1 Impairment losses 1 — — — 1 Changes in derivative instruments (28 ) (32 ) 38 — (22 ) Changes in deferred income taxes and liability for uncertain tax benefits — (3 ) (2 ) — (5 ) Changes in collateral deposits in support of energy risk management activities 128 (3 ) — — 125 Changes in nuclear decommissioning trust liability 17 — — — 17 Changes in other working capital (343 ) (64 ) 19 — (388 ) Cash provided/(used) by continuing operations 592 72 (283 ) — 381 Cash provided/(used) by discontinued operations 17 (9 ) — — 8 Net Cash Provided/(Used) by Operating Activities 609 63 (283 ) — 389 Cash Flows from Investing Activities Intercompany dividends — — 738 (738 ) — Payments for acquisitions of businesses (21 ) — — — (21 ) Capital expenditures (77 ) (15 ) (15 ) — (107 ) Net purchases of emission allowances (1 ) — — — (1 ) Investments in nuclear decommissioning trust fund securities (209 ) — — — (209 ) Proceeds from the sale of nuclear decommissioning trust fund securities 191 — — — 191 Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees 1 400 888 1,289 Net distributions from investments in unconsolidated affiliates — 7 — — 7 Contributions to discontinued operations — (44 ) — — (44 ) Cash (used)/provided by continuing operations (116 ) 348 1,611 (738 ) 1,105 Cash used by discontinued operations — (2 ) — — (2 ) Net Cash (Used)/Provided by Investing Activities (116 ) 346 1,611 (738 ) 1,103 Cash Flows from Financing Activities Payments from/(for) intercompany loans 206 (375 ) 169 — — Intercompany dividends (738 ) — — 738 — Payment of dividends to common stockholders — — (16 ) — (16 ) Payments for treasury stock — — (1,039 ) — (1,039 ) Payments for debt extinguishment — — (24 ) — (24 ) Distributions to noncontrolling interests from subsidiaries — (1 ) — — (1 ) Proceeds from issuance of common stock — — 2 — 2 Proceeds from issuance of long-term debt — — 1,833 — 1,833 Payment of debt issuance costs — — (33 ) — (33 ) Payments for long-term debt — (53 ) (2,432 ) — (2,485 ) Cash used by continuing operations (532 ) (429 ) (1,540 ) 738 (1,763 ) Cash provided by discontinued operations — 43 — — 43 Net Cash Used by Financing Activities (532 ) (386 ) (1,540 ) 738 (1,720 ) Change in cash from discontinued operations 17 32 — — 49 Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash (56 ) (9 ) (212 ) — (277 ) Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period 95 38 480 — 613 Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period $ 39 $ 29 $ 268 $ — $ 336 (a) All significant intercompany transactions have been eliminated in consolidation NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS For the six months ended June 30, 2018 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net income $ 542 $ 32 $ 446 $ (691 ) $ 329 Income/(loss) from discontinued operations 30 60 (26 ) — 64 Income/(loss) from continuing operations 512 (28 ) 472 (691 ) 265 Adjustments to reconcile net income to net cash provided/(used) by operating activities: Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries (8 ) 11 (682 ) 691 12 Depreciation, amortization and accretion 136 99 17 — 252 Provision for bad debts 30 — — — 30 Amortization of nuclear fuel 24 — — — 24 Amortization of financing costs and debt discount/premiums — 1 12 — 13 Loss on debt extinguishment, net — — 3 — 3 Amortization of intangibles and out-of-market contracts 16 4 — — 20 Amortization of unearned equity compensation — — 15 — 15 Loss on sale and disposal of assets (3 ) (13 ) — — (16 ) Impairment losses — 88 — — 88 Changes in derivative instruments (154 ) 19 (10 ) — (145 ) Changes in deferred income taxes and liability for uncertain tax benefits 221 (47 ) (176 ) — (2 ) Changes in collateral deposits in support of energy risk management activities (5 ) (4 ) — — (9 ) Changes in nuclear decommissioning trust liability 41 — — — 41 Loss on deconsolidation of Ivanpah project — 22 — — 22 Changes in other working capital 152 (56 ) (445 ) — (349 ) Cash provided/(used) by continuing operations 962 96 (794 ) — 264 Cash provided by discontinued operations 50 199 — — 249 Net Cash Provided/(Used) by Operating Activities 1,012 295 (794 ) — 513 Cash Flows from Investing Activities Intercompany dividends — — 157 (157 ) — Payments for acquisitions of businesses (2 ) (209 ) — — (211 ) Capital expenditures (103 ) (149 ) (30 ) — (282 ) Net proceeds from sale of emission allowances 3 — — — 3 Investments in nuclear decommissioning trust fund securities (346 ) — — — (346 ) Proceeds from the sale of nuclear decommissioning trust fund securities 303 — — — 303 Proceeds from sale of assets, net of cash disposed of 11 — 135 — 146 Deconsolidation of Ivanpah project — (160 ) — — (160 ) Net contributions for investments in unconsolidated affiliates — (15 ) — — (15 ) Contributions to discontinued operations — (16 ) — — (16 ) Cash (used)/provided by continuing operations (134 ) (549 ) 262 (157 ) (578 ) Cash provided/(used) by discontinued operations 2 (586 ) — — (584 ) Net Cash (Used)/Provided by Investing Activities (132 ) (1,135 ) 262 (157 ) (1,162 ) Cash Flows from Financing Activities Payments (for)/from intercompany loans (611 ) 204 407 — — Intercompany dividends (157 ) — — 157 — Payment of dividends to common stockholders — — (19 ) — (19 ) Payments for treasury stock — — (500 ) — (500 ) Distributions to noncontrolling interests from subsidiaries — (14 ) — — (14 ) Proceeds from issuance of common stock — — 11 — 11 Proceeds from issuance of short and long-term debt — 163 831 — 994 Payment of debt issuance costs — — (19 ) — (19 ) Payments for short and long-term debt — (63 ) (285 ) — (348 ) Cash (used)/provided by continuing operations (768 ) 290 426 157 105 Cash provided by discontinued operations — 345 — — 345 Net Cash (Used)/Provided by Financing Activities (768 ) 635 426 157 450 Change in cash from discontinued operations 52 (42 ) — — 10 Net Increase/(Decrease) in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash 60 (163 ) (106 ) — (209 ) Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period 41 425 620 — 1,086 Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period $ 101 $ 262 $ 514 $ — $ 877 (a) All significant intercompany transactions have been eliminated in consolidation

Nature of Business and Basis _2

Nature of Business and Basis of Presentation - General (Details) MW in Thousands	Jun. 30, 2019MW
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Generation capacity (in MW)	23

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Net (Loss)/Income Attributable to NRG Energy, Inc. After Removing Net Loss Attributable to Noncontrolling Interest (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accounting Policies [Abstract]
Income from continuing operations, net of income tax	$ 188	$ 27	$ 282	$ 272
Income from discontinued operations, net of income tax	13	45	401	79
Net income attributable to NRG Energy, Inc.	$ 201	$ 72	$ 683	$ 351

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Other Balance Sheet Information (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Accounts receivable allowance for doubtful accounts	$ 28	$ 32
Property, plant and equipment accumulated depreciation	1,684	1,811
Intangible assets accumulated amortization	1,182	1,149
Out-of-market contracts accumulated amortization	$ 0	$ 37

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 294	$ 563
Funds deposited by counterparties	31	33
Restricted cash	11	17
Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statement of cash flows	$ 336	$ 613	$ 877	$ 1,086

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Recent Accounting Developments (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities	$ 587
Operating lease right-of-use assets	$ 499
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities		$ 404
Operating lease right-of-use assets		$ 321

Revenue Recognition - Performan

Revenue Recognition - Performance Obligations (Details) $ in Millions	Jun. 30, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue from Contract with Customer [Abstract]
Estimated future fixed fee performance obligations	$ 315
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation period	6 months
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 obligations	$ 512
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 obligations	$ 542
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 obligations	$ 284
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 obligations	$ 29
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue remaining performance obligation period	1 year

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1,783	$ 2,054	$ 3,562	$ 3,859
Mark-to-market for economic hedging activities	21	(76)	41	130
Operating revenues	2,465	2,461	4,630	4,526
Lease revenue	5	5	10	11
Derivative revenue	33	(71)	60	143
Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	249	410	555	853
Derivative revenue	394	348	730	664
Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	155	165	309	307
Derivative revenue	30	39	48	65
Retail revenue | Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,400	1,376	2,720	2,551
Retail revenue | Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	345	437	631	747
Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,745	1,813	3,351	3,298
Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	241	10	261	(86)
Derivative revenue	677	402	1,058	656
Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	75	63	154	154
Total operating revenue
Disaggregation of Revenue [Line Items]
Operating revenues	2,465	2,461	4,630	4,526
Other revenue, derivative
Disaggregation of Revenue [Line Items]
Derivative revenue	12	5	19	13
Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(1)	(9)	(4)	(22)
Operating revenues	(650)	(520)	(915)	(206)
Lease revenue	0	0	0	0
Corporate/Eliminations | Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(365)	(251)	(641)	(411)
Derivative revenue	(365)	(247)	(641)	(404)
Corporate/Eliminations | Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	0	0	(1)
Derivative revenue	1	0	0	0
Corporate/Eliminations | Retail revenue | Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(1)	(1)	(2)	(2)
Corporate/Eliminations | Retail revenue | Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Corporate/Eliminations | Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(1)	(1)	(2)	(2)
Corporate/Eliminations | Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	(285)	(264)	(270)	220
Derivative revenue	(649)	(511)	(911)	(184)
Corporate/Eliminations | Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	(4)	(2)	(12)
Corporate/Eliminations | Total operating revenue
Disaggregation of Revenue [Line Items]
Operating revenues	(650)	(520)	(915)	(206)
Corporate/Eliminations | Other revenue, derivative
Disaggregation of Revenue [Line Items]
Derivative revenue	0	0	0	0
Retail | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,743	1,811	3,347	3,293
Operating revenues	1,748	1,814	3,355	3,294
Lease revenue	3	3	6	7
Retail | Operating Segments | Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Derivative revenue	0	0	0	0
Retail | Operating Segments | Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Derivative revenue	0	0	0	0
Retail | Operating Segments | Retail revenue | Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,401	1,377	2,722	2,553
Retail | Operating Segments | Retail revenue | Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	345	437	631	747
Retail | Operating Segments | Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,746	1,814	3,353	3,300
Retail | Operating Segments | Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	2	0	2	(6)
Derivative revenue	2	0	2	(6)
Retail | Operating Segments | Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Retail | Operating Segments | Total operating revenue
Disaggregation of Revenue [Line Items]
Operating revenues	1,748	1,814	3,355	3,294
Retail | Operating Segments | Other revenue, derivative
Disaggregation of Revenue [Line Items]
Derivative revenue	0	0	0	0
Retail | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Operating revenues	(2)	(4)	(5)	(6)
Generation | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	41	252	219	588
Operating revenues	1,367	1,167	2,190	1,438
Lease revenue	2	2	4	4
Generation | Operating Segments | Texas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(211)	(157)	(357)	(257)
Lease revenue	0	0	0	0
Generation | Operating Segments | East/West/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	252	409	576	845
Lease revenue	2	2	4	4
Generation | Operating Segments | Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	614	661	1,196	1,264
Derivative revenue	759	595	1,371	1,068
Generation | Operating Segments | Energy revenue | Texas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	497	402	855	666
Derivative revenue	717	569	1,242	982
Generation | Operating Segments | Energy revenue | East/West/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	117	259	341	598
Derivative revenue	42	26	129	86
Generation | Operating Segments | Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	154	165	309	308
Derivative revenue	29	39	48	65
Generation | Operating Segments | Capacity revenue | Texas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Derivative revenue	0	0	0	0
Generation | Operating Segments | Capacity revenue | East/West/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	154	165	309	308
Derivative revenue	29	39	48	65
Generation | Operating Segments | Retail revenue | Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Retail revenue | Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Retail revenue | Texas | Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Retail revenue | Texas | Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Retail revenue | East/West/Other | Mass customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Retail revenue | East/West/Other | Business Solutions customers
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Total retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Total retail revenue | Texas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Total retail revenue | East/West/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Generation | Operating Segments | Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	524	274	529	(300)
Derivative revenue	1,324	913	1,967	846
Generation | Operating Segments | Derivative revenue | Texas
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	460	296	473	(273)
Derivative revenue	1,184	865	1,730	714
Generation | Operating Segments | Derivative revenue | East/West/Other
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	64	(22)	56	(27)
Derivative revenue	140	48	237	132
Generation | Operating Segments | Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	75	67	156	166
Generation | Operating Segments | Other revenue | Texas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	10	45	64
Generation | Operating Segments | Other revenue | East/West/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	59	57	111	102
Generation | Operating Segments | Total operating revenue
Disaggregation of Revenue [Line Items]
Operating revenues	1,367	1,167	2,190	1,438
Generation | Operating Segments | Total operating revenue | Texas
Disaggregation of Revenue [Line Items]
Operating revenues	973	708	1,373	457
Generation | Operating Segments | Total operating revenue | East/West/Other
Disaggregation of Revenue [Line Items]
Operating revenues	394	459	817	981
Generation | Operating Segments | Other revenue, derivative
Disaggregation of Revenue [Line Items]
Derivative revenue	12	5	19	13
Generation | Operating Segments | Other revenue, derivative | Texas
Disaggregation of Revenue [Line Items]
Derivative revenue	7	0	15	5
Generation | Operating Segments | Other revenue, derivative | East/West/Other
Disaggregation of Revenue [Line Items]
Derivative revenue	5	5	4	8
Generation | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Operating revenues	$ (627)	$ (514)	$ (862)	$ (205)

Revenue Recognition - Contract

Revenue Recognition - Contract Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Schedule Of Contract Assets And Liabilities [Line Items]
Deferred customer acquisition costs	$ 123		$ 123		$ 111
Total accounts receivable, net	1,062		1,062		1,024
Unbilled revenues (included within Accounts receivable, net - Contracts with customers)	403		403		392
Deferred revenues	89		89		67
Deferred revenue from contract with customers			31		19
Revenue recognized	19	$ 16	13	$ 16
Accounts receivable, net - Contracts with customers
Schedule Of Contract Assets And Liabilities [Line Items]
Total accounts receivable, net	1,015		1,015		999
Accounts receivable, net - Derivative instruments
Schedule Of Contract Assets And Liabilities [Line Items]
Total accounts receivable, net	43		43		20
Accounts receivable, net - Affiliate
Schedule Of Contract Assets And Liabilities [Line Items]
Total accounts receivable, net	$ 4		$ 4		$ 5

Acquisitions, Discontinued Op_3

Acquisitions, Discontinued Operations and Dispositions - Acquisitions (Details) $ in Millions	Aug. 01, 2019USD ($)statecustomer	Jun. 01, 2018USD ($)statecustomer
XOOM Energy, LLC
Business Acquisition [Line Items]
Increase in retail portfolio by RCE's acquired		395,000
Customers acquired		300,000
States in which entity operates | state		19
Purchase price | $		$ 213
Subsequent Event | Stream Energy Acquisition
Business Acquisition [Line Items]
Cash paid to acquire business | $	$ 300
Working capital adjustment | $	$ 25
Increase in retail portfolio by RCE's acquired	600,000
Customers acquired	450,000
States in which entity operates | state	9

Acquisitions, Discontinued Op_4

Acquisitions, Discontinued Operations and Dispositions - Schedule of Purchase Price Allocation (Details) - USD ($) $ in Millions	Jun. 01, 2018	Jun. 30, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill		$ 573	$ 573
XOOM Energy, LLC
Business Acquisition [Line Items]
Net current and non-current working capital	$ 46
Other intangible assets	133
Goodwill	34
Purchase price	$ 213

Acquisitions, Discontinued Op_5

Acquisitions, Discontinued Operations and Dispositions - Discontinued Operations (Details) $ in Billions	Jun. 30, 2019MW	Feb. 04, 2019USD ($)	Dec. 31, 2018MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Generation capacity (in MW)	23,000
South Central Portfolio | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration | $		$ 1
Generation capacity (in MW)			1,153

Acquisitions, Discontinued Op_6

Acquisitions, Discontinued Operations and Dispositions - Summarized of Results of Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposal of discontinued operations, net of tax			$ 0	$ (22)
Gain/(Loss) from discontinued operations, net of tax	$ 13	$ 69	401	64
Discontinued Operations | South Central Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenues	0	107	31	209
Operating costs and expenses	0	(91)	(23)	(177)
Gain from discontinued operations, net of tax	0	16	8	32
Gain on disposal of discontinued operations, net of tax	1	0	28	0
Gain/(Loss) from discontinued operations, net of tax	1	16	36	32
Discontinued Operations | Carlsbad Energy Holdings LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenues	0	368	19	628
Operating costs and expenses	0	(223)	(9)	(453)
Other expenses	0	(65)	(5)	(123)
Gain/(loss) from operations of discontinued components, before tax	0	80	5	52
Income tax expense	0	2	0	(5)
Gain from discontinued operations, net of tax	0	78	5	57
Gain on disposal of discontinued operations, net of tax	(17)	0	331	0
Other Commitments, Indemnification and Fees	27	0	27	0
Gain on disposal of discontinued operations, net of tax	10	0	358	0
Gain/(Loss) from discontinued operations, net of tax	$ 10	$ 78	$ 363	$ 57

Acquisitions, Discontinued Op_7

Acquisitions, Discontinued Operations and Dispositions - Major Classes of Assets and Liabilities Classified as Discontinued Operations (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other current assets	$ 0	$ 1
Current assets - discontinued operations	0	197
Other non-current assets	0	77
Non-current assets - discontinued operations	0	1,012
Current liabilities - discontinued operations	0	72
Other non-current liabilities	0	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 Project | 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 Op_8

Acquisitions, Discontinued Operations and Dispositions - Sale of Ownership in NRG Yield, Inc. and the Renewables Platform (Details) MW in Thousands, $ in Millions	Feb. 06, 2018USD ($)extension	Jun. 30, 2019USD ($)MW	Dec. 31, 2018USD ($)	Aug. 31, 2018USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Generation capacity (in MW) | MW		23
Discontinued Operations | NRG Yield and Renewables
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration				$ 1,348
Discontinued Operations | NRG Yield and Renewables | Cost To Complete Construction
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Additional commitments related to project		$ 17
Discontinued Operations | NRG Yield and Renewables | Property Taxes For Solar Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Additional commitments related to project		22
Discontinued Operations | Carlsbad Project
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration	$ 385
Additional commitments related to project		$ 23	$ 23
Percentage of ownership sold	100.00%
Lease and easement agreement, number of extensions | extension	2
Lease renewal term	10 years

Acquisitions, Discontinued Op_9

Acquisitions, Discontinued Operations and Dispositions - Sale of Assets to NRG Yield, Inc. Prior to Discontinued Operations (Details) $ in Millions	Jun. 30, 2019MW	Jan. 31, 2019USD ($)	Jun. 19, 2018USD ($)	Mar. 30, 2018USD ($)MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Generation capacity (in MW) | MW	23,000
UPMC Thermal Project
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration		$ 3	$ 84
Buckthorn Renewables, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration				$ 42
Percentage of ownership sold				100.00%
Generation capacity (in MW) | MW				154
Debt assumed				$ 183

Acquisitions, Discontinued O_10

Acquisitions, Discontinued Operations and Dispositions - Summarized Results of GenOn (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain/(Loss) from discontinued operations, net of tax	$ 13	$ 69	$ 401	$ 64
GenOn | Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest income - affiliate	0	2	0	3
Pension and post-retirement liability assumption	0	1	0	1
Advisory and consulting fees	0	(1)	0	(2)
Other	2	(27)	2	(27)
Gain/(Loss) from discontinued operations, net of tax	$ 2	$ (25)	$ 2	$ (25)

Acquisitions, Discontinued O_11

Acquisitions, Discontinued Operations and Dispositions - GenOn and GenMA Settlement (Details) - USD ($) $ in Millions	Jul. 16, 2018	Apr. 27, 2018
GenOn | Services Agreement | Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Return of collateral posted to NRG	$ 15
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, new credit support		$ 37.5
Affiliated Entity
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Settlement consideration	261
Professional fees		$ 6
Affiliated Entity | Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Settlement agreement, payment	125
Affiliated Entity | Services Agreement | Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transition services credit	28
Related Party Transaction, Due from (to) Related Party	10
Affiliated Entity | Revolving Credit Facility Borrowings | Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Borrowings under intercompany agreement	151
Affiliated Entity | Accrued Interest On Borrowings | Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Borrowings under intercompany agreement	12
Affiliated Entity | Reduction Of Settlement Payment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Related Party Transaction, Due from (to) Related Party	4
Affiliated Entity | Assignment Of Historical Claims Against REMA
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Related Party Transaction, Due from (to) Related Party	8
Affiliated Entity | Other | Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Related Party Transaction, Due from (to) Related Party	$ 2

Acquisitions, Discontinued O_12

Acquisitions, Discontinued Operations and Dispositions - Dispositions (Details) - USD ($) $ in Millions	Jun. 29, 2018	Jun. 28, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from financing arrangements			$ 1,833	$ 994
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]
Proceeds from other asset sales	$ 16
Gain on sale	$ 17
Proceeds from financing arrangements		$ 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]
Proceeds from other asset sales			$ 18	$ 16

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Estimated Carrying Amounts and Fair Value of Financial Instruments Not Carried at Fair Value (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion	$ 6,042	$ 6,691
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes receivable	12	17
Long-term debt, including current portion	5,951	6,591
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes receivable	8	14
Long-term debt, including current portion	6,422	6,697
Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion	6,305	6,528
Fair Value | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion	$ 117	$ 169

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Assets and Liabilities Measured and Recorded at Fair Value (Details) - USD ($) $ in Millions	Jun. 30, 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)	$ 38	$ 39
U.S. government and federal agency obligations	1	1
Total assets	2,072	1,792
Derivative liabilities	1,152	977
Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,276	1,042
Derivative liabilities	1,152	977
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		39
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	25	19
U.S. government and federal agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	57	46
Federal agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	92	100
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	29	22
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	102	96
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	366	312
Equity contracts	9	8
Foreign government fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	4	4
Equity securities — nuclear trust fund investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity contracts	73	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
U.S. government and federal agency obligations	1	1
Total assets	580	517
Derivative liabilities	245	224
Level 1 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	131	137
Derivative liabilities	245	224
Level 1 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Level 1 | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	25	19
Level 1 | U.S. government and federal agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	57	46
Level 1 | Federal agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 1 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 1 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	366	312
Level 1 | Foreign government fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	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)	19	18
U.S. government and federal agency obligations	0	0
Total assets	1,016	1,075
Derivative liabilities	629	664
Level 2 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	770	796
Derivative liabilities	629	664
Level 2 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		39
Level 2 | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 2 | U.S. government and federal agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 2 | Federal agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	92	100
Level 2 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	29	22
Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	102	96
Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 2 | Foreign government fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	4	4
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)	19	19
U.S. government and federal agency obligations	0	0
Total assets	394	128
Derivative liabilities	278	89
Level 3 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	375	109
Derivative liabilities	278	89
Level 3 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Level 3 | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 3 | U.S. government and federal agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 3 | Federal agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 3 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 3 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	0	0
Level 3 | Foreign government fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear trust fund investments	$ 0	$ 0

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Reconciliation of Level 3 Financial Instruments (Details) - Level 3 - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 16	$ 24	$ 39	$ 4
Contracts added from acquisitions	(1)	12	(1)	12
Total gains (losses) — realized/unrealized included in earnings	(16)	(27)	(26)	(16)
Cash received	0		(1)
Purchases	(10)	(4)	(12)	(3)
Transfers into Level 3	113	193	130	197
Transfers out of Level 3	14	(5)	(13)	(1)
Ending balance	116	193	116	193
Gains (Losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held	(18)	(27)	(30)	(15)
Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	18	19	19	19
Contracts added from acquisitions	0	0	0	0
Total gains (losses) — realized/unrealized included in earnings	1	0	1	0
Cash received	0		(1)
Purchases	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	19	19	19	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	1	0	1	0
Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(2)	5	20	(15)
Contracts added from acquisitions	(1)	12	(1)	12
Total gains (losses) — realized/unrealized included in earnings	(17)	(27)	(27)	(16)
Cash received	0		0
Purchases	(10)	(4)	(12)	(3)
Transfers into Level 3	113	193	130	197
Transfers out of Level 3	14	(5)	(13)	(1)
Ending balance	97	174	97	174
Gains (Losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held	$ (19)	$ (27)	$ (31)	$ (15)

Fair Value of Financial Instr_6

Fair Value of Financial Instruments - Derivative Fair Value Measurements, Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Fair Value Disclosures [Abstract]
Total derivative assets valued with prices provided by models and other valuation techniques (as a percent)	29.00%
Total derivative liabilities valued with prices provided by models and other valuation techniques (as a percent)	24.00%
Decrease in cost of operations	$ 2

Fair Value of Financial Instr_7

Fair Value of Financial Instruments - Derivative Fair Value Measurements (Details) $ in Millions	Jun. 30, 2019USD ($)$ / MWh	Dec. 31, 2018USD ($)$ / MWh
Liabilities
Derivative liabilities	$ 1,152	$ 977
Level 3
Liabilities
Derivative liabilities	278	89
Commodity contracts
Assets
Derivative assets	1,276	1,042
Liabilities
Derivative liabilities	1,152	977
Commodity contracts | Level 3
Assets
Derivative assets	375	109
Liabilities
Derivative liabilities	278	89
Commodity contracts | Level 3 | Power Contracts
Assets
Derivative assets	347	89
Liabilities
Derivative liabilities	$ 261	$ 75
Commodity contracts | Level 3 | Power Contracts | Low
Fair Value Inputs / Range
Forward Market Price (per MWh) | $ / MWh	4	1
Commodity contracts | Level 3 | Power Contracts | High
Fair Value Inputs / Range
Forward Market Price (per MWh) | $ / MWh	142	214
Commodity contracts | Level 3 | Power Contracts | Weighted Average
Fair Value Inputs / Range
Forward Market Price (per MWh) | $ / MWh	25	31
Commodity contracts | Level 3 | FTRs
Assets
Derivative assets	$ 28	$ 20
Liabilities
Derivative liabilities	$ 17	$ 14
Commodity contracts | Level 3 | FTRs | Low
Fair Value Inputs / Range
Derivative, Auction Price | $ / MWh	(134)	(90)
Commodity contracts | Level 3 | FTRs | High
Fair Value Inputs / Range
Derivative, Auction Price | $ / MWh	52	34
Commodity contracts | Level 3 | FTRs | Weighted Average
Fair Value Inputs / Range
Derivative, Auction Price | $ / MWh	0	0

Fair Value of Financial Instr_8

Fair Value of Financial Instruments - Counterparty Credit Risk (Details)	6 Months Ended
	Jun. 30, 2019USD ($)counterparty
Concentration of Credit Risk
Counterparty credit exposure to a portion of the Company's counterparties	$ 273,000,000
Collateral held (cash and letters of credit) against counterparty credit exposure to a portion of the Company's counterparties	93,000,000
Net counterparty credit exposure to a portion of the Company's counterparties	$ 226,000,000
Company's exposure before collateral is expected to roll off by the end of 2019 (as a percent)	60.00%
Net exposure (as a percent)	100.00%
Aggregate counterparty credit risk exposure for counterparties representing exposure above threshold percentage	$ 33,000,000
Wholesale counterparty with net exposure | counterparty	1
Counterparty credit risk exposure to certain counterparties, threshold (as a percent)	10.00%
Period of estimated counterparty credit risk exposure, years	5 years
Ivanpau And Agua Caliente
Concentration of Credit Risk
Estimated counterparty credit risk exposure to certain counterparties	$ 337,000,000
Period of estimated counterparty credit risk exposure, years	5 years
Long-term Contract
Concentration of Credit Risk
Aggregate counterparty credit risk exposure for counterparties representing exposure above threshold percentage	$ 524,000,000
Investment grade
Concentration of Credit Risk
Net exposure (as a percent)	53.00%
Non-investment grade/non-rated
Concentration of Credit Risk
Net exposure (as a percent)	47.00%
Utilities, energy merchants, marketers and other
Concentration of Credit Risk
Net exposure (as a percent)	84.00%
Financial institutions
Concentration of Credit Risk
Net exposure (as a percent)	16.00%

Nuclear Decommissioning Trust_3

Nuclear Decommissioning Trust Fund - Narrative (Details)	Jun. 30, 2019
STP
Investment [Line Items]
Interest in STP	44.00%

Nuclear Decommissioning Trust_4

Nuclear Decommissioning Trust Fund - Summary of aggregate fair values and realized gains and losses (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Nuclear decommissioning trust fund
Fair Value	$ 748	$ 663
Unrealized Gains	303	234
Unrealized Losses	1	6
Cash and cash equivalents
Nuclear decommissioning trust fund
Fair Value	25	19
Unrealized Gains	0	0
Unrealized Losses	0	0
U.S. government and federal agency obligations
Nuclear decommissioning trust fund
Fair Value	57	46
Unrealized Gains	4	1
Unrealized Losses	$ 0	$ 0
Weighted-average Maturities (In years)	12 years	12 years
Federal agency mortgage-backed securities
Nuclear decommissioning trust fund
Fair Value	$ 92	$ 100
Unrealized Gains	2	1
Unrealized Losses	$ 0	$ 2
Weighted-average Maturities (In years)	24 years	23 years
Commercial mortgage-backed securities
Nuclear decommissioning trust fund
Fair Value	$ 29	$ 22
Unrealized Gains	1	0
Unrealized Losses	$ 1	$ 1
Weighted-average Maturities (In years)	23 years	22 years
Corporate debt securities
Nuclear decommissioning trust fund
Fair Value	$ 102	$ 96
Unrealized Gains	5	1
Unrealized Losses	$ 0	$ 2
Weighted-average Maturities (In years)	11 years	11 years
Equity securities
Nuclear decommissioning trust fund
Fair Value	$ 439	$ 376
Unrealized Gains	291	231
Unrealized Losses	0	1
Foreign government fixed income securities
Nuclear decommissioning trust fund
Fair Value	4	4
Unrealized Gains	0	0
Unrealized Losses	$ 0	$ 0
Weighted-average Maturities (In years)	8 years	9 years

Nuclear Decommissioning Trust_5

Nuclear Decommissioning Trust Fund - Summary of proceeds from sales of available-for-sale securities and related gains and losses (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Nuclear Decommissioning Trust Fund Disclosure [Abstract]
Realized gains	$ 5	$ 7
Realized losses	(5)	(6)
Proceeds from sale of securities	$ 191	$ 303

Accounting for Derivative Ins_3

Accounting for Derivative Instruments and Hedging Activities - Net notional volume buy/sell of open derivative transactions (Details) shares in Millions, mw_per_day in Millions, bbl in Millions, T in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019USD ($)MWhMMBTUmw_per_dayTsharesbbl	Dec. 31, 2018USD ($)MWhMMBTUmw_per_dayTsharesbbl
Short | Emissions
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, mass (ton)	1	2
Short | Natural Gas
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, energy (in MMBtu and MWh) | MMBTU	238	330
Short | Capacity
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, flow rate (in MW/Day) | mw_per_day	(1)	(1)
Long | Renewable Energy Certificates
Volumetric Underlying Derivative Transactions
Derivative, non-monetary notional amount (in shares) | shares	1	1
Long | Coal
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, mass (ton)	7	13
Long | Oil
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount (in barrels)) | bbl	0	1
Long | Power
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, energy (in MMBtu and MWh) | MWh	21	1
Long | Interest
Volumetric Underlying Derivative Transactions
Derivative, notional amount (in usd) | $	$ 0	$ 1,000

Accounting for Derivative Ins_4

Accounting for Derivative Instruments and Hedging Activities - Fair value within the derivative instrument valuation (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative Liabilities	$ 1,152	$ 977
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Assets	1,276	1,081
Derivative Liabilities	1,152	977
Not Designated as Hedging Instrument | Interest rate contracts current
Derivative [Line Items]
Derivative Assets	0	17
Derivative Liabilities	0	0
Not Designated as Hedging Instrument | Interest rate contracts long-term
Derivative [Line Items]
Derivative Assets	0	22
Derivative Liabilities	0	0
Not Designated as Hedging Instrument | Commodity contracts current
Derivative [Line Items]
Derivative Assets	850	747
Derivative Liabilities	778	673
Not Designated as Hedging Instrument | Commodity contracts long-term
Derivative [Line Items]
Derivative Assets	426	295
Derivative Liabilities	$ 374	$ 304

Accounting for Derivative Ins_5

Accounting for Derivative Instruments and Hedging Activities - Offsetting of derivatives by counterparty master agreement level and collateral received (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Cash Collateral (Held) / Posted	$ (31)	$ (33)
Derivative liabilities	(1,152)	(977)
Cash Collateral Posted	163	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	1,276	1,042
Derivative Instruments	(1,029)	(778)
Cash Collateral (Held) / Posted	(10)	(31)
Net Amount	237	233
Derivative liabilities	(1,152)	(977)
Derivative Instruments	1,029	778
Cash Collateral Posted	58	114
Net Amount	(65)	(85)
Gross Amounts of Recognized Assets / Liabilities	124	65
Derivative Instruments	0	0
Cash Collateral (Held) / Posted	48	83
Net Amount	$ 172	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 Ins_6

Accounting for Derivative Instruments and Hedging Activities - Effects on accumulated OCL balance attributable to hedge derivatives, net (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2018USD ($)
Derivative [Line Items]
Balance	$ 2,258	$ 1,968
Reclassified from accumulated OCL to income:
Balance	2,071	2,071
Balance, tax	(5)	(5)
AOCI Including Portion Attributable to Noncontrolling Interest | Interest rate contracts
Derivative [Line Items]
Balance	(31)	(54)
Reclassified from accumulated OCL to income:
Balance	(23)	(23)
Accumulated Gain (Loss), Net, Cash Flow Hedge | Interest rate contracts
Reclassified from accumulated OCL to income:
Due to realization of previously deferred amounts	3	7
Accumulated Net Gain (Loss) from Cash Flow Hedges | Interest rate contracts
Reclassified from accumulated OCL to income:
Mark-to-market of cash flow hedge accounting contracts	$ 5	$ 24

Accounting for Derivative Ins_7

Accounting for Derivative Instruments and Hedging Activities - Pre-tax effects of economic hedges not designated a cash flow hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Unrealized mark-to-market results
Reversal of previously recognized unrealized losses/(gains) on settled positions related to economic hedges	$ 11	$ (2)	$ 30	$ (1)
Reversal of acquired loss/(gain) positions related to economic hedges	1	(1)	(1)	(1)
Net unrealized gains/(losses) on open positions related to economic hedges	9	(73)	12	132
Total unrealized mark-to-market gains/(losses) for economic hedging activities	21	(76)	41	130
Reversal of previously recognized unrealized gains on settled positions related to trading activity	(1)	(3)	(7)	(6)
Net unrealized gains on open positions related to trading activity	13	8	26	19
Total unrealized mark-to-market gains for trading activity	12	5	19	13
Total unrealized gains/(losses)	33	(71)	60	143
Credit Risk Related Contingent Features
Unrealized gain (loss) from open economic hedge positions			12	132
Collateral due on net liability position that has not been called by a certain marginable agreement counterparty	3		3
Adequate Assurance Clauses
Credit Risk Related Contingent Features
Derivative net liability position, collateral required Contracts with Credit Rating Contingent Feature	19		19
Credit Rating Contingent Features
Credit Risk Related Contingent Features
Derivative net liability position, collateral required Contracts with Credit Rating Contingent Feature	13		13
Commodity contracts
Unrealized mark-to-market results
Total unrealized gains/(losses)	33	(71)	60	143
Commodity contracts | Operating revenues
Unrealized mark-to-market results
Total unrealized gains/(losses)	253	15	280	(73)
Commodity contracts | Cost of operations
Unrealized mark-to-market results
Total unrealized gains/(losses)	(220)	(86)	(220)	216
Interest rate contracts
Unrealized mark-to-market results
Total unrealized gains/(losses)	$ (29)	$ 3	$ (38)	$ 15

Leases - Lease Cost and Other I

Leases - Lease Cost and Other Information (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)
Lease, Cost [Abstract]
Operating lease cost	$ 33	$ 56
Short-term lease cost	1	1
Variable lease cost	2	3
Sublease income	(5)	(9)
Total lease cost	$ 31	51
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases		53
Right-of-use assets obtained in exchange for new operating lease liabilities		$ 214
Weighted-average remaining lease term
Finance leases	2 years 6 months	2 years 6 months
Operating leases	8 years 1 month 6 days	8 years 1 month 6 days
Weighted-average discount rate
Finance leases	6.50%	6.50%
Operating leases	5.73%	5.73%

Leases - Schedule of Annual Pay

Leases - Schedule of Annual Payments Based on Maturities of Lease (Details) $ in Millions	Jun. 30, 2019USD ($)
Leases [Abstract]
Remainder of 2019	$ 50
2020	95
2021	85
2022	85
2023	86
Thereafter	371
Total undiscounted lease payments	772
Less: present value adjustment	(185)
Total discounted lease payments	$ 587

Impairments (Details)

Impairments (Details) - USD ($)	Jun. 29, 2018	Jun. 30, 2018	Jun. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Carrying amount			$ 383,000,000	$ 412,000,000
Keystone
Schedule of Equity Method Investments [Line Items]
Interest in generating stations	3.70%
Impairment losses	$ 14,000,000
Conemaugh
Schedule of Equity Method Investments [Line Items]
Impairment losses	$ 14,000,000
Dunkirk
Schedule of Equity Method Investments [Line Items]
Impairment losses		$ 46,000,000
Carrying amount		$ 0

Debt and Capital Leases - Sched

Debt and Capital Leases - Schedule of Long-term Debt and Capital Leases (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	May 28, 2019	May 14, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt amount	$ 6,042			$ 6,691
Capital leases	1			1
Subtotal long-term debt and capital leases (including current maturities)	6,043			6,692
Less current maturities	(87)			(72)
Less debt issuance costs	(71)			(70)
Discounts	(91)			(101)
Long-term debt and capital leases	5,794			6,449
Recourse Debt
Debt Instrument [Line Items]
Debt amount	5,925			6,523
Recourse Debt | Senior Notes, due 2024
Debt Instrument [Line Items]
Debt amount	$ 0			733
Interest rate, stated percentage	6.25%
Recourse Debt | Senior Notes, due 2026
Debt Instrument [Line Items]
Debt amount	$ 1,000			1,000
Interest rate, stated percentage	7.25%
Recourse Debt | Senior Notes, due 2027
Debt Instrument [Line Items]
Debt amount	$ 1,230			1,230
Interest rate, stated percentage	6.625%
Recourse Debt | Senior Notes, due 2028
Debt Instrument [Line Items]
Debt amount	$ 821			821
Interest rate, stated percentage	5.75%
Recourse Debt | Senior Notes, due 2029
Debt Instrument [Line Items]
Debt amount	$ 733			0
Interest rate, stated percentage	5.25%		5.25%
Recourse Debt | Convertible Senior Notes, due 2048
Debt Instrument [Line Items]
Debt amount	$ 575			575
Interest rate, stated percentage	2.75%
Recourse Debt | Senior Secured First Lien Notes, due 2024
Debt Instrument [Line Items]
Debt amount	$ 600			0
Interest rate, stated percentage	3.75%	3.75%
Recourse Debt | Senior Secured First Lien Notes, due 2029
Debt Instrument [Line Items]
Debt amount	$ 500			0
Interest rate, stated percentage	4.45%	4.45%
Recourse Debt | Term loan facility
Debt Instrument [Line Items]
Debt amount	$ 0			1,698
Recourse Debt | Term loan facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
Recourse Debt | Tax-exempt bonds
Debt Instrument [Line Items]
Debt amount	$ 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%
Non Recourse Debt
Debt Instrument [Line Items]
Debt amount	$ 117			168
Non Recourse Debt | Agua Caliente Borrower 1, due 2038
Debt Instrument [Line Items]
Debt amount	$ 83			86
Interest rate, stated percentage	5.43%
Non Recourse Debt | Midwest Generation
Debt Instrument [Line Items]
Debt amount	$ 0			48
Interest rate, stated percentage	4.39%
Non Recourse Debt | Other
Debt Instrument [Line Items]
Debt amount	$ 34			$ 34

Debt and Capital Leases - Senio

Debt and Capital Leases - Senior Notes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	May 28, 2019	May 14, 2019
Debt Instrument [Line Items]
Loss on debt extinguishment	$ 47,000,000	$ 1,000,000	$ 47,000,000	$ 3,000,000
Recourse Debt
Debt Instrument [Line Items]
Debt issuance amount					$ 1,100,000,000
Recourse Debt | Senior Notes, due 2029
Debt Instrument [Line Items]
Debt issuance amount						$ 733,000,000
Interest rate, stated percentage	5.25%		5.25%			5.25%
Recourse Debt | Senior Notes, due 2024
Debt Instrument [Line Items]
Interest rate, stated percentage	6.25%		6.25%
Senior Notes redeemed, amount	$ 733,000,000		$ 733,000,000
Loss on debt extinguishment	29,000,000
Write off of previously deferred debt issuance costs	$ 5,000,000
Recourse Debt | Senior Secured First Lien Notes, due 2024
Debt Instrument [Line Items]
Debt issuance amount					$ 600,000,000
Interest rate, stated percentage	3.75%		3.75%		3.75%
Recourse Debt | Senior Secured First Lien Notes, due 2029
Debt Instrument [Line Items]
Debt issuance amount					$ 500,000,000
Interest rate, stated percentage	4.45%		4.45%		4.45%

Debt and Capital Leases - Sen_2

Debt and Capital Leases - Senior Credit Facility (Details) - USD ($)	May 28, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt Instrument [Line Items]
Repayment of Term Loan Facility				$ 2,485,000,000	$ 348,000,000
Decrease in long-term debt	$ 594,000,000
Loss on debt extinguishment		$ 47,000,000	$ 1,000,000	$ 47,000,000	$ 3,000,000
Recourse Debt | 2023 Term Loan Facility
Debt Instrument [Line Items]
Repayment of Term Loan Facility	1,700,000,000
Loss on debt extinguishment	17,000,000
Write off of previously deferred debt issuance costs	13,000,000
Recourse Debt | 2023 Term Loan Facility | Interest Rate Swap Agreements
Debt Instrument [Line Items]
Reduction to interest expense	$ 25,000,000
Revolving Credit Facility | Credit Agreement | Adjusted Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.25%
Revolving Credit Facility | Credit Agreement | Adjusted Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	0.75%
Revolving Credit Facility | Credit Agreement | Eurodollar Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%
Revolving Credit Facility | Credit Agreement | Eurodollar Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
Revolving Credit Facility | Line of Credit | Credit Agreement
Debt Instrument [Line Items]
Amended credit agreement, increase in revolving commitments	$ 184,000,000
Credit agreement	$ 2,600,000,000

Debt and Capital Leases - Non R

Debt and Capital Leases - Non Recourse Debt (Details) - Credit Agreement - Letter of Credit - USD ($)	Jan. 04, 2019	Jun. 30, 2019
Debt Instrument [Line Items]
Credit agreement	$ 80,000,000
Facility fees	1.33%
Letters of credit issued		$ 80,000,000

Investments Accounted for Usi_3

Investments Accounted for Using the Equity Method and Variable Interest Entities, or VIEs (Details) $ in Millions	3 Months Ended	6 Months Ended		9 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)projectMW	Jun. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Investments Accounted for by the Equity Method
Equity investments in affiliates		$ 383			$ 412
Generation capacity (in MW) | MW		23,000
Loss on deconsolidation			$ 22
Current assets		$ 3			3
Net property, plant and equipment		74			76
Other long-term assets		29			28
Total assets		106			107
Current liabilities		1			2
Long-term debt		28			29
Other long-term liabilities		8			7
Total liabilities		37			38
Redeemable noncontrolling interest		19			19
Net assets less noncontrolling interests		50			$ 50
Agua Caliente
Investments Accounted for by the Equity Method
Equity investments in affiliates		206
Ivampah Master Holdings LLC
Investments Accounted for by the Equity Method
Equity investments in affiliates		$ 16
Economic interest in equity method investments (as a percent)		54.50%
Number of solar electric generating projects | project		3
Generation capacity (in MW) | MW		393
Release of reserve funds	$ 95
Decrease in assets due to deconsolidation				$ 1,300
Decrease in liabilities due to deconsolidation			$ 1,200

Changes in Capital Structure -

Changes in Capital Structure - Narrative (Details) - USD ($)	1 Months Ended				2 Months Ended	3 Months Ended
	Aug. 07, 2019	Jul. 31, 2019	Apr. 30, 2019	Mar. 31, 2019	Feb. 28, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018
Capital Structure
Common stock, shares authorized (in shares)						500,000,000				500,000,000
Shares repurchased, value						$ 305,000,000	$ 749,000,000	$ 407,000,000	$ 93,000,000
Employee Stock Purchase Plan, minimum percentage of eligible compensation to purchase shares				1.00%
Employee Stock Purchase Plan, maximum percentage of eligible compensation				10.00%
Employee Stock Purchase Plan, exercise price as percentage of fair value				95.00%
Additional Paid-in Capital
Capital Structure
Shares repurchased, value						$ (10,000,000)	$ 10,000,000	$ 11,000,000
Accelerated Share Repurchase Program
Capital Structure
Shares repurchased, value				$ 390,000,000
Average price paid per share (in usd per share)			$ 42.38
Stock repurchase program, authorized amount					$ 400,000,000
Shares repurchased (in shares)			351,768	9,086,903
Accelerated Share Repurchase Program | Additional Paid-in Capital
Capital Structure
Remaining amount recorded in additional paid in capital			$ 10,000,000
2018 Plan
Capital Structure
Shares repurchased, value					$ 250,000,000
2019 Plan
Capital Structure
Average price paid per share (in usd per share)					$ 40.61
Stock repurchase program, authorized amount					$ 1,000,000,000
2019 Plan | Subsequent Event
Capital Structure
Shares repurchased, value	$ 1,000,000,000
Average price paid per share (in usd per share)	$ 38.38
Additional number of shares authorized to be repurchased		$ 250,000,000

Changes in Capital Structure _2

Changes in Capital Structure - Changes in NRG's common shares outstanding and issued (Details) - shares	Aug. 07, 2019	Aug. 07, 2019	Jun. 30, 2019
Schedule of Stock by Class, Equity [Roll Forward]
Balance as of beginning of period (in shares)		421,830,474	420,288,886
Treasury shares, balance as of beginning of period (in shares)		(163,259,876)	(136,638,847)
Outstanding, as of beginning of period (in shares)		258,570,598	283,650,039
Shares issued under LTIPs (in shares)			1,541,588
Shares repurchased (in shares)			(26,621,029)
Balance as of end of period (in shares)			421,830,474
Treasury shares, balance as of end of the period (in shares)			(163,259,876)
Outstanding, as of end of period (in shares)			258,570,598
Issued
Schedule of Stock by Class, Equity [Roll Forward]
Shares issued under LTIPs (in shares)			1,541,588
Shares repurchased (in shares)			0
Treasury
Schedule of Stock by Class, Equity [Roll Forward]
Shares issued under LTIPs (in shares)			0
Shares repurchased (in shares)			(26,621,029)
Subsequent Event
Schedule of Stock by Class, Equity [Roll Forward]
Shares issued under LTIPs (in shares)		3,827
Shares repurchased (in shares)		(5,586,536)
Balance as of end of period (in shares)	421,834,301	421,834,301
Treasury shares, balance as of end of the period (in shares)	(168,846,412)	(168,846,412)
Outstanding, as of end of period (in shares)	252,987,889	252,987,889
Subsequent Event | Issued
Schedule of Stock by Class, Equity [Roll Forward]
Shares issued under LTIPs (in shares)		3,827
Shares repurchased (in shares)		0
Subsequent Event | Treasury
Schedule of Stock by Class, Equity [Roll Forward]
Shares issued under LTIPs (in shares)		0
Shares repurchased (in shares)		(5,586,536)
Capital Allocation Plan
Schedule of Stock by Class, Equity [Roll Forward]
Shares repurchased (in shares)			(26,621,029)
Capital Allocation Plan | Subsequent Event
Schedule of Stock by Class, Equity [Roll Forward]
Shares repurchased (in shares)	(32,207,565)

Changes in Capital Structure _3

Changes in Capital Structure - Schedule of Repurchases Under Share Repurchase Programs (Details) - USD ($)	Aug. 07, 2019	Aug. 07, 2019	Jul. 31, 2019	Feb. 28, 2019	Jun. 30, 2019	Jun. 30, 2019
Schedule of Capitalization, Equity [Line Items]
Total number of shares purchased (in shares)						26,621,029
Subsequent Event
Schedule of Capitalization, Equity [Line Items]
Total number of shares purchased (in shares)		5,586,536
2018 Plan
Schedule of Capitalization, Equity [Line Items]
Total number of shares purchased (in shares)				6,153,415
Amounts paid for shares purchased				$ 250,000,000
Capital Allocation Plan, Accelerated Repurchase Agreement February 2019
Schedule of Capitalization, Equity [Line Items]
Total number of shares purchased (in shares)					9,438,671
Amounts paid for shares purchased					$ 400,000,000
Capital Allocation Plan, Accelerated Repurchase Agreement February 2019 | Subsequent Event
Schedule of Capitalization, Equity [Line Items]
Total number of shares purchased (in shares)		5,586,536
Amounts paid for shares purchased		$ 196,000,000
Other repurchases
Schedule of Capitalization, Equity [Line Items]
Total number of shares purchased (in shares)					11,028,943
Amounts paid for shares purchased					$ 404,000,000
Other repurchases | Subsequent Event
Schedule of Capitalization, Equity [Line Items]
Additional number of shares authorized to be repurchased			$ 250,000,000
Capital Allocation Plan
Schedule of Capitalization, Equity [Line Items]
Total number of shares purchased (in shares)						26,621,029
Amounts paid for shares purchased						$ 1,054,000,000
Capital Allocation Plan | Subsequent Event
Schedule of Capitalization, Equity [Line Items]
Total number of shares purchased (in shares)	32,207,565
Amounts paid for shares purchased	$ 1,250,000,000

Changes in Capital Structure _4

Changes in Capital Structure - NRG Common Stock Dividends Paid (Details) - $ / shares	Aug. 01, 2019	Jul. 19, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Subsequent Event [Line Items]
Dividends Per Common Share (in usd per share)			$ 0.03	$ 0.03	$ 0.06	$ 0.06
Subsequent Event
Subsequent Event [Line Items]
Common stock dividends declared (in usd per share)		$ 0.03
Common stock dividends proposed annual amount (in usd per share)	$ 0.12

Earnings Per Share - Reconcilia

Earnings Per Share - Reconciliation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Basic income per share attributable to NRG Energy, Inc;
Net income attributable to NRG Energy, Inc. common stockholders	$ 201	$ 72	$ 683	$ 351
Weighted average number of common shares outstanding — basic (in shares)	265	310	272	314
Income per weighted average common share — basic (in usd per share)	$ 0.76	$ 0.23	$ 2.51	$ 1.12
Diluted income per share attributable to NRG Energy, Inc;
Net income attributable to NRG Energy, Inc. available to common shareholders	$ 201	$ 72	$ 683	$ 351
Weighted average number of common shares outstanding - diluted (in shares)	265	310	272	314
Incremental shares attributable to the issuance of equity compensation (treasury stock method) (in shares)	2	4	2	4
Total dilutive shares (in shares)	267	314	274	318
Income per weighted average common share — diluted (in usd per share)	$ 0.75	$ 0.23	$ 2.49	$ 1.10

Earnings Per Share - Anti-dilut

Earnings Per Share - Anti-dilutive Securities (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Equity compensation plans
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	0	0	1

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information
Total operating revenues	$ (2,465)	$ (2,461)	$ (4,630)	$ (4,526)
Depreciation and amortization	85	112	170	232
Impairment losses	1	74	1	74
Reorganization costs	2	23	15	43
Gain on sale of assets	1		2	16
Equity in earnings (losses) of unconsolidated affiliates	0	5	(21)	6
Loss on debt extinguishment, net	(47)	(1)	(47)	(3)
(Loss)/income from continuing operations before income taxes	188	32	286	276
(Loss)/income from continuing operations	189	27	283	265
Income/(Loss) from discontinued operations, net of income tax	13	69	401	64
Net (loss)/income	202	96	684	329
Net (loss)/income attributable to NRG Energy, Inc.	201	72	683	351
Eliminations
Segment Reporting Information
Total operating revenues	650	520	915	206
Depreciation and amortization	0	(1)	0	(2)
Impairment losses	0		0	0
Reorganization costs	0	0	0	0
Gain on sale of assets	0		0	0
Equity in earnings (losses) of unconsolidated affiliates		(2)	0	(2)
Loss on debt extinguishment, net	0		0
(Loss)/income from continuing operations before income taxes	1	1	(1)	(1)
(Loss)/income from continuing operations	1	1	(1)	(1)
Income/(Loss) from discontinued operations, net of income tax	0	0	0	0
Net (loss)/income	1	1	(1)	(1)
Net (loss)/income attributable to NRG Energy, Inc.	1	3	(1)	1
Retail | Operating Segments
Segment Reporting Information
Total operating revenues	(1,748)	(1,814)	(3,355)	(3,294)
Depreciation and amortization	32	30	63	56
Impairment losses	1		1	0
Reorganization costs	2	1	3	5
Gain on sale of assets	0		0	0
Equity in earnings (losses) of unconsolidated affiliates		0	0	0
Loss on debt extinguishment, net	0		0
(Loss)/income from continuing operations before income taxes	(280)	(84)	(169)	860
(Loss)/income from continuing operations	(280)	(84)	(170)	860
Income/(Loss) from discontinued operations, net of income tax	0	0	0	0
Net (loss)/income	(280)	(84)	(170)	860
Net (loss)/income attributable to NRG Energy, Inc.	(281)	(84)	(171)	859
Retail | Eliminations
Segment Reporting Information
Total operating revenues	2	4	5	6
Generation | Operating Segments
Segment Reporting Information
Total operating revenues	(1,367)	(1,167)	(2,190)	(1,438)
Depreciation and amortization	45	74	91	160
Impairment losses	0		0	74
Reorganization costs	0	3	1	6
Gain on sale of assets	0		1	2
Equity in earnings (losses) of unconsolidated affiliates		5	(21)	7
Loss on debt extinguishment, net	0		0
(Loss)/income from continuing operations before income taxes	618	252	731	(319)
(Loss)/income from continuing operations	618	252	731	(319)
Income/(Loss) from discontinued operations, net of income tax	0	0	0	0
Net (loss)/income	618	252	731	(319)
Net (loss)/income attributable to NRG Energy, Inc.	618	250	731	(313)
Generation | Eliminations
Segment Reporting Information
Total operating revenues	627	514	862	205
Corporate | Operating Segments
Segment Reporting Information
Total operating revenues	0	0	0	0
Depreciation and amortization	8	9	16	18
Impairment losses	0		0	0
Reorganization costs	0	19	11	32
Gain on sale of assets	1		1	14
Equity in earnings (losses) of unconsolidated affiliates		2	0	1
Loss on debt extinguishment, net	(47)		(47)
(Loss)/income from continuing operations before income taxes	(151)	(137)	(275)	(264)
(Loss)/income from continuing operations	(150)	(142)	(277)	(275)
Income/(Loss) from discontinued operations, net of income tax	13	69	401	64
Net (loss)/income	(137)	(73)	124	(211)
Net (loss)/income attributable to NRG Energy, Inc.	(137)	(97)	124	(196)
Corporate | Eliminations
Segment Reporting Information
Total operating revenues	$ 21	$ 2	$ 48	$ (5)

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Effective Tax Rate
Income from continuing operations before income taxes	$ 188	$ 32	$ 286	$ 276
Income tax (benefit)/expense from continuing operations	$ (1)	$ 5	$ 3	$ 11
Effective income tax rate	(0.50%)	15.60%	1.00%	4.00%
Uncertain Tax Benefits
Non-current tax liability for uncertain tax benefits	$ 28		$ 28
Uncertain tax benefits, penalties and interest accrued	$ 4		$ 4

Related Party Transactions - Sc

Related Party Transactions - Schedule of NRG's Material Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Related Party Transaction [Line Items]
Revenue from related parties	$ 9	$ 28	$ 21	$ 51
Gladstone
Related Party Transaction [Line Items]
Revenue from related parties	1	1	1	1
GenConn
Related Party Transaction [Line Items]
Revenue from related parties	0	1	0	3
Ivanpah
Related Party Transaction [Line Items]
Revenue from related parties	7	5	18	5
Midway-Sunset
Related Party Transaction [Line Items]
Revenue from related parties	1	0	2	0
GenOn
Related Party Transaction [Line Items]
Revenue from related parties	$ 0	$ 21	$ 0	$ 42

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	May 29, 2019USD ($)	Jun. 01, 2001	Jun. 30, 2019USD ($)facility	Aug. 18, 2016USD ($)
Commonwealth Edison Company And Exelon Generation Company LLC
Loss Contingencies
Payment for litigation settlement	$ 26
CDWR and SDGE v Sunrise Power
Loss Contingencies
PPA period		10 years
Damages sought, amount			$ 1.2
Remaining term			70 months
Sierra Club Et Al V. Midwest Generation LLC
Loss Contingencies
Number of facilities | facility			4
Lignite Contract With Texas Westmoreland Coal Co.
Loss Contingencies
Bond obligation				$ 99

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Amount outstanding	$ 6,042	$ 6,691
Recourse Debt
Debt Instrument [Line Items]
Amount outstanding	5,925	$ 6,523
Senior Notes | Recourse Debt
Debt Instrument [Line Items]
Amount outstanding	4,400
Senior Secured First Lien Notes | Recourse Debt
Debt Instrument [Line Items]
Amount outstanding	$ 1,100

Condensed Consolidating Finan_4

Condensed Consolidating Financial Information - CONSOLIDATING STATEMENTS OF OPERATIONS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating Revenues
Total operating revenues	$ 2,465	$ 2,461	$ 4,630	$ 4,526
Operating Costs and Expenses
Cost of operations	1,845	1,889	3,496	3,274
Depreciation and amortization	85	112	170	232
Impairment losses	1	74	1	74
Selling, general and administrative	211	200	405	376
Reorganization costs	2	23	15	43
Development costs	2	3	4	8
Total operating costs and expenses	2,146	2,301	4,091	4,007
Gain on sale of assets	1	14	2	16
Operating Income/(Loss)	320	174	541	535
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	0	0	0	0
Equity in earnings/(losses) of unconsolidated affiliates	0	5	(21)	6
Other income/(expense), net	20	(23)	32	(23)
Loss on debt extinguishment, net	(47)	(1)	(47)	(3)
Interest expense	(105)	(123)	(219)	(239)
Total other income/(expense)	(132)	(142)	(255)	(259)
Income from Continuing Operations Before Income Taxes	188	32	286	276
Income tax expense/(benefit)	(1)	5	3	11
Income from Continuing Operations	189	27	283	265
Income/(loss) from discontinued operations	13	69	401	64
Net (loss)/income	202	96	684	329
Less: Net income attributable to noncontrolling interest and redeemable interests	1	24	1	(22)
Net income attributable to NRG Energy, Inc.	201	72	683	351
Eliminations
Operating Revenues
Total operating revenues	(7)	(2)	(6)	(10)
Operating Costs and Expenses
Cost of operations	(7)	(3)	(6)	(11)
Depreciation and amortization	0	0	0	0
Impairment losses	0	0	0	0
Selling, general and administrative	0	0	0	0
Reorganization costs	0	0	0	0
Development costs	0	(1)	0	(1)
Total operating costs and expenses	(7)	(4)	(6)	(12)
Gain on sale of assets	0	0	0	0
Operating Income/(Loss)	0	2	0	2
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	(432)	(360)	(741)	(693)
Equity in earnings/(losses) of unconsolidated affiliates		0	0	0
Other income/(expense), net	0	0	0	0
Loss on debt extinguishment, net	0	0	0	0
Interest expense	0	0	0	0
Total other income/(expense)	(432)	(360)	(741)	(693)
Income from Continuing Operations Before Income Taxes	(432)	(358)	(741)	(691)
Income tax expense/(benefit)	0	0	0	0
Income from Continuing Operations	(432)	(358)	(741)	(691)
Income/(loss) from discontinued operations	0	0	0	0
Net (loss)/income	(432)	(358)	(741)	(691)
Less: Net income attributable to noncontrolling interest and redeemable interests	0	2	0	2
Net income attributable to NRG Energy, Inc.	(432)	(360)	(741)	(693)
Guarantor Subsidiaries
Operating Revenues
Total operating revenues	2,140	2,172	3,909	3,916
Operating Costs and Expenses
Cost of operations	1,590	1,702	2,948	2,857
Depreciation and amortization	51	63	105	123
Impairment losses	1	0	1	0
Selling, general and administrative	112	108	234	212
Reorganization costs	0	1	0	3
Development costs	0	0	0	0
Total operating costs and expenses	1,754	1,874	3,288	3,195
Gain on sale of assets	0	0	1	3
Operating Income/(Loss)	386	298	622	724
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	2	7	12	8
Equity in earnings/(losses) of unconsolidated affiliates		0	0	0
Other income/(expense), net	4	3	8	8
Loss on debt extinguishment, net	0	0	0	0
Interest expense	(3)	(4)	(7)	(7)
Total other income/(expense)	3	6	13	9
Income from Continuing Operations Before Income Taxes	389	304	635	733
Income tax expense/(benefit)	0	108	0	221
Income from Continuing Operations	389	196	635	512
Income/(loss) from discontinued operations	0	15	9	30
Net (loss)/income	389	211	644	542
Less: Net income attributable to noncontrolling interest and redeemable interests	0	0	0	0
Net income attributable to NRG Energy, Inc.	389	211	644	542
Non-Guarantor Subsidiaries
Operating Revenues
Total operating revenues	332	291	727	620
Operating Costs and Expenses
Cost of operations	252	195	535	419
Depreciation and amortization	26	40	49	92
Impairment losses	0	74	0	74
Selling, general and administrative	12	16	28	27
Reorganization costs	0	0	0	0
Development costs	1	1	1	2
Total operating costs and expenses	291	326	613	614
Gain on sale of assets	1	14	1	13
Operating Income/(Loss)	42	(21)	115	19
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	0	0	0	0
Equity in earnings/(losses) of unconsolidated affiliates		5	(21)	7
Other income/(expense), net	8	(29)	9	(36)
Loss on debt extinguishment, net	0	0	0	0
Interest expense	(5)	(13)	(9)	(34)
Total other income/(expense)	3	(37)	(21)	(63)
Income from Continuing Operations Before Income Taxes	45	(58)	94	(44)
Income tax expense/(benefit)	1	(71)	1	(16)
Income from Continuing Operations	44	13	93	(28)
Income/(loss) from discontinued operations	0	80	5	60
Net (loss)/income	44	93	98	32
Less: Net income attributable to noncontrolling interest and redeemable interests	1	(56)	1	(119)
Net income attributable to NRG Energy, Inc.	43	149	97	151
NRG Energy, Inc. (Note Issuer)
Operating Revenues
Total operating revenues	0	0	0	0
Operating Costs and Expenses
Cost of operations	10	(5)	19	9
Depreciation and amortization	8	9	16	17
Impairment losses	0	0	0	0
Selling, general and administrative	87	76	143	137
Reorganization costs	2	22	15	40
Development costs	1	3	3	7
Total operating costs and expenses	108	105	196	210
Gain on sale of assets	0	0	0	0
Operating Income/(Loss)	(108)	(105)	(196)	(210)
Other Income/(Expense)
Equity in earnings of consolidated subsidiaries	430	353	729	685
Equity in earnings/(losses) of unconsolidated affiliates		0	0	(1)
Other income/(expense), net	8	3	15	5
Loss on debt extinguishment, net	(47)	(1)	(47)	(3)
Interest expense	(97)	(106)	(203)	(198)
Total other income/(expense)	294	249	494	488
Income from Continuing Operations Before Income Taxes	186	144	298	278
Income tax expense/(benefit)	(2)	(32)	2	(194)
Income from Continuing Operations	188	176	296	472
Income/(loss) from discontinued operations	13	(26)	387	(26)
Net (loss)/income	201	150	683	446
Less: Net income attributable to noncontrolling interest and redeemable interests	0	78	0	95
Net income attributable to NRG Energy, Inc.	$ 201	$ 72	$ 683	$ 351

Condensed Consolidating Finan_5

Condensed Consolidating Financial Information - CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Net Income	$ 202	$ 96	$ 684	$ 329
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net	0	5	0	19
Foreign currency translation adjustments, net	(1)	(4)	0	(6)
Available-for-sale securities, net	1	1	1	1
Defined benefit plans, net	(3)	(1)	(6)	(2)
Other comprehensive (loss)/income	(3)	1	(5)	12
Comprehensive Income	199	97	679	341
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests	1	26	1	(12)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	198	71	678	353
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net Income	(432)	(358)	(741)	(691)
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		(5)		(22)
Foreign currency translation adjustments, net	2	9		14
Available-for-sale securities, net	0	0	0	0
Defined benefit plans, net	0	0	0	0
Other comprehensive (loss)/income	2	4	0	(8)
Comprehensive Income	(430)	(354)	(741)	(699)
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests	0	2	0	2
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	(430)	(356)	(741)	(701)
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net Income	389	211	644	542
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		0		0
Foreign currency translation adjustments, net	(1)	(4)		(6)
Available-for-sale securities, net	0	0	0	0
Defined benefit plans, net	0	0	0	0
Other comprehensive (loss)/income	(1)	(4)	0	(6)
Comprehensive Income	388	207	644	536
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests	0	0	0	0
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	388	207	644	536
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net Income	44	93	98	32
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		4		20
Foreign currency translation adjustments, net	(1)	(4)		(6)
Available-for-sale securities, net	0	0	0	0
Defined benefit plans, net	0	0	0	0
Other comprehensive (loss)/income	(1)	0	0	14
Comprehensive Income	43	93	98	46
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests	1	(56)	1	(119)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	42	149	97	165
NRG Energy, Inc. (Note Issuer)
Condensed Financial Statements, Captions [Line Items]
Net Income	201	150	683	446
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		6		21
Foreign currency translation adjustments, net	(1)	(5)		(8)
Available-for-sale securities, net	1	1	1	1
Defined benefit plans, net	(3)	(1)	(6)	(2)
Other comprehensive (loss)/income	(3)	1	(5)	12
Comprehensive Income	198	151	678	458
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable interests	0	80	0	105
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	$ 198	$ 71	$ 678	$ 353

Condensed Consolidating Finan_6

Condensed Consolidating Financial Information - CONSOLIDATING BALANCE SHEETS (Details) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 294		$ 563
Funds deposited by counterparties	31		33
Restricted cash	11		17
Accounts receivable, net	1,049		1,024
Inventory	370		412
Derivative instruments	850		764
Cash collateral paid in support of energy risk management activities	163		287
Prepayments and other current assets	277		302
Current assets - held-for-sale	0		1
Current assets - discontinued operations	0		197
Total current assets	3,045		3,600
Property, plant and equipment, net	2,610		3,048
Other Assets
Investment in subsidiaries	0		0
Equity investments in affiliates	383		412
Operating lease right-of-use assets, net	499
Goodwill	573		573
Intangible assets, net	561		591
Nuclear decommissioning trust fund	748		663
Derivative instruments	426		317
Deferred income tax	55		46
Other non-current assets	271		289
Non-current assets - held-for-sale	0		77
Non-current assets - discontinued operations	0		1,012
Total other assets	3,516		3,980
Total Assets	9,171		10,628
Current Liabilities
Current portion of long-term debt and capital leases	87		72
Current portion of operating lease liabilities	74
Accounts payable	723		863
Derivative instruments	778		673
Cash collateral received in support of energy risk management activities	31		33
Accrued expenses and other current liabilities	601		680
Current liabilities - held-for-sale	0		5
Current liabilities - discontinued operations	0		72
Total current liabilities	2,294		2,398
Other Liabilities
Long-term debt and capital leases	5,794		6,449
Non-current operating lease liabilities	513
Nuclear decommissioning reserve	290		282
Nuclear decommissioning trust liability	448		371
Derivative instruments	374		304
Deferred income taxes	71		65
Other non-current liabilities	1,016		1,274
Non-current liabilities - held-for-sale	0		65
Non-current liabilities - discontinued operations	0		635
Total other liabilities	8,506		9,445
Total Liabilities	10,800		11,843
Redeemable noncontrolling interest in subsidiaries	19		19
Total Stockholders' Equity	(1,648)	$ (1,538)	(1,234)	$ 2,071	$ 2,258	$ 1,968
Total Liabilities and Stockholders' Equity	9,171		10,628
Eliminations
Current Assets
Cash and cash equivalents	0		0
Funds deposited by counterparties	0		0
Restricted cash	0		0
Accounts receivable, net	(744)		(754)
Inventory	0		0
Derivative instruments	(71)		(81)
Cash collateral paid 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	(815)		(835)
Property, plant and equipment, net	0		0
Other Assets
Investment in subsidiaries	(4,627)		(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	(16)		(5)
Deferred income tax	0		0
Other non-current assets	(3)		(12)
Non-current assets - held-for-sale			0
Non-current assets - discontinued operations			0
Total other assets	(4,646)		(5,170)
Total Assets	(5,461)		(6,005)
Current Liabilities
Current portion of long-term debt and capital leases	0		0
Current portion of operating lease liabilities	0
Accounts payable	(744)		(754)
Derivative instruments	(71)		(81)
Cash collateral received in support of energy risk management activities	0		0
Accrued expenses and other current liabilities	0		0
Current liabilities - held-for-sale			0
Current liabilities - discontinued operations			0
Total current liabilities	(815)		(835)
Other Liabilities
Long-term debt and capital leases	(3)		(12)
Non-current operating lease liabilities	0
Nuclear decommissioning reserve	0		0
Nuclear decommissioning trust liability	0		0
Derivative instruments	(16)		(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	(19)		(17)
Total Liabilities	(834)		(852)
Redeemable noncontrolling interest in subsidiaries	0		0
Total Stockholders' Equity	(4,627)		(5,153)
Total Liabilities and Stockholders' Equity	(5,461)		(6,005)
Guarantor Subsidiaries
Current Assets
Cash and cash equivalents	0		55
Funds deposited by counterparties	31		33
Restricted cash	8		7
Accounts receivable, net	1,383		1,354
Inventory	254		278
Derivative instruments	867		779
Cash collateral paid in support of energy risk management activities	148		275
Prepayments and other current assets	190		180
Current assets - held-for-sale			0
Current assets - discontinued operations			177
Total current assets	2,881		3,138
Property, plant and equipment, net	1,494		1,938
Other Assets
Investment in subsidiaries	436		446
Equity investments in affiliates	0		0
Operating lease right-of-use assets, net	91
Goodwill	359		359
Intangible assets, net	402		422
Nuclear decommissioning trust fund	748		663
Derivative instruments	420		296
Deferred income tax	0		6
Other non-current assets	148		133
Non-current assets - held-for-sale			0
Non-current assets - discontinued operations			405
Total other assets	2,604		2,730
Total Assets	6,979		7,806
Current Liabilities
Current portion of long-term debt and capital leases	0		0
Current portion of operating lease liabilities	22
Accounts payable	937		1,368
Derivative instruments	817		713
Cash collateral received in support of energy risk management activities	31		33
Accrued expenses and other current liabilities	258		291
Current liabilities - held-for-sale			0
Current liabilities - discontinued operations			24
Total current liabilities	2,065		2,429
Other Liabilities
Long-term debt and capital leases	245		244
Non-current operating lease liabilities	73
Nuclear decommissioning reserve	290		282
Nuclear decommissioning trust liability	448		371
Derivative instruments	388		306
Deferred income taxes	(10)		112
Other non-current liabilities	399		402
Non-current liabilities - held-for-sale			0
Non-current liabilities - discontinued operations			58
Total other liabilities	1,833		1,775
Total Liabilities	3,898		4,204
Redeemable noncontrolling interest in subsidiaries	0		0
Total Stockholders' Equity	3,081		3,602
Total Liabilities and Stockholders' Equity	6,979		7,806
Non-Guarantor Subsidiaries
Current Assets
Cash and cash equivalents	27		28
Funds deposited by counterparties	0		0
Restricted cash	2		10
Accounts receivable, net	133		115
Inventory	116		134
Derivative instruments	54		50
Cash collateral paid in support of energy risk management activities	15		12
Prepayments and other current assets	11		32
Current assets - held-for-sale			1
Current assets - discontinued operations			20
Total current assets	358		402
Property, plant and equipment, net	965		957
Other Assets
Investment in subsidiaries	0		0
Equity investments in affiliates	383		412
Operating lease right-of-use assets, net	279
Goodwill	214		214
Intangible assets, net	159		169
Nuclear decommissioning trust fund	0		0
Derivative instruments	22		4
Deferred income tax	56		(143)
Other non-current assets	30		71
Non-current assets - held-for-sale			77
Non-current assets - discontinued operations			607
Total other assets	1,143		1,411
Total Assets	2,466		2,770
Current Liabilities
Current portion of long-term debt and capital leases	87		55
Current portion of operating lease liabilities	31
Accounts payable	107		(185)
Derivative instruments	32		41
Cash collateral received in support of energy risk management activities	0		0
Accrued expenses and other current liabilities	42		36
Current liabilities - held-for-sale			5
Current liabilities - discontinued operations			48
Total current liabilities	299		0
Other Liabilities
Long-term debt and capital leases	89		192
Non-current operating lease liabilities	313
Nuclear decommissioning reserve	0		0
Nuclear decommissioning trust liability	0		0
Derivative instruments	2		3
Deferred income taxes	68		61
Other non-current liabilities	148		320
Non-current liabilities - held-for-sale			65
Non-current liabilities - discontinued operations			577
Total other liabilities	620		1,218
Total Liabilities	919		1,218
Redeemable noncontrolling interest in subsidiaries	19		19
Total Stockholders' Equity	1,528		1,533
Total Liabilities and Stockholders' Equity	2,466		2,770
NRG Energy, Inc. (Note Issuer)
Current Assets
Cash and cash equivalents	267		480
Funds deposited by counterparties	0		0
Restricted cash	1		0
Accounts receivable, net	277		309
Inventory	0		0
Derivative instruments	0		16
Cash collateral paid in support of energy risk management activities	0		0
Prepayments and other current assets	76		90
Current assets - held-for-sale			0
Current assets - discontinued operations			0
Total current assets	621		895
Property, plant and equipment, net	151		153
Other Assets
Investment in subsidiaries	4,191		4,707
Equity investments in affiliates	0		0
Operating lease right-of-use assets, net	129
Goodwill	0		0
Intangible assets, net	0		0
Nuclear decommissioning trust fund	0		0
Derivative instruments	0		22
Deferred income tax	(1)		183
Other non-current assets	96		97
Non-current assets - held-for-sale			0
Non-current assets - discontinued operations			0
Total other assets	4,415		5,009
Total Assets	5,187		6,057
Current Liabilities
Current portion of long-term debt and capital leases	0		17
Current portion of operating lease liabilities	21
Accounts payable	423		434
Derivative instruments	0		0
Cash collateral received in support of energy risk management activities	0		0
Accrued expenses and other current liabilities	301		353
Current liabilities - held-for-sale			0
Current liabilities - discontinued operations			0
Total current liabilities	745		804
Other Liabilities
Long-term debt and capital leases	5,463		6,025
Non-current operating lease liabilities	127
Nuclear decommissioning reserve	0		0
Nuclear decommissioning trust liability	0		0
Derivative instruments	0		0
Deferred income taxes	13		(108)
Other non-current liabilities	469		552
Non-current liabilities - held-for-sale			0
Non-current liabilities - discontinued operations			0
Total other liabilities	6,072		6,469
Total Liabilities	6,817		7,273
Redeemable noncontrolling interest in subsidiaries	0		0
Total Stockholders' Equity	(1,630)		(1,216)
Total Liabilities and Stockholders' Equity	$ 5,187		$ 6,057

Condensed Consolidating Finan_7

Condensed Consolidating Financial Information - CONSOLIDATING STATEMENTS OF CASH FLOWS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Cash Flows from Operating Activities
Net (loss)/income	$ 202	$ 96	$ 684	$ 329
Income/(loss) from discontinued operations	13	69	401	64
Income/(loss) from continuing operations	189	27	283	265
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries			22	12
Depreciation, amortization and accretion			184	252
Provision for bad debts			52	30
Amortization of nuclear fuel			27	24
Amortization of financing costs and debt discount/premiums			13	13
Loss on debt extinguishment, net			47	3
Amortization of intangibles and out-of-market contracts			14	20
Amortization of unearned equity compensation			10	15
(Loss)/gain on sale and disposal of assets			1	(16)
Impairment losses			1	88
Changes in derivative instruments			(22)	(145)
Changes in deferred income taxes and liability for uncertain tax benefits			(5)	(2)
Changes in collateral deposits in support of energy risk management activities			125	(9)
Changes in nuclear decommissioning trust liability			17	41
Loss on deconsolidation of Ivanpah project			0	22
Changes in other working capital			(388)	(349)
Cash provided/(used) by continuing operations			381	264
Cash provided/(used) by discontinued operations			8	249
Net Cash Provided/(Used) by Operating Activities			389	513
Cash Flows from Investing Activities
Intercompany dividends			0	0
Payments for acquisitions of businesses			(21)	(211)
Capital expenditures			(107)	(282)
Net purchases of /proceeds from emission allowances			(1)	3
Investments in nuclear decommissioning trust fund securities			(209)	(346)
Proceeds from the sale of nuclear decommissioning trust fund securities			191	303
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees			1,289	146
Deconsolidation of Ivanpah project			0	(160)
Net contributions for investments in unconsolidated affiliates			7	(15)
Contributions to discontinued operations			(44)	(16)
Cash (used)/provided by continuing operations			1,105	(578)
Cash used by discontinued operations			(2)	(584)
Net Cash (Used)/Provided by Investing Activities			1,103	(1,162)
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			0	0
Intercompany dividends			0	0
Payments of dividends to common stockholders			(16)	(19)
Payments for treasury stock			(1,039)	(500)
Payments for debt extinguishment			(24)	0
Distributions to noncontrolling interests from subsidiaries			(1)	(14)
Proceeds from issuance of common stock			2	11
Proceeds from issuance of long-term debt			1,833
Proceeds from issuance of short and long-term debt			1,833	994
Payment of debt issuance costs			(33)	(19)
Payments for short and long-term debt			(2,485)	(348)
Cash (used)/provided by continuing operations			(1,763)	105
Cash provided by discontinued operations			43	345
Net Cash (Used)/Provided by Financing Activities			(1,720)	450
Change in cash from discontinued operations			49	10
Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			(277)	(209)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			613	1,086
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	336	877	336	877
Eliminations
Cash Flows from Operating Activities
Net (loss)/income	(432)	(358)	(741)	(691)
Income/(loss) from discontinued operations	0	0	0	0
Income/(loss) from continuing operations	(432)	(358)	(741)	(691)
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries			741	691
Depreciation, amortization and accretion			0	0
Provision for bad debts			0	0
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			0	0
Loss on debt extinguishment, net			0	0
Amortization of intangibles and out-of-market contracts			0	0
Amortization of unearned equity compensation			0	0
(Loss)/gain on sale and disposal of assets			0	0
Impairment losses			0	0
Changes in derivative instruments			0	0
Changes in deferred income taxes and liability for uncertain tax benefits			0	0
Changes in collateral deposits in support of energy risk management activities			0	0
Changes in nuclear decommissioning trust liability			0	0
Loss on deconsolidation of Ivanpah project				0
Changes in other working capital			0	0
Cash provided/(used) by continuing operations			0	0
Cash provided/(used) by discontinued operations			0	0
Net Cash Provided/(Used) by Operating Activities			0	0
Cash Flows from Investing Activities
Intercompany dividends			(738)	(157)
Payments for acquisitions of businesses			0	0
Capital expenditures			0	0
Net purchases of /proceeds from emission allowances			0	0
Investments in nuclear decommissioning trust fund securities			0	0
Proceeds from the sale of nuclear decommissioning trust fund securities			0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees				0
Deconsolidation of Ivanpah project				0
Net contributions for investments in unconsolidated affiliates			0	0
Contributions to discontinued operations			0	0
Cash (used)/provided by continuing operations			(738)	(157)
Cash used by discontinued operations			0	0
Net Cash (Used)/Provided by Investing Activities			(738)	(157)
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			0	0
Intercompany dividends			738	157
Payments of dividends to common stockholders			0	0
Payments for treasury stock			0	0
Payments for debt extinguishment			0
Distributions to noncontrolling interests from subsidiaries			0	0
Proceeds from issuance of common stock			0	0
Proceeds from issuance of long-term debt			0
Proceeds from issuance of short and long-term debt				0
Payment of debt issuance costs			0	0
Payments for short and long-term debt			0	0
Cash (used)/provided by continuing operations			738	157
Cash provided by discontinued operations			0	0
Net Cash (Used)/Provided by Financing Activities			738	157
Change in cash from discontinued operations			0	0
Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			0	0
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			0	0
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	0	0	0	0
Guarantor Subsidiaries
Cash Flows from Operating Activities
Net (loss)/income	389	211	644	542
Income/(loss) from discontinued operations	0	15	9	30
Income/(loss) from continuing operations	389	196	635	512
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries			(12)	(8)
Depreciation, amortization and accretion			115	136
Provision for bad debts			42	30
Amortization of nuclear fuel			27	24
Amortization of financing costs and debt discount/premiums			0	0
Loss on debt extinguishment, net			0	0
Amortization of intangibles and out-of-market contracts			13	16
Amortization of unearned equity compensation			0	0
(Loss)/gain on sale and disposal of assets			(3)	(3)
Impairment losses			1	0
Changes in derivative instruments			(28)	(154)
Changes in deferred income taxes and liability for uncertain tax benefits			0	221
Changes in collateral deposits in support of energy risk management activities			128	(5)
Changes in nuclear decommissioning trust liability			17	41
Loss on deconsolidation of Ivanpah project				0
Changes in other working capital			(343)	152
Cash provided/(used) by continuing operations			592	962
Cash provided/(used) by discontinued operations			17	50
Net Cash Provided/(Used) by Operating Activities			609	1,012
Cash Flows from Investing Activities
Intercompany dividends			0	0
Payments for acquisitions of businesses			(21)	(2)
Capital expenditures			(77)	(103)
Net purchases of /proceeds from emission allowances			(1)	3
Investments in nuclear decommissioning trust fund securities			(209)	(346)
Proceeds from the sale of nuclear decommissioning trust fund securities			191	303
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees			1	11
Deconsolidation of Ivanpah project				0
Net contributions for investments in unconsolidated affiliates			0	0
Contributions to discontinued operations			0	0
Cash (used)/provided by continuing operations			(116)	(134)
Cash used by discontinued operations			0	2
Net Cash (Used)/Provided by Investing Activities			(116)	(132)
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			206	(611)
Intercompany dividends			(738)	(157)
Payments of dividends to common stockholders			0	0
Payments for treasury stock			0	0
Payments for debt extinguishment			0
Distributions to noncontrolling interests from subsidiaries			0	0
Proceeds from issuance of common stock			0	0
Proceeds from issuance of long-term debt			0
Proceeds from issuance of short and long-term debt				0
Payment of debt issuance costs			0	0
Payments for short and long-term debt			0	0
Cash (used)/provided by continuing operations			(532)	(768)
Cash provided by discontinued operations			0	0
Net Cash (Used)/Provided by Financing Activities			(532)	(768)
Change in cash from discontinued operations			17	52
Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			(56)	60
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			95	41
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	39	101	39	101
Non-Guarantor Subsidiaries
Cash Flows from Operating Activities
Net (loss)/income	44	93	98	32
Income/(loss) from discontinued operations	0	80	5	60
Income/(loss) from continuing operations	44	13	93	(28)
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries			22	11
Depreciation, amortization and accretion			53	99
Provision for bad debts			4	0
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			0	1
Loss on debt extinguishment, net			0	0
Amortization of intangibles and out-of-market contracts			1	4
Amortization of unearned equity compensation			0	0
(Loss)/gain on sale and disposal of assets			1	(13)
Impairment losses			0	88
Changes in derivative instruments			(32)	19
Changes in deferred income taxes and liability for uncertain tax benefits			(3)	(47)
Changes in collateral deposits in support of energy risk management activities			(3)	(4)
Changes in nuclear decommissioning trust liability			0	0
Loss on deconsolidation of Ivanpah project				22
Changes in other working capital			(64)	(56)
Cash provided/(used) by continuing operations			72	96
Cash provided/(used) by discontinued operations			(9)	199
Net Cash Provided/(Used) by Operating Activities			63	295
Cash Flows from Investing Activities
Intercompany dividends			0	0
Payments for acquisitions of businesses			0	(209)
Capital expenditures			(15)	(149)
Net purchases of /proceeds from emission allowances			0	0
Investments in nuclear decommissioning trust fund securities			0	0
Proceeds from the sale of nuclear decommissioning trust fund securities			0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees			400	0
Deconsolidation of Ivanpah project				(160)
Net contributions for investments in unconsolidated affiliates			7	(15)
Contributions to discontinued operations			(44)	(16)
Cash (used)/provided by continuing operations			348	(549)
Cash used by discontinued operations			(2)	(586)
Net Cash (Used)/Provided by Investing Activities			346	(1,135)
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			(375)	204
Intercompany dividends			0	0
Payments of dividends to common stockholders			0	0
Payments for treasury stock			0	0
Payments for debt extinguishment			0
Distributions to noncontrolling interests from subsidiaries			(1)	(14)
Proceeds from issuance of common stock			0	0
Proceeds from issuance of long-term debt			0
Proceeds from issuance of short and long-term debt				163
Payment of debt issuance costs			0	0
Payments for short and long-term debt			(53)	(63)
Cash (used)/provided by continuing operations			(429)	290
Cash provided by discontinued operations			43	345
Net Cash (Used)/Provided by Financing Activities			(386)	635
Change in cash from discontinued operations			32	(42)
Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			(9)	(163)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			38	425
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	29	262	29	262
NRG Energy, Inc. (Note Issuer)
Cash Flows from Operating Activities
Net (loss)/income	201	150	683	446
Income/(loss) from discontinued operations	13	(26)	387	(26)
Income/(loss) from continuing operations	188	176	296	472
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries			(729)	(682)
Depreciation, amortization and accretion			16	17
Provision for bad debts			6	0
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			13	12
Loss on debt extinguishment, net			47	3
Amortization of intangibles and out-of-market contracts			0	0
Amortization of unearned equity compensation			10	15
(Loss)/gain on sale and disposal of assets			3	0
Impairment losses			0	0
Changes in derivative instruments			38	(10)
Changes in deferred income taxes and liability for uncertain tax benefits			(2)	(176)
Changes in collateral deposits in support of energy risk management activities			0	0
Changes in nuclear decommissioning trust liability			0	0
Loss on deconsolidation of Ivanpah project				0
Changes in other working capital			19	(445)
Cash provided/(used) by continuing operations			(283)	(794)
Cash provided/(used) by discontinued operations			0	0
Net Cash Provided/(Used) by Operating Activities			(283)	(794)
Cash Flows from Investing Activities
Intercompany dividends			738	157
Payments for acquisitions of businesses			0	0
Capital expenditures			(15)	(30)
Net purchases of /proceeds from emission allowances			0	0
Investments in nuclear decommissioning trust fund securities			0	0
Proceeds from the sale of nuclear decommissioning trust fund securities			0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees			888	135
Deconsolidation of Ivanpah project				0
Net contributions for investments in unconsolidated affiliates			0	0
Contributions to discontinued operations			0	0
Cash (used)/provided by continuing operations			1,611	262
Cash used by discontinued operations			0	0
Net Cash (Used)/Provided by Investing Activities			1,611	262
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			169	407
Intercompany dividends			0	0
Payments of dividends to common stockholders			(16)	(19)
Payments for treasury stock			(1,039)	(500)
Payments for debt extinguishment			(24)
Distributions to noncontrolling interests from subsidiaries			0	0
Proceeds from issuance of common stock			2	11
Proceeds from issuance of long-term debt			1,833
Proceeds from issuance of short and long-term debt				831
Payment of debt issuance costs			(33)	(19)
Payments for short and long-term debt			(2,432)	(285)
Cash (used)/provided by continuing operations			(1,540)	426
Cash provided by discontinued operations			0	0
Net Cash (Used)/Provided by Financing Activities			(1,540)	426
Change in cash from discontinued operations			0	0
Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			(212)	(106)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			480	620
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 268	$ 514	$ 268	$ 514