NRG Energy (NRG) 10-Q 3 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 31, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	NRG ENERGY, INC.
Entity Central Index Key	1,013,871
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		316,460,692
Document Fiscal Year Focus	2,017
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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Revenues
Total operating revenues	$ 2,701	$ 2,248	$ 5,083	$ 4,907
Operating Costs and Expenses
Cost of operations	1,837	1,443	3,696	3,271
Depreciation and amortization	260	262	517	528
Impairment losses	63	56	63	56
Selling, general and administrative	223	266	482	520
Acquisition-related transaction and integration costs	1	5	2	6
Development activity expenses	18	18	35	44
Total operating costs and expenses	2,402	2,050	4,795	4,425
Other income - affiliate	42	48	90	96
Gain/(loss) on sale of assets	2	(83)	4	(83)
Operating Income/(Loss)	343	163	382	495
Other Income/(Expense)
Equity in (losses)/earnings of unconsolidated affiliates	(3)	4	2	(3)
Gain/(impairment loss) on investment	0	7	0	(139)
Other income, net	10	5	18	22
Loss on debt extinguishment, net	0	(80)	(2)	(69)
Interest expense	(247)	(237)	(471)	(479)
Total other expense	(240)	(301)	(453)	(668)
Income/(Loss) from Continuing Operations Before Income Taxes	103	(138)	(71)	(173)
Income tax expense/(benefit)	4	25	(1)	47
Income/(Loss) from Continuing Operations	99	(163)	(70)	(220)
Loss from discontinued operations, net of income tax	(741)	(113)	(775)	(9)
Net Income/(Loss)	(642)	(276)	(845)	(229)
Less: Net loss attributable to noncontrolling interest and redeemable noncontrolling interests	(16)	(5)	(55)	(40)
Net Income/(Loss) Attributable to NRG Energy, Inc.	(626)	(271)	(790)	(189)
Dividends for preferred shares	0	0	0	5
Gain on redemption of preferred shares	0	(78)	0	(78)
Loss Available for Common Stockholders	$ (626)	$ (193)	$ (790)	$ (116)
Loss per Share Attributable to NRG Energy, Inc. Common Stockholders
Weighted average number of common shares outstanding — basic and diluted	316	315	316	315
Income/(loss) from continuing operations per weighted average common share — basic and diluted (in dollars per share)	$ 0.36	$ (0.25)	$ (0.05)	$ (0.34)
Loss from discontinued operations per weighted average common share — basic and diluted (in dollars per share)	(2.34)	(0.36)	(2.45)	(0.03)
Loss per Weighted Average Common Share — Basic and Diluted (in dollars per share)	(1.98)	(0.61)	(2.50)	(0.37)
Dividends Per Common Share (in dollars per share)	$ 0.03	$ 0.03	$ 0.06	$ 0.18

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income/(Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (642)	$ (276)	$ (845)	$ (229)
Other comprehensive income/(loss), net of tax
Unrealized loss on derivatives, net of income tax expense of $0, $1, $1, and $2	(5)	(3)	(1)	(35)
Foreign currency translation adjustments, net of income tax expense of $0, $0, $0, and $0	1	(3)	8	3
Available-for-sale securities, net of income tax expense of $0, $0, $0, and $0	1	(2)	1	1
Defined benefit plans, net of income tax expense of $0, $0, $0, and $0	27	0	27	1
Other comprehensive income/(loss)	24	(8)	35	(30)
Comprehensive Income/(Loss)	(618)	(284)	(810)	(259)
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest	(17)	(16)	(56)	(68)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	(601)	(268)	(754)	(191)
Dividends for preferred shares	0	0	0	5
Gain on redemption of preferred shares	0	(78)	0	(78)
Comprehensive Income/(Loss) Available for Common Stockholders	$ (601)	$ (190)	$ (754)	$ (118)

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Comprehensive Income/(Loss) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Unrealized loss on derivatives, income tax expense	$ 0	$ 1	$ 1	$ 2
Foreign currency translation adjustments, income tax expense	0	0	0	0
Available-for-sale securities, income tax expense	0	0	0	0
Defined benefit plans, income tax expense	$ 0	$ 0	$ 0	$ 0

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 752	$ 938
Funds deposited by counterparties	19	2
Restricted cash	469	446
Accounts receivable, net	1,162	1,058
Inventory	713	721
Derivative instruments	644	1,067
Cash collateral paid in support of energy risk management activities	277	150
Current assets - held for sale	33	9
Prepayments and other current assets	400	404
Current assets - discontinued operations	0	1,919
Total current assets	4,469	6,714
Property, plant and equipment, net	15,302	15,369
Other Assets
Equity investments in affiliates	1,127	1,120
Notes receivable, less current portion	9	16
Goodwill	662	662
Intangible assets, net	1,893	1,973
Nuclear decommissioning trust fund	637	610
Derivative instruments	226	181
Deferred income taxes	211	225
Non-current assets held-for-sale	10	10
Other non-current assets	659	841
Non-current assets - discontinued operations	0	2,961
Total other assets	5,434	8,599
Total Assets	25,205	30,682
Current Liabilities
Current portion of long-term debt and capital leases	1,042	516
Accounts payable	757	782
Accounts payable - affiliate	17	31
Derivative instruments	711	1,092
Cash collateral received in support of energy risk management activities	19	81
Accrued expenses and other current liabilities	810	990
Accrued expenses and other current liabilities - affiliate	164	0
Current liabilities - discontinued operations	0	1,210
Total current liabilities	3,520	4,702
Other Liabilities
Long-term debt and capital leases	15,842	15,957
Nuclear decommissioning reserve	262	287
Nuclear decommissioning trust liability	367	339
Deferred income taxes	20	20
Derivative instruments	293	284
Out-of-market contracts, net	219	230
Non-current liabilities held-for-sale	13	11
Other non-current liabilities	1,135	1,151
Non-current liabilities - discontinued operations	0	3,209
Total non-current liabilities	18,151	21,488
Total Liabilities	21,671	26,190
Redeemable noncontrolling interest in subsidiaries	51	46
Commitments and Contingencies
Stockholders’ Equity
Common stock	4	4
Additional paid-in capital	8,383	8,358
Retained deficit	(4,874)	(3,787)
Less treasury stock, at cost — 101,858,284 and 102,140,814 shares, respectively	(2,392)	(2,399)
Accumulated other comprehensive loss	(100)	(135)
Noncontrolling interest	2,462	2,405
Total Stockholders’ Equity	3,483	4,446
Total Liabilities and Stockholders’ Equity	$ 25,205	$ 30,682

Condensed Consolidated Balance6

Condensed Consolidated Balance Sheets (Parenthetical) - shares	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Treasury stock, shares (in shares)	101,858,284	102,140,814

Condensed Consolidated Stateme7

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows from Operating Activities
Net Income/(Loss)	$ (845)	$ (229)
Loss from discontinued operations, net of income tax	(775)	(9)
Loss from continuing operations	(70)	(220)
Adjustments to reconcile net loss to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates	26	32
Depreciation and amortization	517	528
Provision for bad debts	18	20
Amortization of nuclear fuel	24	26
Amortization of financing costs and debt discount/premiums	29	29
Adjustment for debt extinguishment	0	14
Amortization of intangibles and out-of-market contracts	51	82
Amortization of unearned equity compensation	16	16
Impairment losses	63	195
Changes in deferred income taxes and liability for uncertain tax benefits	8	1
Changes in nuclear decommissioning trust liability	2	13
Changes in derivative instruments	7	(7)
Changes in collateral posted in support of risk management activities	(189)	323
Proceeds from sale of emission allowances	11	17
Loss on sale of assets	(22)	83
Changes in other working capital	(379)	(272)
Cash provided by continuing operations	112	880
Cash (used) by discontinued operations	(38)	(69)
Net Cash Provided by Operating Activities	74	811
Cash Flows from Investing Activities
Acquisitions of businesses, net of cash acquired	(16)	(17)
Capital expenditures	(542)	(442)
Increase in notes receivable	8	(3)
Purchases of emission allowances	(30)	(27)
Proceeds from sale of emission allowances	59	25
Investments in nuclear decommissioning trust fund securities	(279)	(280)
Proceeds from the sale of nuclear decommissioning trust fund securities	277	267
Proceeds from renewable energy grants and state rebates	8	10
Proceeds from sale of assets, net of cash disposed of	35	25
Investments in unconsolidated affiliates	(30)	1
Other	18	31
Cash (used)/provided by continuing operations	(492)	(410)
Cash used by discontinued operations	(53)	(60)
Net Cash (Used)/Provided by Investing Activities	(545)	(470)
Cash Flows from Financing Activities
Payment of dividends to common and preferred stockholders	(19)	(57)
Payment for preferred shares	0	(226)
Net receipts from settlement of acquired derivatives that include financing elements	2	4
Proceeds from issuance of long-term debt	946	3,223
Payments for short and long-term debt	(530)	(3,505)
Receivable from affiliate	(125)	0
Distributions to, net of contributions from, noncontrolling interest in subsidiaries	14	(21)
Payment of debt issuance costs	(36)	(35)
Other - contingent consideration	(10)	(10)
Cash provided/(used) by continuing operations	242	(627)
Cash used by discontinued operations	(224)	97
Net Cash provided/(used) by Financing Activities	18	(530)
Effect of exchange rate changes on cash and cash equivalents	(8)	(3)
Change in Cash from discontinued operations	(315)	(32)
Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties	(146)	(160)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period	1,386	1,322
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 1,240	$ 1,162

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation NRG Energy, Inc., or NRG or the Company, is a leading integrated power company built on the strength of a diverse competitive electric generation portfolio and leading retail electricity platform. NRG is continuously focused on excellence in operating performance of its existing assets and optimal hedging of generation assets and retail load operations, as well as serving the energy needs of end-use residential, commercial and industrial customers in competitive markets through multiple brands and channels. The Company owns and operates approximately 31,000 MW of generation; engages in the trading of wholesale energy, capacity and related products; transacts in and trades fuel and transportation services; and directly sells energy, services, and innovative, sustainable products and services to retail customers under the names “NRG”, "Reliant" and other retail brand names owned by NRG. 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 2016 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, 2017 , and the results of operations, comprehensive income/(loss) and cash flows for the three and six months ended June 30, 2017 and 2016 . GenOn Chapter 11 Cases On June 14, 2017, or the Petition Date, GenOn, along with GenOn Americas Generation and certain of their directly and indirectly-owned subsidiaries, or collectively the GenOn Entities, filed voluntary petitions for relief under Chapter 11, or the Chapter 11 Cases, of the U.S. Bankruptcy Code, or the Bankruptcy Code, in the U.S. Bankruptcy Court for the Southern District of Texas, Houston Division, or the Bankruptcy Court. GenOn Mid-Atlantic, as well as its consolidated subsidiaries, REMA and certain other subsidiaries, did not file for relief under Chapter 11. As a result of the bankruptcy filings and beginning on June 14, 2017, GenOn and its subsidiaries were deconsolidated from NRG’s consolidated financial statements. NRG recorded its investment in GenOn under the cost method with an estimated fair value of zero . NRG has determined that this disposal of GenOn and its subsidiaries is a discontinued operation; and, accordingly, the financial information for all historical periods have been recast to reflect GenOn as a discontinued operation. In connection with the disposal, NRG has recorded a loss on deconsolidation of $208 million during the quarter ended June 30, 2017. See Note 3 , Discontinued Operations and Dispositions , for more information. Prior to the GenOn Entities' filing the Chapter 11 Cases, NRG entered into a restructuring support and lock-up agreement, or the Restructuring Support Agreement, with the GenOn Entities and certain holders of the GenOn and GenOn Americas Generation Senior Notes, that provides for a restructuring and recapitalization of the GenOn Entities through a prearranged plan of reorganization. There is no assurance that the GenOn Entities' plan will be approved by the requisite stakeholders, confirmed by the Bankruptcy Court, or successfully implemented thereafter. The principal terms of the Restructuring Support Agreement are described further in Note 3 , Discontinued Operations and Dispositions . Transformation Plan On July 12, 2017, NRG announced its Transformation Plan designed to significantly strengthen earnings and cost competitiveness, lower risk and volatility, and create significant shareholder value. The three-part, three -year plan is comprised of the following targets: Operations and cost excellence — Cost savings and margin enhancement of $1,065 million recurring, which consists of $590 million of annual cost savings, a $215 million net margin enhancement program, $50 million annual reduction in maintenance capital expenditures, and $210 million in permanent selling, general and administrative expense reduction associated with asset sales. Portfolio optimization — Targeting $2.5 - $4.0 billion of asset sale net cash proceeds, including divestitures of 6 GWs of conventional generation and businesses (excluding GenOn) and the monetization of 50 - 100% of its interest in NRG Yield, Inc. and its renewables platform. Capital structure and allocation enhancements — A prioritized capital allocation strategy that targets a reduction in consolidated debt from approximately $19.5 billion ( $18 billion net debt) to approximately $6.5 billion ( $6 billion net debt). Following the completion of the contemplated asset sales, the Company expects $4.8 - $6.3 billion in excess cash to be available for allocation through 2020, after achieving its targeted 3.0 x net debt / Adjusted EBITDA corporate credit ratio. The Company expects to fully implement the Transformation Plan by the end of 2020 with significant completion by the end of 2018. The Company expects to realize (i) $370 million of non-recurring working capital improvements through 2020 and (ii) approximately $290 million , one-time costs to achieve. 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. The reclassifications did not affect results from operations, net assets or cash flows.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies 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, 2017 December 31, 2016 (In millions) Accounts receivable allowance for doubtful accounts $ 39 $ 29 Property, plant and equipment accumulated depreciation 6,180 5,711 Intangible assets accumulated amortization 1,698 1,687 Out-of-market contracts accumulated amortization 346 457 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 sheet that sum to the total of the same such amounts shown in the statement of cash flows. June 30, 2017 December 31, 2016 June 30, 2016 December 31, 2015 (In millions) Cash and cash equivalents $ 752 $ 938 $ 748 $ 853 Funds deposited by counterparties 19 2 1 55 Restricted cash 469 446 413 414 Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statement of cash flows $ 1,240 $ 1,386 $ 1,162 $ 1,322 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. As of December 31, 2016, $79 million of the cash collateral received was from GenOn, previously a consolidated subsidiary, and is included in cash collateral received in current liabilities as a result of deconsolidating GenOn, with the offset included in cash and cash equivalents. 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. Noncontrolling Interest The following table reflects the changes in NRG's noncontrolling interest balance: (In millions) Balance as of December 31, 2016 $ 2,405 Dividends paid to NRG Yield, Inc. public shareholders (52 ) Distributions to noncontrolling interest (39 ) Comprehensive loss attributable to noncontrolling interest (19 ) Non-cash adjustments to noncontrolling interest 88 Contributions from noncontrolling interest 76 Sale of assets to NRG Yield, Inc. 3 Balance as of June 30, 2017 $ 2,462 Redeemable Noncontrolling Interest The following table reflects the changes in the Company's redeemable noncontrolling interest balance: (In millions) Balance as of December 31, 2016 $ 46 Contributions from redeemable noncontrolling interest 42 Comprehensive loss attributable to redeemable noncontrolling interest (37 ) Balance as of June 30, 2017 $ 51 Recent Accounting Developments - Guidance Adopted in 2017 ASU 2016-18 — In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230) , Restricted Cash, or ASU No. 2016-18. The amendments of ASU No. 2016-18 require an entity to include amounts generally described as restricted cash and restricted cash equivalents, including funds deposited by counterparties with cash and cash equivalents when reconciling the beginning of period and end of period total amounts on the statement of cash flows. The amendments of ASU No. 2016-18 are effective for annual reporting periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted and the adoption of ASU No. 2016-18 will be applied retrospectively. The Company adopted the guidance in ASU No. 2016-18 during the second quarter of 2017. In connection with the adoption of the standard, the Company has applied the guidance retrospectively which resulted in a decrease in cash flow from operations of $54 million and a decrease of in cash flow from investing of $1 million on the statement of cash flow for the six months ended June 30, 2016. ASU 2016-16 — In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740) , Intra-Entity Transfers of Assets Other Than Inventory, or ASU No. 2016-16. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party which has resulted in diversity in practice and increased complexity within financial reporting. The amendments of ASU No. 2016-16 would require an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The Company adopted the guidance in ASU No. 2016-16 effective January 1, 2017. In connection with the adoption of the standard, the Company recorded a reduction to non-current assets of $267 million with a corresponding reduction to cumulative retained deficit. ASU 2016-15 — In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230) , Classification of Certain Cash Receipts and Cash Payments, or ASU No. 2016-15. The amendments of ASU No. 2016-15 were issued to address eight specific cash flow issues for which stakeholders have indicated to the FASB that a diversity in practice existed in how entities were presenting and classifying these items in the statement of cash flows. The issues addressed by ASU No. 2016-15 include but are not limited to the classification of debt prepayment and debt extinguishment costs, payments made for contingent consideration for a business combination, proceeds from the settlement of insurance proceeds, distributions received from equity method investees and separately identifiable cash flows and the application of the predominance principle. The Company adopted the guidance in ASU No. 2016-15 effective January 1, 2017. In connection with the adoption of the standard, the Company has applied the guidance retrospectively which resulted in an increase in cash flow from operations of $55 million and a decrease in cash flow from financing of $55 million on the statement of cash flow for the six months ended June 30, 2016. ASU 2016-09 — In March 2016, the FASB issued ASU No. 2016-09, Compensation - Stock Compensation (Topic 718), or ASU No. 2016-09. The amendments focused on simplification specifically with regard to share-based payment transactions, including income tax consequences, classification of awards as equity or liabilities and classification on the statement of cash flows. The Company adopted the guidance in ASU No. 2016-09 effective January 1, 2017 with no material adjustments recorded to the consolidated balance sheet. Recent Accounting Developments - Guidance Not Yet Adopted ASU 2017-07 — In March 2017, the FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715) , Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, or ASU No. 2017-07. Current GAAP does not indicate where the amount of net benefit cost should be presented in an entity’s income statement and does not require entities to disclose the amount of net benefit cost that is included in the income statement. The amendments of ASU No. 2017-07 require an entity to report the service cost component of net benefit costs in the same line item as other compensation costs arising from services rendered by the related employees during the applicable service period. The other components of net benefit cost are required to be presented separately from the service cost component and outside the subtotal of income from operations. Further, ASU No. 2017-07 prescribes that only the service cost component of net benefit costs is eligible for capitalization. The amendments of ASU No. 2017-07 are effective for fiscal years beginning after December 15, 2017, including interim periods therein. Early adoption is permitted and must be applied on a retrospective basis, except for the amendments regarding the capitalization of the service cost component, which must be applied prospectively. The Company is currently assessing the impact that the adoption of ASU No. 2017-07 will have on its results of operations, cash flows, and statement of financial position. ASU 2016-02 — In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) , or Topic 842, 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 expects to adopt the standard effective January 1, 2019 utilizing the required modified retrospective approach for the earliest period presented. The Company expects to elect certain of the practical expedients permitted, including the expedient that permits the Company to retain its existing lease assessment and classification. The Company is currently working through an adoption plan which includes the evaluation of lease contracts compared to the new standard. While the Company is currently evaluating the impact the new guidance will have on its financial position and results of operations, the Company expects to recognize lease liabilities and right of use assets. The extent of the increase to assets and liabilities associated with these amounts remains to be determined pending the Company’s review of its existing lease contracts and service contracts which may contain embedded leases. While this review is still in process, NRG believes the adoption of Topic 842 will have a material impact on its financial statements. ASU 2014-09 — In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , or Topic 606, which was further amended through various updates issued by the FASB thereafter. The amendments of Topic 606 completed the joint effort between the FASB and the IASB, to develop a common revenue standard for GAAP and IFRS, and to improve financial reporting. The guidance under Topic 606 provides that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for the goods or services provided and establishes a five step model to be applied by an entity in evaluating its contracts with customers. The Company expects to adopt the standard effective January 1, 2018 and apply the guidance retrospectively to contracts at the date of adoption. The Company will recognize the cumulative effect of applying Topic 606 at the date of initial application, as prescribed under the modified retrospective transition method. The Company also expects to elect the practical expedient available under Topic 606 for measuring progress toward complete satisfaction of a performance obligation and for disclosure requirements of remaining performance obligations. The practical expedient allows an entity to recognize revenue in the amount to which the entity has the right to invoice such that the entity has a right to the consideration in an amount that corresponds directly with the value to the customer for performance completed to date by the entity. The Company continues to assess the new standard with a focus on identifying the performance obligations included within its revenue arrangements with customers and evaluating the Company’s methods of estimating the amount and timing of variable consideration. While the impact remains subject to continued review, the Company does not believe the adoption of Topic 606 will have a material impact on its financial statements.

Discontinued Operations and Dis

Discontinued Operations and Dispositions	6 Months Ended
	Jun. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations and Dispositions	Discontinued Operations and Dispositions Discontinued Operations As described in Note 1 , Basis of Presentation , on the Petition Date, 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 has concluded that it no longer controls GenOn as it is subject to the control of the Bankruptcy Court; and, accordingly, NRG no longer consolidates GenOn for financial reporting purposes. By eliminating a large portion of its operations in the PJM market with the deconsolidation of GenOn, NRG has concluded that GenOn meets the criteria for discontinued operations, as this represents a strategic shift in the markets in which NRG operates. As such, all prior period results for GenOn have been reclassified as discontinued operations while NRG will record all ongoing results of GenOn as a cost method investment, which was valued at zero at the date of deconsolidation. Summarized results of discontinued operations were as follows: Period from April 1, 2017 through June 14, 2017 Three months ended June 30, 2016 Period from January 1, 2017 through June 14, 2017 Six months ended June 30, 2016 (In millions) Operating revenues $ 265 $ 398 $ 646 $ 977 Operating costs and expenses (327 ) (474 ) (700 ) (941 ) Gain on sale of assets — — — 32 Other expenses (54 ) (40 ) (98 ) (84 ) Loss from operations of discontinued components, before tax (116 ) (116 ) (152 ) (16 ) Income tax expense/(benefit) 8 — 9 (1 ) Loss from operations of discontinued components (124 ) (116 ) (161 ) (15 ) Interest income - affiliate 3 3 6 6 Loss from operations of discontinued components, net of tax (121 ) (113 ) (155 ) (9 ) Pre-tax loss on deconsolidation (208 ) — (208 ) — Settlement consideration and services credit (289 ) — (289 ) — Pension liability assumption (119 ) — (119 ) — Advisory and consulting fees (4 ) — (4 ) — Loss on disposal of discontinued components, net of tax (620 ) — (620 ) — Loss from discontinued operations, net of tax $ (741 ) $ (113 ) $ (775 ) $ (9 ) The following table summarizes the major classes of assets and liabilities classified as discontinued operations as of December 31, 2016. As noted above, NRG no longer consolidates GenOn for financial reporting purposes as of June 30, 2017. (In millions) December 31, 2016 Cash and cash equivalents $ 1,034 Other current assets 885 Current assets - discontinued operations 1,919 Property, plant and equipment, net 2,543 Other non-current assets 418 Non-current assets - discontinued operations 2,961 Current portion of long term debt and capital leases 704 Other current liabilities 506 Current liabilities - discontinued operations 1,210 Long-term debt and capital leases 2,050 Out-of-market contracts 811 Other non-current liabilities 348 Non-current liabilities - discontinued operations $ 3,209 Restructuring Support Agreement Prior to the GenOn Entities filing for relief under the Bankruptcy Code, as described in Note 1 , Basis of Presentation , NRG, GenOn and certain holders representing greater than 93% in aggregate principal amount of GenOn’s Senior Notes and certain holders representing greater than 93% in aggregate principal amount of GenOn Americas Generation’s Senior Notes entered into a Restructuring Support Agreement, on June 12, 2017, that provides for a restructuring and recapitalization of the GenOn Entities through a prearranged plan of reorganization. Completion of the agreed upon terms is contingent upon certain milestones in the Restructuring Support Agreement. Certain principal terms of the Restructuring Support Agreement are detailed below: 1) Full releases from GenOn and GenOn Americas Generation in favor of NRG, including either a full release or indemnification in favor of NRG for any claims relating to GenOn Mid-Atlantic or REMA and the dismissal of all litigation against NRG. 2) NRG will provide settlement cash consideration to GenOn of $261.3 million , which will be paid in cash less any amounts owed to NRG under the intercompany secured revolving credit facility. As of June 30, 2017, GenOn owed NRG approximately $125 million under the intercompany secured revolving credit facility. See Note 14, Related Party Transactions , for further discussion of the intercompany secured revolving credit facility. 3) NRG will consent to the cancellation of its interests in the equity of GenOn. The equity interests in the reorganized GenOn will be issued to the holders of the GenOn Senior Notes. 4) NRG will retain the pension liability, including payment of approximately $13 million of 2017 pension contributions, for GenOn employees for service provided prior to the completion of the reorganization. GenOn’s pension liability as of June 30, 2017 was approximately $119 million . 5) The shared services agreement between NRG and GenOn will be amended such that (i) NRG will provide shared services to GenOn at an annualized rate of $84 million during the pendency of the Chapter 11 Cases, (ii) if the settlement is approved by the bankruptcy court, NRG will provide shared services to GenOn at no charge for two months , and (iii) NRG will then provide an option for up to two , one -month extensions for shared services at an annualized rate of $84 million . See Note 14, Related Party Transactions , for further discussion of the shared services agreement. 6) NRG will provide a credit of $28 million to GenOn to apply against amounts owed under the shared services agreement upon emergence from bankruptcy. Any unused amount can be paid in cash at GenOn’s request. The credit was intended to reimburse GenOn for its payment of financing costs. 7) NRG agreed to provide GenOn with a letter of credit facility during the pendency of the Chapter 11 Cases, which could be utilized for required letters of credit in lieu of the intercompany secured revolving credit facility. GenOn can no longer utilize the intercompany secured revolving credit facility and, on July 27, 2017, the letter of credit facility was terminated, as GenOn had obtained a separate letter of credit facility with a third party financial institution. See Note 14, Related Party Transactions , for further discussion of the intercompany secured revolver credit facility and the letter of credit facility obtained in July 2017. 8) NRG and GenOn have agreed to cooperate to maximize the value of certain development projects. In addition to the Restructuring Support Agreement, additional support and other agreements are being negotiated, including a transition services agreement. Settlement Consideration NRG has determined that the payment of the settlement consideration is probable and has recorded a liability for the amount due of $261.3 million in accrued expenses and other current liabilities - affiliate with a corresponding loss from discontinued operations. NRG expects to pay this amount net of amounts due from GenOn under the intercompany secured revolving credit facility, which is further described in Note 14 , Related Party Transactions . Pension Liability NRG will retain the pension liability, including payment of approximately $13 million of 2017 pension contributions, for the GenOn employees for service provided prior to emergence from bankruptcy. NRG determined that the retention of this liability is probable and has recorded the estimated accumulated pension benefit obligation as of June 30, 2017 of $119 million in other non-current liabilities with a corresponding loss from discontinued operations. NRG's obligation for this liability will be revalued through and at GenOn's emergence from bankruptcy. Services Agreement NRG will continue to provide shared services to GenOn under the Services Agreement at an annualized rate of $84 million during the pendency of the Chapter 11 Cases as well as for two months post-emergence at no charge. NRG then will provide an option for up to two , one -month extensions for shared services at an annualized rate of $84 million . Beginning on June 14, 2017, NRG records operating income for the amounts earned for shared services of approximately $5 million per month. NRG has also agreed to provide GenOn with a credit of $28 million against amounts owed under the Services Agreement. Any unused amount can be paid in cash at GenOn’s request. As a result, NRG has concluded that the liability for this credit is probable and has recorded a payable to GenOn for $28 million in accrued expenses and other current liabilities - affiliate with a corresponding loss from discontinued operations. Commercial Operations For pre-disposal periods, NRG provided GenOn with services as described in Note 14, Related Party Transactions . Under intercompany agreements, NRG Power Marketing LLC has entered into physical and financial intercompany commodity and hedging transactions with GenOn and certain of its subsidiaries. Subject to applicable collateral thresholds, these arrangements may provide for the bilateral exchange of credit support based upon market exposure and potential market movements. The terms and conditions of the agreements are generally consistent with industry practices and other third party arrangements. For current and pre-disposal periods, revenue and expense associated with these transactions is recorded in continuing operations. GenOn Debt As of June 30, 2017, the GenOn Senior Notes and GenOn Americas Generation Senior Notes, which totaled approximately $2.5 billion , were deconsolidated from NRG's consolidated financial statements. The filing of the Chapter 11 Cases constitutes an event of default under the following debt instruments of GenOn: 1) The intercompany secured revolving credit facility with NRG; 2) The indenture governing the GenOn 7.875% Senior Notes due 2017 (as amended or supplemented from time to time); 3) The indenture governing the GenOn 9.500% Notes due 2018 (as amended or supplemented from time to time); 4) The indenture governing the GenOn 9.875% Notes due 2020 (as amended or supplemented from time to time); 5) The indenture governing the GenOn Americas Generation 8.50% Senior Notes due 2021 (as amended or supplemented from time to time); and 6) The indenture governing the GenOn Americas Generation 9.125% Senior Notes due 2031 (as amended or supplemented from time to time). Transfer of Assets Under Common Control On August 1, 2017, NRG closed on the sale of its remaining 25% interest in NRG Wind TE Holdco, a portfolio of 12 wind projects, to NRG Yield, Inc. for total cash consideration of $41.5 million , excluding working capital adjustments. The transaction also includes potential additional payments to NRG dependent upon actual energy prices for merchant periods beginning in 2027. On March 27, 2017, the Company sold to NRG Yield, Inc.: (i) a 16% interest in the Agua Caliente solar project, representing ownership of approximately 46 net MW of capacity and (ii) NRG's interests in seven utility-scale solar projects located in Utah representing 265 net MW of capacity, which have reached commercial operations. NRG Yield, Inc. paid cash consideration of $130 million , plus $1 million in working capital adjustments, and assumed non-recourse debt of approximately $328 million . Dispositions Disposition of Majority Interest in EVgo On June 17, 2016, the Company completed the sale of a majority interest in its EVgo business to Vision Ridge Partners for total consideration of approximately $39 million , including $17 million in cash received, which is net of $2.5 million in working capital adjustments, $15 million contributed as capital to the EVgo business and $7 million of future contributions by Vision Ridge Partners, all of which were determined based on forecasted cash requirements to operate the business in future periods. In addition, the Company has future earnout potential of up to $70 million based on future profitability targets. NRG will retain its original financial obligation of $102.5 million under its agreement with the CPUC whereby EVgo will build at least 200 public fast charging Freedom Station sites and perform the associated work to prepare 10,000 commercial and multi-family parking spaces for electric vehicle charging in California. As part of the sale, NRG has contracted with EVgo to continue to build the remaining required Freedom Stations and commercial and multi-family parking spaces for electric vehicle charging required under this obligation and will be directly reimbursed by NRG for the costs. As a result of the sale, the Company recorded a loss on sale of $83 million during the second quarter of 2016, which reflects the loss on the sale of the equity interest of $27 million and the accrual of NRG's remaining obligation under its agreement with the CPUC of $56 million . On February 22, 2017, the Company and CPUC entered into a second amendment to the agreement which extended the operating period commitment for the Freedom Stations to December 5, 2020. At June 30, 2017, the Company's remaining 35% interest in EVgo of $3 million was accounted for as an equity-method investment. Rockford Disposition On May 12, 2016, the Company entered into an agreement with RA Generation, LLC to sell 100% of its interests in the Rockford I and Rockford II generating stations, or Rockford, for cash consideration of $55 million , subject to adjustments for working capital and the results of the PJM 2019/2020 base residual auction. Rockford is a 450 MW natural gas facility located in Rockford, Illinois. The transaction triggered an indicator of impairment as the sales price was less than the carrying amount of the assets, and, as a result the assets were considered to be impaired. The Company measured the impairment loss as the difference between the carrying amount of the assets and the agreed-upon sales price. The Company recorded an impairment loss of $17 million during the quarter ended June 30, 2016 to reduce the carrying amount of the assets held for sale to the fair market value. At June 30, 2016, the Company had $2 million of current assets and $54 million of non-current assets classified as held for sale for Rockford on its balance sheet. On July 12, 2016, the Company completed the sale of Rockford for cash proceeds of $56 million , including $1 million in adjustments for the PJM base residual auction results. For further discussion on this impairment, refer to Note 7, Impairments, to this Form 10-Q.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments This footnote should be read in conjunction with the complete description under Note 4 , Fair Value of Financial Instruments , to the Company's 2016 Form 10-K. 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 amount approximates fair value because of the short-term maturity of those instruments and are classified as Level 1 within the fair value hierarchy. The estimated carrying amounts and fair values of NRG's recorded financial instruments not carried at fair market value are as follows: As of June 30, 2017 As of December 31, 2016 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable (a) $ 25 $ 24 $ 34 $ 34 Liabilities: Long-term debt, including current portion (b) 17,086 17,246 16,655 16,620 (a) Includes the current portion of notes receivable which is recorded in prepayments and other current assets on the Company's consolidated balance sheets. (b) 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, 2017 and December 31, 2016 : As of June 30, 2017 As of December 31, 2016 Level 2 Level 3 Level 2 Level 3 (In millions) Long-term debt, including current portion $ 9,398 $ 7,848 $ 9,205 $ 7,415 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, 2017 Fair Value (In millions) Level 1 Level 2 Level 3 Total Investment in available-for-sale securities (classified within other non-current assets): Debt securities $ — $ — $ 18 $ 18 Available-for-sale securities 4 — — 4 Nuclear trust fund investments: Cash and cash equivalents 11 — — 11 U.S. government and federal agency obligations 45 — — 45 Federal agency mortgage-backed securities — 71 — 71 Commercial mortgage-backed securities — 17 — 17 Corporate debt securities — 109 — 109 Equity securities 319 — 61 380 Foreign government fixed income securities — 4 — 4 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 186 535 110 831 Interest rate contracts — 39 — 39 Total assets $ 566 $ 775 $ 189 $ 1,530 Derivative liabilities: Commodity contracts 292 496 121 909 Interest rate contracts — 95 — 95 Total liabilities $ 292 $ 591 $ 121 $ 1,004 . As of December 31, 2016 Fair Value (In millions) Level 1 Level 2 Level 3 Total Investment in available-for-sale securities (classified within other non-current assets): Debt securities $ — $ — $ 17 $ 17 Available-for-sale securities 10 — — 10 Nuclear trust fund investments: Cash and cash equivalents 25 — — 25 U.S. government and federal agency obligations 72 1 — 73 Federal agency mortgage-backed securities — 62 — 62 Commercial mortgage-backed securities — 17 — 17 Corporate debt securities — 84 — 84 Equity securities 292 — 54 346 Foreign government fixed income securities — 3 — 3 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 560 549 90 1,199 Interest rate contracts — 49 — 49 Total assets $ 960 $ 765 $ 161 $ 1,886 Derivative liabilities: Commodity contracts 494 636 158 1,288 Interest rate contracts — 88 — 88 Total liabilities $ 494 $ 724 $ 158 $ 1,376 There were no transfers during the three and six months ended June 30, 2017 and 2016 between Levels 1 and 2. The following tables reconcile, for the three and six months ended June 30, 2017 and 2016 , 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, 2017 Six months ended June 30, 2017 (In millions) Debt Securities Trust Fund Investments Derivatives (a) Total Debt Securities Trust Fund Investments Derivatives (a) Total Beginning balance $ 18 $ 58 $ (56 ) $ 20 $ 17 $ 54 $ (68 ) $ 3 Total gains — realized/unrealized: Included in earnings — — 40 40 1 — 46 47 Included in nuclear decommissioning obligation — 3 — 3 — 7 — 7 Purchases — — 5 5 — — 9 9 Transfers into Level 3 (b) — — 3 3 — — (5 ) (5 ) Transfers out of Level 3 (b) — — (3 ) (3 ) — — 7 7 Ending balance as of June 30, 2017 $ 18 $ 61 $ (11 ) $ 68 $ 18 $ 61 $ (11 ) $ 68 Gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of June 30, 2017 $ — $ — $ 22 $ 22 $ — $ — $ 7 $ 7 (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, 2016 Six months ended June 30, 2016 (In millions) Debt Securities Trust Fund Investments Derivatives (a) Total Debt Securities Trust Fund Investments Derivatives (a) Total Beginning balance $ 17 $ 52 $ (2 ) $ 67 $ 17 $ 54 $ (22 ) $ 49 Total gains/(losses) — realized/unrealized: Included in earnings — — 23 23 — — 9 9 Included in OCI (1 ) — — (1 ) (1 ) — — (1 ) Included in nuclear decommissioning obligations — (1 ) — (1 ) — (4 ) — (4 ) Purchases — — 22 22 — 1 27 28 Transfers into Level 3 (b) — — (20 ) (20 ) — — 7 7 Transfers out of Level 3 (b) — — (5 ) (5 ) — — (3 ) (3 ) Ending balance as of June 30, 2016 $ 16 $ 51 $ 18 $ 85 $ 16 $ 51 $ 18 $ 85 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, 2016 $ — $ — $ 11 $ 11 $ — $ — $ (7 ) $ (7 ) (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 for the whole term or for certain delivery months or the contracts are retail and load following power contracts. These contracts are valued using various valuation techniques including but not limited to internal models that apply fundamental analysis of the market and corroboration with similar markets. As of June 30, 2017 , contracts valued with prices provided by models and other valuation techniques make up 13% of the total derivative assets and 12% of the total derivative liabilities. NRG's significant positions classified as Level 3 include physical and financial power and physical coal executed in illiquid markets as well as financial transmission rights, or FTRs. The significant unobservable inputs used in developing fair value include illiquid power and coal 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, 2017 and December 31, 2016 : Significant Unobservable Inputs June 30, 2017 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 57 $ 78 Discounted Cash Flow Forward Market Price (per MWh) $ 10 $ 115 $ 30 FTRs 53 43 Discounted Cash Flow Auction Prices (per MWh) (29 ) 27 — $ 110 $ 121 Significant Unobservable Inputs December 31, 2016 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 39 $ 108 Discounted Cash Flow Forward Market Price (per MWh) $ 11 $ 104 $ 31 FTRs 51 50 Discounted Cash Flow Auction Prices (per MWh) (22 ) 17 — $ 90 $ 158 The following table provides sensitivity of fair value measurements to increases/(decreases) in significant unobservable inputs as of June 30, 2017 and December 31, 2016 : 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, 2017 , there is no credit reserve. As of December 31, 2016 , the credit reserve resulted in a $10 million decrease 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 2016 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 2016 Form 10-K. As of June 30, 2017 , the Company's counterparty credit exposure, excluding credit risk exposure under certain long term agreements, was $145 million with net exposure of $17 million . NRG held collateral (cash and letters of credit) against those positions of $137 million . Approximately 75% of the Company's exposure before collateral is expected to roll off by the end of 2018 . 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 89 % Financial institutions 11 Total as of June 30, 2017 100 % Net Exposure (a) (b) Category by Counterparty Credit Quality (% of Total) Investment grade 78 % Non-Investment grade/Non-Rated 22 Total as of June 30, 2017 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. NRG has counterparty credit risk exposure to certain counterparties, each of which represent more than 10% of total net exposure discussed above. The aggregate of such counterparties' exposure was $43 million as of June 30, 2017 . Changes in hedge positions and market prices will affect credit exposure and counterparty concentration. Given the credit quality, diversification and term of the exposure in the portfolio, NRG does not anticipate a material impact on the Company's financial position or results of operations from nonperformance by any of NRG's counterparties. RTOs and ISOs The Company participates in the organized markets of CAISO, ERCOT, ISO-NE, MISO, NYISO and PJM, known as RTOs or ISOs. Trading in these markets is approved by FERC, or in the case of ERCOT, approved by the PUCT and includes credit policies that, under certain circumstances, require that losses arising from the default of one member on spot market transactions be shared by the remaining participants. As a result, the counterparty credit risk to these markets is limited to NRG’s share of overall market and are excluded from the above exposures. Exchange Traded Transactions The Company enters into commodity transactions on registered exchanges, notably ICE and NYMEX. These clearinghouses act as the counterparty and transactions are subject to extensive collateral and margining requirements. As a result, these commodity transactions have limited counterparty credit risk. Long Term Contracts Counterparty credit exposure described above excludes credit risk exposure under certain long term agreements, including California tolling agreements, Gulf Coast load obligations, and wind and solar PPAs. As external sources or observable market quotes are not available to estimate such exposure, the Company estimates its credit exposure for 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, 2017 , aggregate credit risk exposure managed by NRG to these counterparties was approximately $4.3 billion , including $2.8 billion related to assets of NRG Yield, Inc., for the next five years. This amount excludes potential credit exposures for projects with long-term PPAs that have not reached commercial operations. The majority of these power contracts are with utilities or public power entities with strong credit quality and public utility commission or other regulatory support. However, such regulated utility counterparties can be impacted by changes in government regulations or treatment by regulatory agencies which NRG is unable to predict. Retail Customer Credit Risk NRG is exposed to retail credit risk through the Company's retail electricity providers, which serve commercial, industrial and governmental/institutional customers and the Mass market. Retail credit risk results when a customer fails to pay for products or services rendered. The losses may result from both nonpayment of customer accounts receivable and the loss of in-the-money forward value. NRG 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, 2017 , the Company believes its retail customer credit exposure 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, 2017
Nuclear Decommissioning Trust Fund Disclosure [Abstract]
Nuclear Decommissioning Trust Fund	Nuclear Decommissioning Trust Fund This footnote should be read in conjunction with the complete description under Note 6 , Nuclear Decommissioning Trust Fund , to the Company's 2016 Form 10-K. NRG's Nuclear Decommissioning Trust Fund assets 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 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 (including other-than-temporary impairments) for the securities held in the trust funds, as well as information about the contractual maturities of those securities. As of June 30, 2017 As of December 31, 2016 (In millions, except otherwise noted) Fair Value Unrealized Gains Unrealized Losses Weighted-average Maturities (In years) Fair Value Unrealized Gains Unrealized Losses Weighted-average Maturities (In years) Cash and cash equivalents $ 11 $ — $ — — $ 25 $ — $ — — U.S. government and federal agency obligations 45 2 — 11 73 1 — 11 Federal agency mortgage-backed securities 71 1 1 24 62 1 1 25 Commercial mortgage-backed securities 17 — — 24 17 — 1 26 Corporate debt securities 109 2 1 10 84 1 2 11 Equity securities 380 245 — — 346 214 — — Foreign government fixed income securities 4 — — 7 3 — — 9 Total $ 637 $ 250 $ 2 $ 610 $ 217 $ 4 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, 2017 2016 (In millions) Realized gains $ 3 $ 3 Realized losses 3 2 Proceeds from sale of securities 277 267

Accounting for Derivative Instr

Accounting for Derivative Instruments and Hedging Activities	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Accounting for Derivative Instruments and Hedging Activities	Accounting for Derivative Instruments and Hedging Activities This footnote should be read in conjunction with the complete description under Note 5 , Accounting for Derivative Instruments and Hedging Activities , to the Company's 2016 Form 10-K. Energy-Related Commodities As of June 30, 2017 , NRG had energy-related derivative instruments extending through 2031 . The Company marks these derivatives to market through the statement of operations. Interest Rate Swaps NRG is 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 enters into interest rate swap agreements. As of June 30, 2017 , the Company had interest rate derivative instruments on recourse debt extending through 2021, which are not designated as cash flow hedges. The Company had interest rate swaps on non-recourse debt extending through 2041 , most of which are designated as cash flow hedges. 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, 2017 and December 31, 2016 . 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, 2017 December 31, 2016 Category Units (In millions) Emissions Short Ton (2 ) — Coal Short Ton 22 35 Natural Gas MMBtu 45 (53 ) Oil Barrel — 1 Power MWh 24 7 Capacity MW/Day (1 ) (1 ) Interest Dollars $ 3,701 $ 3,429 Equity Shares 1 1 The increase in the natural gas position was primarily the result of additional generation and retail hedge positions. The increase in the power position was primarily the result of additional retail hedge positions. 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, 2017 December 31, 2016 June 30, 2017 December 31, 2016 (In millions) Derivatives designated as cash flow hedges: Interest rate contracts current $ — $ — $ 9 $ 28 Interest rate contracts long-term 9 12 19 41 Total derivatives designated as cash flow hedges 9 12 28 69 Derivatives not designated as cash flow hedges : Interest rate contracts current 4 — 21 7 Interest rate contracts long-term 26 37 46 12 Commodity contracts current 640 1,067 681 1,057 Commodity contracts long-term 191 132 228 231 Total derivatives not designated as cash flow hedges 861 1,236 976 1,307 Total derivatives $ 870 $ 1,248 $ 1,004 $ 1,376 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 Statement of Financial Position Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount As of June 30, 2017 (In millions) Commodity contracts: Derivative assets $ 831 $ (730 ) $ (2 ) $ 99 Derivative liabilities (909 ) 730 121 (58 ) Total commodity contracts (78 ) — 119 41 Interest rate contracts: Derivative assets 39 (2 ) — 37 Derivative liabilities (95 ) 2 — (93 ) Total interest rate contracts (56 ) — — (56 ) Total derivative instruments $ (134 ) $ — $ 119 $ (15 ) Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount As of December 31, 2016 (In millions) Commodity contracts: Derivative assets $ 1,199 $ (1,021 ) $ (13 ) $ 165 Derivative liabilities (1,288 ) 1,021 13 (254 ) Total commodity contracts (89 ) — — (89 ) Interest rate contracts: Derivative assets 49 (4 ) — 45 Derivative liabilities (88 ) 4 — (84 ) Total interest rate contracts (39 ) — — (39 ) Total derivative instruments $ (128 ) $ — $ — $ (128 ) Accumulated Other Comprehensive Loss The following table summarizes the effects of ASC 815 on the Company's accumulated OCI balance attributable to cash flow hedge derivatives, net of tax: Interest Rate Contracts Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions) Accumulated OCI beginning balance $ (61 ) $ (150 ) $ (66 ) $ (101 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts 3 7 6 10 Mark-to-market of cash flow hedge accounting contracts (9 ) (22 ) (7 ) (74 ) Accumulated OCI ending balance, net of $16, and $26 tax $ (67 ) $ (165 ) $ (67 ) $ (165 ) Losses expected to be realized from OCI during the next 12 months, net of $3 tax $ 15 $ 15 Amounts reclassified from accumulated OCI into income and amounts recognized in income from the ineffective portion of cash flow hedges are recorded to interest expense for interest rate contracts. There was no ineffectiveness for the three and six months ended June 30, 2017 and 2016 . Accounting guidelines require a high degree of correlation between the derivative and the hedged item throughout the period in order to qualify as a cash flow hedge. As of December 31, 2016, the Company's regression analysis for Viento Funding II interest rate swaps, while positively correlated, did not meet the required threshold for cash flow hedge accounting. As a result, the Company de-designated the Viento Funding II cash flow hedges as of December 31, 2016, and will prospectively mark these derivatives to market through the income statement. The Company's regression analysis for Marsh Landing, Walnut Creek, and Avra Valley interest rate swaps, while positively correlated, no longer contain match terms for cash flow hedge accounting. As a result, the Company voluntarily de-designated the Marsh Landing, Walnut Creek, and Avra Valley cash flow hedges as of April 28, 2017, and will prospectively mark these derivatives to market through the income statement. 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 and ineffectiveness of hedge derivatives are reflected in current period consolidated results of operations. The following table summarizes the 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 effect of energy commodity contracts is included within operating revenues and cost of operations and the effect of interest rate contracts is included in interest expense. Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Unrealized mark-to-market results (In millions) Reversal of previously recognized unrealized losses/(gains) on settled positions related to economic hedges $ 22 $ (18 ) $ 25 $ (45 ) Reversal of acquired loss/(gain) positions related to economic hedges 1 (2 ) 1 (4 ) Net unrealized gains/(losses) on open positions related to economic hedges 36 (13 ) 15 77 Total unrealized mark-to-market gains/(losses) for economic hedging activities 59 (33 ) 41 28 Reversal of previously recognized unrealized (gains)/losses on settled positions related to trading activity (4 ) 2 (19 ) 10 Net unrealized gains on open positions related to trading activity 16 11 17 22 Total unrealized mark-to-market gains/(losses) for trading activity 12 13 (2 ) 32 Total unrealized gains/(losses) $ 71 $ (20 ) $ 39 $ 60 Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions) Unrealized gains/(losses) included in operating revenues $ 53 $ (460 ) $ 157 $ (390 ) Unrealized gains/(losses) included in cost of operations 18 440 (118 ) 450 Total impact to statement of operations — energy commodities $ 71 $ (20 ) $ 39 $ 60 Total impact to statement of operations — interest rate contracts $ (24 ) $ (7 ) $ (19 ) $ (18 ) 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, 2017, the $15 million unrealized gain from open economic hedge positions was primarily the result of an increase in value of forward sales of PJM electricity and New York capacity due to decreases in PJM electricity and New York capacity prices, which was offset by a decrease in value of forward purchases of natural gas and coal due to decreases in natural gas and coal prices. For the six months ended June 30, 2016, the $77 million unrealized gain from open economic hedge positions was primarily the result of an increase in value of forward purchases of ERCOT electricity and natural gas due to increases in ERCOT power and natural gas 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 requires 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, 2017 , was $36 million . The collateral required for contracts with credit rating contingent features as of June 30, 2017 , was $39 million . The Company is also a party to certain marginable agreements where NRG has a net liability position, but the counterparty has not called for the collateral due, which was approximately $6 million as of June 30, 2017 . See Note 4 , Fair Value of Financial Instruments , to this Form 10-Q for discussion regarding concentration of credit risk.

Impairments

Impairments	6 Months Ended
	Jun. 30, 2017
Asset Impairment Charges [Abstract]
Impairments	Impairments 2017 Impairment Losses Bacliff Project — On June 16, 2017, NRG Texas Power LLC provided notice to BTEC New Albany, LLC that it was exercising its right to terminate the Amended and Restated Membership Interest Purchase Agreement, or MIPA, due to the Bacliff Project, a new peaking facility at the former P.H. Robinson Electric Generating Station, not achieving commercial completion by the contractual expiration date of May 31, 2017. As a result of the MIPA termination, the Company recorded an impairment loss of $41 million to reduce the carrying amount of the related construction in progress to $0 during the second quarter of 2017. On July 14, 2017, the Company gave notice to BTEC New Albany, LLC that it owes NRG Texas Power LLC approximately $48 million under the terminated MIPA, consisting of $38 million in purchaser incurred costs and $10 million in liquidated damages. Other Impairments — During the second quarter of 2017, the Company recorded impairment losses of approximately $22 million in connection with the Company's Renewables business. 2016 Impairment Losses Rockford — On May 12, 2016, the Company entered into an agreement with RA Generation, LLC to sell 100% of its interests in the Rockford generating stations for cash consideration of $55 million . The transaction triggered an indicator of impairment as the sale price was less than the carrying amount of the assets, and, as a result, the assets were considered to be impaired. The Company measured the impairment loss as the difference between the carrying amount of the assets and the agreed-upon sale price. The Company recorded an impairment loss of $17 million during the quarter ended June 30, 2016 , to reduce the carrying amount of the assets held for sale to the fair market value. Other Impairments — During the second quarter of 2016, the Company recorded impairment losses for intangible assets of $8 million in connection with the Company's strategic change in its residential solar business as well as $10 million of deferred marketing expenses. In addition, the Company also recorded an impairment loss of $17 million to record certain previously purchased solar panels at fair market value. Petra Nova Parish Holdings — During the first quarter of 2016, management changed its plans with respect to its future capital commitments driven in part by the continued decline in oil prices. As a result, the Company reviewed its 50% interest in Petra Nova Parish Holdings for impairment utilizing the other-than-temporary impairment model. In determining fair value, the Company utilized an income approach and considered project specific assumptions for the future project cash flows. The carrying amount of the Company's equity method investment exceeded the fair value of the investment and the Company concluded that the decline is considered to be other than temporary. As a result, the Company measured the impairment loss as the difference between the carrying amount and the fair value of the investment and recorded an impairment loss of $140 million .

Debt and Capital Leases

Debt and Capital Leases	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Debt and Capital Leases	Debt and Capital Leases This footnote should be read in conjunction with the complete description under Note 12 , Debt and Capital Leases , to the Company's 2016 Form 10-K. Long-term debt and capital leases consisted of the following: (In millions, except rates) June 30, 2017 December 31, 2016 June 30, 2017 interest rate % (a) Recourse debt: Senior notes, due 2018 $ 398 $ 398 7.625 Senior notes, due 2021 207 207 7.875 Senior notes, due 2022 992 992 6.250 Senior notes, due 2023 869 869 6.625 Senior notes, due 2024 733 733 6.250 Senior notes, due 2026 1,000 1,000 7.250 Senior notes, due 2027 1,250 1,250 6.625 Term loan facility, due 2023 1,881 1,891 L+2.25 Tax-exempt bonds 455 455 4.125 - 6.00 Subtotal NRG recourse debt 7,785 7,795 Non-recourse debt: NRG Yield Operating LLC Senior Notes, due 2024 500 500 5.375 NRG Yield Operating LLC Senior Notes, due 2026 350 350 5.000 NRG Yield, Inc. Convertible Senior Notes, due 2019 345 345 3.500 NRG Yield, Inc. Convertible Senior Notes, due 2020 288 288 3.250 El Segundo Energy Center, due 2023 414 443 L+1.625 - L+2.25 Marsh Landing, due 2017 and 2023 358 370 L+1.750 - L+1.875 Alta Wind I - V lease financing arrangements, due 2034 and 2035 939 965 5.696 - 7.015 Walnut Creek, term loans due 2023 299 310 L+1.625 Utah Portfolio, due 2022 284 287 L+2.625 Tapestry, due 2021 166 172 L+1.625 CVSR, due 2037 757 771 2.339 - 3.775 CVSR HoldCo, due 2037 193 199 4.680 Alpine, due 2022 142 145 L+1.750 Energy Center Minneapolis, due 2017 and 2025 85 96 5.95 - 7.25 Energy Center Minneapolis, due 2031 125 125 3.55 Viento, due 2023 169 178 L+2.75 NRG Yield - other 569 540 various Subtotal NRG Yield debt (non-recourse to NRG) 5,983 6,084 Ivanpah, due 2033 and 2038 1,108 1,113 2.285 - 4.256 Carlsbad Energy Project 345 — 4.120 Agua Caliente, due 2037 843 849 2.395 - 3.633 Agua Caliente Borrower 1, due 2038 89 — 5.430 Cedro Hill, due 2025 156 163 L+1.75 Midwest Generation, due 2019 194 231 4.390 NRG Other 622 468 various Subtotal other NRG non-recourse debt 3,357 2,824 Subtotal all non-recourse debt 9,340 8,908 Subtotal long-term debt (including current maturities) 17,125 16,703 Capital leases 6 6 various Subtotal long-term debt and capital leases (including current maturities) 17,131 16,709 Less current maturities (1,042 ) (516 ) Less debt issuance costs (208 ) (188 ) Discounts (39 ) (48 ) Total long-term debt and capital leases $ 15,842 $ 15,957 (a) As of June 30, 2017 , L+ equals 3 month LIBOR plus x%, with the exception of the Utah Portfolio term loans. Recourse Debt 2023 Term Loan Facility On January 24, 2017, NRG repriced the 2023 Term Loan Facility, reducing the interest rate margin by 50 basis points to LIBOR plus 2.25% . The LIBOR floor remains 0.75% . Revolving Credit Facility On June 12, 2017, NRG repaid $125 million on the Revolving Credit Facility. As of June 30, 2017, no cash borrowings were outstanding on the revolver. Senior Notes Issuance of 2026 Senior Notes On May 23, 2016, NRG issued $1.0 billion in aggregate principal amount at par of 7.25% senior notes due 2026, or the 2026 Senior Notes. The 2026 Senior Notes are senior unsecured obligations of NRG and are guaranteed by certain of its subsidiaries. Interest is paid semi-annually beginning on November 15, 2016, until the maturity date of May 15, 2026. Issuance of 2027 Senior Notes On August 2, 2016, NRG issued $1.25 billion in aggregate principal amount at par of 6.625% senior notes due 2027, or the 2027 Senior Notes. The 2027 Senior Notes are senior unsecured obligations of NRG and are guaranteed by certain of its subsidiaries. Interest is paid semi-annually beginning on January 15, 2017, until the maturity date of January 15, 2027. The proceeds from the issuance of the 2027 Senior Notes were utilized to retire the Company's 8.250% senior notes due 2020 and reduce the balance of the Company's 7.875% senior notes due 2021. Non-recourse Debt NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility NRG Yield LLC and its direct wholly owned subsidiary, NRG Yield Operating LLC, entered into a senior secured revolving credit facility, which can be used for cash and for the issuance of letters of credit. At June 30, 2017 , there was $68 million of letters of credit issued under the revolving credit facility and no borrowing outstanding on the revolver. Project Financings Agua Caliente Project Financing On February 17, 2017, Agua Caliente Borrower 1 LLC and Agua Caliente Borrower 2 LLC, or Agua Caliente Holdco, the indirect owners of 51% of the Agua Caliente solar facility, issued $130 million of senior secured notes under the Agua Caliente Holdco Financing Agreement, or 2038 Agua Caliente Holdco Notes, that bear interest at 5.43% and mature on December 31, 2038. As described in Note 3 , Discontinued Operations and Dispositions , on March 27, 2017, NRG Yield, Inc. acquired Agua Caliente Borrower 2 LLC from NRG. The debt is joint and several with respect to Agua Caliente Borrower 1 LLC and Agua Caliente Borrower 2 LLC and is secured by the equity interests of each borrower in the Agua Caliente solar facility. Carlsbad Project Financing On May 26, 2017, Carlsbad Energy Holdings, LLC entered into a note payable agreement with financial institutions for the issuance of up to $407 million of senior secured notes that bear interest at a rate of 4.12% , and mature on October 31, 2038. As of June 30, 2017, $345 million of these notes were outstanding. Also on May 26, 2017, Carlsbad Energy Holdings, LLC entered into a credit agreement, or the Carlsbad Financing Agreement, with the issuing banks, for a $194 million construction loan, that will convert to a term loan upon completion of the project. The Carlsbad Financing Agreement also includes a letter of credit facility with an aggregate principle amount not to exceed $83 million , and a working capital loan facility with an aggregate principle amount not to exceed $4 million .

Variable Interest Entities, or

Variable Interest Entities, or VIEs	6 Months Ended
	Jun. 30, 2017
Variable Interest Entities Disclosure [Abstract]
Variable Interest Entities, or VIEs	Variable Interest Entities, or VIEs Entities that are not Consolidated NRG has interests in entities that are considered VIEs under ASC 810, Consolidation , but NRG is not considered the primary beneficiary. NRG accounts for its interests in these entities under the equity method of accounting. GenConn Energy LLC — Through its consolidated subsidiary, NRG Yield Operating LLC, the Company owns a 50% interest in GCE Holding LLC, the owner of GenConn, which owns and operates two 190 MW peaking generation facilities in Connecticut at NRG's Devon and Middletown sites. NRG's maximum exposure to loss is limited to its equity investment, which was $104 million as of June 30, 2017 . Entities that are Consolidated The Company has a controlling financial interest in certain entities which have been identified as VIEs under ASC 810. These arrangements are primarily related to tax equity arrangements entered into with third-parties in order to finance the cost of solar energy systems under operating leases and wind facilities eligible for certain tax credits as further described in Note 2 , Summary of Significant Accounting Policies to the Company's 2016 Form 10-K. For one of the tax equity arrangements, the Company has a deficit restoration obligation equal to $95 million as of June 30, 2017 , which would be required to be funded if the arrangement were to be dissolved. The summarized financial information for the Company's consolidated VIEs consisted of the following: (In millions) June 30, 2017 December 31, 2016 Current assets $ 84 $ 87 Net property, plant and equipment 1,493 1,534 Other long-term assets 1,024 954 Total assets 2,601 2,575 Current liabilities 63 59 Long-term debt 424 442 Other long-term liabilities 187 183 Total liabilities 674 684 Noncontrolling interests 600 529 Net assets less noncontrolling interests $ 1,327 $ 1,362

Changes in Capital Structure

Changes in Capital Structure	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Changes in Capital Structure	Changes in Capital Structure As of June 30, 2017 and December 31, 2016 , 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, 2016 417,583,825 (102,140,814 ) 315,443,011 Shares issued under LTIPs 397,287 — 397,287 Shares issued under ESPP — 282,530 282,530 Balance as of June 30, 2017 417,981,112 (101,858,284 ) 316,122,828 Preferred Stock On May 24, 2016, NRG entered an agreement with Credit Suisse Group to repurchase 100% of the outstanding shares of its $344.5 million 2.822% preferred stock. On June 13, 2016, the Company completed the repurchase from Credit Suisse of 100% of the outstanding shares at a price of $226 million . The transaction resulted in a gain on redemption of $78 million , measured as the difference between the fair value of the cash consideration paid upon redemption of $226 million and the carrying value of the preferred stock at the time of the redemption of $304 million . This amount is reflected in net income/(loss) available to NRG common stockholders in the calculation of earnings per share. Amended and Restated Employee Stock Purchase Plan On April 27, 2017, NRG stockholders approved an increase of 3,000,000 shares available for issuance under the ESPP. As of June 30, 2017 , there were 3,385,289 shares of treasury stock available for issuance under the ESPP. In July 2017, 278,240 shares of NRG common stock were issued to employee accounts from treasury stock under the ESPP. Amended and Restated Long-term Incentive Plan On April 27, 2017, NRG stockholders approved an increase of 3,000,000 shares available for issuance under the NRG Energy, Inc. Amended and Restated Long-term Incentive Plan. NRG Common Stock Dividends The following table lists the dividends paid during the six months ended June 30, 2017 : Second Quarter 2017 First Quarter 2017 Dividends per Common Share $ 0.03 $ 0.03 On July 20, 2017 , NRG declared a quarterly dividend on the Company's common stock of $0.03 per share, payable August 15, 2017 , to stockholders of record as of August 1, 2017 , 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_(Loss) Per Share

Earnings/(Loss) Per Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings/(Loss) Per Share	Earnings/(Loss) Per Share Basic earnings/(loss) per common share is computed by dividing net income/(loss) less accumulated preferred stock dividends 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/(loss) per share is computed in a manner consistent with that of basic income/(loss) per share while giving effect to all potentially dilutive common shares that were outstanding during the period. During the second quarter of 2016, the Company repurchased 100% of the outstanding shares of its 2.822% preferred stock. The reconciliation of NRG's basic and diluted loss per share is shown in the following table: Three months ended June 30, Six months ended June 30, (In millions, except per share data) 2017 2016 2017 2016 Basic and diluted loss per share attributable to NRG Energy, Inc. common stockholders Net loss attributable to NRG Energy, Inc. $ (626 ) $ (271 ) $ (790 ) $ (189 ) Dividends for preferred shares — — — 5 Gain on redemption of 2.822% redeemable perpetual preferred stock — (78 ) — (78 ) Loss available for common stockholders $ (626 ) $ (193 ) $ (790 ) $ (116 ) Weighted average number of common shares outstanding - basic and diluted 316 315 316 315 Loss per weighted average common share — basic and diluted $ (1.98 ) $ (0.61 ) $ (2.50 ) $ (0.37 ) 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 loss per share: Three months ended June 30, Six months ended June 30, (In millions of shares) 2017 2016 2017 2016 Equity compensation plans 6 3 6 3 Total 6 3 6 3

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 30, 2017
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 as follows: Generation, which includes generation, international and BETM; Retail, which includes Mass customers and Business Solutions, which includes C&I customers and other distributed and reliability products; Renewables, which includes solar and wind assets, excluding those in NRG Yield; NRG Yield; and corporate activities. The financial information for the three and six months ended June 30, 2016 has been recast to reflect the current segment structure. On September 1, 2016, NRG Yield acquired the remaining 51.05% interest in CVSR Holdco LLC, which indirectly owns the CVSR solar facility, from the Company. On March 27, 2017, NRG Yield acquired from NRG a 16% interest in the Agua Caliente solar project, and NRG's interests in seven utility-scale solar projects located in Utah. Both acquisitions were treated as a transfer of entities under common control and accordingly, all historical periods have been recast to reflect the acquisition as if they had occurred at the beginning of the financial statement period. On June 14, 2017, as described in Note 3, Discontinued Operations and Dispositions , NRG deconsolidated GenOn for financial reporting purposes. The financial information for all historical periods have been recast to reflect the deconsolidation of GenOn and to present 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). Generation (a) Retail (a) Renewables (a) NRG Yield Corporate (a) Eliminations Total Three months ended June 30, 2017 (In millions) Operating revenues (a) $ 882 $ 1,603 $ 123 $ 284 $ 3 $ (194 ) $ 2,701 Depreciation and amortization 95 29 50 78 8 — 260 Impairment losses 41 — 22 — — — 63 Equity in (losses)/earnings of unconsolidated affiliates (15 ) — (2 ) 16 3 (5 ) (3 ) (Loss)/income from continuing operations before income taxes (89 ) 330 (52 ) 53 (135 ) (4 ) 103 (Loss)/income from continuing operations (90 ) 341 (47 ) 45 (146 ) (4 ) 99 Loss from discontinued operations, net of tax — — — — (741 ) — (741 ) Net (Loss)/Income (90 ) 341 (47 ) 45 (887 ) (4 ) (642 ) Net (Loss)/income attributable to NRG Energy, Inc. $ (90 ) $ 341 $ (22 ) $ 50 — $ (920 ) $ 15 $ (626 ) Total assets as of June 30, 2017 $ 8,539 $ 2,439 $ 5,193 $ 8,513 $ 10,954 $ (10,433 ) $ 25,205 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 171 $ 1 $ 10 $ 3 $ 9 $ — $ 194 Generation (a) Retail (a) Renewables (a) NRG Yield (a) Corporate (a) Eliminations Total Three months ended June 30, 2016 (In millions) Operating revenues (a) $ 504 $ 1,536 $ 101 $ 283 $ 10 $ (186 ) $ 2,248 Depreciation and amortization 97 29 47 75 14 — 262 Impairment losses 17 — 27 — 12 — 56 Equity in earnings/(losses) of unconsolidated affiliates 2 — (2 ) 14 27 (37 ) 4 Loss on sale of assets — — — — (83 ) — (83 ) Loss on debt extinguishment, net — — — — (80 ) — (80 ) (Loss)/income from continuing operations before income taxes (458 ) 657 (75 ) 76 (295 ) (43 ) (138 ) (Loss)/income from continuing operations (458 ) 657 (71 ) 64 (312 ) (43 ) (163 ) Loss from discontinued operations, net of tax — — — — (113 ) — (113 ) Net (Loss)/Income (458 ) 657 (71 ) 64 (425 ) (43 ) (276 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (458 ) $ 661 $ (66 ) $ 48 $ (449 ) $ (7 ) $ (271 ) (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 166 $ 1 $ 4 $ 2 $ 13 $ — $ 186 Generation (a) Retail (a) Renewables (a)(b) NRG Yield Corporate (a) Eliminations Total Six months ended June 30, 2017 (In millions) Operating revenues (a) $ 1,848 $ 2,938 $ 220 $ 502 $ 11 $ (436 ) $ 5,083 Depreciation and amortization 192 57 99 153 16 — 517 Impairment losses 41 — 22 — — — 63 Equity in (losses)/earnings of unconsolidated affiliates (28 ) — (3 ) 35 7 (9 ) 2 (Loss)/income from continuing operations before income taxes (54 ) 303 (89 ) 51 (273 ) (9 ) (71 ) (Loss)/Income from continuing operations (56 ) 311 (79 ) 44 (281 ) (9 ) (70 ) Loss from discontinued operations, net of tax — — — — (775 ) — (775 ) Net (Loss)/Income (56 ) 311 (79 ) 44 (1,056 ) (9 ) (845 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (56 ) $ 311 $ (26 ) $ 58 $ (1,089 ) $ 12 $ (790 ) (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 406 $ 11 $ 4 $ — $ 15 $ — $ 436 Generation (a)(c) Retail (a) Renewables (a) NRG Yield (a) Corporate (a) Eliminations Total Six months ended June 30, 2016 (In millions) Operating revenues (a) $ 1,637 $ 2,906 $ 197 $ 517 $ 28 $ (378 ) $ 4,907 Depreciation and amortization 197 57 95 149 30 — 528 Impairment losses 17 — 27 — 12 — 56 Equity in (losses)/earnings of unconsolidated affiliates (5 ) — (8 ) 18 6 (14 ) (3 ) Loss on sale of assets — — — — (83 ) — (83 ) Impairment loss on investment (137 ) — — — (2 ) — (139 ) Loss on debt extinguishment, net — — — — (69 ) — (69 ) (Loss)/income from continuing operations before income taxes (433 ) 808 (122 ) 78 (495 ) (9 ) (173 ) (Loss)/income from continuing operations (433 ) 807 (111 ) 66 (540 ) (9 ) (220 ) Loss from discontinued operations, net of tax — — — — (9 ) — (9 ) Net (Loss)/Income (433 ) 807 (111 ) 66 (549 ) (9 ) (229 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (433 ) $ 807 $ (96 ) $ 58 $ (558 ) $ 33 $ (189 ) (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 330 $ 5 $ 8 $ 6 $ 29 $ — $ 378

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Tax Rate The income tax provision consisted of the following: Three months ended June 30, Six months ended June 30, (In millions except otherwise noted) 2017 2016 2017 2016 Income/(Loss) before income taxes $ 103 $ (138 ) $ (71 ) $ (173 ) Income tax expense/(benefit) from continuing operations 4 25 (1 ) 47 Effective tax rate 3.9 % (18.1 )% 1.4 % (27.2 )% For the three months ended June 30, 2017 , NRG's overall effective tax rate was different than the statutory rate of 35% primarily due to the tax benefit for the change in valuation allowance and the generation of PTCs and ITCs from various wind and solar facilities, respectively, partially offset by the inclusion of consolidated partnerships and current state tax expense. For the six months ended June 30, 2017 , NRG's overall effective tax rate was different than the statutory rate of 35% primarily due to the tax expense for the change in valuation allowance, current state tax expense partially offset by the generation of PTCs and ITCs from various wind and solar facilities, respectively. For the three and six months ended June 30, 2016 , NRG's overall effective tax rate was different than the statutory rate of 35% primarily due to tax expense resulting from the change in the valuation allowance, amortization of indefinite lived assets, inclusion of consolidated partnerships and the impact of state income taxes. Uncertain Tax Benefits As of June 30, 2017 , NRG has recorded a non-current tax liability of $39 million for uncertain tax benefits from positions taken on various state income tax returns, including accrued interest. For the six months ended June 30, 2017 , NRG accrued an immaterial amount of interest relating to the uncertain tax benefits. As of June 30, 2017 , 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 not 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. The Company's primary foreign operations are also no longer subject to examination by local jurisdictions for years prior to 2010.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Services Agreement with GenOn The Company provides GenOn with various management, personnel and other services, which include human resources, regulatory and public affairs, accounting, tax, legal, information systems, treasury, risk management, commercial operations, and asset management, as set forth in the services agreement with GenOn, or the Services Agreement. The initial term of the Services Agreement was through December 31, 2013, with an automatic renewal absent a request for termination. The fee charged was determined based on a fixed amount as described in the Services Agreement and was calculated based on historical GenOn expenses prior to the NRG Merger. The annual fees under the Services Agreement were approximately $193 million and management has concluded that this method of charging overhead costs is reasonable. As described in Note 3, Discontinued Operations and Dispositions , in connection with the Restructuring Support Agreement, NRG agreed to provide shared services to GenOn under the Services Agreement for an adjusted annualized fee of $84 million through the pendency of the Chapter 11 Cases. Beginning on June 14, 2017, NRG records operating income for the amounts earned for shared services of approximately $5 million per month. Subsequent to the GenOn Entities' emergence from bankruptcy, NRG will provide shared services for two months at no charge; after which GenOn has an additional two, one-month options to provide services at an annualized fee of $84 million . NRG charges these fees on a monthly basis, less amounts incurred directly by GenOn. For the three and six months ended June 30, 2017, NRG recorded other income - affiliate related to these services of $42 million and $90 million , respectively. For the three and six months ended June 30, 2016, NRG recorded other income - affiliate related to these services of $48 million and $96 million , respectively. In addition, as described in Note 3 , Discontinued Operations and Dispositions , under the Restructuring Support Agreement, NRG has agreed to provide GenOn with a $28 million credit against amounts owed to NRG prior to the Petition Date under the current Services Agreement. The credit was intended to reimburse GenOn for its payment of financing costs. In addition, the Restructuring Support Agreement provides that to the extent GenOn has paid for services during the bankruptcy proceedings and the aforementioned credit has not been applied in full, NRG shall, upon request by GenOn, reimburse such payments in cash up to the amount of any unused portion of the credit. Credit Agreement with GenOn NRG and GenOn are party to a secured intercompany revolving credit agreement. The intercompany revolving credit agreement provided for a $500 million revolving credit facility, all of which was available for revolving loans and letters of credit. At June 30, 2017 and December 31, 2016, $140 million and $272 million , respectively, of letters of credit were issued and outstanding under the NRG credit agreement for GenOn. Additionally, as of June 30, 2017, there were $125 million of loans outstanding under the intercompany secured revolving credit facility. As of December 31, 2016, no loans were outstanding under this intercompany secured revolving credit facility. In addition, the intercompany secured revolving credit facility contains customary covenants and events of default. As of June 30, 2017, GenOn was in default under the secured intercompany revolving credit agreement due to the filing of the Chapter 11 Cases. As a result of the Chapter 11 Cases, no additional revolving loans or letters of credit are available to GenOn. In addition, NRG agreed to provide GenOn with a letter of credit facility during the pendency of the Chapter 11 Cases, which could be utilized for required letters of credit in lieu of the intercompany secured revolving credit facility. The letter of credit facility provided availability of up to $330 million less amounts borrowed and letters of credit provided are required to be cash collateralized at 103% of the letter of credit amount. On July 27, 2017, this letter of credit facility was terminated as GenOn has obtained a separate letter of credit facility with a third party financial institution. Effective with completion of the reorganization, GenOn must repay NRG for all revolving loans outstanding, with such amount to be netted against the settlement payment owed from NRG to GenOn. Accordingly, the affiliate receivable is recorded net within accrued expenses and other current liabilities - affiliate on the consolidated balance sheet as of June 30, 2017. Interest continues to accrue during the pendency of the Chapter 11 Cases and borrowings remain secured obligations. Commercial Operations Agreement NRG Power Marketing LLC has entered into physical and financial intercompany commodity and hedging transactions with GenOn and certain of its subsidiaries. Subject to applicable collateral thresholds, these arrangements may provide for the bilateral exchange of credit support based upon market exposure and potential market movements. The terms and conditions of the agreements are generally consistent with industry practices and other third party arrangements. As of June 30, 2017, derivative assets and liabilities associated with these transactions are recorded within NRG's derivative instruments balances on the consolidated balance sheet, with related revenues and costs within operating revenues and cost of operations, respectively.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies This footnote should be read in conjunction with the complete description under Note 22 , Commitments and Contingencies , to the Company's 2016 Form 10-K. Commitments First Lien Structure — NRG has granted first liens to certain counterparties on a substantial portion of the Company's assets, excluding assets acquired in the EME (including Midwest Generation) acquisitions, assets held by NRG Yield, Inc. and NRG's assets that have project-level financing, 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, 2017 , hedges under the first liens were out-of-the-money for NRG on a counterparty aggregate basis. Ivanpah Energy Production Guarantee — The Company's PPAs with PG&E with respect to the Ivanpah plant contain provisions for contract quantity and guaranteed energy production, which require that Ivanpah units 1 and 3 deliver to PG&E no less than the guaranteed energy production amount specified in the PPAs in any period of twenty-four consecutive months, or performance measurement period, during the term of the PPAs. In January 2017, the Company and PG&E executed amendments to the PPAs that provide, among other things, the ability to cure any failure to meet the guaranteed energy production amounts through performance and liquidated damage provisions. On February 2, 2017, PG&E filed a request with the CPUC to approve the amendments. The CPUC approved the amendments without modification on May 11, 2017 and the appeal period expired 30 days later with no appeals filed. Lignite Contract with Texas Westmoreland Coal Co. — The Company has a contract with TWCC for reclamation activities associated with closure of the Jewett mine. NRG is responsible for reclamation costs and has recorded an adequate ARO liability. The Railroad Commission of Texas has imposed a bond obligation of $95.5 million on TWCC for the reclamation of the mine. Pursuant to the contract with TWCC, NRG supports this obligation through surety bonds. Additionally, NRG is obligated to provide additional performance assurance if required by the Railroad Commission of Texas. 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 reserves 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 reserve for the matters discussed below. 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 reserves and that such difference could be material. In addition to the legal proceedings noted below, NRG and its subsidiaries are party to other litigation or legal proceedings arising in the ordinary course of business. In management's opinion, the disposition of these ordinary course matters will not materially adversely affect NRG's consolidated financial position, results of operations, or cash flows. Midwest Generation Asbestos Liabilities — The Company, through its subsidiary, Midwest Generation, may be subject to potential asbestos liabilities as a result of its acquisition of EME. The Company is currently analyzing the scope of potential liability as it may relate to Midwest Generation. The Company believes that it has established an adequate reserve for these cases. Energy Plus Holdings — On August 7, 2012, Energy Plus Holdings received a subpoena from the NYAG which generally sought information and business records related to Energy Plus Holdings' sales, marketing and business practices. Energy Plus Holdings provided documents and information to the NYAG. On June 22, 2015, the NYAG issued another subpoena seeking additional information. Energy Plus Holdings provided responsive documents to this second subpoena. The Company does not expect the resolution of this matter to have a material impact on the Company's consolidated financial position, results of operation, or cash flows. Midwest Generation New Source Review Litigation — In August 2009, the EPA and the Illinois Attorney General, or the Government Plaintiffs, filed a complaint, or the Governments’ Complaint, in the U.S. District Court for the Northern District of Illinois alleging violations of CAA PSD requirements by Midwest Generation arising from maintenance, repair or replacement projects at six Illinois coal-fired electric generating stations performed by Midwest Generation or ComEd, a prior owner of the stations, including alleged failures to obtain PSD construction permits and to comply with BACT requirements. The Government Plaintiffs also alleged violations of opacity and PM standards at the Midwest Generation plants. Finally, the Government Plaintiffs alleged that Midwest Generation violated certain operating permit requirements under Title V of the CAA allegedly arising from such claimed PSD, opacity and PM emission violations. In addition to seeking penalties of up to $37,500 per violation, per day, the complaint seeks an injunction ordering Midwest Generation to install controls sufficient to meet BACT emission rates at the units subject to the complaint and other remedies, which could go well beyond the requirements of the CPS. Several environmental groups intervened as plaintiffs in this litigation and filed a complaint, or the Intervenors’ Complaint, which alleged opacity, PM and related Title V violations. Midwest Generation filed a motion to dismiss nine of the ten PSD counts in the Governments’ Complaint, and to dismiss the tenth PSD count to the extent the Governments’ Complaint sought civil penalties for that count. The trial court granted the motion in March 2010. In June 2010, the Government Plaintiffs and Intervenors each filed an amended complaint. The Governments’ Amended Complaint again alleged that Midwest Generation violated PSD (based upon the same projects as alleged in their original complaint, but adding allegations that the Company was liable as the “successor” to ComEd), Title V and opacity and PM standards. It named EME and ComEd as additional defendants and alleged PSD violations (again, premised on the same projects) against them. The Intervenors’ Amended Complaint named only Midwest Generation as a defendant and alleged Title V and opacity/PM violations, as well as one of the ten PSD violations alleged in the Governments’ Amended Complaint. Midwest Generation again moved to dismiss all but one of the Government Plaintiffs’ PSD claims and the related Title V claims. Midwest Generation also filed a motion to dismiss the PSD claim in the Intervenors’ Amended Complaint and the related Title V claims. In March 2011, the trial court granted Midwest Generation’s partial motion to dismiss the Government Plaintiffs’ PSD claims. The trial court denied Midwest Generation’s motion to dismiss the PSD claim asserted in the Intervenors’ Amended Complaint, but noted that the plaintiffs would be required to convince the court that the statute of limitations should be equitably tolled. The trial court did not address other counts in the amended complaints that allege violations of opacity and PM emission limitations under the Illinois State Implementation Plan and related Title V claims. The trial court also granted the motions to dismiss the PSD claims asserted against EME and ComEd. Following the trial court ruling, the Government Plaintiffs appealed the trial court’s dismissals of their PSD claims, including the dismissal of nine of the ten PSD claims against Midwest Generation and of the PSD claims against the other defendants. Those PSD claim dismissals were affirmed by the U.S. Court of Appeals for the Seventh Circuit in July 2013. In addition, in 2012, all but one of the environmental groups that had intervened in the case dismissed their claims without prejudice. As a result, only one environmental group remains a plaintiff intervenor in the case. The Company does not expect the resolution of this matter to have a material impact on the Company’s consolidated financial position, results of operations or cash flows. Telephone Consumer Protection Act Purported Class Actions — Three purported class action lawsuits have been filed against NRG Residential Solar Solutions, LLC — one in California and two in New Jersey. The plaintiffs generally allege misrepresentation by the call agents and violations of the TCPA, claiming that the defendants engaged in a telemarketing campaign placing unsolicited calls to individuals on the “Do Not Call List.” The plaintiffs seek statutory damages of up to $1,500 per plaintiff, actual damages and equitable relief. On July 8, 2016, NRG filed a Rule 11 Motion seeking dismissal of NRG from the California case. The Rule 11 Motion was denied on August 16, 2016. On June 22, 2017, plaintiffs in the California case filed a motion for leave to file a second amended complaint to substitute new plaintiffs. Defendants’ filed an opposition to this motion on June 26, 2017. The court granted plaintiffs' motion to substitute new plaintiffs and on August 1, 2017, Defendants filed an answer to the second amended complaint. On July 12, 2017, the parties in the New Jersey action reached an agreement in principle to resolve the class allegations which was confirmed by a term sheet signed by the parties on July 28, 2017. The parties to the New Jersey action are seeking to have the New Jersey and California litigation stayed while a final settlement can be executed and approved by the court. California Department of Water Resources and San Diego Gas & Electric Company v. Sunrise Power Company LLC — On January 29, 2016, CDWR and SDG&E filed a lawsuit against Sunrise Power Company, along with NRG and Chevron Power Corporation. 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 have 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 demurrers in response to the plaintiffs' complaint. The demurrers 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 demurrers to the amended complaints. On November 18, 2016, the court sustained the demurrers 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 demurrers without leave to amend. On July 14, 2017, CDWR filed a notice of appeal. Braun v. NRG Yield, Inc. — On April 19, 2016, plaintiffs filed a putative class action lawsuit against NRG Yield, Inc., the current and former members of its board of directors individually, and other parties in California Superior Court in Kern County, CA. Plaintiffs allege various violations of the Securities Act due to the defendants’ alleged failure to disclose material facts related to low wind production prior to the NRG Yield, Inc.'s June 22, 2015 Class C common stock offering. Plaintiffs seek compensatory damages, rescission, attorney’s fees and costs. The Defendants filed demurrers and a motion challenging jurisdiction on October 18, 2016. On June 16, 2017, the court approved the parties' stipulation which provides the plaintiffs' opposition is due on September 15, 2017 and defendants' reply is due on November 15, 2017. Ahmed v. NRG Energy, Inc. and the NRG Yield Board of Directors — On September 15, 2016, plaintiffs filed a putative class action lawsuit against NRG Energy, Inc., the directors of NRG Yield, Inc., and other parties in the Delaware Chancery Court. The complaint alleges that the defendants breached their respective fiduciary duties with regard to the recapitalization of NRG Yield, Inc. common stock in 2015. The plaintiffs generally seek economic damages, attorney’s fees and injunctive relief. The defendants filed a motion to dismiss the lawsuit on December 21, 2016. Plaintiffs filed their objection to the motion to dismiss on February 15, 2017. The Defendants' reply was filed on March 24, 2017. The court heard oral argument on defendants' motion to dismiss on June 20, 2017. Griffoul v. NRG Residential Solar Solutions — On February 28, 2017, plaintiffs, consisting of New Jersey residential solar customers, filed a purported class action lawsuit in New Jersey state court. Plaintiffs allege violations of the New Jersey Consumer Fraud Action and Truth-in-Consumer Contracts, Warranty and Notice Act with regard to certain provisions of their residential solar contracts. The plaintiffs seek damages and injunctive relief as to the proper allocation of the solar renewable energy credits. On June 6, 2017, the defendants filed a motion to compel arbitration or dismiss the lawsuit. Plaintiffs filed their opposition on June 29, 2017. On July 14, 2017, the court denied NRG's motion to compel arbitration or dismiss the case. On July 25, 2017, NRG filed a motion for reconsideration of the appeal. Rice v. NRG — On April 14, 2017, plaintiffs filed a purported class action lawsuit in the U.S. District Court for the Western District of Pennsylvania against NRG, First Energy Corporation and Matt Canastrale Contracting, Inc. Plaintiffs generally claim personal injury, trespass, nuisance and property damage related to the disposal of coal ash from GenOn's Elrama Power Plant and First Energy’s Mitchell and Hatfield Power Plants. Plaintiffs generally seek monetary damages, medical monitoring and remediation of their property. NRG believes that it was incorrectly named as a party to the lawsuit. 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. GenOn Chapter 11 Cases — On the Petition Date, the GenOn Entities filed voluntary petitions for relief under Chapter 11 of the Bankruptcy Code in the Bankruptcy Court. Under the Restructuring Support Agreement to which the GenOn Entities, NRG and certain of GenOn's and GenOn Americas Generation's senior unsecured noteholders are parties, each of them has agreed to support Bankruptcy Court approval of the plan of reorganization. GenOn has a customary "fiduciary out" under the Restructuring Support Agreement. Moreover, the Bankruptcy Court may not approve the plan of reorganization. If the plan of reorganization is not approved, NRG may not be entitled to the benefits of the Settlement Agreement provided under the Restructuring Support Agreement and it will remain subject to any claims of GenOn and the noteholders, including claims relating to or arising out of any shared services and any other relationships or transactions between the companies. See Note 3 , Discontinued Operations and Dispositions , for additional information related to the Chapter 11 Cases. GenOn Noteholders' Lawsuit — On December 13, 2016, certain indenture trustees for an ad hoc group of holders, or the Noteholders, of the GenOn Energy, Inc. 7.875% Senior Notes due 2017, 9.500% Notes due 2018, and 9.875% Notes due 2020, and the GenOn Americas Generation, LLC 8.50% Senior Notes due 2021 and 9.125% Senior Notes due 2031, along with certain of the Noteholders, filed a complaint in the Superior Court of the State of Delaware against NRG and GenOn alleging certain claims related to the Services Agreement between NRG and GenOn. Plaintiffs generally seek return of all monies paid under the Services Agreement and any other damages that the court deems appropriate. On February 3, 2017, the court entered an order approving a Standstill Agreement whereby the parties agreed to suspend all deadlines in the case until March 1, 2017. The Standstill Agreement terminated on March 1, 2017. On April 30, 2017, the Noteholders filed an amended complaint that asserts (i) additional fraudulent transfer claims in relation to GenOn’s sale of the Marsh Landing project to NRG Yield LLC, (ii) alleged breaches of fiduciary duty by certain current and former officers and directors of GenOn in relation to the Services Agreement and the alleged usurpation of corporate opportunities concerning the Mandalay and Canal projects and (iii) claims against NRG for allegedly aiding and abetting such claimed breaches of fiduciary duties. In addition to NRG and GenOn, the amended complaint names NRG Yield LLC and certain current and former officers and directors of GenOn as defendants. The plaintiffs, among other things, generally seek return of all monies paid under the services agreement and any other damages that the court deems appropriate. Pursuant to the terms of the Restructuring Support Agreement, this matter should ultimately be resolved if the GenOn Entities' plan of reorganization is approved by the Bankruptcy Court. Morgantown v. GenOn Mid-Atlantic — On June 8, 2017, Morgantown and Dickerson Owner Lessors filed a lawsuit against GenOn Mid-Atlantic, LLC, NRG North America LLC, GenOn Americas Generation, LLC, NRG Americas, Inc., GenOn Energy Holdings, Inc., GenOn Energy, Inc., and NRG Energy, Inc. in New York State Supreme Court. The plaintiffs, among other things, allege that GenOn Mid-Atlantic was overcharged in connection with the Services Agreement and that GenOn Mid-Atlantic failed to comply with a covenant requiring the maintenance of qualifying credit support. The plaintiffs seek, among other things, the return of certain transferred funds and service charges paid and to bar defendants from executing additional transfers on plaintiffs’ behalf. The litigation has been stayed and a status hearing has been scheduled for September 27, 2017. A claims estimation hearing of this matter is scheduled for September 5, 2017 before the Bankruptcy Court. BTEC v. NRG Texas Power — On July 18, 2017, BTEC New Albany LLC, or BTEC, filed a lawsuit against NRG Texas Power LLC, or NRG Texas Power, in the Harris County District Court in Texas. On January 15, 2013, the parties entered into a Membership Interest and Purchase Agreement, or MIPA, whereby BTEC agreed to dismantle, transport and rebuild an electric power generation facility at the former P.H. Robinson Electric Generating Station in Bacliff, Texas. On June 16, 2017, NRG Texas Power provided notice to BTEC that it was exercising its right to terminate the MIPA due to the project not achieving commercial completion by the contractual expiration date of May 31, 2017. BTEC claims that NRG Texas Power breached the MIPA by improperly terminating it, and seeks a declaratory judgment as to the rights and obligations of the parties. In addition, BTEC seeks damages, interest and attorney’s fees. GenOn Related Contingencies Actions Pursued by MC Asset Recovery — With Mirant Corporation's emergence from bankruptcy protection in 2006, certain actions filed by GenOn Energy Holdings and some of its subsidiaries against third parties were transferred to MC Asset Recovery, a wholly owned subsidiary of GenOn Energy Holdings. MC Asset Recovery is governed by a manager who is independent of NRG and GenOn. MC Asset Recovery is a disregarded entity for income tax purposes. Under the remaining action transferred to MC Asset Recovery, MC Asset Recovery seeks to recover damages from Commerzbank AG and various other banks, or the Commerzbank Defendants, for alleged fraudulent transfers that occurred prior to Mirant's bankruptcy proceedings. In December 2010, the U.S. District Court for the Northern District of Texas dismissed MC Asset Recovery's complaint against the Commerzbank Defendants. In January 2011, MC Asset Recovery appealed the District Court's dismissal of its complaint against the Commerzbank Defendants to the U.S. Court of Appeals for the Fifth Circuit, or the Fifth Circuit. In March 2012, the Fifth Circuit reversed the District Court's dismissal and reinstated MC Asset Recovery's amended complaint against the Commerzbank Defendants. On December 10, 2015, the District Court granted summary judgment in favor of the Commerzbank Defendants. On December 29, 2015, MC Asset Recovery filed a notice to appeal this judgment with the Fifth Circuit. On June 1, 2017, the Fifth Circuit affirmed the District Court's judgment. On June 12, 2017, MC Asset Recovery petitioned the Fifth Circuit for rehearing. The petition for rehearing was denied and a court order and judgment affirming the District Court's judgments was entered on July 17, 2017. Natural Gas Litigation — GenOn is party to several lawsuits, certain of which are class action lawsuits, in state and federal courts in Kansas, Missouri, Nevada and Wisconsin. These lawsuits were filed in the aftermath of the California energy crisis in 2000 and 2001 and the resulting FERC investigations and relate to alleged conduct to increase natural gas prices in violation of state antitrust law and similar laws. The lawsuits seek treble or punitive damages, restitution and/or expenses. The lawsuits also name as parties a number of energy companies unaffiliated with NRG. In July 2011, the U.S. District Court for the District of Nevada, which was handling four of the five cases, granted the defendants' motion for summary judgment and dismissed all claims against GenOn in those cases. The plaintiffs appealed to the U.S. Court of Appeals for the Ninth Circuit, or the Ninth Circuit, which reversed the decision of the District Court. GenOn along with the other defendants in the lawsuit filed a petition for a writ of certiorari to the U.S. Supreme Court challenging the Ninth Circuit's decision and the U.S. Supreme Court granted the petition. On April 21, 2015, the U.S. Supreme Court affirmed the Ninth Circuit’s holding that plaintiffs’ state antitrust law claims are not field-preempted by the federal Natural Gas Act and the Supremacy Clause of the U.S. Constitution. The U.S. Supreme Court left open whether the claims were preempted on the basis of conflict preemption. The U.S. Supreme Court directed that the case be remanded to the U.S. District Court for the District of Nevada for further proceedings. On March 7, 2016, class plaintiffs filed their motions for class certification. Defendants filed their briefs in opposition to class plaintiffs' motions for class certification on June 24, 2016. On March 30, 2017, the court denied the plaintiffs' motions for class certification. On April 13, 2017, the plaintiffs petitioned the Ninth Circuit for interlocutory review of the court’s order denying class certification. On June 13, 2017, the Ninth Circuit granted plaintiffs' petition for interlocutory review. In May 2016 in one of the Kansas cases, the U.S. District Court for the District of Nevada granted the defendants' motion for summary judgment. Subsequently in December 2016, the plaintiffs filed a notice of appeal with the Ninth Circuit. The appeal has been fully briefed by the parties. GenOn has agreed to indemnify CenterPoint against certain losses relating to these lawsuits. In September 2012, the State of Nevada Supreme Court, which was handling the remaining case, affirmed dismissal by the Eighth Judicial District Court for Clark County, Nevada of all plaintiffs' claims against GenOn. In February 2013, the plaintiffs in the Nevada case filed a petition for a writ of certiorari to the U.S. Supreme Court. In June 2013, the U.S. Supreme Court denied the petition for a writ of certiorari, thereby ending one of the five lawsuits. Potomac River Environmental Investigation — In March 2013, NRG Potomac River LLC, a subsidiary of GenOn, received notice that the District of Columbia Department of Environment (now renamed the Department of Energy and Environment, or DOEE) was investigating potential discharges to the Potomac River originating from the Potomac River Generating facility site, a site where the generation facility is no longer in operation. In connection with that investigation, DOEE served a civil subpoena on NRG Potomac River LLC requesting information related to the site and potential discharges occurring from the site. NRG Potomac River LLC provided various responsive materials. In January 2016, DOEE advised NRG Potomac River LLC that DOEE believed various environmental violations had occurred as a result of discharges DOEE believes occurred to the Potomac River from the Potomac River Generating facility site and as a result of associated failures to accurately or sufficiently report such discharges. DOEE has indicated it believes that penalties are appropriate in light of the violations. NRG Potomac River LLC is currently reviewing the information provided by DOEE.

Regulatory Matters

Regulatory Matters	6 Months Ended
	Jun. 30, 2017
Regulatory Matters Disclosure [Abstract]
Regulatory Matters	Regulatory Matters This footnote should be read in conjunction with the complete description under Note 23 , Regulatory Matters , to the Company's 2016 Form 10-K. 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. National Zero-Emission Credits for Nuclear Plants in Illinois — In 2016, Illinois enacted a Zero Emission Credit, or ZEC, program for selected nuclear units in Illinois. In total, the program directs over $2.5 billion over ten years to nuclear plants in Illinois that would otherwise retire. Pursuant to the legislation , the Illinois Power Agency, or IPA, conducts a competitive solicitation to procure ZECs, although both the Governor of Illinois and Exelon have already announced that the ZECs will be awarded to two Exelon-owned nuclear power plants in Illinois. These ZECs are out-of-market subsidies that threaten to artificially suppress market prices and interfere with the wholesale power market. On February 14, 2017, NRG, along with other companies, filed a complaint in the U.S. District Court for the Northern District of Illinois alleging that the state program is preempted by federal law and in violation of the dormant commerce clause. Another plaintiff group filed a similar complaint on the same day. Subsequently, on March 31, 2017, NRG, along with other companies, filed a motion for preliminary injunction. On April 10, 2017, Exelon, as an intervenor defendant, and State defendants filed motions to dismiss. On July 14, 2017, Defendants' motions to dismiss were granted. On July 17, 2017, NRG, along with other companies, filed a notice of appeal to the U.S. Court of Appeals for the Seventh Circuit. On July 18, 2017, the Court of Appeals issued an order setting an expedited briefing schedule for the matter. Zero-Emission Credits for Nuclear Plants in New York — On August 1, 2016, the NYSPSC issued its Clean Energy Standard, or CES, which provided for ZECs which would provide more than $7.6 billion over 12 years in out-of-market subsidy payments to certain selected nuclear generating units in the state. These ZECs are out-of-market subsidies that threaten to artificially suppress market prices and interfere with the wholesale power market. On October 19, 2016, NRG, along with other companies, filed a complaint in the U.S. District Court for the Southern District of New York, challenging the validity of the NYSPSC action and the ZEC program. On March 29, 2017, the U.S. District Court heard oral arguments on a motion to dismiss filed by defendants. On July 25, 2017, the defendants' motions to dismiss were granted. Current Administration and Changeover at FERC — FERC is currently without a quorum and cannot issue orders in contested proceedings until at least two new Commissioners are appointed. FERC continues to issue orders through authority that was delegated by the full Commission to FERC Staff. The legal validity of these actions has been questioned in connection with several of those orders. There are four vacant positions at FERC. The current administration has nominated three individuals for Commissioner positions and has announced its intent to nominate a fourth Commissioner. NRG’s business may be affected because its generation fleet is subject to changes in FERC regulatory policy.

Environmental Matters

Environmental Matters	6 Months Ended
	Jun. 30, 2017
Environmental Matters Disclosure [Abstract]
Environmental Matters	Environmental Matters This footnote should be read in conjunction with the complete description under Note 24 , Environmental Matters , to the Company's 2016 Form 10-K. 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. The EPA finalized CSAPR in 2011, which was intended to replace CAIR in January 2012, to address certain states' obligations to reduce emissions so that downwind states can achieve federal air quality standards. In December 2011, the D.C. Circuit stayed the implementation of CSAPR and then vacated CSAPR in August 2012 but kept CAIR in place until the EPA could replace it. In April 2014, the U.S. Supreme Court reversed and remanded the D.C. Circuit's decision. In October 2014, the D.C. Circuit lifted the stay of CSAPR. In response, the EPA in November 2014 amended the CSAPR compliance dates. Accordingly, CSAPR replaced CAIR on January 1, 2015. On July 28, 2015, the D.C. Circuit held that the EPA had exceeded its authority by requiring certain reductions that were not necessary for downwind states to achieve federal standards. Although the D.C. Circuit kept the rule in place, the court ordered the EPA to revise the Phase 2 (or 2017) (i) SO 2 budgets for four states including Texas and (ii) ozone-season NOx budgets for 11 states including Maryland, New Jersey, New York, Ohio, Pennsylvania and Texas. On October 26, 2016, the EPA finalized the CSAPR Update Rule, which reduces future NOx allocations and discounts the current banked allowances to account for the more stringent 2008 Ozone NAAQS and to address the D.C. Circuit's July 2015 decision. This rule has been challenged in the D.C. Circuit. The Company believes its investment in pollution controls and cleaner technologies leave the fleet well-positioned for compliance. 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 (with some units getting a 1-year extension). In June 2015, the U.S. Supreme Court issued a decision in the case of Michigan v. EPA, and held that the EPA unreasonably refused to consider costs when it determined that it was "appropriate and necessary" to regulate HAPs emitted by electric generating units. The U.S. Supreme Court did not vacate the MATS rule but rather remanded it to the D.C. Circuit for further proceedings. In December 2015, the D.C. Circuit remanded the MATS rule to the EPA without vacatur. On April 25, 2016, the EPA released a supplemental finding that the benefits of this regulation outweigh the costs to address the U.S. Supreme Court's ruling that the EPA had not properly considered costs. This finding has been challenged in the D.C. Circuit. On April 18, 2017, the EPA asked the D.C. Circuit to postpone oral argument that had been scheduled for May 18, 2017 because the EPA is closely reviewing the supplemental finding to determine whether it should reconsider all or part of the rule. On April 27, 2017, the D.C. Circuit granted EPA's request to postpone the oral argument and hold the case in abeyance. 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 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. 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. In April 2017, the EPA granted two petitions to reconsider the rule and also administratively stayed some of the deadlines. This regulation also has been challenged. The legal challenges have been suspended while the EPA reconsiders and likely modifies the rule. Accordingly, the Company has largely 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. A petition for reconsideration has been filed by the Utility Solid Waste Activities Group. The Company has evaluated the impact of the new rule on the Company's consolidated financial position, results of operations, or cash flows and has accrued its environmental and asset retirement obligations under the rule based on current estimates as of June 30, 2017 . East Region Burton Island Old Ash Landfill — In January 2006, NRG's Indian River Power LLC was notified that it may be a potentially responsible party with respect to Burton Island Old Ash Landfill, a historic captive landfill located at the Indian River facility. On October 1, 2007, NRG signed an agreement with DNREC to investigate the site through the Voluntary Clean-up Program, or the VCP. On February 4, 2008, DNREC issued findings that no further action was required in relation to surface water and that a previously planned shoreline stabilization project would satisfactorily address shoreline erosion. The landfill itself required a Remedial Investigation and Feasibility Study to determine the type and scope of any additional required work. DNREC approved the Feasibility Study in December 2012. In January 2013, DNREC proposed a remediation plan based on the Feasibility Study. The remediation plan was approved in October 2013. In December 2015, DNREC approved the Company's remediation design and the Company's Long Term Stewardship Plan. In the second quarter of 2017, the Company completed the remediation requirements in the remediation plan. The cost of completing the work required by the remediation plan was within amounts budgeted in early 2016. The estimated cost to comply with the Long-Term Stewardship Plan was added to the liability in December 2016. In addition to the VCP, on May 29, 2008, DNREC requested that NRG's Indian River Power LLC participate in the development and performance of a Natural Resource Damage Assessment at the Burton Island Old Ash Landfill. NRG is working with DNREC and other trustees to close out the assessment process.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	6 Months Ended
	Jun. 30, 2017
Condensed Consolidating Financial Information Disclosure [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information As of June 30, 2017 , the Company had outstanding $5.4 billion of Senior Notes due from 2018 to 2027, as shown in Note 8 , Debt and Capital Leases . These Senior 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, and NRG Yield, Inc. and its subsidiaries. Unless otherwise noted below, each of the following guarantor subsidiaries fully and unconditionally guaranteed the Senior Notes as of June 30, 2017 : Ace Energy, Inc. Norwalk Power LLC NRG Operating Services, Inc. Allied Home Warranty GP LLC NRG Advisory Services LLC NRG Oswego Harbor Power Operations Inc. Allied Warranty LLC NRG Affiliate Services Inc. NRG PacGen Inc. Arthur Kill Power LLC NRG Artesian Energy LLC NRG Portable Power LLC Astoria Gas Turbine Power LLC NRG Arthur Kill Operations Inc. NRG Power Marketing LLC Bayou Cove Peaking Power, LLC NRG Astoria Gas Turbine Operations Inc. NRG Reliability Solutions LLC BidURenergy, Inc. NRG Bayou Cove LLC NRG Renter's Protection LLC Cabrillo Power I LLC NRG Business Services LLC NRG Retail LLC Cabrillo Power II LLC NRG Business Solutions LLC NRG Retail Northeast LLC Carbon Management Solutions LLC NRG Cabrillo Power Operations Inc. NRG Rockford Acquisition LLC Cirro Group, Inc. NRG California Peaker Operations LLC NRG Saguaro Operations Inc. Cirro Energy Services, Inc. NRG Cedar Bayou Development Company, LLC NRG Security LLC Clean Edge Energy LLC NRG Connected Home LLC NRG Services Corporation Conemaugh Power LLC NRG Connecticut Affiliate Services Inc. NRG SimplySmart Solutions LLC Connecticut Jet Power LLC NRG Construction LLC NRG South Central Affiliate Services Inc. Cottonwood Development LLC NRG Curtailment Solutions Holdings LLC NRG South Central Generating LLC Cottonwood Energy Company LP NRG Curtailment Solutions, Inc NRG South Central Operations Inc. Cottonwood Generating Partners I LLC NRG Development Company Inc. NRG South Texas LP Cottonwood Generating Partners II LLC NRG Devon Operations Inc. NRG SPV #1 LLC Cottonwood Generating Partners III LLC NRG Dispatch Services LLC NRG Texas C&I Supply LLC Cottonwood Technology Partners LP NRG Distributed Generation PR LLC NRG Texas Gregory LLC Devon Power LLC NRG Dunkirk Operations Inc. NRG Texas Holding Inc. Dunkirk Power LLC NRG El Segundo Operations Inc. NRG Texas LLC Eastern Sierra Energy Company LLC NRG Energy Efficiency-L LLC NRG Texas Power LLC El Segundo Power, LLC NRG Energy Labor Services LLC NRG Warranty Services LLC El Segundo Power II LLC NRG ECOKAP Holdings LLC NRG West Coast LLC Energy Alternatives Wholesale, LLC NRG Energy Services Group LLC NRG Western Affiliate Services Inc. Energy Choice Solutions LLC NRG Energy Services International Inc. O'Brien Cogeneration, Inc. II Energy Plus Holdings LLC NRG Energy Services LLC ONSITE Energy, Inc. Energy Plus Natural Gas LLC NRG Generation Holdings, Inc. Oswego Harbor Power LLC Energy Protection Insurance Company NRG Greenco RE Retail Receivables, LLC Everything Energy LLC NRG Home & Business Solutions LLC Reliant Energy Northeast LLC Forward Home Security, LLC NRG Home Services LLC Reliant Energy Power Supply, LLC GCP Funding Company, LLC NRG Home Solutions LLC Reliant Energy Retail Holdings, LLC Green Mountain Energy Company NRG Home Solutions Product LLC Reliant Energy Retail Services, LLC Gregory Partners, LLC NRG Homer City Services LLC RERH Holdings, LLC Gregory Power Partners LLC NRG Huntley Operations Inc. Saguaro Power LLC Huntley Power LLC NRG HQ DG LLC Somerset Operations Inc. Independence Energy Alliance LLC NRG Identity Protect LLC Somerset Power LLC Independence Energy Group LLC NRG Ilion Limited Partnership Texas Genco Financing Corp. Independence Energy Natural Gas LLC NRG Ilion LP LLC Texas Genco GP, LLC Indian River Operations Inc. NRG International LLC Texas Genco Holdings, Inc. Indian River Power LLC NRG Maintenance Services LLC Texas Genco LP, LLC Keystone Power LLC NRG Mextrans Inc. Texas Genco Operating Services, LLC Langford Wind Power, LLC NRG MidAtlantic Affiliate Services Inc. Texas Genco Services, LP Louisiana Generating LLC NRG Middletown Operations Inc. US Retailers LLC Meriden Gas Turbines LLC NRG Montville Operations Inc. Vienna Operations Inc. Middletown Power LLC NRG New Roads Holdings LLC Vienna Power LLC Montville Power LLC NRG North Central Operations Inc. WCP (Generation) Holdings LLC NEO Corporation NRG Northeast Affiliate Services Inc. West Coast Power LLC New Genco GP, LLC NRG Norwalk Harbor 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 under the SEC Regulation S-X. The financial information may not necessarily be indicative of results of operations or financial position had the guarantor subsidiaries or non-guarantor subsidiaries operated as independent entities. In this presentation, NRG Energy, Inc. consists of parent company operations. Guarantor subsidiaries and non-guarantor subsidiaries of NRG are reported on an equity basis. For companies acquired, the fair values of the assets and liabilities acquired have been presented on a push-down accounting basis. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the three months ended June 30, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 1,758 $ 989 $ — $ (46 ) $ 2,701 Operating Costs and Expenses Cost of operations 1,307 558 16 (44 ) 1,837 Depreciation and amortization 102 150 8 — 260 Impairment losses 42 21 — — 63 Selling, general and administrative 86 38 100 (1 ) 223 Acquisition-related transaction and integration costs — 1 — — 1 Development activity expenses — 13 5 — 18 Total operating costs and expenses 1,537 781 129 (45 ) 2,402 Other income - affiliate — — 42 — 42 Gain on sale of assets 2 — — — 2 Operating Income/(Loss) 223 208 (87 ) (1 ) 343 Other Income/(Expense) Equity in earnings/(losses) of consolidated subsidiaries 57 (22 ) (123 ) 88 — Equity in earnings/(losses) of unconsolidated affiliates — 676 (645 ) (34 ) (3 ) Other income — 7 3 — 10 Interest expense (4 ) (121 ) (122 ) (247 ) Total other income/(expense) 53 540 (887 ) 54 (240 ) Income/(Loss) from Continuing Operations Before Income Taxes 276 748 (974 ) 53 103 Income tax expense/(benefit) 113 267 (376 ) — 4 Income/(Loss) from Continuing Operations 163 481 (598 ) 53 99 Loss from Discontinued Operations, net of income tax — (741 ) — — (741 ) Net Income/(Loss) 163 (260 ) (598 ) 53 (642 ) Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests — (9 ) 28 (35 ) (16 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 163 $ (251 ) $ (626 ) $ 88 $ (626 ) (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, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,357 $ 1,851 $ — $ (125 ) $ 5,083 Operating Costs and Expenses Cost of operations 2,568 1,222 31 (125 ) 3,696 Depreciation and amortization 203 298 16 — 517 Impairment losses 42 21 — — 63 Selling, general and administrative 184 84 216 (2 ) 482 Acquisition-related transaction and integration costs — 2 — — 2 Development activity expenses — 25 10 — 35 Total operating costs and expenses 2,997 1,652 273 (127 ) 4,795 Other income - affiliate — — 90 — 90 Gain on sale of assets 4 — — — 4 Operating Income/(Loss) 364 199 (183 ) 2 382 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (20 ) (57 ) (48 ) 125 — Equity in earnings/(losses) of unconsolidated affiliates — 707 (669 ) (36 ) 2 Other income 1 12 5 — 18 Loss on debt extinguishment — (2 ) — — (2 ) Interest expense (7 ) (225 ) (239 ) — (471 ) Total other (expense)/income (26 ) 435 (951 ) 89 (453 ) Income/(Loss) from Continuing Operations Before Income Taxes 338 634 (1,134 ) 91 (71 ) Income tax expense/(benefit) 131 237 (369 ) — (1 ) Income/(Loss) from Continuing Operations 207 397 (765 ) 91 (70 ) Loss from Discontinued Operations, net of income tax — (775 ) — — (775 ) Net Income/(Loss) 207 (378 ) (765 ) 91 (845 ) Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests — (46 ) 25 (34 ) (55 ) Net Income/(Loss) Attributable to $ 207 $ (332 ) $ (790 ) $ 125 $ (790 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the three months ended June 30, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 163 $ (260 ) $ (598 ) $ 53 $ (642 ) Other Comprehensive Income/(Loss), net of tax Unrealized loss on derivatives, net — (6 ) (4 ) 5 (5 ) Foreign currency translation adjustments, net — 1 — — 1 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — 28 28 (29 ) 27 Other comprehensive income/(loss) — 23 25 (24 ) 24 Comprehensive Income/(Loss) 163 (237 ) (573 ) 29 (618 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (10 ) 28 (35 ) (17 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. $ 163 $ (227 ) $ (601 ) $ 64 $ (601 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the six months ended June 30, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 207 $ (378 ) $ (765 ) $ 91 $ (845 ) Other Comprehensive Income/(Loss), net of tax Unrealized gain on derivatives, net — (1 ) — — (1 ) Foreign currency translation adjustments, net 5 5 7 (9 ) 8 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — 29 27 (29 ) 27 Other comprehensive income 5 33 35 (38 ) 35 Comprehensive Income/(Loss) 212 (345 ) (730 ) 53 (810 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (47 ) 25 (34 ) (56 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. $ 212 $ (298 ) $ (755 ) $ 87 $ (754 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS June 30, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ (19 ) $ 363 $ 408 $ — $ 752 Funds deposited by counterparties 14 2 3 — 19 Restricted cash 23 443 3 — 469 Accounts receivable - trade, net 783 376 3 — 1,162 Accounts receivable - affiliate 195 5 1 (102 ) 99 Inventory 472 241 — — 713 Derivative instruments 572 142 4 (74 ) 644 Cash collateral paid in support of energy risk management activities 252 25 — — 277 Prepayments and other current assets 106 155 40 — 301 Current assets - held for sale — 33 — — 33 Total current assets 2,398 1,785 462 (176 ) 4,469 Net property, plant and equipment 4,038 11,049 241 (26 ) 15,302 Other Assets Investment in subsidiaries 1,158 1,040 9,626 (11,824 ) — Equity investments in affiliates — 1,123 4 — 1,127 Notes receivable, less current portion — 9 — — 9 Goodwill 359 303 — — 662 Intangible assets, net 560 1,336 — (3 ) 1,893 Nuclear decommissioning trust fund 637 — — — 637 Derivative instruments 187 47 26 (34 ) 226 Deferred income tax (6 ) (361 ) 578 — 211 Non-current assets held-for-sale — 10 — — 10 Other non-current assets 60 537 62 — 659 Total other assets 2,955 4,044 10,296 (11,861 ) 5,434 Total Assets $ 9,391 $ 16,878 $ 10,999 $ (12,063 ) $ 25,205 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 622 $ 420 $ — $ 1,042 Accounts payable 540 187 30 — 757 Accounts payable — affiliate 724 (441 ) (136 ) (130 ) 17 Derivative instruments 590 195 — (74 ) 711 Cash collateral received in support of energy risk management activities 14 2 3 19 Accrued expenses and other current liabilities 298 5 479 28 810 Accrued expenses and other current liabilities-affiliate — 164 — — 164 Total current liabilities 2,166 734 796 (176 ) 3,520 Other Liabilities Long-term debt and capital leases 244 8,616 6,982 — 15,842 Nuclear decommissioning reserve 262 — — — 262 Nuclear decommissioning trust liability 367 — — — 367 Deferred income taxes 308 — (288 ) — 20 Derivative instruments 179 148 — (34 ) 293 Out-of-market contracts, net 74 145 — — 219 Non-current liabilities held-for-sale — 13 — — 13 Other non-current liabilities 383 316 436 — 1,135 Total non-current liabilities 1,817 9,238 7,130 (34 ) 18,151 Total liabilities 3,983 9,972 7,926 (210 ) 21,671 Redeemable noncontrolling interest in subsidiaries — 51 — — 51 Stockholders’ Equity 5,408 6,855 3,073 (11,853 ) 3,483 Total Liabilities and Stockholders’ Equity $ 9,391 $ 16,878 $ 10,999 $ (12,063 ) $ 25,205 (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, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net income (loss) from continuing operations $ 207 $ 397 $ (765 ) $ 91 $ (70 ) Adjustments to reconcile net income/(loss) to net cash provided by operating activities: Distributions from unconsolidated affiliates — 32 — (4 ) 28 Equity in losses/(earnings) of unconsolidated affiliates — (13 ) 2 9 (2 ) Depreciation and amortization 203 298 16 — 517 Provision for bad debts 17 1 — — 18 Amortization of nuclear fuel 24 — — — 24 Amortization of financing costs and debt discount/premiums — 20 9 — 29 Amortization of intangibles and out-of-market contracts 12 39 — — 51 Amortization of unearned equity compensation — — 16 — 16 Impairment losses 42 21 — — 63 Changes in deferred income taxes and liability for uncertain tax benefits 131 237 (360 ) — 8 Changes in nuclear decommissioning trust liability 2 — — — 2 Changes in derivative instruments 12 (12 ) 7 — 7 Changes in collateral deposits supporting energy risk management activities (203 ) 11 3 (189 ) Proceeds from sale of emission allowances 11 — — — 11 Gain on sale of assets (22 ) — — — (22 ) Cash (used)/provided by changes in other working capital (298 ) (1,138 ) 1,153 (96 ) (379 ) Cash provided/(used) by continuing operations 138 (107 ) 81 — 112 Cash used by discontinued operations — (38 ) — — (38 ) Net Cash Provided/(used) by Operating Activities 138 (145 ) 81 — 74 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. 45 (45 ) — Acquisition of Drop Down Assets, net of cash acquired — (131 ) — 131 — Intercompany dividends — — 129 (129 ) — Acquisition of business, net of cash acquired (16 ) — — (16 ) Capital expenditures (90 ) (436 ) (16 ) — (542 ) Decrease in notes receivable — 8 — — 8 Purchases of emission allowances (30 ) — — (30 ) Proceeds from sale of emission allowances 59 — — — 59 Investments in nuclear decommissioning trust fund securities (279 ) — — — (279 ) Proceeds from sales of nuclear decommissioning trust fund securities 277 — — — 277 Proceeds from renewable energy grants and state rebates 8 — — — — 8 Proceeds from sale of assets, net of cash disposed of 35 — — — 35 Investments in unconsolidated affiliates — (30 ) — — (30 ) Other 18 — — — 18 Cash (used)/provided by continuing operations (2 ) (605 ) 158 (43 ) (492 ) Cash used by discontinued operations (53 ) (53 ) Net Cash (Used)/Provided by Investing Activities (2 ) (658 ) 158 (43 ) (545 ) Cash Flows from Financing Activities Dividends from NRG Yield, Inc. — (45 ) — 45 — Payments (for)/from intercompany loans (122 ) 369 (247 ) — — Acquisition of Drop Down Assets, net of cash acquired — — 131 (131 ) — Intercompany dividends (129 ) 129 — Payment of dividends to common and preferred stockholders — — (19 ) — (19 ) Net receipts from settlement of acquired derivatives that include financing elements — 2 — — 2 Proceeds from issuance of long-term debt — 741 205 — 946 Payments for short and long-term debt — (316 ) (214 ) — (530 ) Receivable from affiliate — (125 ) — — (125 ) Contributions to, net of distributions from, noncontrolling interest in subsidiaries — 14 — — 14 Payment of debt issuance costs — (32 ) (4 ) — (36 ) Other - contingent consideration (10 ) — (10 ) Cash (used)/provided by continuing operations (122 ) 469 (148 ) 43 242 Cash used by discontinued operations — (224 ) — — (224 ) Net Cash (Used)/Provided by Financing Activities (122 ) 245 (148 ) 43 18 Change in cash from discontinued operations — (315 ) — — (315 ) Effect of exchange rate changes on cash and cash equivalents — (8 ) — — (8 ) Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties 14 (251 ) 91 — (146 ) Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties at Beginning of Period 4 1,059 323 — 1,386 Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties at End of Period $ 18 $ 808 $ 414 $ — $ 1,240 (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, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 1,716 $ 569 $ — $ (37 ) $ 2,248 Operating Costs and Expenses Cost of operations 1,128 342 10 (37 ) 1,443 Depreciation and amortization 112 144 6 — 262 Impairment losses — 56 — — 56 Selling, general and administrative 93 46 127 — 266 Acquisition-related transaction and integration costs — — 5 — 5 Development activity expenses — 13 5 — 18 Total operating costs and expenses 1,333 601 153 (37 ) 2,050 Other income - affiliate 48 48 Loss on sale of assets — — (83 ) — (83 ) Operating Income/(Loss) 383 (32 ) (188 ) — 163 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (50 ) (35 ) 67 18 — Equity in earnings of unconsolidated affiliates 2 41 7 (46 ) 4 Gain on investment — — 7 — 7 Other income/(loss), net 1 2 2 — 5 Loss on debt extinguishment — (4 ) (76 ) — (80 ) Interest expense (4 ) (101 ) (132 ) — (237 ) Total other expense (51 ) (97 ) (125 ) (28 ) (301 ) Income/(Loss) from Continuing Operations Before Income Taxes 332 (129 ) (313 ) (28 ) (138 ) Income tax expense/(benefit) 128 (33 ) (70 ) — 25 Income/(Loss) from Continuing Operations 204 (96 ) (243 ) (28 ) (163 ) (Loss)/ Income from Discontinued Operations, net of income tax — (116 ) 3 — (113 ) Net Income/(Loss) 204 (212 ) (240 ) (28 ) (276 ) Less: Net income attributable to noncontrolling interest and redeemable noncontrolling interest — 10 31 (46 ) (5 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 204 $ (222 ) $ (271 ) $ 18 $ (271 ) (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, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,655 $ 1,310 $ — $ (58 ) $ 4,907 Operating Costs and Expenses Cost of operations 2,559 754 19 (61 ) 3,271 Depreciation and amortization 225 291 12 — 528 Impairment losses — 56 — — 56 Selling, general and administrative 191 95 234 — 520 Acquisition-related transaction and integration costs — — 6 — 6 Development activity expenses — 32 12 — 44 Total operating costs and expenses 2,975 1,228 283 (61 ) 4,425 Other income - affiliate — — 96 — 96 Loss on sale of assets — — (83 ) — (83 ) Operating Income/(Loss) 680 82 (270 ) 3 495 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (81 ) (70 ) 342 (191 ) — Equity in earnings/(losses) of unconsolidated affiliates 3 39 10 (55 ) (3 ) Impairment loss on investment — (139 ) — — (139 ) Other income, net 2 19 2 (1 ) 22 Loss on debt extinguishment — (4 ) (65 ) — (69 ) Interest expense (7 ) (207 ) (265 ) — (479 ) Total other (expense)/income (83 ) (362 ) 24 (247 ) (668 ) Income/(Loss) Before Income Taxes 597 (280 ) (246 ) (244 ) (173 ) Income tax expense/(benefit) 228 (94 ) (87 ) — 47 Income/(Loss) from Continuing Operations 369 (186 ) (159 ) (244 ) (220 ) (Loss)/Income from Discontinued Operations, net of income tax — (15 ) 6 — (9 ) Net Income/(Loss) 369 (201 ) (153 ) (244 ) (229 ) Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (23 ) 36 (53 ) (40 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 369 $ (178 ) $ (189 ) $ (191 ) $ (189 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the three months ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 204 $ (212 ) $ (240 ) $ (28 ) $ (276 ) Other Comprehensive Income/(Loss), net of tax Unrealized loss on derivatives, net — (5 ) (4 ) 6 (3 ) Foreign currency translation adjustments, net (2 ) (2 ) (4 ) 5 (3 ) Available-for-sale securities, net — — (2 ) — (2 ) Other comprehensive loss (2 ) (7 ) (10 ) 11 (8 ) Comprehensive Income/(Loss) 202 (219 ) (250 ) (17 ) (284 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (1 ) 31 (46 ) (16 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 202 (218 ) (281 ) 29 (268 ) Gain on redemption of preferred shares — — (78 ) — (78 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 202 $ (218 ) $ (203 ) $ 29 $ (190 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the six months ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 369 $ (201 ) $ (153 ) $ (244 ) $ (229 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net — (55 ) 20 — (35 ) Foreign currency translation adjustments, net 2 2 2 (3 ) 3 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net 1 — — — 1 Other comprehensive income/(loss) 3 (53 ) 23 (3 ) (30 ) Comprehensive Income/(Loss) 372 (254 ) (130 ) (247 ) (259 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (51 ) 36 (53 ) (68 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 372 (203 ) (166 ) (194 ) (191 ) Dividends for preferred shares — — 5 — 5 Gain on redemption of preferred shares — — (78 ) — (78 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 372 $ (203 ) $ (93 ) $ (194 ) $ (118 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2016 Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ (9 ) $ 624 $ 323 $ 938 Funds deposited by counterparties 2 — — 2 Restricted cash 11 435 — — 446 Accounts receivable - trade, net 734 321 3 — 1,058 Accounts receivable - affiliate 307 (254 ) 200 (139 ) 114 Inventory 482 239 — — 721 Derivative instruments 962 196 1 (92 ) 1,067 Cash collateral paid in support of energy risk management activities 116 34 — — 150 Current assets held-for-sale — 9 — — 9 Prepayments and other current assets 76 152 62 — 290 Current assets - discontinued operations — 1,919 — — 1,919 Total current assets 2,681 3,675 589 (231 ) 6,714 Net Property, Plant and Equipment 4,219 10,926 251 (27 ) 15,369 Other Assets Investment in subsidiaries 1,090 1,054 10,128 (12,272 ) — Equity investments in affiliates (13 ) 1,128 5 — 1,120 Notes receivable, less current portion — 16 — — 16 Goodwill 359 303 — — 662 Intangible assets, net 592 1,384 — (3 ) 1,973 Nuclear decommissioning trust fund 610 — — — 610 Derivative instruments 144 44 36 (43 ) 181 Deferred income taxes 3 — 222 — 225 Non-current assets held for sale — 10 — — 10 Other non-current assets 67 446 328 — 841 Non-current assets - discontinued operations — 2,961 — — 2,961 Total other assets 2,852 7,346 10,719 (12,318 ) 8,599 Total Assets $ 9,752 $ 21,947 $ 11,559 $ (12,576 ) $ 30,682 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 498 $ 18 $ — $ 516 Accounts payable 501 247 34 — 782 Accounts payable — affiliate 744 (452 ) (122 ) (139 ) 31 Derivative instruments 947 237 — (92 ) 1,092 Cash collateral received in support of energy risk management activities 81 — — — 81 Accrued expenses and other current liabilities 316 209 465 — 990 Current liabilities - discontinued operations — 1,210 — — 1,210 Total current liabilities 2,589 1,949 395 (231 ) 4,702 Other Liabilities Long-term debt and capital leases 244 8,252 7,461 — 15,957 Nuclear decommissioning reserve 287 — — — 287 Nuclear decommissioning trust liability 339 — — — 339 Deferred income taxes 186 125 (291 ) — 20 Derivative instruments 157 170 — (43 ) 284 Out-of-market contracts, net 80 150 — — 230 Non-current liabilities held-for-sale — 11 — — 11 Other non-current liabilities 396 431 324 — 1,151 Non-current liabilities - discontinued operations — 3,209 — — 3,209 Total non-current liabilities 1,689 12,348 7,494 (43 ) 21,488 Total Liabilities 4,278 14,297 7,889 (274 ) 26,190 Redeemable noncontrolling interest in subsidiaries — 46 — — 46 Stockholders’ Equity 5,474 7,604 3,670 (12,302 ) 4,446 Total Liabilities and Stockholders’ Equity $ 9,752 $ 21,947 $ 11,559 $ (12,576 ) $ 30,682 (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, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net income/(loss) from continuing operations $ 369 $ (186 ) $ (159 ) $ (244 ) $ (220 ) Adjustments to reconcile net income/(loss) to net cash provided by operating activities: Distributions from unconsolidated affiliates — 40 — (11 ) 29 Equity in (earnings)/losses of unconsolidated affiliates (3 ) 2 — 4 3 Depreciation and amortization 225 291 12 — 528 Provision for bad debts 16 4 — — 20 Amortization of nuclear fuel 26 — — — 26 Amortization of financing costs and debt discount/premiums — 16 13 — 29 Adjustment for debt extinguishment — 4 10 — 14 Amortization of intangibles and out-of-market contracts 20 62 — — 82 Amortization of unearned equity compensation — — 16 — 16 Impairment losses — 195 — — 195 Changes in deferred income taxes and liability for uncertain tax benefits 460 (208 ) (251 ) — 1 Changes in nuclear decommissioning trust liability 13 — — — 13 Changes in derivative instruments (64 ) 54 3 — (7 ) Changes in collateral deposits supporting energy risk management activities 344 (21 ) — — 323 Proceeds from sale of emission allowances 47 (30 ) — — 17 Loss on sale of assets — 8 75 — 83 Cash (used)/provided by changes in other working capital (1,148 ) 239 386 251 (272 ) Net cash provided by continuing operations 305 470 105 — 880 Cash used by discontinued operations (69 ) (69 ) Net Cash Provided by Operating Activities 305 401 105 — 811 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. — — 39 (39 ) — Intercompany dividends — — 12 (12 ) — Acquisition of businesses, net of cash acquired — (17 ) — — (17 ) Capital expenditures (80 ) (329 ) (33 ) — (442 ) Increase in notes receivable — (3 ) — — (3 ) Purchases of emission allowances (27 ) — — — (27 ) Proceeds from sale of emission allowances 25 — — — 25 Investments in nuclear decommissioning trust fund securities (280 ) — — — (280 ) Proceeds from sales of nuclear decommissioning trust fund securities 267 — — — 267 Proceeds from renewable energy grants and state rebates — 10 — — 10 Proceeds from sale of assets, net of cash disposed of — — 25 — 25 Investments in unconsolidated affiliates 1 — — — 1 Other 27 4 — — 31 Net cash (used)/provided by continuing operations (67 ) (335 ) 43 (51 ) (410 ) Cash used by discontinued operations (60 ) (60 ) Net Cash (Used)/Provided by Investing Activities (67 ) (395 ) 43 (51 ) (470 ) Cash Flows from Financing Activities Dividends from NRG Yield, Inc. — (39 ) — 39 — Payments (for)/from intercompany loans (179 ) 45 134 — — Intercompany dividends (52 ) 40 — 12 — Payment of dividends to common and preferred stockholders — — (57 ) — (57 ) Payment for preferred shares — — (226 ) — (226 ) Net receipts for settlement of acquired derivatives that include financing elements — 4 — — 4 Proceeds from issuance of long-term debt — 332 2,891 — 3,223 Payments for short and long-term debt (1 ) (279 ) (3,225 ) — (3,505 ) Distributions from, net of contributions to, noncontrolling interest in subsidiaries — (21 ) — — (21 ) Payment of debt issuance costs — — (35 ) — (35 ) Other (3 ) (7 ) — — (10 ) Net cash used/provided by continuing operations (235 ) 75 (518 ) 51 (627 ) Cash provided by discontinued operations 97 97 Net Cash (Used)/Provided by Financing Activities (235 ) 172 (518 ) 51 (530 ) Change in cash from discontinued operations (32 ) (32 ) Effect of exchange rate changes on cash and cash equivalents — (3 ) — — (3 ) Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties 3 207 (370 ) — (160 ) Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties at Beginning of Period — 629 693 — 1,322 Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties at End of Period $ 3 $ 836 $ 323 $ — $ 1,162 (a) All significant intercompany transactions have been eliminated in consolidation.

Summary of Significant Accoun26

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
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. The reclassifications did not affect results from operations, net assets or cash flows.
Recent Accounting Developments	Recent Accounting Developments - Guidance Adopted in 2017 ASU 2016-18 — In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230) , Restricted Cash, or ASU No. 2016-18. The amendments of ASU No. 2016-18 require an entity to include amounts generally described as restricted cash and restricted cash equivalents, including funds deposited by counterparties with cash and cash equivalents when reconciling the beginning of period and end of period total amounts on the statement of cash flows. The amendments of ASU No. 2016-18 are effective for annual reporting periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted and the adoption of ASU No. 2016-18 will be applied retrospectively. The Company adopted the guidance in ASU No. 2016-18 during the second quarter of 2017. In connection with the adoption of the standard, the Company has applied the guidance retrospectively which resulted in a decrease in cash flow from operations of $54 million and a decrease of in cash flow from investing of $1 million on the statement of cash flow for the six months ended June 30, 2016. ASU 2016-16 — In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740) , Intra-Entity Transfers of Assets Other Than Inventory, or ASU No. 2016-16. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party which has resulted in diversity in practice and increased complexity within financial reporting. The amendments of ASU No. 2016-16 would require an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The Company adopted the guidance in ASU No. 2016-16 effective January 1, 2017. In connection with the adoption of the standard, the Company recorded a reduction to non-current assets of $267 million with a corresponding reduction to cumulative retained deficit. ASU 2016-15 — In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230) , Classification of Certain Cash Receipts and Cash Payments, or ASU No. 2016-15. The amendments of ASU No. 2016-15 were issued to address eight specific cash flow issues for which stakeholders have indicated to the FASB that a diversity in practice existed in how entities were presenting and classifying these items in the statement of cash flows. The issues addressed by ASU No. 2016-15 include but are not limited to the classification of debt prepayment and debt extinguishment costs, payments made for contingent consideration for a business combination, proceeds from the settlement of insurance proceeds, distributions received from equity method investees and separately identifiable cash flows and the application of the predominance principle. The Company adopted the guidance in ASU No. 2016-15 effective January 1, 2017. In connection with the adoption of the standard, the Company has applied the guidance retrospectively which resulted in an increase in cash flow from operations of $55 million and a decrease in cash flow from financing of $55 million on the statement of cash flow for the six months ended June 30, 2016. ASU 2016-09 — In March 2016, the FASB issued ASU No. 2016-09, Compensation - Stock Compensation (Topic 718), or ASU No. 2016-09. The amendments focused on simplification specifically with regard to share-based payment transactions, including income tax consequences, classification of awards as equity or liabilities and classification on the statement of cash flows. The Company adopted the guidance in ASU No. 2016-09 effective January 1, 2017 with no material adjustments recorded to the consolidated balance sheet. Recent Accounting Developments - Guidance Not Yet Adopted ASU 2017-07 — In March 2017, the FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715) , Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, or ASU No. 2017-07. Current GAAP does not indicate where the amount of net benefit cost should be presented in an entity’s income statement and does not require entities to disclose the amount of net benefit cost that is included in the income statement. The amendments of ASU No. 2017-07 require an entity to report the service cost component of net benefit costs in the same line item as other compensation costs arising from services rendered by the related employees during the applicable service period. The other components of net benefit cost are required to be presented separately from the service cost component and outside the subtotal of income from operations. Further, ASU No. 2017-07 prescribes that only the service cost component of net benefit costs is eligible for capitalization. The amendments of ASU No. 2017-07 are effective for fiscal years beginning after December 15, 2017, including interim periods therein. Early adoption is permitted and must be applied on a retrospective basis, except for the amendments regarding the capitalization of the service cost component, which must be applied prospectively. The Company is currently assessing the impact that the adoption of ASU No. 2017-07 will have on its results of operations, cash flows, and statement of financial position. ASU 2016-02 — In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) , or Topic 842, 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 expects to adopt the standard effective January 1, 2019 utilizing the required modified retrospective approach for the earliest period presented. The Company expects to elect certain of the practical expedients permitted, including the expedient that permits the Company to retain its existing lease assessment and classification. The Company is currently working through an adoption plan which includes the evaluation of lease contracts compared to the new standard. While the Company is currently evaluating the impact the new guidance will have on its financial position and results of operations, the Company expects to recognize lease liabilities and right of use assets. The extent of the increase to assets and liabilities associated with these amounts remains to be determined pending the Company’s review of its existing lease contracts and service contracts which may contain embedded leases. While this review is still in process, NRG believes the adoption of Topic 842 will have a material impact on its financial statements. ASU 2014-09 — In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , or Topic 606, which was further amended through various updates issued by the FASB thereafter. The amendments of Topic 606 completed the joint effort between the FASB and the IASB, to develop a common revenue standard for GAAP and IFRS, and to improve financial reporting. The guidance under Topic 606 provides that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for the goods or services provided and establishes a five step model to be applied by an entity in evaluating its contracts with customers. The Company expects to adopt the standard effective January 1, 2018 and apply the guidance retrospectively to contracts at the date of adoption. The Company will recognize the cumulative effect of applying Topic 606 at the date of initial application, as prescribed under the modified retrospective transition method. The Company also expects to elect the practical expedient available under Topic 606 for measuring progress toward complete satisfaction of a performance obligation and for disclosure requirements of remaining performance obligations. The practical expedient allows an entity to recognize revenue in the amount to which the entity has the right to invoice such that the entity has a right to the consideration in an amount that corresponds directly with the value to the customer for performance completed to date by the entity. The Company continues to assess the new standard with a focus on identifying the performance obligations included within its revenue arrangements with customers and evaluating the Company’s methods of estimating the amount and timing of variable consideration. While the impact remains subject to continued review, the Company does not believe the adoption of Topic 606 will have a material impact on its financial statements.
Nuclear Decommissioning	NRG's Nuclear Decommissioning Trust Fund assets 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 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 as follows: Generation, which includes generation, international and BETM; Retail, which includes Mass customers and Business Solutions, which includes C&I customers and other distributed and reliability products; Renewables, which includes solar and wind assets, excluding those in NRG Yield; NRG Yield; and corporate activities. The financial information for the three and six months ended June 30, 2016 has been recast to reflect the current segment structure. On September 1, 2016, NRG Yield acquired the remaining 51.05% interest in CVSR Holdco LLC, which indirectly owns the CVSR solar facility, from the Company. On March 27, 2017, NRG Yield acquired from NRG a 16% interest in the Agua Caliente solar project, and NRG's interests in seven utility-scale solar projects located in Utah. Both acquisitions were treated as a transfer of entities under common control and accordingly, all historical periods have been recast to reflect the acquisition as if they had occurred at the beginning of the financial statement period. On June 14, 2017, as described in Note 3, Discontinued Operations and Dispositions , NRG deconsolidated GenOn for financial reporting purposes. The financial information for all historical periods have been recast to reflect the deconsolidation of GenOn and to present 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).

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
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, 2017 December 31, 2016 (In millions) Accounts receivable allowance for doubtful accounts $ 39 $ 29 Property, plant and equipment accumulated depreciation 6,180 5,711 Intangible assets accumulated amortization 1,698 1,687 Out-of-market contracts accumulated amortization 346 457
Restrictions on Cash and Cash Equivalents	The following table provides a reconciliation of cash and cash equivalents, restricted cash and funds deposited by counterparties reported within the consolidated balance sheet that sum to the total of the same such amounts shown in the statement of cash flows. June 30, 2017 December 31, 2016 June 30, 2016 December 31, 2015 (In millions) Cash and cash equivalents $ 752 $ 938 $ 748 $ 853 Funds deposited by counterparties 19 2 1 55 Restricted cash 469 446 413 414 Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statement of cash flows $ 1,240 $ 1,386 $ 1,162 $ 1,322
Schedule of Change in Noncontrolling Interest	Noncontrolling Interest The following table reflects the changes in NRG's noncontrolling interest balance: (In millions) Balance as of December 31, 2016 $ 2,405 Dividends paid to NRG Yield, Inc. public shareholders (52 ) Distributions to noncontrolling interest (39 ) Comprehensive loss attributable to noncontrolling interest (19 ) Non-cash adjustments to noncontrolling interest 88 Contributions from noncontrolling interest 76 Sale of assets to NRG Yield, Inc. 3 Balance as of June 30, 2017 $ 2,462
Redeemable Noncontrolling Interest	Redeemable Noncontrolling Interest The following table reflects the changes in the Company's redeemable noncontrolling interest balance: (In millions) Balance as of December 31, 2016 $ 46 Contributions from redeemable noncontrolling interest 42 Comprehensive loss attributable to redeemable noncontrolling interest (37 ) Balance as of June 30, 2017 $ 51

Discontinued Operations and D28

Discontinued Operations and Dispositions (Tables)	6 Months Ended
	Jun. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Summary of Results of Discontinued Operations and Major Classes of Assets and Liabilities	Summarized results of discontinued operations were as follows: Period from April 1, 2017 through June 14, 2017 Three months ended June 30, 2016 Period from January 1, 2017 through June 14, 2017 Six months ended June 30, 2016 (In millions) Operating revenues $ 265 $ 398 $ 646 $ 977 Operating costs and expenses (327 ) (474 ) (700 ) (941 ) Gain on sale of assets — — — 32 Other expenses (54 ) (40 ) (98 ) (84 ) Loss from operations of discontinued components, before tax (116 ) (116 ) (152 ) (16 ) Income tax expense/(benefit) 8 — 9 (1 ) Loss from operations of discontinued components (124 ) (116 ) (161 ) (15 ) Interest income - affiliate 3 3 6 6 Loss from operations of discontinued components, net of tax (121 ) (113 ) (155 ) (9 ) Pre-tax loss on deconsolidation (208 ) — (208 ) — Settlement consideration and services credit (289 ) — (289 ) — Pension liability assumption (119 ) — (119 ) — Advisory and consulting fees (4 ) — (4 ) — Loss on disposal of discontinued components, net of tax (620 ) — (620 ) — Loss from discontinued operations, net of tax $ (741 ) $ (113 ) $ (775 ) $ (9 ) The following table summarizes the major classes of assets and liabilities classified as discontinued operations as of December 31, 2016. As noted above, NRG no longer consolidates GenOn for financial reporting purposes as of June 30, 2017. (In millions) December 31, 2016 Cash and cash equivalents $ 1,034 Other current assets 885 Current assets - discontinued operations 1,919 Property, plant and equipment, net 2,543 Other non-current assets 418 Non-current assets - discontinued operations 2,961 Current portion of long term debt and capital leases 704 Other current liabilities 506 Current liabilities - discontinued operations 1,210 Long-term debt and capital leases 2,050 Out-of-market contracts 811 Other non-current liabilities 348 Non-current liabilities - discontinued operations $ 3,209

Fair Value of Financial Instr29

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 As of December 31, 2016 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable (a) $ 25 $ 24 $ 34 $ 34 Liabilities: Long-term debt, including current portion (b) 17,086 17,246 16,655 16,620 (a) Includes the current portion of notes receivable which is recorded in prepayments and other current assets on the Company's consolidated balance sheets. (b) Excludes deferred financing costs, which are recorded as a reduction to long-term debt on the Company's consolidated balance sheets. The following table presents the level within the fair value hierarchy for long-term debt, including current portion as of June 30, 2017 and December 31, 2016 : As of June 30, 2017 As of December 31, 2016 Level 2 Level 3 Level 2 Level 3 (In millions) Long-term debt, including current portion $ 9,398 $ 7,848 $ 9,205 $ 7,415
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, 2017 Fair Value (In millions) Level 1 Level 2 Level 3 Total Investment in available-for-sale securities (classified within other non-current assets): Debt securities $ — $ — $ 18 $ 18 Available-for-sale securities 4 — — 4 Nuclear trust fund investments: Cash and cash equivalents 11 — — 11 U.S. government and federal agency obligations 45 — — 45 Federal agency mortgage-backed securities — 71 — 71 Commercial mortgage-backed securities — 17 — 17 Corporate debt securities — 109 — 109 Equity securities 319 — 61 380 Foreign government fixed income securities — 4 — 4 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 186 535 110 831 Interest rate contracts — 39 — 39 Total assets $ 566 $ 775 $ 189 $ 1,530 Derivative liabilities: Commodity contracts 292 496 121 909 Interest rate contracts — 95 — 95 Total liabilities $ 292 $ 591 $ 121 $ 1,004 . As of December 31, 2016 Fair Value (In millions) Level 1 Level 2 Level 3 Total Investment in available-for-sale securities (classified within other non-current assets): Debt securities $ — $ — $ 17 $ 17 Available-for-sale securities 10 — — 10 Nuclear trust fund investments: Cash and cash equivalents 25 — — 25 U.S. government and federal agency obligations 72 1 — 73 Federal agency mortgage-backed securities — 62 — 62 Commercial mortgage-backed securities — 17 — 17 Corporate debt securities — 84 — 84 Equity securities 292 — 54 346 Foreign government fixed income securities — 3 — 3 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 560 549 90 1,199 Interest rate contracts — 49 — 49 Total assets $ 960 $ 765 $ 161 $ 1,886 Derivative liabilities: Commodity contracts 494 636 158 1,288 Interest rate contracts — 88 — 88 Total liabilities $ 494 $ 724 $ 158 $ 1,376
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	The following tables reconcile, for the three and six months ended June 30, 2017 and 2016 , 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, 2017 Six months ended June 30, 2017 (In millions) Debt Securities Trust Fund Investments Derivatives (a) Total Debt Securities Trust Fund Investments Derivatives (a) Total Beginning balance $ 18 $ 58 $ (56 ) $ 20 $ 17 $ 54 $ (68 ) $ 3 Total gains — realized/unrealized: Included in earnings — — 40 40 1 — 46 47 Included in nuclear decommissioning obligation — 3 — 3 — 7 — 7 Purchases — — 5 5 — — 9 9 Transfers into Level 3 (b) — — 3 3 — — (5 ) (5 ) Transfers out of Level 3 (b) — — (3 ) (3 ) — — 7 7 Ending balance as of June 30, 2017 $ 18 $ 61 $ (11 ) $ 68 $ 18 $ 61 $ (11 ) $ 68 Gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of June 30, 2017 $ — $ — $ 22 $ 22 $ — $ — $ 7 $ 7 (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, 2016 Six months ended June 30, 2016 (In millions) Debt Securities Trust Fund Investments Derivatives (a) Total Debt Securities Trust Fund Investments Derivatives (a) Total Beginning balance $ 17 $ 52 $ (2 ) $ 67 $ 17 $ 54 $ (22 ) $ 49 Total gains/(losses) — realized/unrealized: Included in earnings — — 23 23 — — 9 9 Included in OCI (1 ) — — (1 ) (1 ) — — (1 ) Included in nuclear decommissioning obligations — (1 ) — (1 ) — (4 ) — (4 ) Purchases — — 22 22 — 1 27 28 Transfers into Level 3 (b) — — (20 ) (20 ) — — 7 7 Transfers out of Level 3 (b) — — (5 ) (5 ) — — (3 ) (3 ) Ending balance as of June 30, 2016 $ 16 $ 51 $ 18 $ 85 $ 16 $ 51 $ 18 $ 85 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, 2016 $ — $ — $ 11 $ 11 $ — $ — $ (7 ) $ (7 ) (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 valueets, 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, 2017 and December 31, 2016 : Significant Unobservable Inputs June 30, 2017 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 57 $ 78 Discounted Cash Flow Forward Market Price (per MWh) $ 10 $ 115 $ 30 FTRs 53 43 Discounted Cash Flow Auction Prices (per MWh) (29 ) 27 — $ 110 $ 121 Significant Unobservable Inputs December 31, 2016 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 39 $ 108 Discounted Cash Flow Forward Market Price (per MWh) $ 11 $ 104 $ 31 FTRs 51 50 Discounted Cash Flow Auction Prices (per MWh) (22 ) 17 — $ 90 $ 158
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, 2017 and December 31, 2016 : 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 89 % Financial institutions 11 Total as of June 30, 2017 100 % Net Exposure (a) (b) Category by Counterparty Credit Quality (% of Total) Investment grade 78 % Non-Investment grade/Non-Rated 22 Total as of June 30, 2017 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 Trust30

Nuclear Decommissioning Trust Fund (Tables)	6 Months Ended
	Jun. 30, 2017
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 (including other-than-temporary impairments) for the securities held in the trust funds, as well as information about the contractual maturities of those securities. As of June 30, 2017 As of December 31, 2016 (In millions, except otherwise noted) Fair Value Unrealized Gains Unrealized Losses Weighted-average Maturities (In years) Fair Value Unrealized Gains Unrealized Losses Weighted-average Maturities (In years) Cash and cash equivalents $ 11 $ — $ — — $ 25 $ — $ — — U.S. government and federal agency obligations 45 2 — 11 73 1 — 11 Federal agency mortgage-backed securities 71 1 1 24 62 1 1 25 Commercial mortgage-backed securities 17 — — 24 17 — 1 26 Corporate debt securities 109 2 1 10 84 1 2 11 Equity securities 380 245 — — 346 214 — — Foreign government fixed income securities 4 — — 7 3 — — 9 Total $ 637 $ 250 $ 2 $ 610 $ 217 $ 4
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, 2017 2016 (In millions) Realized gains $ 3 $ 3 Realized losses 3 2 Proceeds from sale of securities 277 267

Accounting for Derivative Ins31

Accounting for Derivative Instruments and Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 and December 31, 2016 . 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, 2017 December 31, 2016 Category Units (In millions) Emissions Short Ton (2 ) — Coal Short Ton 22 35 Natural Gas MMBtu 45 (53 ) Oil Barrel — 1 Power MWh 24 7 Capacity MW/Day (1 ) (1 ) Interest Dollars $ 3,701 $ 3,429 Equity Shares 1 1
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, 2017 December 31, 2016 June 30, 2017 December 31, 2016 (In millions) Derivatives designated as cash flow hedges: Interest rate contracts current $ — $ — $ 9 $ 28 Interest rate contracts long-term 9 12 19 41 Total derivatives designated as cash flow hedges 9 12 28 69 Derivatives not designated as cash flow hedges : Interest rate contracts current 4 — 21 7 Interest rate contracts long-term 26 37 46 12 Commodity contracts current 640 1,067 681 1,057 Commodity contracts long-term 191 132 228 231 Total derivatives not designated as cash flow hedges 861 1,236 976 1,307 Total derivatives $ 870 $ 1,248 $ 1,004 $ 1,376
Offsetting of derivatives by counterparty master agreement level and collateral received or paid	The following table summarizes the offsetting of derivatives by counterparty master agreement level and collateral received or paid: Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount As of June 30, 2017 (In millions) Commodity contracts: Derivative assets $ 831 $ (730 ) $ (2 ) $ 99 Derivative liabilities (909 ) 730 121 (58 ) Total commodity contracts (78 ) — 119 41 Interest rate contracts: Derivative assets 39 (2 ) — 37 Derivative liabilities (95 ) 2 — (93 ) Total interest rate contracts (56 ) — — (56 ) Total derivative instruments $ (134 ) $ — $ 119 $ (15 ) Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Assets / Liabilities Derivative Instruments Cash Collateral (Held) / Posted Net Amount As of December 31, 2016 (In millions) Commodity contracts: Derivative assets $ 1,199 $ (1,021 ) $ (13 ) $ 165 Derivative liabilities (1,288 ) 1,021 13 (254 ) Total commodity contracts (89 ) — — (89 ) Interest rate contracts: Derivative assets 49 (4 ) — 45 Derivative liabilities (88 ) 4 — (84 ) Total interest rate contracts (39 ) — — (39 ) Total derivative instruments $ (128 ) $ — $ — $ (128 )
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 of ASC 815 on the Company's accumulated OCI balance attributable to cash flow hedge derivatives, net of tax: Interest Rate Contracts Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions) Accumulated OCI beginning balance $ (61 ) $ (150 ) $ (66 ) $ (101 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts 3 7 6 10 Mark-to-market of cash flow hedge accounting contracts (9 ) (22 ) (7 ) (74 ) Accumulated OCI ending balance, net of $16, and $26 tax $ (67 ) $ (165 ) $ (67 ) $ (165 ) Losses expected to be realized from OCI during the next 12 months, net of $3 tax $ 15 $ 15
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, ineffectiveness on cash flow hedges and trading activity on the Company's statement of operations. The effect of energy commodity contracts is included within operating revenues and cost of operations and the effect of interest rate contracts is included in interest expense. Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Unrealized mark-to-market results (In millions) Reversal of previously recognized unrealized losses/(gains) on settled positions related to economic hedges $ 22 $ (18 ) $ 25 $ (45 ) Reversal of acquired loss/(gain) positions related to economic hedges 1 (2 ) 1 (4 ) Net unrealized gains/(losses) on open positions related to economic hedges 36 (13 ) 15 77 Total unrealized mark-to-market gains/(losses) for economic hedging activities 59 (33 ) 41 28 Reversal of previously recognized unrealized (gains)/losses on settled positions related to trading activity (4 ) 2 (19 ) 10 Net unrealized gains on open positions related to trading activity 16 11 17 22 Total unrealized mark-to-market gains/(losses) for trading activity 12 13 (2 ) 32 Total unrealized gains/(losses) $ 71 $ (20 ) $ 39 $ 60 Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions) Unrealized gains/(losses) included in operating revenues $ 53 $ (460 ) $ 157 $ (390 ) Unrealized gains/(losses) included in cost of operations 18 440 (118 ) 450 Total impact to statement of operations — energy commodities $ 71 $ (20 ) $ 39 $ 60 Total impact to statement of operations — interest rate contracts $ (24 ) $ (7 ) $ (19 ) $ (18 )

Debt and Capital Leases (Tables

Debt and Capital Leases (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 December 31, 2016 June 30, 2017 interest rate % (a) Recourse debt: Senior notes, due 2018 $ 398 $ 398 7.625 Senior notes, due 2021 207 207 7.875 Senior notes, due 2022 992 992 6.250 Senior notes, due 2023 869 869 6.625 Senior notes, due 2024 733 733 6.250 Senior notes, due 2026 1,000 1,000 7.250 Senior notes, due 2027 1,250 1,250 6.625 Term loan facility, due 2023 1,881 1,891 L+2.25 Tax-exempt bonds 455 455 4.125 - 6.00 Subtotal NRG recourse debt 7,785 7,795 Non-recourse debt: NRG Yield Operating LLC Senior Notes, due 2024 500 500 5.375 NRG Yield Operating LLC Senior Notes, due 2026 350 350 5.000 NRG Yield, Inc. Convertible Senior Notes, due 2019 345 345 3.500 NRG Yield, Inc. Convertible Senior Notes, due 2020 288 288 3.250 El Segundo Energy Center, due 2023 414 443 L+1.625 - L+2.25 Marsh Landing, due 2017 and 2023 358 370 L+1.750 - L+1.875 Alta Wind I - V lease financing arrangements, due 2034 and 2035 939 965 5.696 - 7.015 Walnut Creek, term loans due 2023 299 310 L+1.625 Utah Portfolio, due 2022 284 287 L+2.625 Tapestry, due 2021 166 172 L+1.625 CVSR, due 2037 757 771 2.339 - 3.775 CVSR HoldCo, due 2037 193 199 4.680 Alpine, due 2022 142 145 L+1.750 Energy Center Minneapolis, due 2017 and 2025 85 96 5.95 - 7.25 Energy Center Minneapolis, due 2031 125 125 3.55 Viento, due 2023 169 178 L+2.75 NRG Yield - other 569 540 various Subtotal NRG Yield debt (non-recourse to NRG) 5,983 6,084 Ivanpah, due 2033 and 2038 1,108 1,113 2.285 - 4.256 Carlsbad Energy Project 345 — 4.120 Agua Caliente, due 2037 843 849 2.395 - 3.633 Agua Caliente Borrower 1, due 2038 89 — 5.430 Cedro Hill, due 2025 156 163 L+1.75 Midwest Generation, due 2019 194 231 4.390 NRG Other 622 468 various Subtotal other NRG non-recourse debt 3,357 2,824 Subtotal all non-recourse debt 9,340 8,908 Subtotal long-term debt (including current maturities) 17,125 16,703 Capital leases 6 6 various Subtotal long-term debt and capital leases (including current maturities) 17,131 16,709 Less current maturities (1,042 ) (516 ) Less debt issuance costs (208 ) (188 ) Discounts (39 ) (48 ) Total long-term debt and capital leases $ 15,842 $ 15,957 (a) As of June 30, 2017 , L+ equals 3 month LIBOR plus x%, with the exception of the Utah Portfolio term loans.

Variable Interest Entities, o33

Variable Interest Entities, or VIEs (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 December 31, 2016 Current assets $ 84 $ 87 Net property, plant and equipment 1,493 1,534 Other long-term assets 1,024 954 Total assets 2,601 2,575 Current liabilities 63 59 Long-term debt 424 442 Other long-term liabilities 187 183 Total liabilities 674 684 Noncontrolling interests 600 529 Net assets less noncontrolling interests $ 1,327 $ 1,362

Changes in Capital Structure (T

Changes in Capital Structure (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2016 417,583,825 (102,140,814 ) 315,443,011 Shares issued under LTIPs 397,287 — 397,287 Shares issued under ESPP — 282,530 282,530 Balance as of June 30, 2017 417,981,112 (101,858,284 ) 316,122,828
Schedule of dividends paid	The following table lists the dividends paid during the six months ended June 30, 2017 : Second Quarter 2017 First Quarter 2017 Dividends per Common Share $ 0.03 $ 0.03

Earnings_(Loss) Per Share (Tabl

Earnings/(Loss) Per Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Reconciliation of NRG's basic and diluted earnings per share	The reconciliation of NRG's basic and diluted loss per share is shown in the following table: Three months ended June 30, Six months ended June 30, (In millions, except per share data) 2017 2016 2017 2016 Basic and diluted loss per share attributable to NRG Energy, Inc. common stockholders Net loss attributable to NRG Energy, Inc. $ (626 ) $ (271 ) $ (790 ) $ (189 ) Dividends for preferred shares — — — 5 Gain on redemption of 2.822% redeemable perpetual preferred stock — (78 ) — (78 ) Loss available for common stockholders $ (626 ) $ (193 ) $ (790 ) $ (116 ) Weighted average number of common shares outstanding - basic and diluted 316 315 316 315 Loss per weighted average common share — basic and diluted $ (1.98 ) $ (0.61 ) $ (2.50 ) $ (0.37 )
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 loss per share: Three months ended June 30, Six months ended June 30, (In millions of shares) 2017 2016 2017 2016 Equity compensation plans 6 3 6 3 Total 6 3 6 3

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Schedule of segment reporting information, by segment	Generation (a) Retail (a) Renewables (a) NRG Yield Corporate (a) Eliminations Total Three months ended June 30, 2017 (In millions) Operating revenues (a) $ 882 $ 1,603 $ 123 $ 284 $ 3 $ (194 ) $ 2,701 Depreciation and amortization 95 29 50 78 8 — 260 Impairment losses 41 — 22 — — — 63 Equity in (losses)/earnings of unconsolidated affiliates (15 ) — (2 ) 16 3 (5 ) (3 ) (Loss)/income from continuing operations before income taxes (89 ) 330 (52 ) 53 (135 ) (4 ) 103 (Loss)/income from continuing operations (90 ) 341 (47 ) 45 (146 ) (4 ) 99 Loss from discontinued operations, net of tax — — — — (741 ) — (741 ) Net (Loss)/Income (90 ) 341 (47 ) 45 (887 ) (4 ) (642 ) Net (Loss)/income attributable to NRG Energy, Inc. $ (90 ) $ 341 $ (22 ) $ 50 — $ (920 ) $ 15 $ (626 ) Total assets as of June 30, 2017 $ 8,539 $ 2,439 $ 5,193 $ 8,513 $ 10,954 $ (10,433 ) $ 25,205 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 171 $ 1 $ 10 $ 3 $ 9 $ — $ 194 Generation (a) Retail (a) Renewables (a) NRG Yield (a) Corporate (a) Eliminations Total Three months ended June 30, 2016 (In millions) Operating revenues (a) $ 504 $ 1,536 $ 101 $ 283 $ 10 $ (186 ) $ 2,248 Depreciation and amortization 97 29 47 75 14 — 262 Impairment losses 17 — 27 — 12 — 56 Equity in earnings/(losses) of unconsolidated affiliates 2 — (2 ) 14 27 (37 ) 4 Loss on sale of assets — — — — (83 ) — (83 ) Loss on debt extinguishment, net — — — — (80 ) — (80 ) (Loss)/income from continuing operations before income taxes (458 ) 657 (75 ) 76 (295 ) (43 ) (138 ) (Loss)/income from continuing operations (458 ) 657 (71 ) 64 (312 ) (43 ) (163 ) Loss from discontinued operations, net of tax — — — — (113 ) — (113 ) Net (Loss)/Income (458 ) 657 (71 ) 64 (425 ) (43 ) (276 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (458 ) $ 661 $ (66 ) $ 48 $ (449 ) $ (7 ) $ (271 ) (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 166 $ 1 $ 4 $ 2 $ 13 $ — $ 186 Generation (a) Retail (a) Renewables (a)(b) NRG Yield Corporate (a) Eliminations Total Six months ended June 30, 2017 (In millions) Operating revenues (a) $ 1,848 $ 2,938 $ 220 $ 502 $ 11 $ (436 ) $ 5,083 Depreciation and amortization 192 57 99 153 16 — 517 Impairment losses 41 — 22 — — — 63 Equity in (losses)/earnings of unconsolidated affiliates (28 ) — (3 ) 35 7 (9 ) 2 (Loss)/income from continuing operations before income taxes (54 ) 303 (89 ) 51 (273 ) (9 ) (71 ) (Loss)/Income from continuing operations (56 ) 311 (79 ) 44 (281 ) (9 ) (70 ) Loss from discontinued operations, net of tax — — — — (775 ) — (775 ) Net (Loss)/Income (56 ) 311 (79 ) 44 (1,056 ) (9 ) (845 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (56 ) $ 311 $ (26 ) $ 58 $ (1,089 ) $ 12 $ (790 ) (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 406 $ 11 $ 4 $ — $ 15 $ — $ 436 Generation (a)(c) Retail (a) Renewables (a) NRG Yield (a) Corporate (a) Eliminations Total Six months ended June 30, 2016 (In millions) Operating revenues (a) $ 1,637 $ 2,906 $ 197 $ 517 $ 28 $ (378 ) $ 4,907 Depreciation and amortization 197 57 95 149 30 — 528 Impairment losses 17 — 27 — 12 — 56 Equity in (losses)/earnings of unconsolidated affiliates (5 ) — (8 ) 18 6 (14 ) (3 ) Loss on sale of assets — — — — (83 ) — (83 ) Impairment loss on investment (137 ) — — — (2 ) — (139 ) Loss on debt extinguishment, net — — — — (69 ) — (69 ) (Loss)/income from continuing operations before income taxes (433 ) 808 (122 ) 78 (495 ) (9 ) (173 ) (Loss)/income from continuing operations (433 ) 807 (111 ) 66 (540 ) (9 ) (220 ) Loss from discontinued operations, net of tax — — — — (9 ) — (9 ) Net (Loss)/Income (433 ) 807 (111 ) 66 (549 ) (9 ) (229 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (433 ) $ 807 $ (96 ) $ 58 $ (558 ) $ 33 $ (189 ) (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 330 $ 5 $ 8 $ 6 $ 29 $ — $ 378

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2017
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 otherwise noted) 2017 2016 2017 2016 Income/(Loss) before income taxes $ 103 $ (138 ) $ (71 ) $ (173 ) Income tax expense/(benefit) from continuing operations 4 25 (1 ) 47 Effective tax rate 3.9 % (18.1 )% 1.4 % (27.2 )%

Condensed Consolidating Finan38

Condensed Consolidating Financial Information (Tables)	6 Months Ended
	Jun. 30, 2017
Condensed Consolidating Financial Information Disclosure [Abstract]
Condensed Consolidating Statements of Operations	NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the three months ended June 30, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 1,758 $ 989 $ — $ (46 ) $ 2,701 Operating Costs and Expenses Cost of operations 1,307 558 16 (44 ) 1,837 Depreciation and amortization 102 150 8 — 260 Impairment losses 42 21 — — 63 Selling, general and administrative 86 38 100 (1 ) 223 Acquisition-related transaction and integration costs — 1 — — 1 Development activity expenses — 13 5 — 18 Total operating costs and expenses 1,537 781 129 (45 ) 2,402 Other income - affiliate — — 42 — 42 Gain on sale of assets 2 — — — 2 Operating Income/(Loss) 223 208 (87 ) (1 ) 343 Other Income/(Expense) Equity in earnings/(losses) of consolidated subsidiaries 57 (22 ) (123 ) 88 — Equity in earnings/(losses) of unconsolidated affiliates — 676 (645 ) (34 ) (3 ) Other income — 7 3 — 10 Interest expense (4 ) (121 ) (122 ) (247 ) Total other income/(expense) 53 540 (887 ) 54 (240 ) Income/(Loss) from Continuing Operations Before Income Taxes 276 748 (974 ) 53 103 Income tax expense/(benefit) 113 267 (376 ) — 4 Income/(Loss) from Continuing Operations 163 481 (598 ) 53 99 Loss from Discontinued Operations, net of income tax — (741 ) — — (741 ) Net Income/(Loss) 163 (260 ) (598 ) 53 (642 ) Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests — (9 ) 28 (35 ) (16 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 163 $ (251 ) $ (626 ) $ 88 $ (626 ) (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, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,357 $ 1,851 $ — $ (125 ) $ 5,083 Operating Costs and Expenses Cost of operations 2,568 1,222 31 (125 ) 3,696 Depreciation and amortization 203 298 16 — 517 Impairment losses 42 21 — — 63 Selling, general and administrative 184 84 216 (2 ) 482 Acquisition-related transaction and integration costs — 2 — — 2 Development activity expenses — 25 10 — 35 Total operating costs and expenses 2,997 1,652 273 (127 ) 4,795 Other income - affiliate — — 90 — 90 Gain on sale of assets 4 — — — 4 Operating Income/(Loss) 364 199 (183 ) 2 382 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (20 ) (57 ) (48 ) 125 — Equity in earnings/(losses) of unconsolidated affiliates — 707 (669 ) (36 ) 2 Other income 1 12 5 — 18 Loss on debt extinguishment — (2 ) — — (2 ) Interest expense (7 ) (225 ) (239 ) — (471 ) Total other (expense)/income (26 ) 435 (951 ) 89 (453 ) Income/(Loss) from Continuing Operations Before Income Taxes 338 634 (1,134 ) 91 (71 ) Income tax expense/(benefit) 131 237 (369 ) — (1 ) Income/(Loss) from Continuing Operations 207 397 (765 ) 91 (70 ) Loss from Discontinued Operations, net of income tax — (775 ) — — (775 ) Net Income/(Loss) 207 (378 ) (765 ) 91 (845 ) Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests — (46 ) 25 (34 ) (55 ) Net Income/(Loss) Attributable to $ 207 $ (332 ) $ (790 ) $ 125 $ (790 ) (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, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 1,716 $ 569 $ — $ (37 ) $ 2,248 Operating Costs and Expenses Cost of operations 1,128 342 10 (37 ) 1,443 Depreciation and amortization 112 144 6 — 262 Impairment losses — 56 — — 56 Selling, general and administrative 93 46 127 — 266 Acquisition-related transaction and integration costs — — 5 — 5 Development activity expenses — 13 5 — 18 Total operating costs and expenses 1,333 601 153 (37 ) 2,050 Other income - affiliate 48 48 Loss on sale of assets — — (83 ) — (83 ) Operating Income/(Loss) 383 (32 ) (188 ) — 163 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (50 ) (35 ) 67 18 — Equity in earnings of unconsolidated affiliates 2 41 7 (46 ) 4 Gain on investment — — 7 — 7 Other income/(loss), net 1 2 2 — 5 Loss on debt extinguishment — (4 ) (76 ) — (80 ) Interest expense (4 ) (101 ) (132 ) — (237 ) Total other expense (51 ) (97 ) (125 ) (28 ) (301 ) Income/(Loss) from Continuing Operations Before Income Taxes 332 (129 ) (313 ) (28 ) (138 ) Income tax expense/(benefit) 128 (33 ) (70 ) — 25 Income/(Loss) from Continuing Operations 204 (96 ) (243 ) (28 ) (163 ) (Loss)/ Income from Discontinued Operations, net of income tax — (116 ) 3 — (113 ) Net Income/(Loss) 204 (212 ) (240 ) (28 ) (276 ) Less: Net income attributable to noncontrolling interest and redeemable noncontrolling interest — 10 31 (46 ) (5 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 204 $ (222 ) $ (271 ) $ 18 $ (271 ) (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, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,655 $ 1,310 $ — $ (58 ) $ 4,907 Operating Costs and Expenses Cost of operations 2,559 754 19 (61 ) 3,271 Depreciation and amortization 225 291 12 — 528 Impairment losses — 56 — — 56 Selling, general and administrative 191 95 234 — 520 Acquisition-related transaction and integration costs — — 6 — 6 Development activity expenses — 32 12 — 44 Total operating costs and expenses 2,975 1,228 283 (61 ) 4,425 Other income - affiliate — — 96 — 96 Loss on sale of assets — — (83 ) — (83 ) Operating Income/(Loss) 680 82 (270 ) 3 495 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (81 ) (70 ) 342 (191 ) — Equity in earnings/(losses) of unconsolidated affiliates 3 39 10 (55 ) (3 ) Impairment loss on investment — (139 ) — — (139 ) Other income, net 2 19 2 (1 ) 22 Loss on debt extinguishment — (4 ) (65 ) — (69 ) Interest expense (7 ) (207 ) (265 ) — (479 ) Total other (expense)/income (83 ) (362 ) 24 (247 ) (668 ) Income/(Loss) Before Income Taxes 597 (280 ) (246 ) (244 ) (173 ) Income tax expense/(benefit) 228 (94 ) (87 ) — 47 Income/(Loss) from Continuing Operations 369 (186 ) (159 ) (244 ) (220 ) (Loss)/Income from Discontinued Operations, net of income tax — (15 ) 6 — (9 ) Net Income/(Loss) 369 (201 ) (153 ) (244 ) (229 ) Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (23 ) 36 (53 ) (40 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 369 $ (178 ) $ (189 ) $ (191 ) $ (189 ) (a) All significant intercompany transactions have been eliminated in consolidation.
Condensed Consolidating Statements of Comprehensive Income/(Loss)	NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the three months ended June 30, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 163 $ (260 ) $ (598 ) $ 53 $ (642 ) Other Comprehensive Income/(Loss), net of tax Unrealized loss on derivatives, net — (6 ) (4 ) 5 (5 ) Foreign currency translation adjustments, net — 1 — — 1 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — 28 28 (29 ) 27 Other comprehensive income/(loss) — 23 25 (24 ) 24 Comprehensive Income/(Loss) 163 (237 ) (573 ) 29 (618 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (10 ) 28 (35 ) (17 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. $ 163 $ (227 ) $ (601 ) $ 64 $ (601 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the six months ended June 30, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 207 $ (378 ) $ (765 ) $ 91 $ (845 ) Other Comprehensive Income/(Loss), net of tax Unrealized gain on derivatives, net — (1 ) — — (1 ) Foreign currency translation adjustments, net 5 5 7 (9 ) 8 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net — 29 27 (29 ) 27 Other comprehensive income 5 33 35 (38 ) 35 Comprehensive Income/(Loss) 212 (345 ) (730 ) 53 (810 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (47 ) 25 (34 ) (56 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. $ 212 $ (298 ) $ (755 ) $ 87 $ (754 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the three months ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 204 $ (212 ) $ (240 ) $ (28 ) $ (276 ) Other Comprehensive Income/(Loss), net of tax Unrealized loss on derivatives, net — (5 ) (4 ) 6 (3 ) Foreign currency translation adjustments, net (2 ) (2 ) (4 ) 5 (3 ) Available-for-sale securities, net — — (2 ) — (2 ) Other comprehensive loss (2 ) (7 ) (10 ) 11 (8 ) Comprehensive Income/(Loss) 202 (219 ) (250 ) (17 ) (284 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (1 ) 31 (46 ) (16 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 202 (218 ) (281 ) 29 (268 ) Gain on redemption of preferred shares — — (78 ) — (78 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 202 $ (218 ) $ (203 ) $ 29 $ (190 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the six months ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 369 $ (201 ) $ (153 ) $ (244 ) $ (229 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net — (55 ) 20 — (35 ) Foreign currency translation adjustments, net 2 2 2 (3 ) 3 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net 1 — — — 1 Other comprehensive income/(loss) 3 (53 ) 23 (3 ) (30 ) Comprehensive Income/(Loss) 372 (254 ) (130 ) (247 ) (259 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (51 ) 36 (53 ) (68 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 372 (203 ) (166 ) (194 ) (191 ) Dividends for preferred shares — — 5 — 5 Gain on redemption of preferred shares — — (78 ) — (78 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 372 $ (203 ) $ (93 ) $ (194 ) $ (118 ) (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, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ (19 ) $ 363 $ 408 $ — $ 752 Funds deposited by counterparties 14 2 3 — 19 Restricted cash 23 443 3 — 469 Accounts receivable - trade, net 783 376 3 — 1,162 Accounts receivable - affiliate 195 5 1 (102 ) 99 Inventory 472 241 — — 713 Derivative instruments 572 142 4 (74 ) 644 Cash collateral paid in support of energy risk management activities 252 25 — — 277 Prepayments and other current assets 106 155 40 — 301 Current assets - held for sale — 33 — — 33 Total current assets 2,398 1,785 462 (176 ) 4,469 Net property, plant and equipment 4,038 11,049 241 (26 ) 15,302 Other Assets Investment in subsidiaries 1,158 1,040 9,626 (11,824 ) — Equity investments in affiliates — 1,123 4 — 1,127 Notes receivable, less current portion — 9 — — 9 Goodwill 359 303 — — 662 Intangible assets, net 560 1,336 — (3 ) 1,893 Nuclear decommissioning trust fund 637 — — — 637 Derivative instruments 187 47 26 (34 ) 226 Deferred income tax (6 ) (361 ) 578 — 211 Non-current assets held-for-sale — 10 — — 10 Other non-current assets 60 537 62 — 659 Total other assets 2,955 4,044 10,296 (11,861 ) 5,434 Total Assets $ 9,391 $ 16,878 $ 10,999 $ (12,063 ) $ 25,205 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 622 $ 420 $ — $ 1,042 Accounts payable 540 187 30 — 757 Accounts payable — affiliate 724 (441 ) (136 ) (130 ) 17 Derivative instruments 590 195 — (74 ) 711 Cash collateral received in support of energy risk management activities 14 2 3 19 Accrued expenses and other current liabilities 298 5 479 28 810 Accrued expenses and other current liabilities-affiliate — 164 — — 164 Total current liabilities 2,166 734 796 (176 ) 3,520 Other Liabilities Long-term debt and capital leases 244 8,616 6,982 — 15,842 Nuclear decommissioning reserve 262 — — — 262 Nuclear decommissioning trust liability 367 — — — 367 Deferred income taxes 308 — (288 ) — 20 Derivative instruments 179 148 — (34 ) 293 Out-of-market contracts, net 74 145 — — 219 Non-current liabilities held-for-sale — 13 — — 13 Other non-current liabilities 383 316 436 — 1,135 Total non-current liabilities 1,817 9,238 7,130 (34 ) 18,151 Total liabilities 3,983 9,972 7,926 (210 ) 21,671 Redeemable noncontrolling interest in subsidiaries — 51 — — 51 Stockholders’ Equity 5,408 6,855 3,073 (11,853 ) 3,483 Total Liabilities and Stockholders’ Equity $ 9,391 $ 16,878 $ 10,999 $ (12,063 ) $ 25,205 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2016 Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ (9 ) $ 624 $ 323 $ 938 Funds deposited by counterparties 2 — — 2 Restricted cash 11 435 — — 446 Accounts receivable - trade, net 734 321 3 — 1,058 Accounts receivable - affiliate 307 (254 ) 200 (139 ) 114 Inventory 482 239 — — 721 Derivative instruments 962 196 1 (92 ) 1,067 Cash collateral paid in support of energy risk management activities 116 34 — — 150 Current assets held-for-sale — 9 — — 9 Prepayments and other current assets 76 152 62 — 290 Current assets - discontinued operations — 1,919 — — 1,919 Total current assets 2,681 3,675 589 (231 ) 6,714 Net Property, Plant and Equipment 4,219 10,926 251 (27 ) 15,369 Other Assets Investment in subsidiaries 1,090 1,054 10,128 (12,272 ) — Equity investments in affiliates (13 ) 1,128 5 — 1,120 Notes receivable, less current portion — 16 — — 16 Goodwill 359 303 — — 662 Intangible assets, net 592 1,384 — (3 ) 1,973 Nuclear decommissioning trust fund 610 — — — 610 Derivative instruments 144 44 36 (43 ) 181 Deferred income taxes 3 — 222 — 225 Non-current assets held for sale — 10 — — 10 Other non-current assets 67 446 328 — 841 Non-current assets - discontinued operations — 2,961 — — 2,961 Total other assets 2,852 7,346 10,719 (12,318 ) 8,599 Total Assets $ 9,752 $ 21,947 $ 11,559 $ (12,576 ) $ 30,682 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 498 $ 18 $ — $ 516 Accounts payable 501 247 34 — 782 Accounts payable — affiliate 744 (452 ) (122 ) (139 ) 31 Derivative instruments 947 237 — (92 ) 1,092 Cash collateral received in support of energy risk management activities 81 — — — 81 Accrued expenses and other current liabilities 316 209 465 — 990 Current liabilities - discontinued operations — 1,210 — — 1,210 Total current liabilities 2,589 1,949 395 (231 ) 4,702 Other Liabilities Long-term debt and capital leases 244 8,252 7,461 — 15,957 Nuclear decommissioning reserve 287 — — — 287 Nuclear decommissioning trust liability 339 — — — 339 Deferred income taxes 186 125 (291 ) — 20 Derivative instruments 157 170 — (43 ) 284 Out-of-market contracts, net 80 150 — — 230 Non-current liabilities held-for-sale — 11 — — 11 Other non-current liabilities 396 431 324 — 1,151 Non-current liabilities - discontinued operations — 3,209 — — 3,209 Total non-current liabilities 1,689 12,348 7,494 (43 ) 21,488 Total Liabilities 4,278 14,297 7,889 (274 ) 26,190 Redeemable noncontrolling interest in subsidiaries — 46 — — 46 Stockholders’ Equity 5,474 7,604 3,670 (12,302 ) 4,446 Total Liabilities and Stockholders’ Equity $ 9,752 $ 21,947 $ 11,559 $ (12,576 ) $ 30,682 (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, 2017 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net income (loss) from continuing operations $ 207 $ 397 $ (765 ) $ 91 $ (70 ) Adjustments to reconcile net income/(loss) to net cash provided by operating activities: Distributions from unconsolidated affiliates — 32 — (4 ) 28 Equity in losses/(earnings) of unconsolidated affiliates — (13 ) 2 9 (2 ) Depreciation and amortization 203 298 16 — 517 Provision for bad debts 17 1 — — 18 Amortization of nuclear fuel 24 — — — 24 Amortization of financing costs and debt discount/premiums — 20 9 — 29 Amortization of intangibles and out-of-market contracts 12 39 — — 51 Amortization of unearned equity compensation — — 16 — 16 Impairment losses 42 21 — — 63 Changes in deferred income taxes and liability for uncertain tax benefits 131 237 (360 ) — 8 Changes in nuclear decommissioning trust liability 2 — — — 2 Changes in derivative instruments 12 (12 ) 7 — 7 Changes in collateral deposits supporting energy risk management activities (203 ) 11 3 (189 ) Proceeds from sale of emission allowances 11 — — — 11 Gain on sale of assets (22 ) — — — (22 ) Cash (used)/provided by changes in other working capital (298 ) (1,138 ) 1,153 (96 ) (379 ) Cash provided/(used) by continuing operations 138 (107 ) 81 — 112 Cash used by discontinued operations — (38 ) — — (38 ) Net Cash Provided/(used) by Operating Activities 138 (145 ) 81 — 74 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. 45 (45 ) — Acquisition of Drop Down Assets, net of cash acquired — (131 ) — 131 — Intercompany dividends — — 129 (129 ) — Acquisition of business, net of cash acquired (16 ) — — (16 ) Capital expenditures (90 ) (436 ) (16 ) — (542 ) Decrease in notes receivable — 8 — — 8 Purchases of emission allowances (30 ) — — (30 ) Proceeds from sale of emission allowances 59 — — — 59 Investments in nuclear decommissioning trust fund securities (279 ) — — — (279 ) Proceeds from sales of nuclear decommissioning trust fund securities 277 — — — 277 Proceeds from renewable energy grants and state rebates 8 — — — — 8 Proceeds from sale of assets, net of cash disposed of 35 — — — 35 Investments in unconsolidated affiliates — (30 ) — — (30 ) Other 18 — — — 18 Cash (used)/provided by continuing operations (2 ) (605 ) 158 (43 ) (492 ) Cash used by discontinued operations (53 ) (53 ) Net Cash (Used)/Provided by Investing Activities (2 ) (658 ) 158 (43 ) (545 ) Cash Flows from Financing Activities Dividends from NRG Yield, Inc. — (45 ) — 45 — Payments (for)/from intercompany loans (122 ) 369 (247 ) — — Acquisition of Drop Down Assets, net of cash acquired — — 131 (131 ) — Intercompany dividends (129 ) 129 — Payment of dividends to common and preferred stockholders — — (19 ) — (19 ) Net receipts from settlement of acquired derivatives that include financing elements — 2 — — 2 Proceeds from issuance of long-term debt — 741 205 — 946 Payments for short and long-term debt — (316 ) (214 ) — (530 ) Receivable from affiliate — (125 ) — — (125 ) Contributions to, net of distributions from, noncontrolling interest in subsidiaries — 14 — — 14 Payment of debt issuance costs — (32 ) (4 ) — (36 ) Other - contingent consideration (10 ) — (10 ) Cash (used)/provided by continuing operations (122 ) 469 (148 ) 43 242 Cash used by discontinued operations — (224 ) — — (224 ) Net Cash (Used)/Provided by Financing Activities (122 ) 245 (148 ) 43 18 Change in cash from discontinued operations — (315 ) — — (315 ) Effect of exchange rate changes on cash and cash equivalents — (8 ) — — (8 ) Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties 14 (251 ) 91 — (146 ) Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties at Beginning of Period 4 1,059 323 — 1,386 Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties at End of Period $ 18 $ 808 $ 414 $ — $ 1,240 (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, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net income/(loss) from continuing operations $ 369 $ (186 ) $ (159 ) $ (244 ) $ (220 ) Adjustments to reconcile net income/(loss) to net cash provided by operating activities: Distributions from unconsolidated affiliates — 40 — (11 ) 29 Equity in (earnings)/losses of unconsolidated affiliates (3 ) 2 — 4 3 Depreciation and amortization 225 291 12 — 528 Provision for bad debts 16 4 — — 20 Amortization of nuclear fuel 26 — — — 26 Amortization of financing costs and debt discount/premiums — 16 13 — 29 Adjustment for debt extinguishment — 4 10 — 14 Amortization of intangibles and out-of-market contracts 20 62 — — 82 Amortization of unearned equity compensation — — 16 — 16 Impairment losses — 195 — — 195 Changes in deferred income taxes and liability for uncertain tax benefits 460 (208 ) (251 ) — 1 Changes in nuclear decommissioning trust liability 13 — — — 13 Changes in derivative instruments (64 ) 54 3 — (7 ) Changes in collateral deposits supporting energy risk management activities 344 (21 ) — — 323 Proceeds from sale of emission allowances 47 (30 ) — — 17 Loss on sale of assets — 8 75 — 83 Cash (used)/provided by changes in other working capital (1,148 ) 239 386 251 (272 ) Net cash provided by continuing operations 305 470 105 — 880 Cash used by discontinued operations (69 ) (69 ) Net Cash Provided by Operating Activities 305 401 105 — 811 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. — — 39 (39 ) — Intercompany dividends — — 12 (12 ) — Acquisition of businesses, net of cash acquired — (17 ) — — (17 ) Capital expenditures (80 ) (329 ) (33 ) — (442 ) Increase in notes receivable — (3 ) — — (3 ) Purchases of emission allowances (27 ) — — — (27 ) Proceeds from sale of emission allowances 25 — — — 25 Investments in nuclear decommissioning trust fund securities (280 ) — — — (280 ) Proceeds from sales of nuclear decommissioning trust fund securities 267 — — — 267 Proceeds from renewable energy grants and state rebates — 10 — — 10 Proceeds from sale of assets, net of cash disposed of — — 25 — 25 Investments in unconsolidated affiliates 1 — — — 1 Other 27 4 — — 31 Net cash (used)/provided by continuing operations (67 ) (335 ) 43 (51 ) (410 ) Cash used by discontinued operations (60 ) (60 ) Net Cash (Used)/Provided by Investing Activities (67 ) (395 ) 43 (51 ) (470 ) Cash Flows from Financing Activities Dividends from NRG Yield, Inc. — (39 ) — 39 — Payments (for)/from intercompany loans (179 ) 45 134 — — Intercompany dividends (52 ) 40 — 12 — Payment of dividends to common and preferred stockholders — — (57 ) — (57 ) Payment for preferred shares — — (226 ) — (226 ) Net receipts for settlement of acquired derivatives that include financing elements — 4 — — 4 Proceeds from issuance of long-term debt — 332 2,891 — 3,223 Payments for short and long-term debt (1 ) (279 ) (3,225 ) — (3,505 ) Distributions from, net of contributions to, noncontrolling interest in subsidiaries — (21 ) — — (21 ) Payment of debt issuance costs — — (35 ) — (35 ) Other (3 ) (7 ) — — (10 ) Net cash used/provided by continuing operations (235 ) 75 (518 ) 51 (627 ) Cash provided by discontinued operations 97 97 Net Cash (Used)/Provided by Financing Activities (235 ) 172 (518 ) 51 (530 ) Change in cash from discontinued operations (32 ) (32 ) Effect of exchange rate changes on cash and cash equivalents — (3 ) — — (3 ) Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties 3 207 (370 ) — (160 ) Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties at Beginning of Period — 629 693 — 1,322 Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties at End of Period $ 3 $ 836 $ 323 $ — $ 1,162 (a) All significant intercompany transactions have been eliminated in consolidation.

Basis of Presentation - Basis o

Basis of Presentation - Basis of Presentation (Details) MW in Thousands	2 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Jun. 14, 2017USD ($)	Jun. 30, 2017USD ($)MW	Jun. 30, 2016USD ($)	Jun. 14, 2017USD ($)	Jun. 30, 2016USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Generation capacity (in MW) | MW		31
GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cost method investments, fair value	$ 0			$ 0
GenOn | Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on disposal of discontinued operation	$ 620,000,000	$ 208,000,000	$ 0	$ 620,000,000	$ 0

Basis of Presentation - Transfo

Basis of Presentation - Transformation Plan (Details) $ in Millions	Jul. 12, 2017USD ($)MW	Dec. 31, 2020USD ($)	Jun. 30, 2017MW
Restructuring Cost and Reserve [Line Items]
Generation capacity (in MW) | MW			31,000
Transformation Plan | Subsequent Event
Restructuring Cost and Reserve [Line Items]
Term of plan	3 years
Non-recurring working capital improvements		$ 370
Costs expected to be spent		$ 290
Transformation Plan | Subsequent Event | Operations and cost excellence
Restructuring Cost and Reserve [Line Items]
Cost savings	$ 1,065
Transformation Plan | Subsequent Event | Operations and cost excellence | Annual cost savings
Restructuring Cost and Reserve [Line Items]
Cost savings	590
Transformation Plan | Subsequent Event | Operations and cost excellence | Net margin enhancement program
Restructuring Cost and Reserve [Line Items]
Cost savings	215
Transformation Plan | Subsequent Event | Operations and cost excellence | Annual reduction in maintenance capital expenditures
Restructuring Cost and Reserve [Line Items]
Cost savings	50
Transformation Plan | Subsequent Event | Operations and cost excellence | Permanent selling general and administrative reduction associated with asset sales
Restructuring Cost and Reserve [Line Items]
Cost savings	$ 210
Transformation Plan | Subsequent Event | Portfolio optimization
Restructuring Cost and Reserve [Line Items]
Generation capacity (in MW) | MW	6,000
Transformation Plan | Subsequent Event | Portfolio optimization | Minimum
Restructuring Cost and Reserve [Line Items]
Effect on cash flows	$ 2,500
Transformation Plan | Subsequent Event | Portfolio optimization | Minimum | NRG Yield, Inc.
Restructuring Cost and Reserve [Line Items]
Ownership interest	50.00%
Transformation Plan | Subsequent Event | Portfolio optimization | Maximum
Restructuring Cost and Reserve [Line Items]
Effect on cash flows	$ 4,000
Transformation Plan | Subsequent Event | Portfolio optimization | Maximum | NRG Yield, Inc.
Restructuring Cost and Reserve [Line Items]
Ownership interest	100.00%
Transformation Plan | Subsequent Event | Capital structure and allocation enhancements
Restructuring Cost and Reserve [Line Items]
Reduction in consolidated debt, original amount	$ 19,500
Reduction in consolidated debt	18,000
Cnsolidated debt original amount reduction	6,500
Consolidated debt, net amount reduction	$ 6,000
Corporate net debt (corporate debt less cash and cash equivalents) to EBITDA ratio	3
Transformation Plan | Subsequent Event | Capital structure and allocation enhancements | Minimum
Restructuring Cost and Reserve [Line Items]
Effect on cash flows	$ 0
Transformation Plan | Subsequent Event | Capital structure and allocation enhancements | Maximum
Restructuring Cost and Reserve [Line Items]
Effect on cash flows	$ 6,300

Summary of Significant Accoun41

Summary of Significant Accounting Policies - Other Balance Sheet Information (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Accounts receivable allowance for doubtful accounts	$ 39	$ 29
Property, plant and equipment accumulated depreciation	6,180	5,711
Intangible assets accumulated amortization	1,698	1,687
Out-of-market contracts accumulated amortization	$ 346	$ 457

Summary of Significant Accoun42

Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Collateral received from GenOn		$ 79
Cash and cash equivalents	$ 752	938	$ 748	$ 853
Funds deposited by counterparties	19	2	1	55
Restricted cash	469	446	413	414
Cash and cash equivalents, funds deposited by counterparties and restricted cash shown in the statement of cash flows	$ 1,240	$ 1,386	$ 1,162	$ 1,322

Summary of Significant Accoun43

Summary of Significant Accounting Policies - Noncontrolling Interest (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Noncontrolling Interest [Roll Forward]
Balance as of beginning of period			$ 2,405
Dividends paid to NRG Yield, Inc. public shareholders			(52)
Distributions to noncontrolling interest			(39)
Comprehensive loss attributable to noncontrolling interest	$ (17)	$ (16)	(56)	$ (68)
Contributions from noncontrolling interest			76
Sale of assets to NRG Yield, Inc.			3
Balance as of end of period	$ 2,462		2,462
Noncontrolling Interest
Noncontrolling Interest [Roll Forward]
Comprehensive loss attributable to noncontrolling interest			(19)
Non-cash adjustments to noncontrolling interest			$ 88

Summary of Significant Accoun44

Summary of Significant Accounting Policies - Redeemable Noncontrolling Interest (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Noncontrolling Interest [Line Items]
Balance as of beginning of period			$ 46
Contributions from redeemable noncontrolling interest			42
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest	$ (17)	$ (16)	(56)	$ (68)
Balance as of end of period	$ 51		51
Redeemable noncontrolling interest [Member]
Noncontrolling Interest [Line Items]
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest			$ (37)

Summary of Significant Accoun45

Summary of Significant Accounting Policies - Guidance Adopted in 2017 (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in cash flow from operations		$ 74	$ 811
Decrease in cash flow from investing		545	470
Decrease in cash flow from financing		(18)	530
ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in cash flow from operations			(54)
Decrease in cash flow from investing			$ 1
ASU 2016-16 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustments for change in accounting pronouncement	$ (267)
ASU 2016-16 | Noncurrent Assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustments for change in accounting pronouncement	$ 267
ASU 2016-15
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in cash flow from operations		55
Decrease in cash flow from financing		$ 55

Discontinued Operations and D46

Discontinued Operations and Dispositions - Discontinued Operations (Details)	Jun. 14, 2017USD ($)	Jun. 12, 2017USD ($)extension	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt			$ 17,125,000,000	$ 16,703,000,000
GenOn Senior Notes Due in 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest rate, stated percentage			7.875%
Senior Notes Due In 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest rate, stated percentage			9.50%
GenOn Senior Notes Due in 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest rate, stated percentage			9.875%
GenOn Americas Generation Senior Notes Due in 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest rate, stated percentage			8.50%
GenOn Americas Generation Senior Notes Due in 2031
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest rate, stated percentage			9.125%
GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pension liability			$ 119,000,000
Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of aggregate principal amount		93.00%
Intercompany secured revolving credit facility			125,000,000
Payment of pension contributions			13,000,000
Restructuring Support Agreement | GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Settlement consideration		$ 261,300,000
Estimated accumulated pension benefit obligation			119,000,000
Settlement Consideration | Restructuring Support Agreement | GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accrued liabilities - affiliate			261,300,000
Services Agreement | GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Shared services, annualized rate		84,000,000
Credit applied		28,000,000
Services Agreement | Restructuring Support Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Shared services, annualized rate		$ 84,000,000
Monthly shared services	$ 5,000,000
Shared services, waived period		2 months
Shared services, number of extensions | extension		2
Shared services, extension period		1 month
Credit applied		$ 28,000,000
Services Agreement | Restructuring Support Agreement | GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accrued liabilities - affiliate			28,000,000
Discontinued Operations | GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt			2,500,000,000
GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cost method investment			$ 0

Discontinued Operations and D47

Discontinued Operations and Dispositions - Summary of Results (Details) - USD ($) $ in Millions	2 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Jun. 14, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 14, 2017	Jun. 30, 2017	Jun. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of assets					$ 22	$ (83)
Loss from discontinued operations, net of tax		$ (741)	$ (113)		$ (775)	(9)
Discontinued Operations | GenOn
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenues	$ 265		398	$ 646		977
Operating costs and expenses	(327)		(474)	(700)		(941)
Gain on sale of assets	0		0	0		32
Other expenses	(54)		(40)	(98)		(84)
Loss from operations of discontinued components, before tax	(116)		(116)	(152)		(16)
Income tax expense/(benefit)	8		0	9		(1)
Loss from operations of discontinued components	(124)		(116)	(161)		(15)
Interest income - affiliate	3		3	6		6
Net loss from discontinued operations	(121)		(113)	(155)		(9)
Pre-tax loss on deconsolidation	(208)		0	(208)		0
Settlement consideration and services credit	(289)		0	(289)		0
Pension liability assumption	(119)		0	(119)		0
Advisory and consulting fees	(4)		0	(4)		0
Loss on disposal of discontinued components, net of tax	(620)	$ (208)	0	(620)		0
Loss from discontinued operations, net of tax	$ (741)		$ (113)	$ (775)		$ (9)

Discontinued Operations and D48

Discontinued Operations and Dispositions - Major Classes of Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other current assets	$ 0	$ 1,919
Current assets - discontinued operations	33	9
Other non-current assets	10	10
Non-current assets - discontinued operations	0	2,961
Current liabilities - discontinued operations	0	1,210
Other non-current liabilities	0	3,209
Non-current liabilities - discontinued operations	$ 13	11
GenOn | Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents		1,034
Other current assets		885
Current assets - discontinued operations		1,919
Property, plant and equipment, net		2,543
Other non-current assets		418
Non-current assets - discontinued operations		2,961
Current portion of long term debt and capital leases		704
Other current liabilities		506
Current liabilities - discontinued operations		1,210
Long-term debt and capital leases		2,050
Out-of-market contracts		811
Other non-current liabilities		348
Non-current liabilities - discontinued operations		$ 3,209

Discontinued Operations and D49

Discontinued Operations and Dispositions - Transfer of Assets Under Common Control (Details) $ in Millions	Aug. 01, 2017USD ($)wind_project	Jun. 30, 2017MW	Mar. 27, 2017USD ($)MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Generation capacity (in MW) | MW		31,000
Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of ownership sold	25.00%
Number of wind projects | wind_project	12
Cash consideration	$ 41.5
Agua Caliente solar project
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration			$ 130
Working capital adjustments			1
Assumed non-recourse debt in transaction			$ 328
Agua Caliente solar project | Agua Caliente
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of ownership sold			16.00%
Generation capacity (in MW) | MW			46
Agua Caliente solar project | Utah Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Generation capacity (in MW) | MW			265

Discontinued Operations and D50

Discontinued Operations and Dispositions - Disposition of Majority Interest in EVgo (Details) $ in Millions	Jun. 17, 2016USD ($)charging_stationparking_space	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale		$ (2)	$ 83	$ (4)	$ 83
Equity method investments		1,127		$ 1,127		$ 1,120
EVgo | Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration	$ 39
Cash received	17
Working capital adjustments	2.5
Capital contributions	15
Future contributions	7
Future earnout potential	70
Original financial obligation	$ 102.5
Number of public fast charging Freedom Station sites | charging_station	200
Number of commercial and multi-family parking spaces | parking_space	10,000
Loss on sale			83
Loss on the sale of the equity interest			$ 27
Remaining obligation	$ 56
Remaining interest				35.00%
Equity method investments		$ 3		$ 3

Discontinued Operations and D51

Discontinued Operations and Dispositions - Rockford Disposition (Details) $ in Millions	Jul. 12, 2016USD ($)	May 13, 2016USD ($)	Jun. 30, 2017USD ($)MW	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)MW	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)	May 12, 2016USD ($)MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Generation capacity (in MW) | MW			31,000		31,000
Impairment losses			$ 63	$ 56	$ 63	$ 56
Current assets - discontinued operations			0		0		$ 1,919
Non-current assets - discontinued operations			$ 0		$ 0		$ 2,961
Rockford
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of ownership								100.00%
Impairment losses				17
Proceeds from sale of property, plant, and equipment		$ 55
Rockford | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of ownership								100.00%
Cash consideration								$ 55
Generation capacity (in MW) | MW								450
Impairment losses				17
Current assets - discontinued operations				2		2
Non-current assets - discontinued operations				$ 54		$ 54
Proceeds from sale of property, plant, and equipment	$ 56
Adjustments for base residual auction results	$ 1

Fair Value of Financial Instr52

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, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion	$ 17,125	$ 16,703
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes receivable	25	34
Long-term debt, including current portion	17,086	16,655
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes receivable	24	34
Long-term debt, including current portion	17,246	16,620
Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion	9,398	9,205
Fair Value | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion	$ 7,848	$ 7,415

Fair Value of Financial Instr53

Fair Value of Financial Instruments - Assets and liabilities measured and recorded at fair value (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 870	$ 1,248
Derivative liabilities	1,004	1,376
Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	831	1,199
Derivative liabilities	909	1,288
Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	39	49
Derivative liabilities	95	88
Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities	18	17
Available-for-sale securities	4	10
U.S. government and federal agency obligations	1	1
Total assets	1,530	1,886
Derivative liabilities	1,004	1,376
Fair value, measurements, recurring | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	831	1,199
Derivative liabilities	909	1,288
Fair value, measurements, recurring | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	39	49
Derivative liabilities	95	88
Fair value, measurements, recurring | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	11	25
Fair value, measurements, recurring | U.S. government and federal agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	45	73
Fair value, measurements, recurring | Federal agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	71	62
Fair value, measurements, recurring | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	17	17
Fair value, measurements, recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	109	84
Fair value, measurements, recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	380	346
Fair value, measurements, recurring | Foreign government fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	4	3
Fair value, measurements, recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities	0	0
Available-for-sale securities	4	10
U.S. government and federal agency obligations	1	1
Total assets	566	960
Derivative liabilities	292	494
Fair value, measurements, recurring | Level 1 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	186	560
Derivative liabilities	292	494
Fair value, measurements, recurring | Level 1 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair value, measurements, recurring | Level 1 | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	11	25
Fair value, measurements, recurring | Level 1 | U.S. government and federal agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	45	72
Fair value, measurements, recurring | Level 1 | Federal agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 1 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 1 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	319	292
Fair value, measurements, recurring | Level 1 | Foreign government fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities	0	0
Available-for-sale securities	0	0
U.S. government and federal agency obligations	0	0
Total assets	775	765
Derivative liabilities	591	724
Fair value, measurements, recurring | Level 2 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	535	549
Derivative liabilities	496	636
Fair value, measurements, recurring | Level 2 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	39	49
Derivative liabilities	95	88
Fair value, measurements, recurring | Level 2 | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 2 | U.S. government and federal agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	1
Fair value, measurements, recurring | Level 2 | Federal agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	71	62
Fair value, measurements, recurring | Level 2 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	17	17
Fair value, measurements, recurring | Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	109	84
Fair value, measurements, recurring | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 2 | Foreign government fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	4	3
Fair value, measurements, recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities	18	17
Available-for-sale securities	0	0
U.S. government and federal agency obligations	0	0
Total assets	189	161
Derivative liabilities	121	158
Fair value, measurements, recurring | Level 3 | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	110	90
Derivative liabilities	121	158
Fair value, measurements, recurring | Level 3 | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair value, measurements, recurring | Level 3 | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 3 | U.S. government and federal agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 3 | Federal agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 3 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 3 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	0	0
Fair value, measurements, recurring | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	61	54
Fair value, measurements, recurring | Level 3 | Foreign government fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decommissioning Fund Investments	$ 0	$ 0

Fair Value of Financial Instr54

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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 20	$ 67	$ 3	$ 49
Total gains — realized/unrealized
Included in earnings	40	23	47	9
Included in OCI		(1)		(1)
Included in nuclear decommissioning obligation	3	(1)	7	(4)
Purchases	5	22	9	28
Transfers into Level 3	3	(20)	(5)	7
Transfers out of Level 3	(3)	(5)	7	(3)
Ending balance	68	85	68	85
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, 2017 and 2016	22	11	7	(7)
Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	18	17	17	17
Total gains — realized/unrealized
Included in earnings	0	0	1	0
Included in OCI		(1)		(1)
Included in nuclear decommissioning obligation	0	0	0	0
Purchases	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	18	16	18	16
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, 2017 and 2016	0	0	0	0
Trust Fund Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	58	52	54	54
Total gains — realized/unrealized
Included in earnings	0	0	0	0
Included in OCI		0		0
Included in nuclear decommissioning obligation	3	(1)	7	(4)
Purchases	0	0	0	1
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	61	51	61	51
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, 2017 and 2016	0	0	0	0
Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(56)	(2)	(68)	(22)
Total gains — realized/unrealized
Included in earnings	40	23	46	9
Included in OCI		0		0
Included in nuclear decommissioning obligation	0	0	0	0
Purchases	5	22	9	27
Transfers into Level 3	3	(20)	(5)	7
Transfers out of Level 3	(3)	(5)	7	(3)
Ending balance	(11)	18	(11)	18
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, 2017 and 2016	$ 22	$ 11	$ 7	$ (7)

Fair Value of Financial Instr55

Fair Value of Financial Instruments - Derivative Fair Value Measurements, Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Total derivative assets valued with prices provied by models and other valuation techniques (as a percent)	13.00%
Total derivative liabilities valued with prices provied by models and other valuation techniques (as a percent)	12.00%
Credit reserve		$ 10

Fair Value of Financial Instr56

Fair Value of Financial Instruments - Derivative Fair Value Measurements (Details) $ in Millions	Jun. 30, 2017USD ($)$ / MWh	Dec. 31, 2016USD ($)$ / MWh
Assets
Derivative assets	$ 870	$ 1,248
Liabilities
Derivative liabilities	1,004	1,376
Fair value, measurements, recurring
Liabilities
Derivative liabilities	1,004	1,376
Fair value, measurements, recurring | Level 3
Liabilities
Derivative liabilities	121	158
Commodity contracts
Assets
Derivative assets	831	1,199
Liabilities
Derivative liabilities	909	1,288
Commodity contracts | Fair value, measurements, recurring
Assets
Derivative assets	831	1,199
Liabilities
Derivative liabilities	909	1,288
Commodity contracts | Fair value, measurements, recurring | Level 3
Assets
Derivative assets	110	90
Liabilities
Derivative liabilities	121	158
Commodity contracts | Fair value, measurements, recurring | Level 3 | Power Contracts
Assets
Derivative assets	57	39
Liabilities
Derivative liabilities	$ 78	$ 108
Commodity contracts | Fair value, measurements, recurring | Level 3 | Power Contracts | Low
Fair Value Inputs / Range
Forward Market Price (per MWh) | $ / MWh	10	11
Commodity contracts | Fair value, measurements, recurring | Level 3 | Power Contracts | High
Fair Value Inputs / Range
Forward Market Price (per MWh) | $ / MWh	115	104
Commodity contracts | Fair value, measurements, recurring | Level 3 | Power Contracts | Weighted Average
Fair Value Inputs / Range
Forward Market Price (per MWh) | $ / MWh	30	31
Commodity contracts | Fair value, measurements, recurring | Level 3 | FTRs
Assets
Derivative assets	$ 53	$ 51
Liabilities
Derivative liabilities	$ 43	$ 50
Commodity contracts | Fair value, measurements, recurring | Level 3 | FTRs | Low
Fair Value Inputs / Range
Auction Prices (per MWh) | $ / MWh	(29)	(22)
Commodity contracts | Fair value, measurements, recurring | Level 3 | FTRs | High
Fair Value Inputs / Range
Auction Prices (per MWh) | $ / MWh	27	17
Commodity contracts | Fair value, measurements, recurring | Level 3 | FTRs | Weighted Average
Fair Value Inputs / Range
Auction Prices (per MWh) | $ / MWh	0	0

Fair Value of Financial Instr57

Fair Value of Financial Instruments - Counterparty Credit Risk (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017USD ($)
Concentration of Credit Risk
Counterparty credit exposure to a portion of the Company's counterparties	$ 145
Net counterparty credit exposure to a portion of the Company's counterparties	17
Collateral held (cash and letters of credit) against counterparty credit exposure to a portion of the Company's counterparties	$ 137
Company's exposure before collateral is expected to roll off by the end of 2014 (as a percent)	75.00%
Net exposure (as a percent)	100.00%
Counterparty credit risk exposure to certain counterparties, threshold (as a percent)	10.00%
Aggregate counterparty credit risk exposure for counterparties representing exposure above threshold percentage	$ 43
Estimated counterparty credit risk exposure under certain long term agreements, including California tolling agreements, South Central load obligations and solar power purchase agreements for the next 5 years	$ 4,300
Period of estimated counterparty credit risk exposure under certain long term agreements, including California tolling agreements, South Central load obligations and solar power purchase agreements (in years)	5 years
Investment grade
Concentration of Credit Risk
Net exposure (as a percent)	78.00%
Non-Investment grade/Non-Rated
Concentration of Credit Risk
Net exposure (as a percent)	22.00%
Utilities, energy merchants, marketers and other
Concentration of Credit Risk
Net exposure (as a percent)	89.00%
Financial institutions
Concentration of Credit Risk
Net exposure (as a percent)	11.00%
NRG Yield, Inc.
Concentration of Credit Risk
Estimated counterparty credit risk exposure under certain long term agreements, including California tolling agreements, South Central load obligations and solar power purchase agreements for the next 5 years	$ 2,800

Nuclear Decommissioning Trust58

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, 2017	Dec. 31, 2016
Nuclear decommissioning trust fund
Fair Value	$ 637	$ 610
Unrealized Gains	250	217
Unrealized Losses	2	4
Cash and cash equivalents
Nuclear decommissioning trust fund
Fair Value	11	25
Unrealized Gains	0	0
Unrealized Losses	0	0
U.S. government and federal agency obligations
Nuclear decommissioning trust fund
Fair Value	45	73
Unrealized Gains	2	1
Unrealized Losses	$ 0	$ 0
Weighted-average Maturities (In years)	11 years	11 years
Federal agency mortgage-backed securities
Nuclear decommissioning trust fund
Fair Value	$ 71	$ 62
Unrealized Gains	1	1
Unrealized Losses	$ 1	$ 1
Weighted-average Maturities (In years)	24 years	25 years
Commercial mortgage-backed securities
Nuclear decommissioning trust fund
Fair Value	$ 17	$ 17
Unrealized Gains	0	0
Unrealized Losses	$ 0	$ 1
Weighted-average Maturities (In years)	24 years	26 years
Corporate debt securities
Nuclear decommissioning trust fund
Fair Value	$ 109	$ 84
Unrealized Gains	2	1
Unrealized Losses	$ 1	$ 2
Weighted-average Maturities (In years)	10 years	11 years
Equity securities
Nuclear decommissioning trust fund
Fair Value	$ 380	$ 346
Unrealized Gains	245	214
Unrealized Losses	0	0
Foreign government fixed income securities
Nuclear decommissioning trust fund
Fair Value	4	3
Unrealized Gains	0	0
Unrealized Losses	$ 0	$ 0
Weighted-average Maturities (In years)	7 years	9 years

Nuclear Decommissioning Trust59

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, 2017	Jun. 30, 2016
Nuclear Decommissioning Trust Fund Disclosure [Abstract]
Realized gains	$ 3	$ 3
Realized losses	3	2
Proceeds from sale of securities	$ 277	$ 267

Accounting for Derivative Ins60

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, 2017USD ($)MWhMMBTUmw_per_dayTsharesbbl	Dec. 31, 2016USD ($)MWhMMBTUmw_per_dayTsharesbbl
Short | Emissions
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, mass	2
Short | Natural Gas
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, energy measure | MMBTU		53
Short | Capacity
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, flow rate | mw_per_day	1	1
Long | Emissions
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, mass		0
Long | Coal
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, mass	22	35
Long | Natural Gas
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, energy measure | MMBTU	45
Long | Oil
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, volume | bbl	0	1
Long | Power
Volumetric Underlying Derivative Transactions
Derivative, nonmonetary notional amount, energy measure | MWh	24	7
Long | Interest
Volumetric Underlying Derivative Transactions
Derivative, notional amount (in usd) | $	$ 3,701	$ 3,429
Long | Equity
Volumetric Underlying Derivative Transactions
Derivative, non-monetary notional amount (in shares) | shares	1	1

Accounting for Derivative Ins61

Accounting for Derivative Instruments and Hedging Activities - Fair value within the derivative instrument valuation (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Assets	$ 870	$ 1,248
Derivative Liabilities	1,004	1,376
Designated as Hedging Instrument
Derivative [Line Items]
Derivative Assets	9	12
Derivative Liabilities	28	69
Designated as Hedging Instrument | Interest rate contracts current
Derivative [Line Items]
Derivative Assets	0	0
Derivative Liabilities	9	28
Designated as Hedging Instrument | Interest rate contracts long-term
Derivative [Line Items]
Derivative Assets	9	12
Derivative Liabilities	19	41
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Assets	861	1,236
Derivative Liabilities	976	1,307
Not Designated as Hedging Instrument | Interest rate contracts current
Derivative [Line Items]
Derivative Assets	4	0
Derivative Liabilities	21	7
Not Designated as Hedging Instrument | Interest rate contracts long-term
Derivative [Line Items]
Derivative Assets	26	37
Derivative Liabilities	46	12
Not Designated as Hedging Instrument | Commodity contracts current
Derivative [Line Items]
Derivative Assets	640	1,067
Derivative Liabilities	681	1,057
Not Designated as Hedging Instrument | Commodity contracts long-term
Derivative [Line Items]
Derivative Assets	191	132
Derivative Liabilities	$ 228	$ 231

Accounting for Derivative Ins62

Accounting for Derivative Instruments and Hedging Activities - Offsetting of derivatives by counterparty master agreement level and collateral received (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative assets	$ 870	$ 1,248
Cash Collateral (Held) / Posted	(19)	(81)
Gross Amounts of Recognized Derivative Liabilities	(1,004)	(1,376)
Cash Collateral Posted	277	150
Gross Amounts of Recognized Assets / Liabilities	(134)	(128)
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0	0
Derivative, Collateral, Obligation to Return Cash Net Of Derivative, Collateral, Right to Reclaim Cash	119	0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	(15)	(128)
Commodity contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative assets	831	1,199
Derivative Instruments	(730)	(1,021)
Cash Collateral (Held) / Posted	(2)	(13)
Net Amount	99	165
Gross Amounts of Recognized Derivative Liabilities	(909)	(1,288)
Derivative Instruments	730	1,021
Cash Collateral Posted	121	13
Derivative Liability, Fair Value, Amount Offset Against Collateral	(58)	(254)
Gross Amounts of Recognized Assets / Liabilities	(78)	(89)
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0	0
Derivative, Collateral, Obligation to Return Cash Net Of Derivative, Collateral, Right to Reclaim Cash	119	0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	41	(89)
Interest rate contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative assets	39	49
Derivative Instruments	(2)	(4)
Cash Collateral (Held) / Posted	0	0
Net Amount	37	45
Gross Amounts of Recognized Derivative Liabilities	(95)	(88)
Derivative Instruments	2	4
Cash Collateral Posted	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(93)	(84)
Gross Amounts of Recognized Assets / Liabilities	(56)	(39)
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0	0
Derivative, Collateral, Obligation to Return Cash Net Of Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	$ (56)	$ (39)

Accounting for Derivative Ins63

Accounting for Derivative Instruments and Hedging Activities - Effect of ASC 815 on accumulated OCI balance attributable to hedge derivatives, net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassified from accumulated OCI to income:
Accumulated other comprehensive income (loss), tax	$ 16	$ 26	$ 16	$ 26
Losses expected to be realized from OCI during the next twelve months, tax	3		3
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	0	0	0	0
Interest rate contracts
Effects of ASC 815 on NRG's Accumulated OCI Balance Attributable to Cash Flow Hedge Derivatives, net of tax
Accumulated OCI beginning balance	(61)	(150)	(66)	(101)
Reclassified from accumulated OCI to income:
Due to realization of previously deferred amounts	3	7	6	10
Mark-to-market of cash flow hedge accounting contracts	(9)	(22)	(7)	(74)
Accumulated OCI ending balance, net of $16, and $26 tax	(67)	$ (165)	(67)	$ (165)
Losses expected to be realized from OCI during the next 12 months, net of $3 tax	$ 15		$ 15

Accounting for Derivative Ins64

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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative [Line Items]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments			$ 15	$ 77
Unrealized mark-to-market results
Reversal of previously recognized unrealized losses/(gains) on settled positions related to economic hedges	$ 22	$ (18)	25	(45)
Reversal of acquired loss/(gain) positions related to economic hedges	1	(2)	1	(4)
Net unrealized gains/(losses) on open positions related to economic hedges	36	(13)	15	77
Total unrealized mark-to-market gains/(losses) for economic hedging activities	59	(33)	41	28
Reversal of previously recognized unrealized (gains)/losses on settled positions related to trading activity	(4)	2	(19)	10
Net unrealized gains on open positions related to trading activity	16	11	17	22
Total unrealized mark-to-market gains/(losses) for trading activity	12	13	(2)	32
Total unrealized losses	71	(20)	39	60
Credit Risk Related Contingent Features
Collateral due on net liability position that has not been called by a certain marginable agreement counterparty	6		6
Adequate Assurance Clauses
Credit Risk Related Contingent Features
Derivative net liability position, collateral required Contracts with Credit Rating Contingent Feature	36		36
Credit Rating Contingent Features
Credit Risk Related Contingent Features
Derivative net liability position, collateral required Contracts with Credit Rating Contingent Feature	39		39
Commodity contracts
Unrealized mark-to-market results
Total unrealized losses	71	(20)	39	60
Commodity contracts | Sales
Unrealized mark-to-market results
Total unrealized losses	53	(460)	157	(390)
Commodity contracts | Cost of Sales
Unrealized mark-to-market results
Total unrealized losses	18	440	(118)	450
Interest rate contracts
Unrealized mark-to-market results
Total unrealized losses	$ (24)	$ (7)	$ (19)	$ (18)

Impairments (Details)

Impairments (Details) - USD ($)	May 13, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jul. 14, 2017	May 12, 2016
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses		$ 63,000,000	$ 56,000,000		$ 63,000,000	$ 56,000,000
Construction in progress		0			$ 0
Impairment loss on investment						$ 139,000,000
Petra Nova Parish Holdings
Impaired Long-Lived Assets Held and Used [Line Items]
Ownership percentage				50.00%
Impairment loss on investment				$ 140,000,000
Other Intangible Assets
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses			8,000,000
Deferred Marketing Expenses
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses			10,000,000
Rockford
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses			17,000,000
Percentage of ownership								100.00%
Proceeds from sale of property, plant, and equipment	$ 55,000,000
Renewables
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses		22,000,000
Subsequent Event | Collectibility of receivables | BTEC New Albany, LLC
Impaired Long-Lived Assets Held and Used [Line Items]
Amount owed from BTEC New Albany, LLC							$ 48,000,000
Subsequent Event | Collectibility of receivables | Purchaser incurred costs | BTEC New Albany, LLC
Impaired Long-Lived Assets Held and Used [Line Items]
Amount owed from BTEC New Albany, LLC							38,000,000
Subsequent Event | Collectibility of receivables | Liquidation damages | BTEC New Albany, LLC
Impaired Long-Lived Assets Held and Used [Line Items]
Amount owed from BTEC New Albany, LLC							$ 10,000,000
Construction in Progress
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses		$ 41,000,000
Solar Panels
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment losses			$ 17,000,000

Debt and Capital Leases - Sched

Debt and Capital Leases - Schedule of Long-term Debt and Capital Leases (Details) - USD ($) $ in Millions	Jan. 24, 2017	Jun. 30, 2017	May 26, 2017	Dec. 31, 2016	Sep. 30, 2016	May 23, 2016
Debt Instrument [Line Items]
Long-term debt		$ 17,125		$ 16,703
Capital leases		6		6
Subtotal long-term debt and capital leases (including current maturities)		17,131		16,709
Current portion of long-term debt and capital leases		(1,042)		(516)
Less debt issuance costs		(208)		(188)
Discounts		(39)		(48)
Long-term debt and capital leases		15,842		15,957
Recourse Debt
Debt Instrument [Line Items]
Long-term debt		7,785		7,795
Recourse Debt | Senior notes, due 2018
Debt Instrument [Line Items]
Long-term debt		$ 398		398
Interest rate, stated percentage		7.625%
Recourse Debt | Senior notes, due 2021
Debt Instrument [Line Items]
Long-term debt		$ 207		207
Interest rate, stated percentage		7.875%			7.875%
Recourse Debt | Senior notes, due 2022
Debt Instrument [Line Items]
Long-term debt		$ 992		992
Interest rate, stated percentage		6.25%
Recourse Debt | Senior notes, due 2023
Debt Instrument [Line Items]
Long-term debt		$ 869		869
Interest rate, stated percentage		6.625%
Recourse Debt | Senior notes, due 2024
Debt Instrument [Line Items]
Long-term debt		$ 733		733
Interest rate, stated percentage		6.25%
Recourse Debt | Senior notes, due 2026
Debt Instrument [Line Items]
Long-term debt		$ 1,000		1,000		$ 1,000
Interest rate, stated percentage		7.25%				7.25%
Recourse Debt | Senior notes, due 2027
Debt Instrument [Line Items]
Long-term debt		$ 1,250		1,250
Interest rate, stated percentage		6.625%			6.625%
Recourse Debt | Term loan facility, due 2023
Debt Instrument [Line Items]
Long-term debt		$ 1,881		1,891
Recourse Debt | Term loan facility, due 2023 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%	2.25%
Recourse Debt | Tax-exempt bonds
Debt Instrument [Line Items]
Long-term debt		$ 455		455
Recourse Debt | Tax-exempt bonds | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage		4.125%
Recourse Debt | Tax-exempt bonds | Maximum
Debt Instrument [Line Items]
Interest rate, stated percentage		6.00%
Recourse Debt | Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		2.25%
Non Recourse Debt
Debt Instrument [Line Items]
Long-term debt		$ 9,340		8,908
Non Recourse Debt | NRG Yield Operating LLC Senior Notes, due 2024
Debt Instrument [Line Items]
Long-term debt		$ 500		500
Interest rate, stated percentage		5.375%
Non Recourse Debt | NRG Yield Operating LLC Senior Notes, due 2026
Debt Instrument [Line Items]
Long-term debt		$ 350		350
Interest rate, stated percentage		5.00%
Non Recourse Debt | NRG Yield, Inc. Convertible Senior Notes, due 2019
Debt Instrument [Line Items]
Long-term debt		$ 345		345
Interest rate, stated percentage		3.50%
Non Recourse Debt | NRG Yield, Inc. Convertible Senior Notes, due 2020
Debt Instrument [Line Items]
Long-term debt		$ 288		288
Interest rate, stated percentage		3.25%
Non Recourse Debt | El Segundo Energy Center, due 2023
Debt Instrument [Line Items]
Long-term debt		$ 414		443
Non Recourse Debt | El Segundo Energy Center, due 2023 | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		1.625%
Non Recourse Debt | El Segundo Energy Center, due 2023 | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate		2.25%
Non Recourse Debt | Marsh Landing, due 2017 and 2023
Debt Instrument [Line Items]
Long-term debt		$ 358		370
Non Recourse Debt | Alta Wind I - V lease financing arrangements, due 2034 and 2035
Debt Instrument [Line Items]
Long-term debt		939		965
Non Recourse Debt | Walnut Creek, term loans due 2023
Debt Instrument [Line Items]
Long-term debt		$ 299		310
Non Recourse Debt | Walnut Creek, term loans due 2023 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.625%
Non Recourse Debt | Utah Portfolio, due 2022
Debt Instrument [Line Items]
Long-term debt		$ 284		287
Non Recourse Debt | Utah Portfolio, due 2022 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		2.625%
Non Recourse Debt | Tapestry, due 2021
Debt Instrument [Line Items]
Long-term debt		$ 166		172
Non Recourse Debt | Tapestry, due 2021 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.625%
Non Recourse Debt | CVSR, due 2037
Debt Instrument [Line Items]
Long-term debt		$ 757		771
Non Recourse Debt | CVSR, due 2037 | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage		2.339%
Non Recourse Debt | CVSR, due 2037 | Maximum
Debt Instrument [Line Items]
Interest rate, stated percentage		3.775%
Non Recourse Debt | CVSR HoldCo, due 2037
Debt Instrument [Line Items]
Long-term debt		$ 193		199
Interest rate, stated percentage		4.68%
Non Recourse Debt | Alpine, due 2022
Debt Instrument [Line Items]
Long-term debt		$ 142		145
Non Recourse Debt | Alpine, due 2022 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.75%
Non Recourse Debt | Energy Center Minneapolis, due 2017 and 2025
Debt Instrument [Line Items]
Long-term debt		$ 85		96
Non Recourse Debt | Energy Center Minneapolis, due 2017 and 2025 | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage		5.95%
Non Recourse Debt | Energy Center Minneapolis, due 2017 and 2025 | Maximum
Debt Instrument [Line Items]
Interest rate, stated percentage		7.25%
Non Recourse Debt | NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2025
Debt Instrument [Line Items]
Interest rate, stated percentage		5.95%
Non Recourse Debt | Energy Center Minneapolis, due 2031
Debt Instrument [Line Items]
Long-term debt		$ 125		125
Interest rate, stated percentage		3.55%
Non Recourse Debt | Viento, due 2023
Debt Instrument [Line Items]
Long-term debt		$ 169		178
Non Recourse Debt | Viento, due 2023 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		2.75%
Non Recourse Debt | NRG Yield - other
Debt Instrument [Line Items]
Long-term debt		$ 569		540
Non Recourse Debt | Subtotal NRG Yield debt (non-recourse to NRG)
Debt Instrument [Line Items]
Long-term debt		5,983		6,084
Non Recourse Debt | Ivanpah, due 2033 and 2038
Debt Instrument [Line Items]
Long-term debt		$ 1,108		1,113
Non Recourse Debt | Ivanpah, due 2033 and 2038 | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage		2.285%
Non Recourse Debt | Ivanpah, due 2033 and 2038 | Maximum
Debt Instrument [Line Items]
Interest rate, stated percentage		4.256%
Non Recourse Debt | Carlsbad Energy Project
Debt Instrument [Line Items]
Long-term debt		$ 345		0
Interest rate, stated percentage		4.12%	4.12%
Non Recourse Debt | Agua Caliente, due 2037
Debt Instrument [Line Items]
Long-term debt		$ 843		849
Non Recourse Debt | Agua Caliente, due 2037 | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage		2.395%
Non Recourse Debt | Agua Caliente, due 2037 | Maximum
Debt Instrument [Line Items]
Interest rate, stated percentage		3.633%
Non Recourse Debt | Agua Caliente Borrower 1, due 2038
Debt Instrument [Line Items]
Long-term debt		$ 89		0
Interest rate, stated percentage		5.43%
Non Recourse Debt | Cedro Hill, due 2025
Debt Instrument [Line Items]
Long-term debt		$ 156		163
Non Recourse Debt | Cedro Hill, due 2025 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.75%
Non Recourse Debt | Midwest Generation, due 2019
Debt Instrument [Line Items]
Long-term debt		$ 194		231
Interest rate, stated percentage		4.39%
Non Recourse Debt | NRG Other
Debt Instrument [Line Items]
Long-term debt		$ 622		468
Non Recourse Debt | Subtotal other NRG non-recourse debt
Debt Instrument [Line Items]
Long-term debt		$ 3,357		$ 2,824
Non Recourse Debt | Marsh Landing Term Loan Due 2017 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.75%
Non Recourse Debt | Marsh Landing Term Loan Due 2023 | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		1.875%
Non Recourse Debt | Alta Wind I
Debt Instrument [Line Items]
Interest rate, stated percentage		7.015%
Non Recourse Debt | Alta Wind II
Debt Instrument [Line Items]
Interest rate, stated percentage		5.696%
Non Recourse Debt | Alta Wind III
Debt Instrument [Line Items]
Interest rate, stated percentage		6.067%
Non Recourse Debt | Alta Wind IV
Debt Instrument [Line Items]
Interest rate, stated percentage		5.938%
Non Recourse Debt | Alta Wind V
Debt Instrument [Line Items]
Interest rate, stated percentage		6.071%

Debt and Capital Leases - Narra

Debt and Capital Leases - Narrative (Details) - USD ($)	May 26, 2017	Jan. 24, 2017	Jun. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	May 23, 2016
Debt Instrument [Line Items]
Description of variable rate basis					3 month LIBOR
Long-term debt			$ 17,125,000,000		$ 17,125,000,000	$ 16,703,000,000
Recourse Debt
Debt Instrument [Line Items]
Long-term debt			7,785,000,000		7,785,000,000	7,795,000,000
Non Recourse Debt
Debt Instrument [Line Items]
Long-term debt			9,340,000,000		9,340,000,000	8,908,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Repayment of debt					125,000,000
Revolving Credit Facility | Letter of Credit
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 83,000,000
Revolving Credit Facility | Carlsbad Financing Agreement
Debt Instrument [Line Items]
Long-term construction loan	194,000,000
Revolving Credit Facility | Working Capital Facility
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	4,000,000
Term loan facility, due 2023 | Recourse Debt
Debt Instrument [Line Items]
Long-term debt			$ 1,881,000,000		$ 1,881,000,000	1,891,000,000
Term loan facility, due 2023 | Recourse Debt | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		2.25%			2.25%
Description of variable rate basis		LIBOR
Change in interest rate		5000.00%
Term loan facility, due 2023 | Recourse Debt | London Interbank Offered Rate (LIBOR) floor
Debt Instrument [Line Items]
Basis spread on variable rate		0.75%
Description of variable rate basis		LIBOR
Senior Notes Due In 2020 | Recourse Debt
Debt Instrument [Line Items]
Interest rate, stated percentage				8.25%
Senior notes, due 2021 | Recourse Debt
Debt Instrument [Line Items]
Interest rate, stated percentage			7.875%	7.875%	7.875%
Long-term debt			$ 207,000,000		$ 207,000,000	207,000,000
NRG Yield Revolving Credit Facility
Debt Instrument [Line Items]
Borrowing outstanding under revolver			0		0
NRG Yield Revolving Credit Facility | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding under revolver			$ 68,000,000		$ 68,000,000
Agua Caliente Borrower 1, due 2038 | Non Recourse Debt
Debt Instrument [Line Items]
Interest rate, stated percentage			5.43%		5.43%
Proceeds from issuance of senior secured debt			$ 130,000,000
Percentage of ownership			51.00%		51.00%
Long-term debt			$ 89,000,000		$ 89,000,000	0
Senior notes, due 2026 | Recourse Debt
Debt Instrument [Line Items]
Interest rate, stated percentage			7.25%		7.25%		7.25%
Long-term debt			$ 1,000,000,000		$ 1,000,000,000	1,000,000,000	$ 1,000,000,000
Senior notes, due 2027 | Recourse Debt
Debt Instrument [Line Items]
Proceeds from issuance of debt				$ 1,250,000,000
Interest rate, stated percentage			6.625%	6.625%	6.625%
Long-term debt			$ 1,250,000,000		$ 1,250,000,000	1,250,000,000
Carlsbad Energy Project | Non Recourse Debt
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 407,000,000
Interest rate, stated percentage	4.12%		4.12%		4.12%
Long-term debt			$ 345,000,000		$ 345,000,000	$ 0

Variable Interest Entities, o68

Variable Interest Entities, or VIEs (Details) $ in Millions	Jun. 30, 2017USD ($)facilityMW	Dec. 31, 2016USD ($)
Investments Accounted for by the Equity Method
Generation capacity (in MW) | MW	31,000
Equity investments in affiliates	$ 1,127	$ 1,120
Deficit Restoration Obligation	95
Current assets	84	87
Net property, plant and equipment	1,493	1,534
Other long-term assets	1,024	954
Total assets	2,601	2,575
Current liabilities	63	59
Long-term debt	424	442
Other long-term liabilities	187	183
Total liabilities	674	684
Noncontrolling interests	600	529
Net assets less noncontrolling interests	$ 1,327	$ 1,362
GenConn Energy LLC
Investments Accounted for by the Equity Method
Economic interest in equity method investments (as a percent)	50.00%
Power generation facilities | facility	2
Generation capacity (in MW) | MW	190
Equity investments in affiliates	$ 104

Changes in Capital Structure -

Changes in Capital Structure - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Jul. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Apr. 27, 2017	Jun. 13, 2016	May 24, 2016
Capital Structure
Common stock, shares authorized (in shares)		500,000,000	500,000,000	500,000,000	500,000,000
Redemption of shares (as percent)		100.00%		100.00%
Increase in shares available for issuance under the Amended and Restated Long-term Incentive Plan						3,000,000
Shares of treasury stock available for issuance under the ESPP			3,385,289
Shares issued under ESPP			282,530
Increase in Shares Available for Issuance, LTIP						3,000,000
Issued
Capital Structure
Shares issued under ESPP			0
Issued | Subsequent Event
Capital Structure
Shares issued under ESPP	278,240
Treasury
Capital Structure
Shares issued under ESPP			282,530
Convertible Preferred Stock
Capital Structure
Redemption of shares (as percent)							100.00%	100.00%
Preferred shares repurchased (in shares)								$ 344.5
Preferred stock, dividend rate amended (as percent)				2.822%	2.822%
Repurchase of outstanding shares		$ 226
Gain on redemption		$ 78
Carrying value of preferred stock at time of redemption Attributable to Parent							$ 304

Changes in Capital Structure 70

Changes in Capital Structure - Changes in NRG's common shares outstanding and issued (Details)	6 Months Ended
	Jun. 30, 2017shares
Class of Stock [Line Items]
Balance as of beginning of period	417,583,825
Treasury shares, balance as of beginning of period	(102,140,814)
Outstanding, as of beginning of period	315,443,011
Shares issued under LTIPs	397,287
Shares issued under ESPP	282,530
Balance as of end of period	417,981,112
Treasury shares, balance as of end of the period	(101,858,284)
Outstanding, as of end of period	316,122,828
Issued
Class of Stock [Line Items]
Shares issued under LTIPs	397,287
Shares issued under ESPP	0
Treasury
Class of Stock [Line Items]
Shares issued under LTIPs	0
Shares issued under ESPP	282,530

Changes in Capital Structure 71

Changes in Capital Structure - Schedule of dividends paid (Details) - $ / shares	Jul. 20, 2017	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Dividends Payable [Line Items]
Dividends Per Common Share (in dollars per share)		$ 0.03	$ 0.03	$ 0.03	$ 0.06	$ 0.18
Subsequent Event
Dividends Payable [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_(Loss) Per Share - Rec

Earnings/(Loss) Per Share - Reconciliation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Jun. 13, 2016	May 24, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Repurchase of shares (as percent)		100.00%		100.00%
Basic and diluted loss per share attributable to NRG Energy, Inc. common stockholders
Net loss attributable to NRG Energy, Inc.	$ (626)	$ (271)	$ (790)	$ (189)
Dividends for preferred shares	0	0	0	5
Gain on redemption of preferred shares	0	(78)	0	(78)
Loss Available for Common Stockholders	$ (626)	$ (193)	$ (790)	$ (116)
Weighted average number of common shares outstanding - basic and diluted (in shares)	316	315	316	315
Loss per weighted average common share — basic and diluted (dollars per share)	$ (1.98)	$ (0.61)	$ (2.50)	$ (0.37)
Convertible Preferred Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Repurchase of shares (as percent)						100.00%	100.00%
Preferred stock, dividend rate amended (as percent)				2.822%	2.822%

Earnings_(Loss) Per Share - Ant

Earnings/(Loss) Per Share - Anti-dilutive Securities (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	6	3	6	3
Equity compensation plans
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	6	3	6	3

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 27, 2017	Dec. 31, 2016	Sep. 01, 2016
Segment Reporting Information
Operating revenues	$ 2,701	$ 2,248	$ 5,083	$ 4,907
Depreciation and amortization	260	262	517	528
Impairment losses	63	56	63	56
Equity in earnings/(losses) of unconsolidated affiliates	(3)	4	2	(3)
Gain/(loss) on sale of assets	2	(83)	4	(83)
Impairment loss on investment				(139)
Loss on debt extinguishment, net	0	(80)	(2)	(69)
Income/(Loss) before income taxes	103	(138)	(71)	(173)
Loss from continuing operations	99	(163)	(70)	(220)
Loss from discontinued operations, net of income tax	(741)	(113)	(775)	(9)
Net Income/(Loss)	(642)	(276)	(845)	(229)
Net loss attributable to NRG Energy, Inc.	(626)	(271)	(790)	(189)
Total assets	25,205		25,205			$ 30,682
Renewables
Segment Reporting Information
Impairment losses	22
Operating Segments | Generation/Business
Segment Reporting Information
Operating revenues	882	504	1,848	1,637
Depreciation and amortization	95	97	192	197
Impairment losses	41	17	41	17
Equity in earnings/(losses) of unconsolidated affiliates	(15)	2	(28)	(5)
Gain/(loss) on sale of assets		0		0
Impairment loss on investment				(137)
Loss on debt extinguishment, net		0		0
Income/(Loss) before income taxes	(89)	(458)	(54)	(433)
Loss from continuing operations	(90)	(458)	(56)	(433)
Loss from discontinued operations, net of income tax	0	0	0	0
Net Income/(Loss)	(90)	(458)	(56)	(433)
Net loss attributable to NRG Energy, Inc.	(90)	(458)	(56)	(433)
Total assets	8,539		8,539
Operating Segments | Retail
Segment Reporting Information
Operating revenues	1,603	1,536	2,938	2,906
Depreciation and amortization	29	29	57	57
Impairment losses	0	0	0	0
Equity in earnings/(losses) of unconsolidated affiliates	0	0	0	0
Gain/(loss) on sale of assets		0		0
Impairment loss on investment				0
Loss on debt extinguishment, net		0		0
Income/(Loss) before income taxes	330	657	303	808
Loss from continuing operations	341	657	311	807
Loss from discontinued operations, net of income tax	0	0	0	0
Net Income/(Loss)	341	657	311	807
Net loss attributable to NRG Energy, Inc.	341	661	311	807
Total assets	2,439		2,439
Operating Segments | Renewables
Segment Reporting Information
Operating revenues	123	101	220	197
Depreciation and amortization	50	47	99	95
Impairment losses	22	27	22	27
Equity in earnings/(losses) of unconsolidated affiliates	(2)	(2)	(3)	(8)
Gain/(loss) on sale of assets		0		0
Impairment loss on investment				0
Loss on debt extinguishment, net		0		0
Income/(Loss) before income taxes	(52)	(75)	(89)	(122)
Loss from continuing operations	(47)	(71)	(79)	(111)
Loss from discontinued operations, net of income tax	0	0	0	0
Net Income/(Loss)	(47)	(71)	(79)	(111)
Net loss attributable to NRG Energy, Inc.	(22)	(66)	(26)	(96)
Total assets	5,193		5,193
Operating Segments | NRG Yield
Segment Reporting Information
Operating revenues	284	283	502	517
Depreciation and amortization	78	75	153	149
Impairment losses	0	0	0	0
Equity in earnings/(losses) of unconsolidated affiliates	16	14	35	18
Gain/(loss) on sale of assets		0		0
Impairment loss on investment				0
Loss on debt extinguishment, net		0		0
Income/(Loss) before income taxes	53	76	51	78
Loss from continuing operations	45	64	44	66
Loss from discontinued operations, net of income tax	0	0		0
Net Income/(Loss)	45	64	44	66
Net loss attributable to NRG Energy, Inc.	50	48	58	58
Total assets	8,513		8,513
Operating Segments | Corporate
Segment Reporting Information
Operating revenues	3	10	11	28
Depreciation and amortization	8	14	16	30
Impairment losses	0	12	0	12
Equity in earnings/(losses) of unconsolidated affiliates	3	27	7	6
Gain/(loss) on sale of assets		(83)		(83)
Impairment loss on investment				(2)
Loss on debt extinguishment, net		(80)		(69)
Income/(Loss) before income taxes	(135)	(295)	(273)	(495)
Loss from continuing operations	(146)	(312)	(281)	(540)
Loss from discontinued operations, net of income tax	(741)	(113)	(775)	(9)
Net Income/(Loss)	(887)	(425)	(1,056)	(549)
Net loss attributable to NRG Energy, Inc.	(920)	(449)	(1,089)	(558)
Total assets	10,954		10,954
Eliminations
Segment Reporting Information
Operating revenues	(194)	(186)	(436)	(378)
Depreciation and amortization	0	0		0
Impairment losses	0	0	0	0
Equity in earnings/(losses) of unconsolidated affiliates	(5)	(37)	(9)	(14)
Gain/(loss) on sale of assets		0		0
Impairment loss on investment				0
Loss on debt extinguishment, net		0		0
Income/(Loss) before income taxes	(4)	(43)	(9)	(9)
Loss from continuing operations	(4)	(43)	(9)	(9)
Loss from discontinued operations, net of income tax	0	0		0
Net Income/(Loss)	(4)	(43)	(9)	(9)
Net loss attributable to NRG Energy, Inc.	15	(7)	12	33
Total assets	(10,433)		(10,433)
Eliminations | Generation/Business
Segment Reporting Information
Operating revenues	(171)	(166)	(406)	(330)
Eliminations | Retail
Segment Reporting Information
Operating revenues	(1)	(1)	(11)	(5)
Eliminations | Renewables
Segment Reporting Information
Operating revenues	(10)	(4)	(4)	(8)
Eliminations | NRG Yield
Segment Reporting Information
Operating revenues	(3)	(2)	0	(6)
Eliminations | Corporate
Segment Reporting Information
Operating revenues	$ (9)	$ (13)	$ (15)	$ (29)
CVSR
Segment Reporting Information
Percentage of ownership sold of subsidiary							51.05%
Agua Caliente
Segment Reporting Information
Percentage of ownership sold of subsidiary					16.00%

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Effective Tax Rate
Income/(Loss) before income taxes	$ 103	$ (138)	$ (71)	$ (173)
Income tax expense/(benefit)	$ 4	$ 25	$ (1)	$ 47
Effective tax rate	3.90%	(18.10%)	1.40%	(27.20%)
Statutory tax rate (as a percent)	35.00%	35.00%	35.00%	35.00%
Uncertain Tax Benefits
Non-current tax liability for uncertain tax benefits	$ 39		$ 39
Unrecognized tax benefits, penalties and interest accrued	$ 4		$ 4

Related Party Transactions - Se

Related Party Transactions - Service Agreement with GenOn (Details) - USD ($) $ in Millions	Jun. 14, 2017	Jun. 12, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Related Party Transaction [Line Items]
Other income - affiliate			$ 42	$ 48	$ 90	$ 96
GenOn | Services Agreement
Related Party Transaction [Line Items]
Service fees					$ 193
Shared services, annualized rate		$ 84
Credit applied		28
Restructuring Support Agreement | Services Agreement
Related Party Transaction [Line Items]
Shared services, annualized rate		84
Monthly shared services	$ 5
Credit applied		$ 28

Related Party Transactions - Cr

Related Party Transactions - Credit Agreement with GenOn (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Long-term debt	$ 17,125,000,000	$ 16,703,000,000
GenOn | Revolving Credit Facility | Intercompany Credit Agreement
Related Party Transaction [Line Items]
Credit facility maximum borrowing capacity	500,000,000
Letters of credit outstanding under revolver	140,000,000	272,000,000
Long-term debt	125,000,000	$ 0
GenOn | Revolving Credit Facility | Restructuring Support Agreement, Letter of Credit Credit Facility
Related Party Transaction [Line Items]
Credit facility maximum borrowing capacity	$ 330,000,000
Line of credit facility cash collateralized percentage required	103.00%

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	1 Months Ended	6 Months Ended
	Aug. 31, 2009	Jun. 30, 2017	Dec. 13, 2016
Midwest Generation New Source Review
Loss Contingencies
Damages sought, amount	$ 37,500
Telephone Consumer Protection Act Purported Class Actions
Loss Contingencies
Damages sought, amount		$ 1,500
CDWR and SDGE v Sunrise Power
Loss Contingencies
Damages sought, amount		$ 1,200,000
Remaining term		70 months
Texas Westmoreland Coal Co. [Member] | Lignite Contract with Texas Westmoreland Coal Co.
Loss Contingencies
Bond obligation		$ 95,500,000
Senior Notes | Senior Unsecured Notes 2021 | GenOn Americas Generation, LLC
Loss Contingencies
Interest rate, stated percentage			8.50%
Senior Notes | Senior Unsecured Notes 2017 | GenOn Energy
Loss Contingencies
Interest rate, stated percentage			7.875%
Senior Notes | Senior Unsecured Notes 2031 | GenOn Americas Generation, LLC
Loss Contingencies
Interest rate, stated percentage			9.125%
Senior Notes | Senior Unsecured Notes 2018 | GenOn Energy
Loss Contingencies
Interest rate, stated percentage			9.50%
Senior Notes | Senior Unsecured Notes 2020 | GenOn Energy
Loss Contingencies
Interest rate, stated percentage			9.875%

Condensed Consolidating Finan79

Condensed Consolidating Financial Information - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt	$ 17,125	$ 16,703
Recourse Debt
Debt Instrument [Line Items]
Long-term debt	7,785	$ 7,795
Senior Notes | Recourse Debt
Debt Instrument [Line Items]
Long-term debt	$ 5,400

Condensed Consolidating Finan80

Condensed Consolidating Financial Information - STATEMENTS OF OPERATIONS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Revenues
Total operating revenues	$ 2,701	$ 2,248	$ 5,083	$ 4,907
Operating Costs and Expenses
Cost of operations	1,837	1,443	3,696	3,271
Depreciation and amortization	260	262	517	528
Impairment losses	63	56	63	56
Selling, general and administrative	223	266	482	520
Acquisition-related transaction and integration costs	1	5	2	6
Development activity expenses	18	18	35	44
Total operating costs and expenses	2,402	2,050	4,795	4,425
Other income - affiliate	42	48	90	96
Gain/(loss) on sale of assets	2	(83)	4	(83)
Operating Income/(Loss)	343	163	382	495
Other Income/(Expense)
Equity in earnings/(losses) of consolidated subsidiaries	0	0	0	0
Equity in (losses)/earnings of unconsolidated affiliates	(3)	4	2	(3)
Gain/(impairment loss) on investment	0	7	0	(139)
Other income	10	5	18	22
Loss on debt extinguishment, net	0	(80)	(2)	(69)
Interest expense	(247)	(237)	(471)	(479)
Total other expense	(240)	(301)	(453)	(668)
Income/(Loss) from Continuing Operations Before Income Taxes	103	(138)	(71)	(173)
Income tax expense/(benefit)	4	25	(1)	47
Income/(Loss) from Continuing Operations	99	(163)	(70)	(220)
Loss from discontinued operations, net of income tax	(741)	(113)	(775)	(9)
Net Income/(Loss)	(642)	(276)	(845)	(229)
Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests	(16)	(5)	(55)	(40)
Net Income/(Loss) Attributable to NRG Energy, Inc.	(626)	(271)	(790)	(189)
Eliminations
Operating Revenues
Total operating revenues	(46)	(37)	(125)	(58)
Operating Costs and Expenses
Cost of operations	(44)	(37)	(125)	(61)
Depreciation and amortization	0	0	0	0
Impairment losses	0	0	0	0
Selling, general and administrative	(1)	0	(2)	0
Acquisition-related transaction and integration costs	0	0	0	0
Development activity expenses	0	0	0	0
Total operating costs and expenses	(45)	(37)	(127)	(61)
Other income - affiliate	0		0
Gain/(loss) on sale of assets	0	0	0	0
Operating Income/(Loss)	(1)	0	2	3
Other Income/(Expense)
Equity in earnings/(losses) of consolidated subsidiaries	88	18	125	(191)
Equity in (losses)/earnings of unconsolidated affiliates	(34)	(46)	(36)	(55)
Gain/(impairment loss) on investment		0		0
Other income	0	0	0	(1)
Loss on debt extinguishment, net		0	0	0
Interest expense		0	0	0
Total other expense	54	(28)	89	(247)
Income/(Loss) from Continuing Operations Before Income Taxes	53	(28)	91	(244)
Income tax expense/(benefit)	0	0	0	0
Income/(Loss) from Continuing Operations	53	(28)	91	(244)
Loss from discontinued operations, net of income tax	0		0
Net Income/(Loss)	53	(28)	91	(244)
Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests	(35)	(46)	(34)	(53)
Net Income/(Loss) Attributable to NRG Energy, Inc.	88	18	125	(191)
Guarantor Subsidiaries
Operating Revenues
Total operating revenues	1,758	1,716	3,357	3,655
Operating Costs and Expenses
Cost of operations	1,307	1,128	2,568	2,559
Depreciation and amortization	102	112	203	225
Impairment losses	42	0	42	0
Selling, general and administrative	86	93	184	191
Acquisition-related transaction and integration costs	0	0	0	0
Development activity expenses	0	0	0	0
Total operating costs and expenses	1,537	1,333	2,997	2,975
Other income - affiliate	0		0
Gain/(loss) on sale of assets	2	0	4	0
Operating Income/(Loss)	223	383	364	680
Other Income/(Expense)
Equity in earnings/(losses) of consolidated subsidiaries	57	(50)	(20)	(81)
Equity in (losses)/earnings of unconsolidated affiliates	0	2	0	3
Gain/(impairment loss) on investment		0		0
Other income	0	1	1	2
Loss on debt extinguishment, net		0	0	0
Interest expense	(4)	(4)	(7)	(7)
Total other expense	53	(51)	(26)	(83)
Income/(Loss) from Continuing Operations Before Income Taxes	276	332	338	597
Income tax expense/(benefit)	113	128	131	228
Income/(Loss) from Continuing Operations	163	204	207	369
Loss from discontinued operations, net of income tax	0		0
Net Income/(Loss)	163	204	207	369
Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests	0	0	0	0
Net Income/(Loss) Attributable to NRG Energy, Inc.	163	204	207	369
Non-Guarantor Subsidiaries
Operating Revenues
Total operating revenues	989	569	1,851	1,310
Operating Costs and Expenses
Cost of operations	558	342	1,222	754
Depreciation and amortization	150	144	298	291
Impairment losses	21	56	21	56
Selling, general and administrative	38	46	84	95
Acquisition-related transaction and integration costs	1	0	2	0
Development activity expenses	13	13	25	32
Total operating costs and expenses	781	601	1,652	1,228
Other income - affiliate	0		0
Gain/(loss) on sale of assets	0	0	0	0
Operating Income/(Loss)	208	(32)	199	82
Other Income/(Expense)
Equity in earnings/(losses) of consolidated subsidiaries	(22)	(35)	(57)	(70)
Equity in (losses)/earnings of unconsolidated affiliates	676	41	707	39
Gain/(impairment loss) on investment		0		(139)
Other income	7	2	12	19
Loss on debt extinguishment, net		(4)	(2)	(4)
Interest expense	(121)	(101)	(225)	(207)
Total other expense	540	(97)	435	(362)
Income/(Loss) from Continuing Operations Before Income Taxes	748	(129)	634	(280)
Income tax expense/(benefit)	267	(33)	237	(94)
Income/(Loss) from Continuing Operations	481	(96)	397	(186)
Loss from discontinued operations, net of income tax	(741)	(116)	(775)	(15)
Net Income/(Loss)	(260)	(212)	(378)	(201)
Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests	(9)	10	(46)	(23)
Net Income/(Loss) Attributable to NRG Energy, Inc.	(251)	(222)	(332)	(178)
NRG Energy, Inc. (Note Issuer)
Operating Revenues
Total operating revenues	0	0	0	0
Operating Costs and Expenses
Cost of operations	16	10	31	19
Depreciation and amortization	8	6	16	12
Impairment losses	0	0	0	0
Selling, general and administrative	100	127	216	234
Acquisition-related transaction and integration costs	0	5	0	6
Development activity expenses	5	5	10	12
Total operating costs and expenses	129	153	273	283
Other income - affiliate	42	48	90	96
Gain/(loss) on sale of assets	0	(83)	0	(83)
Operating Income/(Loss)	(87)	(188)	(183)	(270)
Other Income/(Expense)
Equity in earnings/(losses) of consolidated subsidiaries	(123)	67	(48)	342
Equity in (losses)/earnings of unconsolidated affiliates	(645)	7	(669)	10
Gain/(impairment loss) on investment		7		0
Other income	3	2	5	2
Loss on debt extinguishment, net		(76)	0	(65)
Interest expense	(122)	(132)	(239)	(265)
Total other expense	(887)	(125)	(951)	24
Income/(Loss) from Continuing Operations Before Income Taxes	(974)	(313)	(1,134)	(246)
Income tax expense/(benefit)	(376)	(70)	(369)	(87)
Income/(Loss) from Continuing Operations	(598)	(243)	(765)	(159)
Loss from discontinued operations, net of income tax	0	3	0	6
Net Income/(Loss)	(598)	(240)	(765)	(153)
Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests	28	31	25	36
Net Income/(Loss) Attributable to NRG Energy, Inc.	$ (626)	$ (271)	$ (790)	$ (189)

Condensed Consolidating Finan81

Condensed Consolidating Financial Information - COMPREHENSIVE INCOME/(LOSS) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Net Income/(Loss)	$ (642)	$ (276)	$ (845)	$ (229)
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net	(5)	(3)	(1)	(35)
Foreign currency translation adjustments, net	1	(3)	8	3
Available-for-sale securities, net	1	(2)	1	1
Defined benefit plans, net	27	0	27	1
Other comprehensive income/(loss)	24	(8)	35	(30)
Comprehensive Income/(Loss)	(618)	(284)	(810)	(259)
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest	(17)	(16)	(56)	(68)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	(601)	(268)	(754)	(191)
Dividends for preferred shares	0	0	0	5
Gain on redemption of preferred shares	0	(78)	0	(78)
Comprehensive Income/(Loss) Available for Common Stockholders	(601)	(190)	(754)	(118)
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net Income/(Loss)	53	(28)	91	(244)
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net	5	6	0	0
Foreign currency translation adjustments, net	0	5	(9)	(3)
Available-for-sale securities, net	0	0	0	0
Defined benefit plans, net	(29)		(29)	0
Other comprehensive income/(loss)	(24)	11	(38)	(3)
Comprehensive Income/(Loss)	29	(17)	53	(247)
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest	(35)	(46)	(34)	(53)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	64	29	87	(194)
Dividends for preferred shares				0
Gain on redemption of preferred shares		0		0
Comprehensive Income/(Loss) Available for Common Stockholders		29		(194)
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net Income/(Loss)	163	204	207	369
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net	0	0	0	0
Foreign currency translation adjustments, net	0	(2)	5	2
Available-for-sale securities, net	0	0	0	0
Defined benefit plans, net	0		0	1
Other comprehensive income/(loss)	0	(2)	5	3
Comprehensive Income/(Loss)	163	202	212	372
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest	0	0	0	0
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	163	202	212	372
Dividends for preferred shares				0
Gain on redemption of preferred shares		0		0
Comprehensive Income/(Loss) Available for Common Stockholders		202		372
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net Income/(Loss)	(260)	(212)	(378)	(201)
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net	(6)	(5)	(1)	(55)
Foreign currency translation adjustments, net	1	(2)	5	2
Available-for-sale securities, net	0	0	0	0
Defined benefit plans, net	28		29	0
Other comprehensive income/(loss)	23	(7)	33	(53)
Comprehensive Income/(Loss)	(237)	(219)	(345)	(254)
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest	(10)	(1)	(47)	(51)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	(227)	(218)	(298)	(203)
Dividends for preferred shares				0
Gain on redemption of preferred shares		0		0
Comprehensive Income/(Loss) Available for Common Stockholders		(218)		(203)
NRG Energy, Inc. (Note Issuer)
Condensed Financial Statements, Captions [Line Items]
Net Income/(Loss)	(598)	(240)	(765)	(153)
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net	(4)	(4)	0	20
Foreign currency translation adjustments, net	0	(4)	7	2
Available-for-sale securities, net	1	(2)	1	1
Defined benefit plans, net	28		27	0
Other comprehensive income/(loss)	25	(10)	35	23
Comprehensive Income/(Loss)	(573)	(250)	(730)	(130)
Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest	28	31	25	36
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	$ (601)	(281)	$ (755)	(166)
Dividends for preferred shares				5
Gain on redemption of preferred shares		(78)		(78)
Comprehensive Income/(Loss) Available for Common Stockholders		$ (203)		$ (93)

Condensed Consolidating Finan82

Condensed Consolidating Financial Information - BALANCE SHEETS (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 752	$ 938	$ 748	$ 853
Funds deposited by counterparties	19	2	1	55
Restricted cash	469	446	$ 413	$ 414
Accounts receivable - trade, net	1,162	1,058
Accounts receivable - affiliate	99	114
Inventory	713	721
Derivative instruments	644	1,067
Cash collateral paid in support of energy risk management activities	277	150
Current assets held-for-sale	33	9
Prepayments and other current assets	301	290
Current assets - discontinued operations	0	1,919
Total current assets	4,469	6,714
Net property, plant and equipment	15,302	15,369
Other Assets
Investment in subsidiaries	0	0
Equity investments in affiliates	1,127	1,120
Notes receivable, less current portion	9	16
Goodwill	662	662
Intangible assets, net	1,893	1,973
Nuclear decommissioning trust fund	637	610
Derivative instruments	226	181
Deferred income tax	211	225
Non-current assets held-for-sale	10	10
Other non-current assets	659	841
Non-current assets - discontinued operations	0	2,961
Total other assets	5,434	8,599
Total Assets	25,205	30,682
Current Liabilities
Current portion of long-term debt and capital leases	1,042	516
Accounts payable	757	782
Accounts payable - affiliate	17	31
Derivative instruments	711	1,092
Cash collateral received in support of energy risk management activities	19	81
Accrued expenses and other current liabilities	810	990
Accrued expenses and other current liabilities-affiliate	164	0
Current liabilities - discontinued operations	0	1,210
Total current liabilities	3,520	4,702
Other Liabilities
Long-term debt and capital leases	15,842	15,957
Nuclear decommissioning reserve	262	287
Nuclear decommissioning trust liability	367	339
Deferred income taxes	20	20
Derivative instruments	293	284
Out-of-market contracts, net	219	230
Non-current liabilities held-for-sale	13	11
Other non-current liabilities	1,135	1,151
Non-current liabilities - discontinued operations	0	3,209
Total non-current liabilities	18,151	21,488
Total Liabilities	21,671	26,190
Redeemable noncontrolling interest in subsidiaries	51	46
Stockholders’ Equity	3,483	4,446
Total Liabilities and Stockholders’ Equity	25,205	30,682
Eliminations
Current Assets
Cash and cash equivalents	0
Funds deposited by counterparties	0
Restricted cash	0	0
Accounts receivable - trade, net	0	0
Accounts receivable - affiliate	(102)	(139)
Inventory	0	0
Derivative instruments	(74)	(92)
Cash collateral paid in support of energy risk management activities	0	0
Current assets held-for-sale	0	0
Prepayments and other current assets	0	0
Current assets - discontinued operations		0
Total current assets	(176)	(231)
Net property, plant and equipment	(26)	(27)
Other Assets
Investment in subsidiaries	(11,824)	(12,272)
Equity investments in affiliates	0	0
Notes receivable, less current portion	0	0
Goodwill	0	0
Intangible assets, net	(3)	(3)
Nuclear decommissioning trust fund	0	0
Derivative instruments	(34)	(43)
Deferred income tax	0	0
Non-current assets held-for-sale	0	0
Other non-current assets	0	0
Non-current assets - discontinued operations		0
Total other assets	(11,861)	(12,318)
Total Assets	(12,063)	(12,576)
Current Liabilities
Current portion of long-term debt and capital leases	0	0
Accounts payable	0	0
Accounts payable - affiliate	(130)	(139)
Derivative instruments	(74)	(92)
Cash collateral received in support of energy risk management activities		0
Accrued expenses and other current liabilities	28	0
Accrued expenses and other current liabilities-affiliate	0
Current liabilities - discontinued operations		0
Total current liabilities	(176)	(231)
Other Liabilities
Long-term debt and capital leases	0	0
Nuclear decommissioning reserve	0	0
Nuclear decommissioning trust liability	0	0
Deferred income taxes	0	0
Derivative instruments	(34)	(43)
Out-of-market contracts, net	0	0
Non-current liabilities held-for-sale	0	0
Other non-current liabilities	0	0
Non-current liabilities - discontinued operations		0
Total non-current liabilities	(34)	(43)
Total Liabilities	(210)	(274)
Redeemable noncontrolling interest in subsidiaries	0	0
Stockholders’ Equity	(11,853)	(12,302)
Total Liabilities and Stockholders’ Equity	(12,063)	(12,576)
Guarantor Subsidiaries
Current Assets
Cash and cash equivalents	(19)	(9)
Funds deposited by counterparties	14	2
Restricted cash	23	11
Accounts receivable - trade, net	783	734
Accounts receivable - affiliate	195	307
Inventory	472	482
Derivative instruments	572	962
Cash collateral paid in support of energy risk management activities	252	116
Current assets held-for-sale	0	0
Prepayments and other current assets	106	76
Current assets - discontinued operations		0
Total current assets	2,398	2,681
Net property, plant and equipment	4,038	4,219
Other Assets
Investment in subsidiaries	1,158	1,090
Equity investments in affiliates	0	(13)
Notes receivable, less current portion	0	0
Goodwill	359	359
Intangible assets, net	560	592
Nuclear decommissioning trust fund	637	610
Derivative instruments	187	144
Deferred income tax	(6)	3
Non-current assets held-for-sale	0	0
Other non-current assets	60	67
Non-current assets - discontinued operations		0
Total other assets	2,955	2,852
Total Assets	9,391	9,752
Current Liabilities
Current portion of long-term debt and capital leases	0	0
Accounts payable	540	501
Accounts payable - affiliate	724	744
Derivative instruments	590	947
Cash collateral received in support of energy risk management activities	14	81
Accrued expenses and other current liabilities	298	316
Accrued expenses and other current liabilities-affiliate	0
Current liabilities - discontinued operations		0
Total current liabilities	2,166	2,589
Other Liabilities
Long-term debt and capital leases	244	244
Nuclear decommissioning reserve	262	287
Nuclear decommissioning trust liability	367	339
Deferred income taxes	308	186
Derivative instruments	179	157
Out-of-market contracts, net	74	80
Non-current liabilities held-for-sale	0	0
Other non-current liabilities	383	396
Non-current liabilities - discontinued operations		0
Total non-current liabilities	1,817	1,689
Total Liabilities	3,983	4,278
Redeemable noncontrolling interest in subsidiaries	0	0
Stockholders’ Equity	5,408	5,474
Total Liabilities and Stockholders’ Equity	9,391	9,752
Non-Guarantor Subsidiaries
Current Assets
Cash and cash equivalents	363	624
Funds deposited by counterparties	2	0
Restricted cash	443	435
Accounts receivable - trade, net	376	321
Accounts receivable - affiliate	5	(254)
Inventory	241	239
Derivative instruments	142	196
Cash collateral paid in support of energy risk management activities	25	34
Current assets held-for-sale	33	9
Prepayments and other current assets	155	152
Current assets - discontinued operations		1,919
Total current assets	1,785	3,675
Net property, plant and equipment	11,049	10,926
Other Assets
Investment in subsidiaries	1,040	1,054
Equity investments in affiliates	1,123	1,128
Notes receivable, less current portion	9	16
Goodwill	303	303
Intangible assets, net	1,336	1,384
Nuclear decommissioning trust fund	0	0
Derivative instruments	47	44
Deferred income tax	(361)	0
Non-current assets held-for-sale	10	10
Other non-current assets	537	446
Non-current assets - discontinued operations		2,961
Total other assets	4,044	7,346
Total Assets	16,878	21,947
Current Liabilities
Current portion of long-term debt and capital leases	622	498
Accounts payable	187	247
Accounts payable - affiliate	(441)	(452)
Derivative instruments	195	237
Cash collateral received in support of energy risk management activities	2	0
Accrued expenses and other current liabilities	5	209
Accrued expenses and other current liabilities-affiliate	164
Current liabilities - discontinued operations		1,210
Total current liabilities	734	1,949
Other Liabilities
Long-term debt and capital leases	8,616	8,252
Nuclear decommissioning reserve	0	0
Nuclear decommissioning trust liability	0	0
Deferred income taxes	0	125
Derivative instruments	148	170
Out-of-market contracts, net	145	150
Non-current liabilities held-for-sale	13	11
Other non-current liabilities	316	431
Non-current liabilities - discontinued operations		3,209
Total non-current liabilities	9,238	12,348
Total Liabilities	9,972	14,297
Redeemable noncontrolling interest in subsidiaries	51	46
Stockholders’ Equity	6,855	7,604
Total Liabilities and Stockholders’ Equity	16,878	21,947
NRG Energy, Inc. (Note Issuer)
Current Assets
Cash and cash equivalents	408	323
Funds deposited by counterparties	3	0
Restricted cash	3	0
Accounts receivable - trade, net	3	3
Accounts receivable - affiliate	1	200
Inventory	0	0
Derivative instruments	4	1
Cash collateral paid in support of energy risk management activities	0	0
Current assets held-for-sale	0	0
Prepayments and other current assets	40	62
Current assets - discontinued operations		0
Total current assets	462	589
Net property, plant and equipment	241	251
Other Assets
Investment in subsidiaries	9,626	10,128
Equity investments in affiliates	4	5
Notes receivable, less current portion	0	0
Goodwill	0	0
Intangible assets, net	0	0
Nuclear decommissioning trust fund	0	0
Derivative instruments	26	36
Deferred income tax	578	222
Non-current assets held-for-sale	0	0
Other non-current assets	62	328
Non-current assets - discontinued operations		0
Total other assets	10,296	10,719
Total Assets	10,999	11,559
Current Liabilities
Current portion of long-term debt and capital leases	420	18
Accounts payable	30	34
Accounts payable - affiliate	(136)	(122)
Derivative instruments	0	0
Cash collateral received in support of energy risk management activities	3	0
Accrued expenses and other current liabilities	479	465
Accrued expenses and other current liabilities-affiliate	0
Current liabilities - discontinued operations		0
Total current liabilities	796	395
Other Liabilities
Long-term debt and capital leases	6,982	7,461
Nuclear decommissioning reserve	0	0
Nuclear decommissioning trust liability	0	0
Deferred income taxes	(288)	(291)
Derivative instruments	0	0
Out-of-market contracts, net	0	0
Non-current liabilities held-for-sale	0	0
Other non-current liabilities	436	324
Non-current liabilities - discontinued operations		0
Total non-current liabilities	7,130	7,494
Total Liabilities	7,926	7,889
Redeemable noncontrolling interest in subsidiaries	0	0
Stockholders’ Equity	3,073	3,670
Total Liabilities and Stockholders’ Equity	$ 10,999	$ 11,559

Condensed Consolidating Finan83

Condensed Consolidating Financial Information - CASH FLOWS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Cash Flows from Operating Activities
Net income (loss) from continuing operations	$ 99	$ (163)	$ (70)	$ (220)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions from unconsolidated affiliates			28	29
Equity in losses/(earnings) of unconsolidated affiliates			(2)	3
Depreciation and amortization	260	262	517	528
Provision for bad debts			18	20
Amortization of nuclear fuel			24	26
Amortization of financing costs and debt discount/premiums			29	29
Adjustment for debt extinguishment			0	14
Amortization of intangibles and out-of-market contracts			51	82
Amortization of unearned equity compensation			16	16
Impairment losses			63	195
Changes in deferred income taxes and liability for uncertain tax benefits			8	1
Changes in nuclear decommissioning trust liability			2	13
Changes in derivative instruments			7	(7)
Changes in collateral posted in support of risk management activities			(189)	323
Proceeds from sale of emission allowances			11	17
Gain on sale of assets			(22)	83
Cash (used)/provided by changes in other working capital			(379)	(272)
Cash provided by continuing operations			112	880
Cash (used/)provided by discontinued operations			(38)	(69)
Net Cash Provided by Operating Activities			74	811
Cash Flows from Investing Activities
Dividends from NRG Yield, Inc.			0	0
Intercompany dividends			0	0
Acquisition of Drop Down Assets, net of cash acquired			0
Acquisitions of businesses, net of cash acquired			(16)	(17)
Capital expenditures			(542)	(442)
Decrease in notes receivable			8	(3)
Purchases of emission allowances			(30)	(27)
Proceeds from sale of emission allowances			59	25
Investments in nuclear decommissioning trust fund securities			(279)	(280)
Proceeds from the sale of nuclear decommissioning trust fund securities			277	267
Proceeds from renewable energy grants and state rebates			8	10
Proceeds from sale of assets, net of cash disposed of			35	25
Investments in unconsolidated affiliates			(30)	1
Other			18	31
Cash (used)/provided by continuing operations			(492)	(410)
Cash used by discontinued operations			(53)	(60)
Net Cash (Used)/Provided by Investing Activities			(545)	(470)
Cash Flows from Financing Activities
Dividends from NRG Yield, Inc.			0	0
Payments (for)/from intercompany loans			0	0
Acquisition of Drop Down Assets, net of cash acquired			0
Intercompany dividends			0	0
Payment of dividends to common and preferred stockholders			(19)	(57)
Payment for preferred shares			0	(226)
Net receipts from settlement of acquired derivatives that include financing elements			2	4
Proceeds from issuance of long-term debt			946	3,223
Payments for short and long-term debt			(530)	(3,505)
Receivable from affiliate			(125)	0
Contributions to, net of distributions from, noncontrolling interest in subsidiaries			14	(21)
Payment of debt issuance costs			(36)	(35)
Other			(10)	(10)
Cash provided/(used) by continuing operations			242	(627)
Cash used by discontinued operations			(224)	97
Net Cash provided/(used) by Financing Activities			18	(530)
Change in Cash from discontinued operations			(315)	(32)
Effect of exchange rate changes on cash and cash equivalents			(8)	(3)
Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties			(146)	(160)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			1,386	1,322
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	1,240	1,162	1,240	1,162
Eliminations
Cash Flows from Operating Activities
Net income (loss) from continuing operations	53	(28)	91	(244)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions from unconsolidated affiliates			(4)	(11)
Equity in losses/(earnings) of unconsolidated affiliates			9	4
Depreciation and amortization	0	0	0	0
Provision for bad debts			0	0
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			0	0
Adjustment for debt extinguishment				0
Amortization of intangibles and out-of-market contracts			0	0
Amortization of unearned equity compensation			0	0
Impairment losses			0	0
Changes in deferred income taxes and liability for uncertain tax benefits			0	0
Changes in nuclear decommissioning trust liability			0	0
Changes in derivative instruments			0	0
Changes in collateral posted in support of risk management activities				0
Proceeds from sale of emission allowances			0	0
Gain on sale of assets			0	0
Cash (used)/provided by changes in other working capital			(96)	251
Cash provided by continuing operations			0	0
Cash (used/)provided by discontinued operations			0
Net Cash Provided by Operating Activities			0	0
Cash Flows from Investing Activities
Dividends from NRG Yield, Inc.			(45)	(39)
Intercompany dividends			(129)	(12)
Acquisition of Drop Down Assets, net of cash acquired			131
Acquisitions of businesses, net of cash acquired			0	0
Capital expenditures			0	0
Decrease in notes receivable			0	0
Purchases of emission allowances			0	0
Proceeds from sale of 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 renewable energy grants and state rebates			0	0
Proceeds from sale of assets, net of cash disposed of			0	0
Investments in unconsolidated affiliates			0	0
Other			0	0
Cash (used)/provided by continuing operations			(43)	(51)
Net Cash (Used)/Provided by Investing Activities			(43)	(51)
Cash Flows from Financing Activities
Dividends from NRG Yield, Inc.			45	39
Payments (for)/from intercompany loans			0	0
Acquisition of Drop Down Assets, net of cash acquired			(131)
Intercompany dividends			129	12
Payment of dividends to common and preferred stockholders			0	0
Payment for preferred shares				0
Net receipts from settlement of acquired derivatives that include financing elements			0	0
Proceeds from issuance of long-term debt			0	0
Payments for short and long-term debt			0	0
Receivable from affiliate			0
Contributions to, net of distributions from, noncontrolling interest in subsidiaries			0	0
Payment of debt issuance costs			0	0
Other			0	0
Cash provided/(used) by continuing operations			43	51
Cash used by discontinued operations			0
Net Cash provided/(used) by Financing Activities			43	51
Change in Cash from discontinued operations			0
Effect of exchange rate changes on cash and cash equivalents			0	0
Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties			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 income (loss) from continuing operations	163	204	207	369
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions from unconsolidated affiliates			0	0
Equity in losses/(earnings) of unconsolidated affiliates			0	(3)
Depreciation and amortization	102	112	203	225
Provision for bad debts			17	16
Amortization of nuclear fuel			24	26
Amortization of financing costs and debt discount/premiums			0	0
Adjustment for debt extinguishment				0
Amortization of intangibles and out-of-market contracts			12	20
Amortization of unearned equity compensation			0	0
Impairment losses			42	0
Changes in deferred income taxes and liability for uncertain tax benefits			131	460
Changes in nuclear decommissioning trust liability			2	13
Changes in derivative instruments			12	(64)
Changes in collateral posted in support of risk management activities			(203)	344
Proceeds from sale of emission allowances			11	47
Gain on sale of assets			(22)	0
Cash (used)/provided by changes in other working capital			(298)	(1,148)
Cash provided by continuing operations			138	305
Cash (used/)provided by discontinued operations			0
Net Cash Provided by Operating Activities			138	305
Cash Flows from Investing Activities
Dividends from NRG Yield, Inc.				0
Intercompany dividends			0	0
Acquisition of Drop Down Assets, net of cash acquired			0
Acquisitions of businesses, net of cash acquired				0
Capital expenditures			(90)	(80)
Decrease in notes receivable			0	0
Purchases of emission allowances			(30)	(27)
Proceeds from sale of emission allowances			59	25
Investments in nuclear decommissioning trust fund securities			(279)	(280)
Proceeds from the sale of nuclear decommissioning trust fund securities			277	267
Proceeds from renewable energy grants and state rebates			8	0
Proceeds from sale of assets, net of cash disposed of			35	0
Investments in unconsolidated affiliates			0	1
Other			18	27
Cash (used)/provided by continuing operations			(2)	(67)
Net Cash (Used)/Provided by Investing Activities			(2)	(67)
Cash Flows from Financing Activities
Dividends from NRG Yield, Inc.			0	0
Payments (for)/from intercompany loans			(122)	(179)
Acquisition of Drop Down Assets, net of cash acquired			0
Intercompany dividends				(52)
Payment of dividends to common and preferred stockholders			0	0
Payment for preferred shares				0
Net receipts from settlement of acquired derivatives that include financing elements			0	0
Proceeds from issuance of long-term debt			0	0
Payments for short and long-term debt			0	(1)
Receivable from affiliate			0
Contributions to, net of distributions from, noncontrolling interest in subsidiaries			0	0
Payment of debt issuance costs			0	0
Other				(3)
Cash provided/(used) by continuing operations			(122)	(235)
Cash used by discontinued operations			0
Net Cash provided/(used) by Financing Activities			(122)	(235)
Change in Cash from discontinued operations			0
Effect of exchange rate changes on cash and cash equivalents			0	0
Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties			14	3
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			4	0
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	18	3	18	3
Non-Guarantor Subsidiaries
Cash Flows from Operating Activities
Net income (loss) from continuing operations	481	(96)	397	(186)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions from unconsolidated affiliates			32	40
Equity in losses/(earnings) of unconsolidated affiliates			(13)	2
Depreciation and amortization	150	144	298	291
Provision for bad debts			1	4
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			20	16
Adjustment for debt extinguishment				4
Amortization of intangibles and out-of-market contracts			39	62
Amortization of unearned equity compensation			0	0
Impairment losses			21	195
Changes in deferred income taxes and liability for uncertain tax benefits			237	(208)
Changes in nuclear decommissioning trust liability			0	0
Changes in derivative instruments			(12)	54
Changes in collateral posted in support of risk management activities			11	(21)
Proceeds from sale of emission allowances			0	(30)
Gain on sale of assets			0	8
Cash (used)/provided by changes in other working capital			(1,138)	239
Cash provided by continuing operations			(107)	470
Cash (used/)provided by discontinued operations			(38)	(69)
Net Cash Provided by Operating Activities			(145)	401
Cash Flows from Investing Activities
Dividends from NRG Yield, Inc.				0
Intercompany dividends			0	0
Acquisition of Drop Down Assets, net of cash acquired			(131)
Acquisitions of businesses, net of cash acquired			(16)	(17)
Capital expenditures			(436)	(329)
Decrease in notes receivable			8	(3)
Purchases of emission allowances			0	0
Proceeds from sale of 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 renewable energy grants and state rebates			0	10
Proceeds from sale of assets, net of cash disposed of			0	0
Investments in unconsolidated affiliates			(30)	0
Other			0	4
Cash (used)/provided by continuing operations			(605)	(335)
Cash used by discontinued operations			(53)	(60)
Net Cash (Used)/Provided by Investing Activities			(658)	(395)
Cash Flows from Financing Activities
Dividends from NRG Yield, Inc.			(45)	(39)
Payments (for)/from intercompany loans			369	45
Acquisition of Drop Down Assets, net of cash acquired			0
Intercompany dividends			(129)	40
Payment of dividends to common and preferred stockholders			0	0
Payment for preferred shares				0
Net receipts from settlement of acquired derivatives that include financing elements			2	4
Proceeds from issuance of long-term debt			741	332
Payments for short and long-term debt			(316)	(279)
Receivable from affiliate			(125)
Contributions to, net of distributions from, noncontrolling interest in subsidiaries			14	(21)
Payment of debt issuance costs			(32)	0
Other			(10)	(7)
Cash provided/(used) by continuing operations			469	75
Cash used by discontinued operations			(224)	97
Net Cash provided/(used) by Financing Activities			245	172
Change in Cash from discontinued operations			(315)	(32)
Effect of exchange rate changes on cash and cash equivalents			(8)	(3)
Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties			(251)	207
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			1,059	629
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	808	836	808	836
NRG Energy, Inc. (Note Issuer)
Cash Flows from Operating Activities
Net income (loss) from continuing operations	(598)	(243)	(765)	(159)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions from unconsolidated affiliates			0	0
Equity in losses/(earnings) of unconsolidated affiliates			2	0
Depreciation and amortization	8	6	16	12
Provision for bad debts			0	0
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			9	13
Adjustment for debt extinguishment				10
Amortization of intangibles and out-of-market contracts			0	0
Amortization of unearned equity compensation			16	16
Impairment losses			0	0
Changes in deferred income taxes and liability for uncertain tax benefits			(360)	(251)
Changes in nuclear decommissioning trust liability			0	0
Changes in derivative instruments			7	3
Changes in collateral posted in support of risk management activities			3	0
Proceeds from sale of emission allowances			0	0
Gain on sale of assets			0	75
Cash (used)/provided by changes in other working capital			1,153	386
Cash provided by continuing operations			81	105
Cash (used/)provided by discontinued operations			0
Net Cash Provided by Operating Activities			81	105
Cash Flows from Investing Activities
Dividends from NRG Yield, Inc.			45	39
Intercompany dividends			129	12
Acquisition of Drop Down Assets, net of cash acquired			0
Acquisitions of businesses, net of cash acquired			0	0
Capital expenditures			(16)	(33)
Decrease in notes receivable			0	0
Purchases of emission allowances				0
Proceeds from sale of 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 renewable energy grants and state rebates			0	0
Proceeds from sale of assets, net of cash disposed of			0	25
Investments in unconsolidated affiliates			0	0
Other				0
Cash (used)/provided by continuing operations			158	43
Net Cash (Used)/Provided by Investing Activities			158	43
Cash Flows from Financing Activities
Dividends from NRG Yield, Inc.			0	0
Payments (for)/from intercompany loans			(247)	134
Acquisition of Drop Down Assets, net of cash acquired			131
Intercompany dividends				0
Payment of dividends to common and preferred stockholders			(19)	(57)
Payment for preferred shares				(226)
Net receipts from settlement of acquired derivatives that include financing elements			0	0
Proceeds from issuance of long-term debt			205	2,891
Payments for short and long-term debt			(214)	(3,225)
Receivable from affiliate			0
Contributions to, net of distributions from, noncontrolling interest in subsidiaries			0	0
Payment of debt issuance costs			(4)	(35)
Other				0
Cash provided/(used) by continuing operations			(148)	(518)
Cash used by discontinued operations			0
Net Cash provided/(used) by Financing Activities			(148)	(518)
Change in Cash from discontinued operations			0
Effect of exchange rate changes on cash and cash equivalents			0	0
Net Increase (Decrease) in Cash and Cash Equivalents, Restricted Cash, and Funds Restricted by Counterparties			91	(370)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			323	693
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 414	$ 323	$ 414	$ 323