NRG Energy (NRG) 10-Q 4 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 31, 2016
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	Sep. 30, 2016
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		315,442,997
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015
Operating Revenues
Total operating revenues	$ 3,952	[1]	$ 4,434	[2]	$ 9,819	[1]	$ 11,663	[2]
Operating Costs and Expenses
Cost of operations	2,793		3,042		6,738		8,551
Depreciation and amortization	357		382		979		1,173
Impairment losses	8		263		123		263
Selling, general and administrative	282		327		802		878
Acquisition-related transaction and integration costs	0		3		7		16
Development activity expenses	23		38		67		109
Total operating costs and expenses	3,463		4,055		8,716		10,990
Gain on sale of assets and postretirement benefits curtailment, net	266		0		215		14
Operating Income	755		379		1,318		687
Other Income/(Expense)
Equity in earnings of unconsolidated affiliates	16		24		13		29
Impairment loss on investment	(8)		0		(147)		0
Other income, net	9		4		35		27
Loss on debt extinguishment, net	(50)		(2)		(119)		(9)
Interest expense	(280)		(291)		(841)		(855)
Total other expense	(313)		(265)		(1,059)		(808)
Income/(Loss) Before Income Taxes	442		114		259		(121)
Income tax expense/(benefit)	49		47		95		(43)
Net Income/(Loss)	393		67		164		(78)
Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests	(9)		1		(49)		(10)
Net Income/(Loss) Attributable to NRG Energy, Inc.	402		66		213		(68)
Gain on redemption, net of dividends for preferred shares	0		5		(73)		15
Income/(Loss) Available for Common Stockholders	$ 402		$ 61		$ 286		$ (83)
Earnings/(Loss) per Share Attributable to NRG Energy, Inc. Common Stockholders
Weighted average number of common shares outstanding — basic	316		331		315		334
Earnings/(Loss) per Weighted Average Common Share — Basic	$ 1.27		$ 0.18		$ 0.91		$ (0.25)
Weighted average number of common shares outstanding — diluted	317		332		316		334
Earnings/(Loss) per Weighted Average Common Share — Diluted	$ 1.27		$ 0.18		$ 0.91		$ (0.25)
Dividends Per Common Share	$ 0.03		$ 0.15		$ 0.21		$ 0.44
[1]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$555 $— $9 $2 $47 $— $613(b) Includes loss on debt extinguishment$— $— $— $— $(50) $— $(50)
[2]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$309 $2 $(6) $18 $49 $— $372(b) Includes loss on debt extinguishment$— $— $— $2 $— $— $2

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income/(Loss) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net Income/(Loss)	$ 393	$ 67	$ 164	$ (78)
Other Comprehensive Income/(Loss), net of tax
Unrealized gains/(losses) on derivatives, net of income tax (benefit)/expense of $(1), $(12), $1 and $(6)	27	(6)	(8)	(2)
Foreign currency translation adjustments, net of income tax benefit of $0 , $5, $0 and $6	3	(8)	6	(10)
Available-for-sale securities, net of income tax expense of $0, $6, $0 and $1	0	(7)	1	(11)
Defined benefit plans, net of tax expense of $0, $2, $0 and $6	31	3	32	9
Other comprehensive income/(loss)	61	(18)	31	(14)
Comprehensive Income/(Loss)	454	49	195	(92)
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests	(2)	(17)	(70)	(34)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	456	66	265	(58)
Gain on redemption, net of dividends for preferred shares	0	5	(73)	15
Comprehensive Income/(Loss) Available for Common Stockholders	$ 456	$ 61	$ 338	$ (73)

Condensed Consolidated Stateme4

Condensed Consolidated Statement of Comprehensive Loss Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Unrealized (loss)/gain on derivatives, income tax (benefit)/expense	$ (1)	$ (12)	$ 1	$ (6)
Foreign currency translation adjustments, income tax expense/(benefit)	0	(5)	0	(6)
Available-for-sale securities, income tax benefit	0	6	0	1
Defined benefit plans, net of tax expense	$ 0	$ 2	$ 0	$ 6

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 2,435	$ 1,518
Funds deposited by counterparties	16	106
Restricted cash	480	414
Accounts receivable, net	1,362	1,157
Inventory	1,017	1,252
Derivative instruments	964	1,915
Cash collateral paid in support of energy risk management activities	337	568
Renewable energy grant receivable, net	34	13
Current assets held-for-sale	0	6
Prepayments and other current assets	369	442
Total current assets	7,014	7,391
Property, plant and equipment, net	18,203	18,732
Other Assets
Equity investments in affiliates	900	1,045
Notes receivable, less current portion	21	53
Goodwill	999	999
Intangible assets, net	2,106	2,310
Nuclear decommissioning trust fund	605	561
Derivative instruments	256	305
Deferred income taxes	189	167
Non-current assets held-for-sale	0	105
Other non-current assets	1,198	1,214
Total other assets	6,274	6,759
Total Assets	31,491	32,882
Current Liabilities
Current portion of long-term debt and capital leases	1,221	481
Accounts payable	945	869
Derivative instruments	969	1,721
Cash collateral received in support of energy risk management activities	16	106
Current liabilities held-for-sale	0	2
Accrued expenses and other current liabilities	1,150	1,196
Total current liabilities	4,301	4,375
Other Liabilities
Long-term debt and capital leases	18,018	18,983
Nuclear decommissioning reserve	284	326
Nuclear decommissioning trust liability	309	283
Deferred income taxes	47	19
Derivative instruments	475	493
Out-of-market contracts, net	1,065	1,146
Non-current liabilities held-for-sale	0	4
Other non-current liabilities	1,480	1,488
Total non-current liabilities	21,678	22,742
Total Liabilities	25,979	27,117
2.822% convertible perpetual preferred stock	0	302
Redeemable noncontrolling interest in subsidiaries	19	29
Stockholders’ Equity
Common stock	4	4
Additional paid-in capital	8,370	8,296
Retained deficit	(2,791)	(3,007)
Less treasury stock, at cost — 102,140,814 and 102,749,908 shares, respectively	(2,399)	(2,413)
Accumulated other comprehensive loss	(142)	(173)
Noncontrolling interest	2,451	2,727
Total Stockholders’ Equity	5,493	5,434
Total Liabilities and Stockholders’ Equity	$ 31,491	$ 32,882

Condensed Consolidated Balance6

Condensed Consolidated Balance Sheets (Parenthetical) - shares	Sep. 30, 2016	May 24, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Convertible perpetual preferred stock, interest rate (as a percentage)	2.822%	2.822%	2.822%
Treasury stock, shares (in shares)	102,140,814		102,749,908

Condensed Consolidated Stateme7

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash Flows from Operating Activities
Net Income/(Loss)	$ 164	$ (78)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates	44	28
Depreciation and amortization	979	1,173
Provision for bad debts	36	49
Amortization of nuclear fuel	39	36
Amortization of financing costs and debt discount/premiums	3	(9)
Adjustment to loss on debt extinguishment	21	9
Amortization of intangibles and out-of-market contracts	73	68
Amortization of unearned equity compensation	23	37
Impairment losses	270	263
Changes in deferred income taxes and liability for uncertain tax benefits	29	(72)
Changes in nuclear decommissioning trust liability	24	1
Changes in derivative instruments	82	180
Changes in collateral deposits supporting energy risk management activities	231	(180)
Proceeds from sale of emission allowances	47	(6)
Gain on sale of assets, net and postretirement benefits curtailment	(224)	(14)
Cash used by changes in other working capital	(108)	(93)
Net Cash Provided by Operating Activities	1,733	1,392
Cash Flows from Investing Activities
Acquisitions of businesses, net of cash acquired	(18)	(31)
Capital expenditures	(898)	(889)
Increase in restricted cash, net	(30)	(41)
(Increase)/decrease in restricted cash to support equity requirements for U.S. DOE funded projects	(36)	1
Decrease in notes receivable	2	10
Purchases of emission allowances	32	40
Proceeds from sale of emission allowances	47	45
Investments in nuclear decommissioning trust fund securities	(378)	(500)
Proceeds from the sale of nuclear decommissioning trust fund securities	354	499
Proceeds from renewable energy grants and state rebates	11	62
Proceeds from sale of assets, net of cash disposed of	636	1
Investments in unconsolidated affiliates	(23)	(357)
Other	44	8
Net Cash Used by Investing Activities	(321)	(1,232)
Cash Flows from Financing Activities
Payment of dividends to common and preferred stockholders	(66)	(152)
Payment for treasury stock	0	(353)
Payment for preferred shares	(226)	0
Net receipts from settlement of acquired derivatives that include financing elements	129	138
Proceeds from issuance of long-term debt	5,237	679
Payments for short and long-term debt	(5,357)	(954)
Distributions from, net of contributions to, noncontrolling interest in subsidiaries	(127)	(651)
Proceeds from issuance of common stock	1	1
Payments of Debt Issuance Costs	70	14
Other - contingent consideration	(10)	(22)
Net Cash Used by Financing Activities	(489)	(26)
Effect of exchange rate changes on cash and cash equivalents	(6)	15
Net Increase in Cash and Cash Equivalents	917	149
Cash and Cash Equivalents at Beginning of Period	1,518	2,116
Cash and Cash Equivalents at End of Period	$ 2,435	$ 2,265

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]	Basis of Presentation NRG Energy, Inc., or NRG or the Company, is an integrated competitive power company that aims to create a sustainable energy future by producing, selling and delivering energy and energy products and services in major competitive power markets in the U.S. in a manner that delivers value to all of NRG's stakeholders. NRG has one of the nation's largest and most diverse competitive generation portfolios balanced with a leading retail electricity platform. The Company owns and operates approximately 46,000 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 2015 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 September 30, 2016, and the results of operations, comprehensive income/(loss) and cash flows for the three and nine months ended September 30, 2016 and 2015. 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. The Company decreased accumulated depreciation and facilities and equipment within total property, plant and equipment by approximately $1 billion respectively, to adjust amounts previously presented as of December 31, 2015. This adjustment had no impact on net assets at December 31, 2015. Accordingly, the Company does not consider the adjustment to be material to the consolidated balance sheet. Consolidated operating income and net income for the three months and nine months ended September 30, 2016 were not impacted by the adjustment.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
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. September 30, 2016 December 31, 2015 (In millions) Accounts receivable allowance for doubtful accounts $ 28 $ 26 Property plant and equipment accumulated depreciation 6,424 5,761 Intangible assets accumulated amortization 1,729 1,590 Out-of-market contracts accumulated amortization 740 639 Other Cash Flow Information NRG’s investing activities exclude capital expenditures of $112 million which were accrued and unpaid at September 30, 2016 . Noncontrolling Interest The following table reflects the changes in NRG's noncontrolling interest balance: (In millions) Balance as of December 31, 2015 $ 2,727 Distributions to noncontrolling interest (135 ) Dividends paid to NRG Yield, Inc. public shareholders (68 ) Comprehensive loss attributable to noncontrolling interest (45 ) Sale of assets to NRG Yield, Inc. (37 ) Redemption of noncontrolling interest (7 ) Contributions from noncontrolling interest 16 Balance as of September 30, 2016 $ 2,451 Redeemable Noncontrolling Interest The following table reflects the changes in the Company's redeemable noncontrolling interest balance: (In millions) Balance as of December 31, 2015 $ 29 Distributions to redeemable noncontrolling interest (46 ) Contributions from redeemable noncontrolling interest 61 Comprehensive loss attributable to redeemable noncontrolling interest (25 ) Balance as of September 30, 2016 $ 19 Recent Accounting Developments 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. The amendments of ASU No. 2016-16 were issued to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. 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 and do not require new disclosure requirements. The amendments of ASU No. 2016-16 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. 2016-16 should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company is currently evaluating the impact of the standard on the Company’s results of operations, cash flows and financial position. 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 amendments of ASU No. 2016-15 are effective for public entities for fiscal years beginning after December 15, 2017 and interim periods in those fiscal years. Early adoption is permitted, including adoption in an interim fiscal period with all amendments adopted in the same period. The adoption of ASU No. 2016-15 is required to be applied retrospectively. The Company is currently evaluating the impact of the standard on the Company's statement of cash flows. 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 of ASU No. 2016-09 were issued as part of the FASB's Simplification Initiative focused on improving areas of GAAP for which cost and complexity may be reduced while maintaining or improving the usefulness of information disclosed within the financial statements. 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 guidance in ASU No. 2016-09 is effective for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted. The Company does not expect the standard to have a material impact on its results of operations, cash flows and financial position. ASU 2016-07 — In March 2016, the FASB issued ASU No. 2016-07, Investments - Equity Method and Joint Ventures (Topic 323), or ASU No. 2016-07. The amendments of ASU No. 2016-07 eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting with no retroactive adjustment to the investment. In addition, ASU No. 2016-07 requires that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The guidance in ASU No. 2016-07 is effective for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. The adoption of ASU No. 2016-07 is required to be applied prospectively and early adoption is permitted. The Company does not expect the standard to have a material impact on its results of operations, cash flows and financial position. ASU 2016-02 — In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or ASU No. 2016-02. The amendments of ASU No. 2016-02 complete the joint effort between the FASB and the International Accounting Standards Board, or IASB, to develop a common leasing standard for GAAP and International Financial Reporting Standards, or IFRS, 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. The guidance in ASU No. 2016-02 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, ASU No. 2016-02 expands the required quantitative and qualitative disclosures with regards to lease arrangements. The guidance in ASU No. 2016-02 is effective for fiscal years beginning after December 15, 2018, and interim periods within those annual periods. The adoption of ASU No. 2016-02 is required to be applied using a modified retrospective approach for the earliest period presented and early adoption is permitted. The Company is currently working through an adoption plan which includes the evaluation of lease contracts compared to the new standard and evaluating the impact of ASU No. 2016-02 on the Company's results of operations, cash flows and financial position. ASU 2016-01 — In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, or ASU No. 2016-01. The amendments of ASU No. 2016-01 eliminate available-for-sale classification of equity investments and require that equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be generally measured at fair value with changes in fair value recognized in net income. Further, the amendments require that financial assets and financial liabilities to be presented separately in the notes to the financial statements, grouped by measurement category and form of financial asset. The guidance in ASU No. 2016-01 is effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within those annual periods. The Company is currently evaluating the impact of the standard on the Company's results of operations, cash flows and financial position. ASU 2015-16 — In September 2015, the FASB issued ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments , or ASU No. 2015-16. The amendments of ASU No. 2015-16 require that an acquirer recognize measurement period adjustments to the provisional amounts recognized in a business combination in the reporting period during which the adjustments are determined. Additionally, the amendments of ASU No. 2015-16 require the acquirer to record in the same period's financial statements the effect on earnings of changes in depreciation, amortization or other income effects, if any, as a result of the measurement period adjustment, calculated as if the accounting had been completed at the acquisition date as well as disclosing either on the face of the income statement or in the notes the portion of the amount recorded in current period earnings that would have been recorded in previous reporting periods. The guidance in ASU No. 2015-16 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. The amendments should be applied prospectively. The Company adopted ASU No. 2015-16 for the year ended December 31, 2016, and the adoption did not have a material impact on the Company's results of operations, cash flows and financial position. ASU 2014-09 — In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU No. 2014-09. The amendments of ASU No. 2014-09 complete the joint effort between the FASB and the IASB, to develop a common revenue standard for GAAP and IFRS, and to improve financial reporting. In addition to ASU No. 2014-09, the FASB has issued additional guidance which provides further clarification on Topic 606 including ASU No. 2016-08, ASU No. 2016-10 and ASU No. 2016-12. 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 four step process to be applied by an entity in evaluating its contracts with customers. In August 2015, the FASB issued ASU No. 2015-14, which formally deferred the effective date by one year to make the guidance of ASU No. 2014-09 effective for annual reporting periods beginning after December 15, 2017, including interim periods therein. Early adoption is permitted, but not prior to the original effective date, which was for annual reporting periods beginning after December 15, 2016. The Company is working through an adoption plan which includes the evaluation of revenue contracts compared to the new standard and evaluating the impact of Topic 606 on the Company's results of operations, cash flows and financial position.

Business Acquisitions and Dispo

Business Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	Business Acquisitions and Dispositions The Company has completed the following business acquisitions and dispositions that are material to the Company's financial statements: Acquisitions 2015 Acquisition of Desert Sunlight On June 29, 2015, NRG Yield, Inc., through its subsidiary NRG Yield Operating LLC, acquired 25% of the membership interest in Desert Sunlight Investment Holdings, LLC, which owns two solar photovoltaic facilities that total 550 MW located in Desert Center, California from EFS Desert Sun, LLC, an affiliate of GE Energy Financial Services, for a purchase price of $285 million . The Company accounts for its 25% investment as an equity method investment. SunEdison Utility-Scale Solar and Wind Acquisition On September 15, 2016, the Company entered into an agreement with SunEdison to acquire (i) an equity interest in a tax-equity portfolio of 530 MW mechanically-complete solar assets of which NRG’s net interest based on cash to be distributed will be 265 MW, and an additional 937 MW of solar and wind assets in development, (ii) a 154 MW construction-ready solar facility in Texas and (iii) a 182 MW portfolio of construction-ready and development solar assets in Hawaii. The acquisition of the portfolio of solar assets in Hawaii was completed on October 7, 2016 for upfront cash consideration of $2 million and the acquisition of the 530 MW tax equity portfolio and 937 MW development assets was completed on November 2, 2016 for upfront cash consideration of $111 million . The Company expects to pay total upfront cash consideration for the three acquisitions of $129 million , with an estimated $59 million in additional payments contingent upon future development milestones. SunEdison Solar Distributed Generation Acquisition On October 3, 2016, the Company acquired a 29 MW portfolio of mechanically-complete and construction-ready distributed generation solar assets from SunEdison for cash consideration of approximately $68 million , subject to post closing adjustments. The Company expects to sell these assets into a tax-equity financed portfolio within the DGPV Holdco partnership between NRG and NRG Yield, Inc. Dispositions Potrero Disposition On September 26, 2016, NRG Potrero LLC, or Potrero, an indirect wholly owned subsidiary of GenOn Americas Generation, completed the sale of real property at the Potrero generating station located in San Francisco, CA to California Barrel Company, LLC for total consideration of $86 million , consisting of $74 million of cash received, which is net of $8 million of closing costs and $4 million to be held in escrow in order to cover post closing obligations. This transaction resulted in a gain on sale of $74 million . 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 retained 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. 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 EVgo will be directly reimbursed by NRG for the costs. As a result of the sale, the Company recorded a loss on sale of $78 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 , of which $50 million remains as of September 30, 2016. At September 30, 2016, the Company's remaining 35% interest in EVgo of $10 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. 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 . Aurora Disposition On May 12, 2016, GenOn entered into an agreement with RA Generation, LLC to sell the Aurora Generating Station, or Aurora, for cash consideration of $365 million , subject to adjustments for working capital and the results of the PJM 2019/2020 base residual auction. Aurora is a 878 MW natural gas facility located in Aurora, Illinois. On July 12, 2016, GenOn completed the sale of Aurora for cash proceeds of $369 million , including $4 million in adjustments for the PJM base residual auction results and estimated working capital, which is subject to further adjustment. The Company recorded a gain of approximately $188 million recognized within the Company's consolidated results of operations during the quarter ended September 30, 2016. Seward Disposition On November 24, 2015, GenOn entered into an agreement with Seward Generation, LLC and an affiliate of Robindale Energy Services, Inc. to sell the Seward Generating Station, a 525 MW coal-fired facility in Pennsylvania, for cash consideration of $75 million . At December 31, 2015, GenOn had classified on its balance sheet the assets and liabilities of Seward as held for sale. On February 2, 2016, GenOn completed the sale of Seward and received gross cash proceeds of $75 million , excluding $3 million cash on hand transferred to the buyer. GenOn will also receive $5 million in deferred cash consideration in five $1 million annual installments and up to $2.5 million in payments contingent upon certain environmental requirements being imposed by August 2017. In addition, Robindale committed to future inventory purchases from GenOn of $13 million through 2019. Shelby Disposition On November 9, 2015, GenOn entered into an agreement with an affiliate of Rockland Power Partners II, LP to sell the Shelby Generating Station, a 352 MW natural gas-fired facility located in Illinois for cash consideration of $46 million . At December 31, 2015, GenOn had classified on its balance sheet the assets and liabilities of Shelby as held for sale. On March 1, 2016, GenOn completed the sale of Shelby for cash proceeds of $46 million , which resulted in a gain of $29 million recognized during the first quarter of 2016. In addition, GenOn retained $10 million related to future revenue rights retained as part of the agreement of which $7 million had been received as of September 30, 2016. Transfer of Assets under Common Control On September 1, 2016, the Company completed the sale of its remaining 51.05% interest in the CVSR project to NRG Yield, Inc. for total cash consideration of $78.5 million , plus an immaterial working capital adjustment. In addition, NRG Yield, Inc. assumed non-recourse project level debt of $496 million . On November 3, 2015, the Company sold 75% of the Class B interests of NRG Wind TE Holdco, which owns a portfolio of 12 wind facilities totaling 814 net MW, to NRG Yield, Inc. NRG Yield, Inc. paid total cash consideration of $209 million , subject to working capital adjustments. NRG Yield, Inc. is responsible for its pro-rata share of non-recourse project debt of $193 million and noncontrolling interest associated with a tax equity structure of $159 million (as of the acquisition date). In February 2016, the Company made a final working capital payment of $2 million to NRG Yield, Inc. reducing total cash consideration to $207 million .

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2016
Fair Value of Financial Instruments Disclosure [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 2015 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 September 30, 2016 As of December 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable (a) $ 50 $ 50 $ 73 $ 73 Liabilities: Long-term debt, including current portion (b) 19,411 18,888 19,620 18,263 (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 September 30, 2016 and December 31, 2015: As of September 30, 2016 As of December 31, 2015 Level 2 Level 3 Level 2 Level 3 (In millions) Long-term debt, including current portion $ 11,767 $ 7,121 $ 11,028 $ 7,235 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 September 30, 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 Other (a) 10 — — 10 Nuclear trust fund investments: Cash and cash equivalents 24 — — 24 U.S. government and federal agency obligations 51 1 — 52 Federal agency mortgage-backed securities — 68 — 68 Commercial mortgage-backed securities — 17 — 17 Corporate debt securities — 87 — 87 Equity securities 301 — 54 355 Foreign government fixed income securities — 2 — 2 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 308 798 107 1,213 Interest rate contracts — 7 — 7 Total assets $ 705 $ 980 $ 178 $ 1,863 Derivative liabilities: Commodity contracts 375 773 133 1,281 Interest rate contracts — 163 — 163 Total liabilities $ 375 $ 936 $ 133 $ 1,444 (a) Consists primarily of mutual funds held in a Rabbi Trust for non-qualified deferred compensation plans for certain former employees. As of December 31, 2015 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 9 — — 9 Other (a) 14 — — 14 Nuclear trust fund investments: Cash and cash equivalents 6 — — 6 U.S. government and federal agency obligations 54 1 — 55 Federal agency mortgage-backed securities — 59 — 59 Commercial mortgage-backed securities — 25 — 25 Corporate debt securities — 81 — 81 Equity securities 280 — 54 334 Foreign government fixed income securities — 1 — 1 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 622 1,449 149 2,220 Total assets $ 986 $ 1,616 $ 220 $ 2,822 Derivative liabilities: Commodity contracts 868 1,036 182 2,086 Interest rate contracts — 128 — 128 Total liabilities $ 868 $ 1,164 $ 182 $ 2,214 (a) Primarily consists of mutual funds held in rabbi trusts for non-qualified deferred compensation plans for certain former employees and a total return swap that does not meet the definition of a derivative. There were no transfers during the three and nine months ended September 30, 2016 , and 2015 between Levels 1 and 2. The following tables reconcile, for the three and nine months ended September 30, 2016 , and 2015 , 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 September 30, 2016 Nine months ended September 30, 2016 (In millions) Debt Securities Trust Fund Investments Derivatives (a) Total Debt Securities Trust Fund Investments Derivatives (a) Total Beginning balance $ 16 $ 51 $ 7 $ 74 $ 17 $ 54 $ (33 ) $ 38 Total gains/(losses) — realized/unrealized: Included in earnings — — 2 2 — — 9 9 Included in OCI 1 — — 1 — — — — Included in nuclear decommissioning obligation — 3 — 3 — (1 ) — (1 ) Purchases — — (26 ) (26 ) — 1 3 4 Transfers into Level 3 (b) — — (12 ) (12 ) — — (5 ) (5 ) Transfers out of Level 3 (b) — — 3 3 — — — — Ending balance as of September 30, 2016 $ 17 $ 54 $ (26 ) $ 45 $ 17 $ 54 $ (26 ) $ 45 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 September 30, 2016 $ — $ — $ 1 $ 1 $ — $ — $ (14 ) $ (14 ) (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 September 30, 2015 Nine months ended September 30, 2015 (In millions) Debt Securities Other Trust Fund Investments Derivatives (a) Total Debt Securities Other Trust Fund Investments Derivatives (a) Total Beginning balance $ 18 $ — $ 55 $ 49 $ 122 $ 18 $ 11 $ 52 $ 80 $ 161 Total losses — realized/unrealized: Included in earnings — — — (17 ) (17 ) — (11 ) — (95 ) (106 ) Included in nuclear decommissioning obligations — — (6 ) — (6 ) — — (4 ) — (4 ) Purchases — — — 9 9 — — 1 44 45 Transfers into Level 3 (b) — — — (10 ) (10 ) — — — 1 1 Transfers out of Level 3 (b) — — — 2 2 — — — 3 3 Ending balance as of September 30, 2015 $ 18 $ — $ 49 $ 33 $ 100 $ 18 $ — $ 49 $ 33 $ 100 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 September 30, 2015 $ — $ — $ — $ (9 ) $ (9 ) $ — $ — $ — $ (37 ) $ (37 ) (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 September 30, 2016 , contracts valued with prices provided by models and other valuation techniques make up 9% of the total derivative assets and 9% 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 September 30, 2016 and December 31, 2015 : Significant Unobservable Inputs September 30, 2016 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 53 $ 78 Discounted Cash Flow Forward Market Price (per MWh) $ 11 $ 81 $ 27 Coal Contracts — 5 Discounted Cash Flow Forward Market Price (per ton) 44 44 44 FTRs 54 50 Discounted Cash Flow Auction Prices (per MWh) (63 ) 55 — $ 107 $ 133 Significant Unobservable Inputs December 31, 2015 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 86 $ 100 Discounted Cash Flow Forward Market Price (per MWh) $ 10 $ 92 $ 27 Coal Contracts — 12 Discounted Cash Flow Forward Market Price (per ton) 28 45 35 FTRs 63 70 Discounted Cash Flow Auction Prices (per MWh) (98 ) 87 — $ 149 $ 182 The following table provides sensitivity of fair value measurements to increases/(decreases) in significant unobservable inputs as of September 30, 2016 and December 31, 2015 : Significant Unobservable Input Position Change In Input Impact on Fair Value Measurement Forward Market Price Power/Coal Buy Increase/(Decrease) Higher/(Lower) Forward Market Price Power/Coal 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 September 30, 2016 , the credit reserve resulted in a $2 million decrease in fair value, which is composed of a $3 million gain in OCI and a $5 million loss in operating revenue and cost of operations. As of September 30, 2015 , the credit reserve resulted in a $7 million increase in fair value, which was composed of a $4 million gain in OCI and a $3 million gain in operating revenues 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 2015 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 2015 Form 10-K. As of September 30, 2016 , the Company's counterparty credit exposure, excluding credit risk exposure under certain long term agreements, was $635 million with net exposure of $607 million . NRG held collateral (cash and letters of credit) against those positions of $45 million . Approximately 79% of the Company's exposure before collateral is expected to roll off by the end of 2017 . 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) Category by Industry Sector (% of Total) Financial institutions 33 % Utilities, energy merchants, marketers and other 42 ISOs 25 Total as of September 30, 2016 100 % Net Exposure (a) Category by Counterparty Credit Quality (% of Total) Investment grade 90 % Non-rated (b) 3 Non-investment grade 7 Total as of September 30, 2016 100 % (a) Counterparty credit exposure excludes uranium and coal transportation contracts because of the unavailability of market prices. (b) For non-rated counterparties, a significant portion are related to ISO and municipal public power entities, which are considered investment grade equivalent ratings based on NRG's internal credit ratings. 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 $295 million as of September 30, 2016 . 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. Counterparty credit exposure described above excludes credit risk exposure under certain long term agreements, including California tolling agreements, Gulf Coast load obligations, wind and solar PPAs, and a coal supply agreement. 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 September 30, 2016 , aggregate credit risk exposure managed by NRG to these counterparties was approximately $4.1 billion , including $2.6 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 and other technology and market factors, which NRG is unable to predict. In the case of the coal supply agreement, NRG holds a lien against the underlying asset, which significantly reduces the risk of loss. 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 September 30, 2016 , 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	9 Months Ended
	Sep. 30, 2016
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 2015 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 September 30, 2016 As of December 31, 2015 (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 $ 24 $ — $ — — $ 6 $ — $ — — U.S. government and federal agency obligations 52 4 — 11 55 1 — 11 Federal agency mortgage-backed securities 68 2 — 25 59 1 — 25 Commercial mortgage-backed securities 17 — 1 26 25 — 2 28 Corporate debt securities 87 3 1 11 81 1 1 10 Equity securities 355 213 — — 334 199 — — Foreign government fixed income securities 2 — — 9 1 — — 9 Total $ 605 $ 222 $ 2 $ 561 $ 202 $ 3 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. Nine months ended September 30, 2016 2015 (In millions) Realized gains $ 7 $ 14 Realized losses 3 10 Proceeds from sale of securities 354 499

Accounting for Derivative Instr

Accounting for Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2016
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 2015 Form 10-K. Energy-Related Commodities As of September 30, 2016 , NRG had energy-related derivative instruments extending through 2027 . 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 September 30, 2016 , 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 2032 , 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 September 30, 2016 and December 31, 2015 . 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 September 30, 2016 December 31, 2015 Category Units (In millions) Emissions Short Ton 1 1 Coal Short Ton 29 35 Natural Gas MMBtu 73 293 Oil Barrel — 1 Power MWh (35 ) (74 ) Capacity MW/Day (1 ) (1 ) Interest Dollars $ 3,219 $ 2,326 Equity Shares 1 1 The decrease in the natural gas position was primarily the result of settlement of generation and retail hedge positions. The increase in the interest rate position was primarily the result of entering into new interest rate swaps to hedge the Term Loan Facility, as described in Note 8 , Debt and Capital Leases . 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 September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 (In millions) Derivatives designated as cash flow hedges: Interest rate contracts current $ — $ — $ 31 $ 42 Interest rate contracts long-term 1 — 99 68 Total derivatives designated as cash flow hedges 1 — 130 110 Derivatives not designated as cash flow hedges : Interest rate contracts current — — 8 5 Interest rate contracts long-term 6 — 25 13 Commodity contracts current 964 1,915 930 1,674 Commodity contracts long-term 249 305 351 412 Total derivatives not designated as cash flow hedges 1,219 2,220 1,314 2,104 Total derivatives $ 1,220 $ 2,220 $ 1,444 $ 2,214 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 September 30, 2016 (In millions) Commodity contracts: Derivative assets $ 1,213 $ (1,027 ) $ (23 ) $ 163 Derivative liabilities (1,281 ) 1,027 121 (133 ) Total commodity contracts (68 ) — 98 30 Interest rate contracts: Derivative assets 7 (4 ) — 3 Derivative liabilities (163 ) 4 — (159 ) Total interest rate contracts (156 ) — — (156 ) Total derivative instruments $ (224 ) $ — $ 98 $ (126 ) 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, 2015 (In millions) Commodity contracts: Derivative assets $ 2,220 $ (1,616 ) $ (113 ) $ 491 Derivative liabilities (2,086 ) 1,616 271 (199 ) Total commodity contracts 134 — 158 292 Interest rate contracts: Derivative liabilities (128 ) — — (128 ) Total derivative instruments $ 6 $ — $ 158 $ 164 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: Three months ended September 30, 2016 Nine months ended September 30, 2016 Energy Commodities Interest Rate Total Energy Commodities Interest Rate Total (In millions) Accumulated OCI beginning balance $ — $ (165 ) $ (165 ) $ — $ (101 ) $ (101 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts — 2 2 — 12 12 Mark-to-market of cash flow hedge accounting contracts — 32 32 — (42 ) (42 ) Accumulated OCI ending balance, net of $28 tax $ — $ (131 ) $ (131 ) $ — $ (131 ) $ (131 ) Losses expected to be realized from OCI during the next 12 months, net of $4 tax $ — $ 17 $ 17 $ — $ 17 $ 17 Three months ended September 30, 2015 Nine months ended September 30, 2015 Energy Commodities Interest Rate Total Energy Commodities Interest Rate Total (In millions) Accumulated OCI beginning balance $ (1 ) $ (62 ) $ (63 ) $ (1 ) $ (67 ) $ (68 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts 1 3 4 1 7 8 Mark-to-market of cash flow hedge accounting contracts — (33 ) (33 ) — (32 ) (32 ) Accumulated OCI ending balance, net of $54 tax $ — $ (92 ) $ (92 ) $ — $ (92 ) $ (92 ) Amounts reclassified from accumulated OCI into income and amounts recognized in income from the ineffective portion of cash flow hedges are recorded to operating revenue for commodity contracts and interest expense for interest rate contracts. There was no ineffectiveness for the three and nine months ended September 30, 2016 , and 2015 . 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 September 30, Nine months ended September 30, 2016 2015 2016 2015 Unrealized mark-to-market results (In millions) Reversal of previously recognized unrealized gains on settled positions related to economic hedges $ (44 ) $ (29 ) $ (182 ) $ (179 ) Reversal of acquired gain positions related to economic hedges (19 ) (33 ) (47 ) (83 ) Net unrealized (losses)/gains on open positions related to economic hedges (121 ) 55 (19 ) (26 ) Total unrealized mark-to-market losses for economic hedging activities (184 ) (7 ) (248 ) (288 ) Reversal of previously recognized unrealized losses/(gains) on settled positions related to trading activity 3 2 13 (34 ) Reversal of acquired gain positions related to trading activity — (1 ) — (13 ) Net unrealized (losses)/gains on open positions related to trading activity (8 ) (2 ) 14 — Total unrealized mark-to-market (losses)/gains for trading activity (5 ) (1 ) 27 (47 ) Total unrealized losses $ (189 ) $ (8 ) $ (221 ) $ (335 ) Three months ended September 30, Nine months ended September 30, 2016 2015 2016 2015 (In millions) Unrealized (losses)/gains included in operating revenues $ (84 ) $ 34 $ (565 ) $ (212 ) Unrealized (losses)/gains included in cost of operations (105 ) (42 ) 344 (123 ) Total impact to statement of operations — energy commodities $ (189 ) $ (8 ) $ (221 ) $ (335 ) Total impact to statement of operations — interest rate contracts $ 9 $ (9 ) $ (9 ) $ 12 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 nine months ended September 30, 2016 , the $19 million unrealized loss from open economic hedge positions was primarily the result of a decrease in value of forward purchases of ERCOT heat rate due to ERCOT heat rate contraction, partially offset by an increase in value of forward sales of PJM electricity due to decreases in PJM power prices. For the nine months ended September 30, 2015 , the $26 million unrealized loss from open economic hedge positions was primarily the result of a decrease in value of forward purchases of ERCOT electricity and coal due to decreases in ERCOT power and coal prices partially offset by an increase in value of forward sales of PJM electricity due to decreases in PJM power prices. During 2016, the Company has been undergoing the process of closing out and financially settling certain open positions with counterparties. The closure and financial settlements with these counterparties were necessary to manage the increase in collateral posting requirements following rating agency downgrades for GenOn and to reduce expected collateral costs associated with exchange cleared hedge transactions. GenOn realized approximately $38 million due to the closure and financial settlement of all open positions with one of GenOn's counterparties during the second quarter of 2016, for which $18 million , $19 million and $1 million would have been realized during the remainder of 2016, 2017 and 2018, respectively. During the third quarter of 2016, GenOn realized $98 million due to the closure and financial settlement of certain positions with an additional counterparty for which $82 million , $13 million and $3 million would have otherwise been realized in 2017, 2018, and 2019, respectively. GenOn has entered into additional transactions with NRG Power Marketing LLC and an external counterparty in order to re-hedge the positions settled with certain counterparties. 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 September 30, 2016 , was $73 million . The collateral required for contracts with credit rating contingent features as of September 30, 2016 , was $42 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 $10 million as of September 30, 2016 . See Note 4 , Fair Value of Financial Instruments , to this Form 10-Q for discussion regarding concentration of credit risk.

Impairments Impairments

Impairments Impairments	9 Months Ended
	Sep. 30, 2016
Asset Impairment Charges [Abstract]
Asset Impairment Charges [Text Block]	Impairments Rockford — As described in Note 3, Business Acquisitions and Dispositions , 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. Mandalay and Ormond Beach — On May 26 , 2016, the CPUC rejected a multi-year resource adequacy contract between Mandalay and SCE. Also during the second quarter of 2016, the Statewide Advisory Committee on Cooling Water Intake Structures, or SACCWIS, issued a draft April 2016 Report noting that CAISO plans to continue to assume in its transmission studies that Ormond Beach will not operate after December 31, 2020, the deadline for Ormond Beach compliance with California regulations to mitigate once-through cooling (OTC) impacts. The Company does not anticipate that contracts of sufficient value can be secured to support the significant investment required to design, permit, construct and operate measures required for OTC compliance. As a result, on May 6, 2016, the Company notified SACCWIS that it does not expect to continue to operate Ormond Beach beyond 2020. Additionally, during the second quarter of 2016, CAISO issued its Local Capacity Requirements report for 2017 indicating unfavorable changes within the local reliability areas in which both Mandalay and Ormond Beach are located. The culmination of these events were considered to be indicators of impairment and as a result, the Company performed impairment tests for the Mandalay and Ormond Beach assets under ASC 360, Property, Plant and Equipment . Based on the results of the impairment tests, the Company determined that the carrying amount of these assets was higher than the estimated future net cash flows expected to be generated by the respective assets and that the Mandalay and Ormond Beach assets were impaired. The fair value of the Mandalay and Ormond Beach operating units was determined using the income approach which utilizes estimates of discounted future cash flows, which were Level 3 fair value measurements and include key inputs such as forecasted contract prices, forecasted operating expenses and discount rates. The Company measured the impairment losses as the difference between the carrying amount of the Mandalay and Ormond Beach operating units and the present value of the estimated future net cash flows for each respective operating unit. The Company recorded an impairment loss of $16 million and $43 million for Mandalay and Ormond Beach, respectively, during the quarter ended June 30, 2016. 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. During the third quarter of 2016, the Company recorded an additional $8 million in impairments losses related to investments and $8 million in other impairments. 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	9 Months Ended
	Sep. 30, 2016
Long Term 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 2015 Form 10-K. Long-term debt and capital leases consisted of the following: (In millions, except rates) September 30, 2016 December 31, 2015 September 30, 2016 interest rate % (a) Recourse debt: Senior notes, due 2018 $ 584 $ 1,039 7.625 Senior notes, due 2020 — 1,058 8.250 Senior notes, due 2021 399 1,128 7.875 Senior notes, due 2022 992 1,100 6.250 Senior notes, due 2023 869 936 6.625 Senior notes, due 2024 733 904 6.250 Senior notes, due 2026 1,000 — 7.250 Senior notes, due 2027 1,250 — 6.625 Term loan facility, due 2018 — 1,964 L+2.00 Term loan facility, due 2023 1,886 — L+2.75 Tax-exempt bonds 455 455 4.125 - 6.00 Subtotal NRG recourse debt 8,168 8,584 Non-recourse debt: GenOn senior notes 1,922 1,956 7.875 - 9.875 GenOn Americas Generation senior notes 747 752 8.500 - 9.125 GenOn other 52 56 Subtotal GenOn debt (non-recourse to NRG) 2,721 2,764 NRG Yield Operating LLC Senior Notes, due 2024 500 500 5.375 NRG Yield Operating LLC Senior Notes, due 2026 350 — 5.000 NRG Yield LLC and Yield Operating LLC Revolving Credit Facility, due 2019 — 306 L+2.75 NRG Yield Inc. Convertible Senior Notes, due 2019 334 330 3.500 NRG Yield Inc. Convertible Senior Notes, due 2020 270 266 3.250 El Segundo Energy Center, due 2023 443 485 L+1.625 - L+2.25 Marsh Landing, due 2017 and 2023 385 418 L+1.175 - L+1.875 Alta Wind I - V lease financing arrangements, due 2034 and 2035 978 1,002 5.696 - 7.015 Walnut Creek, term loans due 2023 322 351 L+1.625 Tapestry, due 2021 175 181 L+1.625 CVSR, due 2037 771 793 2.339 - 3.775 CVSR HoldCo, due 2037 199 — 4.680 Alpine, due 2022 147 154 L+1.750 Energy Center Minneapolis, due 2017 and 2025 98 108 5.95 - 7.25 Viento, due 2023 183 189 L+2.75 NRG Yield - other 549 573 various Subtotal NRG Yield debt (non-recourse to NRG) 5,704 5,656 Ivanpah, due 2033 and 2038 1,135 1,149 2.285 - 4.256 Agua Caliente, due 2037 864 879 2.395 - 3.633 Dandan, due 2033 100 98 L+2.25 Peaker bonds, due 2019 — 72 L+1.07 Cedro Hill, due 2025 165 103 L+1.75 Midwest Generation, due 2019 234 — 4.390 NRG Other 320 315 various Subtotal other NRG non-recourse debt 2,818 2,616 Subtotal all non-recourse debt 11,243 11,036 Subtotal long-term debt (including current maturities) 19,411 19,620 Capital leases 11 16 various Subtotal long-term debt and capital leases (including current maturities) 19,422 19,636 Less current maturities 1,221 481 Less debt issuance costs 183 172 Total long-term debt and capital leases $ 18,018 $ 18,983 (a) As of September 30, 2016 , L+ equals 3 month LIBOR plus x%, with the exception of the Viento Funding II term loan, which is 6 month LIBOR plus x%, and the Alpine Term Loan, the NRG Marsh Landing term loan, the Walnut Creek term loan, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%. NRG Recourse Debt 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. The proceeds from the issuance of the 2026 Senior Notes were utilized to redeem a portion of the Senior Notes discussed below. 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. Senior Notes Repurchases During the nine months ended September 30, 2016, the Company repurchased $2.6 billion in aggregate principal of its Senior Notes in the open market for $2.7 billion , which included accrued interest of $67 million . In connection with the repurchases, a $94 million loss on debt extinguishment was recorded, which included the write-off of previously deferred financing costs of $15 million . Principal Repurchased Cash Paid (a) Average Early Redemption Percentage Amount in millions, except rates 7.625% senior notes due 2018 $ 455 $ 502 107.95 % 8.250% senior notes due 2020 1,058 1,129 103.12 % 7.875% senior notes due 2021 729 771 104.02 % 6.250% senior notes due 2022 108 105 94.73 % 6.625% senior notes due 2023 67 64 94.13 % 6.250% senior notes due 2024 171 163 94.52 % Total at September 30, 2016 $ 2,588 $ 2,734 7.625% senior notes due 2018 (b) 186 204 107.75 % 7.875% senior notes due 2021 (b) 193 207 103.94 % Total at November 4, 2016 $ 2,967 $ 3,145 (a) Includes payment for accrued interest (b) Redemptions financed by cash on hand Senior Credit Facility On June 30, 2016, NRG replaced its Senior Credit Facility, consisting of its Term Loan Facility and Revolving Credit Facility with a new senior secured facility, or the 2016 Senior Credit Facility, which includes the following: • A $1.9 billion term loan facility, or the 2016 Term Loan Facility, with a maturity date of June 30, 2023, which will pay interest at a rate of LIBOR plus 2.75% , with a LIBOR floor of 0.75% . The debt was issued at 99.50% of face value; the discount will be amortized to interest expense over the life of the loan. Repayments under the 2016 Term Loan Facility will consist of 0.25% of principal per quarter, with the remainder due at maturity. The proceeds of the new term loan facility as well as cash on hand were used to repay the existing 2018 Term Loan Facility balance outstanding. A $21 million loss on extinguishment of the Term Loan Facility was recorded during the second quarter of 2016, which consisted of the write-off of previously deferred financing costs. • The 2016 Revolving Credit Facility, which includes a $289 million revolving senior credit facility, or the Tranche A Revolving Facility, with a maturity date of July 1, 2018 and a $2.2 billion revolving senior credit facility, or the Tranche B Revolving Facility, with a maturity date of June 30, 2021 will pay interest at a rate of LIBOR plus 2.25% . The 2016 Senior Credit Facility is guaranteed by substantially all of NRG's existing and future direct and indirect subsidiaries, with certain customary or agreed-upon exceptions for unrestricted foreign subsidiaries, and certain other subsidiaries, including GenOn, NRG Yield, Inc. and their respective subsidiaries. The capital stock of these guarantor subsidiaries has been pledged for the benefit of the 2016 Senior Credit Facility's lenders. The 2016 Senior Credit Facility is also secured by first-priority perfected security interests in substantially all of the property and assets owned or acquired by NRG and its subsidiaries, other than certain limited exceptions. These exceptions include assets of certain unrestricted subsidiaries, equity interests in certain of NRG's affiliates that have non-recourse debt financing, including GenOn, NRG Yield, Inc. and their respective subsidiaries, and voting equity interests in excess of 66% of the total outstanding voting equity interest of certain of NRG's foreign subsidiaries. Non-recourse Debt GenOn Senior Notes As of September 30, 2016, $703 million of GenOn's Senior Notes outstanding are classified as current within the consolidated balance sheet as they mature on June 15, 2017. Based on current projections, GenOn is not expected to have sufficient liquidity, exclusive of cash subject to the restrictions under the GenOn Mid-Atlantic and REMA operating leases, to make this principal payment as it becomes due. As a result of these factors, there is no assurance GenOn will continue as a going concern. GenOn is currently considering all options available to it, including negotiations with creditors and lessors, refinancing the Senior Notes, potential sales of certain generating assets as well as the possibility of a need to file for protection under Chapter 11 of the U.S. Bankruptcy Code. During the second quarter of 2016, GenOn appointed two independent directors as part of this process. Any resolution may have a material impact on the Company's statement of operations, cash flows and financial position. 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 September 30, 2016, there was $64 million of letters of credit issued under the revolving credit facility and no borrowing outstanding on the revolver. Thermal Financing On October 31, 2016, NRG Energy Center Minneapolis LLC, a subsidiary of NRG Yield, Inc. received proceeds of $125 million from the issuance of 3.55% Series D notes due October 31, 2031, or the Series D Notes, and entered into a shelf facility for an additional $70 million of notes. The Series D Notes are, and the additional notes, if issued, will be secured by substantially all of the assets of NRG Energy Center Minneapolis LLC. NRG Thermal LLC has guaranteed the indebtedness and its guarantee is secured by a pledge of the equity interests in all of NRG Thermal LLC’s subsidiaries. NRG Energy Center Minneapolis LLC distributed the proceeds of the Series D Notes to NRG Thermal LLC, who in turn distributed the proceeds to NRG Yield Operating LLC to be utilized for general corporate purposes, including potential acquisitions. Project Financings Peakers In June 2002, NRG Peaker Finance Company LLC, or Peakers, an indirect wholly-owned subsidiary of NRG, issued bonds due June 2019. These notes were also secured by, among other things, substantially all of the assets of and membership interests in Big Cajun I Peaking Power LLC, NRG Sterlington Power LLC, NRG Rockford LLC, NRG Rockford II LLC, and NRG Rockford Equipment LLC. On June 30, 2016, in contemplation of the sale of Rockford as further discussed in Note 3 , Business Acquisitions and Dispositions , NRG Peaker Finance Company LLC elected to redeem all of the outstanding bonds at a redemption price equal to the principal amount plus a redemption premium, accrued and unpaid interest, swap breakage, and other fees, totaling approximately $85 million in connection with the removal of NRG Rockford LLC, and NRG Rockford II, LLC from the peaker financing collateral package. The Company recognized a $3 million loss on extinguishment of the debt related to the write-off of unamortized discount during the second quarter of 2016. On July 12, 2016, NRG completed the sale of the Rockford generating stations. High Lonesome Mesa Facility Prior to the Company's acquisition of EME, an intercompany tax credit agreement related to the High Lonesome Mesa facility was terminated. The termination resulted in an event of default under the project financing arrangement. The Company received additional default notices for various items. The facility is secured by the assets of High Lonesome Mesa and is non-recourse to NRG. On November 3, 2015, the lender sent a notice of acceleration and indicated that it would accept the Company's interest in the assets in lieu of repayment. On January 27, 2016, High Lonesome Mesa, LLC, or HLM, filed at FERC for approval to transfer 100% of the ownership interests in HLM to subsidiaries of the lien holders, Macquarie Bank Limited and Hannon Armstrong Capital, LLC. On March 2, 2016 HLM received FERC approval and on March 31, 2016 the Company transferred 100% of its interest in HLM to the lien holders and deconsolidated HLM. Dandan Financing In December 2013, NRG, through its wholly-owned subsidiary, NRG Solar Dandan LLC, or Dandan, entered into a credit agreement with a bank, or the Dandan Financing Agreement, for an $81 million construction loan and a $23 million cash grant loan. On January 29, 2016, the construction loan converted to a $79 million term loan with $23 million outstanding under the cash grant loan. In addition, a $4 million debt service letter of credit was issued replacing the $5 million construction letter of credit that was outstanding at year end. As of September 30, 2016, $77 million was outstanding under the term loan, $23 million was outstanding under the cash grant loan and $4 million in letters of credit in support of the project were issued. Midwest Generation On April 7, 2016, Midwest Generation, LLC, or MWG, entered into an agreement to sell certain quantities of unforced capacity that has cleared various PJM Reliability Pricing Model auctions to a trading counterparty for net proceeds of $253 million . MWG will continue to operate the applicable generation facilities and remains responsible for performance penalties and eligible for performance bonus payments, if any. Accordingly, MWG will continue to account for all revenues and costs as before; however, the proceeds will be recorded as a financing obligation while capacity payments by PJM to the counterparty will be reflected as debt amortization and interest expense through the end of the 2018/19 delivery year. MWG will amortize the upfront discount to interest expense, at an effective interest rate of 4.39% , over the term of the arrangement, through June 2019. As of September 30, 2016, $234 million was outstanding. CVSR On July 15, 2016, CVSR Holdco LLC, the indirect owner of the CVSR project, issued $200 million of senior secured notes. The $199 million of net proceeds from the notes were distributed to a subsidiary of NRG and NRG Yield Operating LLC, the owners of CVSR Holdco LLC, based on their pro-rata ownership. The notes were issued at par and bear an interest rate at 4.68% . Interest is payable semi-annually beginning on September 30, 2016, until the maturity date of March 31, 2037. Capistrano Refinancing On July 13 2016, Cedro Hill, Broken Bow and Crofton Bluffs, subsidiaries of Capistrano Wind Partners, each amended their respective credit facilities to increase borrowings to a total of $312 million and to lower their respective interest rates. The net proceeds of $87 million , were distributed to Capistrano Wind Partners and subsequently distributed to the holders of the Class B preferred equity interests of tax Capistrano Wind Partners. NRG Yield Operating 2026 Senior Notes On August 18, 2016, NRG Yield Operating LLC issued $350 million of senior unsecured notes, or the NRG Yield Operating 2026 Senior Notes. The NRG Yield Operating 2026 Senior Notes bear interest of 5.00% and mature on September 15, 2026. Interest on the notes is payable semi-annually on March 15 and September 15 of each year, and will commence on March 15, 2017. The Yield Operating 2026 Senior Notes are senior unsecured obligations of NRG Yield Operating LLC and are guaranteed by NRG Yield LLC, and by certain of NRG Yield Operating LLC’s wholly owned current and future subsidiaries. A portion of the proceeds from the 2026 Senior Notes was used to repay NRG Yield Operating LLC's revolving credit facility.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2016
Variable Interest Entities Disclosure [Abstract]
Variable Interest Entity	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 $106 million as of September 30, 2016 . Sherbino I Wind Farm LLC — NRG owns a 50% interest in Sherbino, a joint venture with BP Wind Energy North America Inc. NRG's maximum exposure to loss is limited to its equity investment, which was $72 million as of September 30, 2016 . 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 2015 Form 10-K. For one of the tax equity arrangements, the Company has a deficit restoration obligation equal to $44 million as of September 30, 2016 , 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) September 30, 2016 December 31, 2015 Current assets $ 76 $ 84 Net property, plant and equipment 1,742 1,807 Other long-term assets 945 863 Total assets 2,763 2,754 Current liabilities 59 56 Long-term debt 450 366 Other long-term liabilities 194 179 Total liabilities 703 601 Noncontrolling interests 562 493 Net assets less noncontrolling interests $ 1,498 $ 1,660

Changes in Capital Structure

Changes in Capital Structure	9 Months Ended
	Sep. 30, 2016
Changes in Capital Structure Disclosure [Abstract]
Changes in Capital Structure	Changes in Capital Structure As of September 30, 2016 , and December 31, 2015 , 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, 2015 416,939,950 (102,749,908 ) 314,190,042 Shares issued under LTIPs 643,642 — 643,642 Shares issued under ESPP — 609,094 609,094 Balance as of September 30, 2016 417,583,592 (102,140,814 ) 315,442,778 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. Employee Stock Purchase Plan As of September 30, 2016 , there were 667,819 shares of treasury stock available for issuance under the ESPP. NRG Common Stock Dividends The following table lists the dividends paid during the nine months ended September 30, 2016 : Third Quarter 2016 Second Quarter 2016 First Quarter 2016 Dividends per Common Share $ 0.030 $ 0.030 $ 0.145 On October 19, 2016 , NRG declared a quarterly dividend on the Company's common stock of $0.03 per share, payable November 15, 2016 , to stockholders of record as of November 1, 2016 , 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	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Earnings 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. The reconciliation of NRG's basic and diluted earnings/(loss) per share is shown in the following table: Three months ended September 30, Nine months ended September 30, (In millions, except per share data) 2016 2015 2016 2015 Basic earnings/(loss) per share attributable to NRG Energy, Inc. common stockholders Net income/(loss) attributable to NRG Energy, Inc. $ 402 $ 66 $ 213 $ (68 ) Dividends for preferred shares — 5 5 15 Gain on redemption of 2.822% redeemable perpetual preferred stock — — (78 ) — Income/(loss) available for common stockholders $ 402 $ 61 $ 286 $ (83 ) Weighted average number of common shares outstanding - basic 316 331 315 334 Earnings/(Loss) per weighted average common share — basic $ 1.27 $ 0.18 $ 0.91 $ (0.25 ) Diluted earnings/(loss) per share attributable to NRG Energy, Inc. common stockholders Weighted average number of common shares outstanding 316 331 315 334 Incremental shares attributable to the issuance of equity compensation (treasury stock method) 1 1 1 — Total dilutive shares 317 332 316 334 Earnings/(loss) per weighted average common share — diluted $ 1.27 $ 0.18 $ 0.91 $ (0.25 ) 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 September 30, Nine months ended September 30, (In millions of shares) 2016 2015 2016 2015 Equity compensation plans 2 3 3 6 Embedded derivative of 2.822% redeemable perpetual preferred stock — 16 — 16 Total 2 19 3 22

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2016
Segment Reporting Disclosure [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 (previously Generation/Business), which includes generation, international and business solutions; Retail Mass (previously NRG Home Retail); Renewables (previously NRG Renew), which includes solar and wind assets; NRG Yield; and corporate activities. The Company's corporate segment includes BETM, residential solar and electric vehicle services. Effective January 1, 2016, the Company began reporting the results of its residential solar business in its corporate segment. Effective April 1, 2016, the Company began reporting the results of its international business in its Generation segment. The financial information for the three months and nine months ended September 30, 2015 has been recast to reflect the change. 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 November 3, 2015, NRG Yield acquired 75% of the class B interests in NRG Wind TE Holdco, which owns a portfolio of 12 wind facilities, from the Company. 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. 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). (In millions) Generation (a) Retail Mass (a) Renewables (a) NRG Yield (a) Corporate (a)(b) Eliminations Total Three months ended September 30, 2016 Operating revenues (a) $ 2,494 $ 1,619 $ 140 $ 272 $ 40 $ (613 ) $ 3,952 Depreciation and amortization 193 25 48 75 16 — 357 Impairment losses 8 — — — — — 8 Equity in earnings/(losses) of unconsolidated affiliates 6 — (4 ) 13 1 — 16 Gain on sale of assets 262 — — — 4 — 266 (Impairment loss)/gain on investment (5 ) — 1 — (4 ) — (8 ) Income/(loss) before income taxes 628 2 8 60 (252 ) (4 ) 442 Net Income/(Loss) 630 2 11 47 (293 ) (4 ) 393 Net Income/(Loss) attributable to NRG Energy, Inc. $ 630 $ 2 $ — $ 52 $ (317 ) $ 35 $ 402 Total assets as of September 30, 2016 $ 14,153 $ 1,601 $ 4,920 $ 8,482 $ 16,970 $ (14,635 ) 31,491 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 555 $ — $ 9 $ 2 $ 47 $ — $ 613 (b) Includes loss on debt extinguishment $ — $ — $ — $ — $ (50 ) $ — $ (50 ) (In millions) Generation (a) Retail Mass (a) Renewables (a) NRG Yield (a)(b) Corporate (a) Eliminations Total Three months ended September 30, 2015 Operating revenues (a) $ 2,726 $ 1,699 $ 124 $ 256 $ 1 $ (372 ) $ 4,434 Depreciation and amortization 220 30 46 69 17 — 382 Impairment losses 222 36 5 — — — 263 Equity in earnings/(loss) of unconsolidated affiliates 7 — (2 ) 12 1 6 24 Income/(Loss) before income taxes 166 197 (20 ) 40 (276 ) 7 114 Net Income/(Loss) 164 197 (16 ) 32 (317 ) 7 67 Net Income/(Loss) attributable to NRG Energy, Inc. $ 164 $ 197 $ (33 ) $ 20 $ (315 ) $ 33 $ 66 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 309 $ 2 $ (6 ) $ 18 $ 49 $ — $ 372 (b) Includes loss on debt extinguishment $ — $ — $ — $ 2 $ — $ — $ 2 (In millions) Generation (a) Retail Mass (a) Renewables (a) NRG Yield (a) Corporate (a)(b) Eliminations Total Nine months ended September 30, 2016 Operating revenues (a) $ 5,920 $ 3,868 $ 335 $ 789 $ 128 $ (1,221 ) $ 9,819 Depreciation and amortization 483 80 143 224 49 — 979 Impairment losses 84 — 26 — 13 — 123 Equity in earnings/(losses) of unconsolidated affiliates 1 — (13 ) 29 3 (7 ) 13 Gain/(loss) on sale of assets 293 — — — (78 ) — 215 (Impairment loss)/gain on investment (142 ) — 1 — (6 ) — (147 ) Income/(loss) before income taxes 417 644 (116 ) 136 (815 ) (7 ) 259 Net Income/(Loss) 418 644 (102 ) 111 (900 ) (7 ) 164 Net Income/(Loss) attributable to NRG Energy, Inc. $ 418 $ 644 $ (98 ) $ 108 $ (931 ) $ 72 $ 213 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 1,025 $ 2 $ 19 $ 6 $ 169 $ — $ 1,221 (b) Includes loss on debt extinguishment $ — $ — $ — $ — $ (119 ) $ — $ (119 ) (In millions) Generation (a) Retail Mass (a) Renewables (a) NRG Yield (a)(b) Corporate (a) Eliminations Total Nine months ended September 30, 2015 Operating revenues (a) $ 7,345 $ 4,308 $ 305 $ 729 $ 9 $ (1,033 ) $ 11,663 Depreciation and amortization 681 93 135 222 42 — 1,173 Impairment losses 222 36 5 — — — 263 Gain on postretirement benefits curtailment 14 — — — — — 14 Equity in earnings/(losses) of unconsolidated affiliates 9 — (2 ) 19 — 3 29 Income/(loss) before income taxes 216 523 (87 ) 61 (834 ) — (121 ) Net Income/(Loss) 213 523 (74 ) 53 (793 ) — (78 ) Net Income/(Loss) attributable to NRG Energy, Inc. $ 213 $ 523 $ (100 ) $ 29 $ (765 ) $ 32 $ (68 ) (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 853 $ 4 $ 18 $ 27 $ 131 $ — $ 1,033 (b) Includes loss on debt extinguishment $ — $ — $ — $ 9 $ — $ — $ 9

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Tax Rate The income tax provision consisted of the following: Three months ended September 30, Nine months ended September 30, (In millions except otherwise noted) 2016 2015 2016 2015 Income/(loss) before income taxes $ 442 $ 114 $ 259 $ (121 ) Income tax (benefit)/expense 49 47 95 (43 ) Effective tax rate 11.1 % 41.2 % 36.7 % 35.5 % For the three months ended September 30, 2016 , NRG's overall effective tax rate was different than the statutory rate of 35% primarily due to the change in valuation allowance, partially offset by state tax expense and tax expense attributable to consolidated partnerships. For the three months ended September 30, 2015 , NRG's overall effective tax rate was different than the statutory rate of 35% primarily due to non-deductible impairment of goodwill, partially offset by production tax credits generated from the Company's wind assets. For the nine months ended September 30, 2016, NRG's overall effective tax rate was different than the statutory rate of 35% primarily due to state tax expense and amortization of indefinite lived assets, partially offset by the change in valuation allowance. For the nine months ended September 30, 2015 , NRG's overall effective tax rate was different than the statutory rate of 35% primarily due to the impact of production tax credits generated from the Company's wind assets, partially offset by tax expense attributable to consolidated partnerships. Uncertain Tax Benefits As of September 30, 2016 , NRG has recorded a non-current tax liability of $44 million for uncertain tax benefits from positions taken on various state income tax returns, including accrued interest. For the nine months ended September 30, 2016 , NRG accrued $1 million of interest relating to the uncertain tax benefits. As of September 30, 2016 , 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 2009. The Company's primary foreign operations are also no longer subject to examination by local jurisdictions for years prior to 2010.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
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 2015 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 GenOn and 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 September 30, 2016 , hedges under the first liens were in-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 project 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. If either of Ivanpah units 1 and 3 deliver less than the guaranteed energy production amount in any performance measurement period, PG&E may, at its option, declare an event of default. The two units did not meet their guaranteed energy production amount for the initial performance measurement period. On December 18, 2015, PG&E filed a request with the CPUC that it approve forbearance agreements relating to Ivanpah units 1 and 3. On March 17, 2016, the CPUC adopted a resolution approving the forbearance agreements, which are final and non-appealable and in full effect. Under the forbearance agreements, PG&E agrees to refrain from taking certain actions (including declaring an event of default and invoking associated remedies) for an initial six-month period of time. If the units meet certain production requirements during such period, then the forbearance agreements provide for a six-month extension of such period. In the third quarter of 2016, each of Ivanpah's unit 1 and unit 3 satisfied its respective production requirement for the initial six-month measurement period under the forbearance agreements. Lignite Contract with Texas Westmoreland Coal Co. — The Company's Limestone facility utilizes a blend of coal including lignite obtained from the Jewett mine, a surface mine adjacent to the Limestone facility, under a long-term contract with Texas Westmoreland Coal Co., or TWCC. The contract is a cost-plus arrangement with certain performance incentives and penalties. On August 18, 2016, NRG gave notice to TWCC terminating the active mining of lignite under the contract, effective on December 31, 2016. Under the contract, TWCC continues to be responsible for reclamation activities. NRG is responsible for reclamation costs and has recorded an adequate ARO liability. The Railroad Commission of Texas has imposed a bond obligation of $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. 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. The appeal has been fully briefed by the parties. Oral argument is scheduled for December 5, 2016. 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 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 Court of Appeals' decision and the Supreme Court granted the petition. On April 21, 2015, the 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 Supreme Court left open whether the claims were preempted on the basis of conflict preemption. The 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 December 8, 2016, the court will hear oral argument on several motions, including plaintiffs' motion on class certification. On May 20, 2016, the U.S. District Court for the District of Nevada heard argument on the defendants' motion for summary judgment in one of the Kansas cases. On May 24, 2016, the court granted the motion for summary judgment as to the GenOn entity in one of the Kansas cases. 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 Supreme Court denied the petition for a writ of certiorari, thereby ending one of the five lawsuits. 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. Maryland Department of the Environment v. GenOn Chalk Point and GenOn Mid-Atlantic — On January 25, 2013, Food & Water Watch, the Patuxent Riverkeeper and the Potomac Riverkeeper (together, the Citizens Group) sent GenOn Mid-Atlantic a letter alleging that the Chalk Point, Dickerson and Morgantown generating facilities were violating the terms of the three National Pollution Discharge Elimination System permits by discharging nitrogen and phosphorous in excess of the limits in each permit. On March 21, 2013, the MDE sent GenOn Mid-Atlantic a similar letter with respect to the Chalk Point and Dickerson generating facilities, threatening to sue within 60 days if the generating facilities were not brought into compliance. On June 11, 2013, the Maryland Attorney General on behalf of the MDE filed a complaint in the U.S. District Court for the District of Maryland alleging violations of the CWA and Maryland environmental laws related to water. In August 2016, the court approved a consent decree to settle the matter. The consent decree requires: (1) improving the wastewater treatment systems at the Chalk Point and Dickerson facilities which was completed in October 2016; (2) completing supplemental environmental projects worth $1 million ; and (3) paying a civil penalty of $1 million . The Company has improved the wastewater treatment systems at the Chalk Point and Dickerson facilities and paid the civil penalty of $1 million . 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. Potomac River Environmental Investigation — In March 2013, NRG Potomac River LLC 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 is currently reviewing the information provided by DOEE. 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. 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. The hearing on the demurrers is scheduled for November 9, 2016. 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. On August 3, 2016, the court approved a stipulation entered into by the parties. The stipulation provided that the plaintiffs would file an amended complaint by August 19, 2016, which they did on August 18, 2016. The Defendants filed demurrers and a motion challenging jurisdiction on October 18, 2016. 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 responsive pleadings on November 4, 2016.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2016
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 2015 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. PJM Capacity Performance Appeals — On or about July 8, 2016, four petitions were filed at the U.S. Court of Appeals for the D.C. Circuit seeking review of the FERC orders approving PJM’s Capacity Performance revisions to its forward capacity market after motions for rehearing at FERC were denied on May 10, 2016. The Company intervened in these matters on July 29, 2016. Briefing is underway. This case concerns capacity revenues already received by the Company, as well as revenues that would be received in the future. Midwest Generation, LLC Reactive Power Compensation — On June 21, 2016, FERC issued an order directing MWG to make a compliance filing setting forth refunds for payments received in violation of its 2004 reactive power settlement or to show cause why it has not violated the settlement and ordered MWG to revise its tariff to reflect the costs of units continuing to provide reactive power or show cause why it should not be required to do so. The Commission also referred this matter to the Commission's Office of Enforcement. On June 30, 2016, MWG filed a revised tariff, and on July 22, 2016, MWG made a compliance filing as ordered by FERC. On October 13, 2016, FERC found that MWG should only be liable for refunds that accrued after bankruptcy on April 1, 2014 through June 30, 2016. The matter is still pending at the Commission's Office of Enforcement.

Environmental Matters

Environmental Matters	9 Months Ended
	Sep. 30, 2016
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 2015 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. Environmental laws have become increasingly stringent and NRG expects this trend to continue. The electric generation industry is facing new requirements regarding GHGs, combustion byproducts, water discharge and use, and threatened and endangered species. 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. 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 NO x 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. 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 limits 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. 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. 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. 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 September 30, 2016. Environmental Capital Expenditures NRG estimates that environmental capital expenditures from 2016 through 2020 required to comply with environmental laws will be approximately $328 million , which includes $76 million for GenOn and $234 million for Midwest Generation. These costs, the majority of which will be expended by the end of 2016, are primarily associated with (i) DSI/ESP upgrades at the Powerton facility and the Joliet gas conversion to satisfy the IL CPS and (ii) MATS compliance at the Avon Lake facility.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	9 Months Ended
	Sep. 30, 2016
Condensed Consolidating Financial Information Disclosure [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information As of September 30, 2016 , the Company had outstanding $5.8 billion of Senior Notes due from 2018 - 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, including GenOn and its 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 September 30, 2016 : Ace Energy, Inc. New Genco GP, LLC NRG Norwalk Harbor Operations Inc. Allied Home Warranty GP LLC Norwalk Power LLC NRG Operating Services, Inc. Allied Warranty LLC NRG Advisory Services LLC NRG Oswego Harbor Power Operations Inc. Arthur Kill Power LLC NRG Affiliate Services Inc. NRG PacGen Inc. Astoria Gas Turbine Power LLC NRG Artesian Energy LLC NRG Portable Power LLC Bayou Cove Peaking Power, LLC NRG Arthur Kill Operations Inc. NRG Power Marketing LLC BidURenergy, Inc. NRG Astoria Gas Turbine Operations Inc. NRG Reliability Solutions LLC Cabrillo Power I LLC NRG Bayou Cove LLC NRG Renter's Protection LLC Cabrillo Power II LLC NRG Business Services LLC NRG Retail LLC Carbon Management Solutions LLC NRG Business Solutions LLC NRG Retail Northeast LLC Cirro Group, Inc. NRG Cabrillo Power Operations Inc. NRG Rockford Acquisition LLC Cirro Energy Services, Inc. NRG California Peaker Operations LLC NRG Saguaro Operations Inc. Clean Edge Energy LLC NRG Cedar Bayou Development Company, LLC NRG Security LLC Conemaugh Power LLC NRG Connected Home LLC NRG Services Corporation Connecticut Jet Power LLC NRG Connecticut Affiliate Services Inc. NRG SimplySmart Solutions LLC Cottonwood Development LLC NRG Construction LLC NRG South Central Affiliate Services Inc. Cottonwood Energy Company LP NRG Curtailment Solutions Holdings LLC NRG South Central Generating LLC Cottonwood Generating Partners I LLC NRG Curtailment Solutions, Inc NRG South Central Operations Inc. Cottonwood Generating Partners II LLC NRG Development Company Inc. NRG South Texas LP Cottonwood Generating Partners III LLC NRG Devon Operations Inc. NRG SPV #1 LLC Cottonwood Technology Partners LP NRG Dispatch Services LLC NRG Texas C&I Supply LLC Devon Power LLC NRG Distributed Generation PR LLC NRG Texas Gregory LLC Dunkirk Power LLC NRG Dunkirk Operations Inc. NRG Texas Holding Inc. Eastern Sierra Energy Company LLC NRG El Segundo Operations Inc. NRG Texas LLC El Segundo Power, LLC NRG Energy Efficiency-L LLC NRG Texas Power LLC El Segundo Power II LLC NRG Energy Efficiency-P LLC NRG Warranty Services LLC Energy Alternatives Wholesale, LLC NRG Energy Labor Services LLC NRG West Coast LLC Energy Choice Solutions LLC NRG ECOKAP Holdings LLC NRG Western Affiliate Services Inc. Energy Plus Holdings LLC NRG Energy Services Group LLC O'Brien Cogeneration, Inc. II Energy Plus Natural Gas LLC NRG Energy Services International Inc. ONSITE Energy, Inc. Energy Protection Insurance Company NRG Energy Services LLC Oswego Harbor Power LLC Everything Energy LLC NRG Generation Holdings, Inc. RE Retail Receivables, LLC Forward Home Security, LLC NRG Greenco Reliant Energy Northeast LLC GCP Funding Company, LLC NRG Home & Business Solutions LLC Reliant Energy Power Supply, LLC Green Mountain Energy Company NRG Home Services LLC Reliant Energy Retail Holdings, LLC Gregory Partners, LLC NRG Home Solutions LLC Reliant Energy Retail Services, LLC Gregory Power Partners LLC NRG Home Solutions Product LLC RERH Holdings, LLC Huntley Power LLC NRG Homer City Services LLC Saguaro Power LLC Independence Energy Alliance LLC NRG Huntley Operations Inc. Somerset Operations Inc. Independence Energy Group LLC NRG HQ DG LLC Somerset Power LLC Independence Energy Natural Gas LLC NRG Identity Protect LLC Texas Genco Financing Corp. Indian River Operations Inc. NRG Ilion Limited Partnership Texas Genco GP, LLC Indian River Power LLC NRG Ilion LP LLC Texas Genco Holdings, Inc. Keystone Power LLC NRG International LLC Texas Genco LP, LLC Langford Wind Power, LLC NRG Maintenance Services LLC Texas Genco Operating Services, LLC Louisiana Generating LLC NRG Mextrans Inc. Texas Genco Services, LP Meriden Gas Turbines LLC NRG MidAtlantic Affiliate Services Inc. US Retailers LLC Middletown Power LLC NRG Middletown Operations Inc. Vienna Operations Inc. Montville Power LLC NRG Montville Operations Inc. Vienna Power LLC NEO Corporation NRG New Roads Holdings LLC WCP (Generation) Holdings LLC NEO Freehold-Gen LLC NRG North Central Operations Inc. West Coast Power LLC NEO Power Services Inc. NRG Northeast Affiliate Services Inc. NRG conducts much of its business through and derives much of its income from its subsidiaries. Therefore, the Company's ability to make required payments with respect to its indebtedness and other obligations depends on the financial results and condition of its subsidiaries and NRG's ability to receive funds from its subsidiaries. There are no restrictions on the ability of any of the guarantor subsidiaries to transfer funds to NRG. 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 September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 2,424 $ 1,622 $ — $ (94 ) $ 3,952 Operating Costs and Expenses Cost of operations 1,718 1,158 11 (94 ) 2,793 Depreciation and amortization 147 203 7 — 357 Impairment losses 8 — — — 8 Selling, general and administrative 114 105 63 — 282 Acquisition-related transaction and integration costs — 1 (1 ) — — Development activity expenses — 12 11 — 23 Total operating costs and expenses 1,987 1,479 91 (94 ) 3,463 Loss on sale of assets — 262 4 — 266 Operating Income/(Loss) 437 405 (87 ) — 755 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (110 ) (13 ) 485 (362 ) — Equity in earnings/(losses) of unconsolidated affiliates 2 22 (2 ) (6 ) 16 Impairment loss on investment — (8 ) — — (8 ) Other income 1 8 — — 9 Loss on debt extinguishment — — (50 ) — (50 ) Interest expense (4 ) (148 ) (128 ) — (280 ) Total other (expense)/income (111 ) (139 ) 305 (368 ) (313 ) Income Before Income Taxes 326 266 218 (368 ) 442 Income tax expense/(benefit) 134 90 (218 ) 43 49 Net Income 192 176 436 (411 ) 393 Less: Net income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests — 6 34 (49 ) (9 ) Net Income Attributable to NRG Energy, Inc. $ 192 $ 170 $ 402 $ (362 ) $ 402 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Nine Months Ended September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 6,079 $ 3,907 $ — $ (167 ) $ 9,819 Operating Costs and Expenses Cost of operations 4,278 2,602 29 (171 ) 6,738 Depreciation and amortization 372 588 19 — 979 Impairment losses 8 115 — — 123 Selling, general and administrative 306 296 200 — 802 Acquisition-related transaction and integration costs — 1 6 — 7 Development activity expenses — 44 23 — 67 Total operating costs and expenses 4,964 3,646 277 (171 ) 8,716 Gain/(loss) on sale of assets — 294 (79 ) — 215 Operating Income/(Loss) 1,115 555 (356 ) 4 1,318 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (178 ) (36 ) 796 (582 ) — Equity in earnings/(losses) of unconsolidated affiliates 5 20 (2 ) (10 ) 13 Impairment loss on investment — (147 ) — — (147 ) Other income 3 31 2 (1 ) 35 Loss on debt extinguishment — (4 ) (115 ) — (119 ) Interest expense (11 ) (443 ) (387 ) — (841 ) Total other (expense)/income (181 ) (579 ) 294 (593 ) (1,059 ) Income/(Loss) Before Income Taxes 934 (24 ) (62 ) (589 ) 259 Income tax expense/(benefit) 367 (22 ) (345 ) 95 95 Net Income 567 (2 ) 283 (684 ) 164 Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests — (17 ) 70 (102 ) (49 ) Net Income Attributable to $ 567 $ 15 $ 213 $ (582 ) $ 213 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the Three Months Ended September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 192 $ 176 $ 436 $ (411 ) $ 393 Other Comprehensive Income/(Loss), net of tax Unrealized gain on derivatives, net — 40 26 (39 ) 27 Foreign currency translation adjustments, net 2 2 4 (5 ) 3 Available-for-sale securities, net — — — — — Defined benefit plans, net 54 — (23 ) — 31 Other comprehensive income 56 42 7 (44 ) 61 Comprehensive Income 248 218 443 (455 ) 454 Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest — 13 34 (49 ) (2 ) Comprehensive Income Attributable to NRG Energy, Inc. 248 205 409 (406 ) 456 Comprehensive Income Available for Common Stockholders $ 248 $ 205 $ 409 $ (406 ) $ 456 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the Nine Months Ended September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 567 $ (2 ) $ 283 $ (684 ) $ 164 Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net — (15 ) 46 (39 ) (8 ) Foreign currency translation adjustments, net 4 4 6 (8 ) 6 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net 55 — (23 ) — 32 Other comprehensive income/(loss) 59 (11 ) 30 (47 ) 31 Comprehensive Income/(Loss) 626 (13 ) 313 (731 ) 195 Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (38 ) 70 (102 ) (70 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 626 25 243 (629 ) 265 Gain on redemption, net of dividends for preferred shares — — (73 ) — (73 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 626 $ 25 $ 316 $ (629 ) $ 338 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ — $ 1,744 $ 691 $ — $ 2,435 Funds deposited by counterparties 6 10 — — 16 Restricted cash 10 470 — — 480 Accounts receivable - trade, net 880 482 — — 1,362 Accounts receivable - affiliate 308 (133 ) 173 (343 ) 5 Inventory 425 592 — — 1,017 Derivative instruments 700 384 — (120 ) 964 Cash collateral paid in support of energy risk management activities 206 131 — — 337 Renewable energy grant receivable, net — 34 — — 34 Prepayments and other current assets 70 237 57 — 364 Total current assets 2,605 3,951 921 (463 ) 7,014 Net property, plant and equipment 4,310 13,667 253 (27 ) 18,203 Other Assets Investment in subsidiaries 875 2,054 10,781 (13,710 ) — Equity investments in affiliates (14 ) 906 8 — 900 Notes receivable, less current portion — 21 — — 21 Goodwill 697 302 — — 999 Intangible assets, net 651 1,457 1 (3 ) 2,106 Nuclear decommissioning trust fund 605 — — — 605 Derivative instruments 231 80 6 (61 ) 256 Deferred income tax — 182 7 — 189 Other non-current assets 43 814 341 — 1,198 Total other assets 3,088 5,816 11,144 (13,774 ) 6,274 Total Assets $ 10,003 $ 23,434 $ 12,318 $ (14,264 ) $ 31,491 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 1,475 $ (254 ) $ — $ 1,221 Accounts payable 577 330 38 — 945 Accounts payable — affiliate 128 158 57 (343 ) — Derivative instruments 601 485 3 (120 ) 969 Cash collateral received in support of energy risk management activities 6 10 — — 16 Accrued expenses and other current liabilities 301 489 360 — 1,150 Total current liabilities 1,613 2,947 204 (463 ) 4,301 Other Liabilities Long-term debt and capital leases 244 10,011 7,763 — 18,018 Nuclear decommissioning reserve 284 — — — 284 Nuclear decommissioning trust liability 309 — — — 309 Deferred income taxes 1,068 (112 ) (909 ) — 47 Derivative instruments 233 303 — (61 ) 475 Out-of-market contracts, net 84 981 — — 1,065 Other non-current liabilities 361 787 332 — 1,480 Total non-current liabilities 2,583 11,970 7,186 (61 ) 21,678 Total liabilities 4,196 14,917 7,390 (524 ) 25,979 Redeemable noncontrolling interest in subsidiaries — 19 — — 19 Stockholders’ Equity 5,807 8,498 4,928 (13,740 ) 5,493 Total Liabilities and Stockholders’ Equity $ 10,003 $ 23,434 $ 12,318 $ (14,264 ) $ 31,491 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS For the Nine Months Ended September 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 $ 567 $ (2 ) $ 283 $ (684 ) $ 164 Adjustments to reconcile net income/(loss) to net cash provided by operating activities: Distributions from unconsolidated affiliates — 65 — (8 ) 57 Equity in (earnings)/losses of unconsolidated affiliates (5 ) (20 ) 2 10 (13 ) Depreciation and amortization 372 588 19 — 979 Provision for bad debts 31 5 — — 36 Amortization of nuclear fuel 39 — — — 39 Amortization of financing costs and debt discount/premiums — (14 ) 17 — 3 Adjustment for debt extinguishment — 4 17 — 21 Amortization of intangibles and out-of-market contracts 32 41 — — 73 Amortization of unearned equity compensation — — 23 — 23 Impairment losses 8 262 — — 270 Changes in deferred income taxes and liability for uncertain tax benefits (134 ) (90 ) 253 — 29 Changes in nuclear decommissioning trust liability 24 — — — 24 Changes in derivative instruments (173 ) 258 (3 ) — 82 Changes in collateral deposits supporting energy risk management activities 268 (37 ) — — 231 Proceeds from sale of emission allowances 47 — — — 47 (Gain)/loss on sale of assets — (294 ) 70 (224 ) Cash (used)/provided by changes in other working capital (887 ) 305 (208 ) 682 (108 ) Net Cash Provided by Operating Activities 189 1,071 473 — 1,733 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. — — 59 (59 ) — Acquisition of September 2016 Drop Down Assets, net of cash acquired — (77 ) — 77 — Intercompany dividends — — 12 (12 ) — Acquisition of businesses, net of cash acquired — (18 ) — — (18 ) Capital expenditures (145 ) (713 ) (40 ) — (898 ) Increase in restricted cash, net (5 ) (25 ) — — (30 ) Increase in restricted cash — U.S. DOE funded projects — (36 ) — — (36 ) Decrease in notes receivable — 2 — — 2 Purchases of emission allowances (32 ) — — — (32 ) Proceeds from sale of emission allowances 47 — — — 47 Investments in nuclear decommissioning trust fund securities (378 ) — — — (378 ) Proceeds from sales of nuclear decommissioning trust fund securities 354 — — — 354 Proceeds from renewable energy grants and state rebates — 11 — — 11 Proceeds from sale of assets, net of cash disposed of — 619 17 — 636 Proceeds from (investments in) unconsolidated affiliates 2 (25 ) — — (23 ) Other 27 9 8 — 44 Net Cash (Used)/Provided by Investing Activities (130 ) (253 ) 56 6 (321 ) Cash Flows from Financing Activities Dividends from NRG Yield, Inc. — (59 ) — 59 — Payments (for)/from intercompany loans (2 ) (134 ) 136 — — Acquisition of September 2016 Drop Down Assets, net of cash acquired — — 77 (77 ) — Intercompany dividends (52 ) 40 — 12 — Payment of dividends to common and preferred stockholders — — (66 ) — (66 ) Payment for preferred shares — — (226 ) — (226 ) Net receipts from settlement of acquired derivatives that include financing elements — 129 — — 129 Proceeds from issuance of long-term debt — 1,097 4,140 — 5,237 Payments for short and long-term debt (2 ) (815 ) (4,540 ) — (5,357 ) Distributions from, net of contributions to, noncontrolling interest in subsidiaries — (127 ) — — (127 ) Proceeds from issuance of common stock — — 1 — 1 Payment of debt issuance costs — (17 ) (53 ) — (70 ) Other - contingent consideration (3 ) (7 ) — — (10 ) Net Cash (Used)/Provided by Financing Activities (59 ) 107 (531 ) (6 ) (489 ) Effect of exchange rate changes on cash and cash equivalents — (6 ) — — (6 ) Net Increase/(Decrease) in Cash and Cash Equivalents — 919 (2 ) — 917 Cash and Cash Equivalents at Beginning of Period — 825 693 — 1,518 Cash and Cash Equivalents at End of Period $ — $ 1,744 $ 691 $ — $ 2,435 (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 September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,132 $ 1,331 $ — $ (29 ) $ 4,434 Operating Costs and Expenses Cost of operations 2,276 792 14 (40 ) 3,042 Depreciation and amortization 190 187 5 — 382 Selling, general and administrative 136 91 100 — 327 Impairment losses 222 41 — — 263 Acquisition-related transaction and integration costs — 2 1 — 3 Development activity expenses — 17 21 — 38 Total operating costs and expenses 2,824 1,130 141 (40 ) 4,055 Operating Income/(Loss) 308 201 (141 ) 11 379 Other Income/(Expense) Equity in earnings of consolidated subsidiaries — 42 228 (270 ) — Equity in earnings of unconsolidated affiliates 3 27 1 (7 ) 24 Other income, net 2 3 1 (2 ) 4 Loss on debt extinguishment — (2 ) — — (2 ) Interest expense (4 ) (151 ) (136 ) — (291 ) Total other income/(expense) 1 (81 ) 94 (279 ) (265 ) Income/(Loss) Before Income Taxes 309 120 (47 ) (268 ) 114 Income tax expense/(benefit) 88 56 (130 ) 33 47 Net Income 221 64 83 (301 ) 67 Less: Net income attributable to noncontrolling interest and redeemable noncontrolling interest — 15 17 (31 ) 1 Net Income Attributable to NRG Energy, Inc. $ 221 $ 49 $ 66 $ (270 ) $ 66 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Nine Months Ended September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 7,959 $ 3,801 $ — $ (97 ) $ 11,663 Operating Costs and Expenses Cost of operations 6,083 2,554 10 (96 ) 8,551 Depreciation and amortization 590 568 15 — 1,173 Selling, general and administrative 351 280 247 — 878 Impairment losses 222 41 — — 263 Acquisition-related transaction and integration costs — 3 13 — 16 Development activity expenses — 43 66 — 109 Total operating costs and expenses 7,246 3,489 351 (96 ) 10,990 Gain on postretirement benefits curtailment — 14 — — 14 Operating Income/(Loss) 713 326 (351 ) (1 ) 687 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (35 ) (15 ) 432 (382 ) — Equity in earnings of unconsolidated affiliates 6 33 — (10 ) 29 Other income, net 3 23 3 (2 ) 27 Loss on debt extinguishment — (9 ) — — (9 ) Interest expense (13 ) (430 ) (412 ) — (855 ) Total other (expense)/income (39 ) (398 ) 23 (394 ) (808 ) Income/(Loss) Before Income Taxes 674 (72 ) (328 ) (395 ) (121 ) Income tax expense/(benefit) 225 (20 ) (281 ) 33 (43 ) Net Income/(Loss) 449 (52 ) (47 ) (428 ) (78 ) Less: Net income attributable to noncontrolling interest and redeemable noncontrolling interest — 15 21 (46 ) (10 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 449 $ (67 ) $ (68 ) $ (382 ) $ (68 ) (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 September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 221 $ 64 $ 83 $ (301 ) $ 67 Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net (5 ) (24 ) 20 3 (6 ) Foreign currency translation adjustments, net — (6 ) (2 ) — (8 ) Available-for-sale securities, net — 12 (19 ) — (7 ) Defined benefit plans, net 4 (1 ) — — 3 Other comprehensive loss (1 ) (19 ) (1 ) 3 (18 ) Comprehensive Income 220 45 82 (298 ) 49 Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest — (3 ) 17 (31 ) (17 ) Comprehensive Income Attributable to NRG Energy, Inc. 220 48 65 (267 ) 66 Dividends for preferred shares — — 5 — 5 Comprehensive Income Available for Common Stockholders $ 220 $ 48 $ 60 $ (267 ) $ 61 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the Nine Months Ended September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 449 $ (52 ) $ (47 ) $ (428 ) $ (78 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net (10 ) (9 ) 29 (12 ) (2 ) Foreign currency translation adjustments, net — (6 ) (4 ) — (10 ) Available-for-sale securities, net — 11 (22 ) — (11 ) Defined benefit plans, net 1 (2 ) 10 — 9 Other comprehensive (loss)/income (9 ) (6 ) 13 (12 ) (14 ) Comprehensive Income/(Loss) 440 (58 ) (34 ) (440 ) (92 ) Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest — (9 ) 21 (46 ) (34 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 440 (49 ) (55 ) (394 ) (58 ) Dividends for preferred shares — — 15 — 15 Comprehensive Income/(Loss) Available for Common Stockholders $ 440 $ (49 ) $ (70 ) $ (394 ) $ (73 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2015 Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ — $ 825 $ 693 $ — $ 1,518 Funds deposited by counterparties 55 51 — — 106 Restricted cash 5 409 — — 414 Accounts receivable - trade, net 851 304 2 — 1,157 Accounts receivable - affiliate 395 260 571 (1,222 ) 4 Inventory 570 682 — — 1,252 Derivative instruments 1,202 871 — (158 ) 1,915 Cash collateral paid in support of energy risk management activities 474 94 — — 568 Renewable energy grant receivable, net — 13 — — 13 Current assets held-for-sale — 6 — — 6 Prepayments and other current assets 93 274 71 — 438 Total current assets 3,645 3,789 1,337 (1,380 ) 7,391 Net Property, Plant and Equipment 4,767 13,773 219 (27 ) 18,732 Other Assets Investment in subsidiaries 842 2,244 11,039 (14,125 ) — Equity investments in affiliates (14 ) 1,160 1 (102 ) 1,045 Notes receivable, less current portion — 46 7 — 53 Goodwill 697 302 — — 999 Intangible assets, net 763 1,551 2 (6 ) 2,310 Nuclear decommissioning trust fund 561 — — — 561 Derivative instruments 153 184 — (32 ) 305 Deferred income taxes (6 ) 815 (642 ) — 167 Non-current assets held for sale — 105 — — 105 Other non-current assets 80 749 385 — 1,214 Total other assets 3,076 7,156 10,792 (14,265 ) 6,759 Total Assets $ 11,488 $ 24,718 $ 12,348 $ (15,672 ) $ 32,882 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ 2 $ 460 $ 19 $ — $ 481 Accounts payable 553 277 39 — 869 Accounts payable — affiliate 151 2,000 (929 ) (1,222 ) — Derivative instruments 1,130 749 — (158 ) 1,721 Cash collateral received in support of energy risk management activities 55 51 — — 106 Current liabilities held-for-sale — 2 — — 2 Accrued expenses and other current liabilities 319 429 449 (1 ) 1,196 Total current liabilities 2,210 3,968 (422 ) (1,381 ) 4,375 Other Liabilities Long-term debt and capital leases 302 10,496 8,185 — 18,983 Nuclear decommissioning reserve 326 — — — 326 Nuclear decommissioning trust liability 283 — — — 283 Deferred income taxes 179 (1,088 ) 928 — 19 Derivative instruments 301 224 — (32 ) 493 Out-of-market contracts, net 95 1,051 — — 1,146 Non-current liabilities held-for-sale — 4 — — 4 Other non-current liabilities 554 735 199 — 1,488 Total non-current liabilities 2,040 11,422 9,312 (32 ) 22,742 Total Liabilities 4,250 15,390 8,890 (1,413 ) 27,117 2.822% Preferred Stock — — 302 — 302 Redeemable noncontrolling interest in subsidiaries — 29 — — 29 Stockholders’ Equity 7,238 9,299 3,156 (14,259 ) 5,434 Total Liabilities and Stockholders’ Equity $ 11,488 $ 24,718 $ 12,348 $ (15,672 ) $ 32,882 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS For the Nine Months Ended September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net Income/(Loss) $ 449 $ (52 ) $ (47 ) $ (428 ) $ (78 ) Adjustments to reconcile net loss to net cash provided by operating activities: Distributions from unconsolidated affiliates — 77 — (20 ) 57 Equity in earnings of unconsolidated affiliates (6 ) (33 ) — 10 (29 ) Depreciation and amortization 590 568 15 — 1,173 Provision for bad debts 46 — 3 — 49 Amortization of nuclear fuel 36 — — — 36 Amortization of financing costs and debt discount/premiums — (29 ) 20 (9 ) Adjustment for debt extinguishment — 9 — — 9 Amortization of intangibles and out-of-market contracts 43 25 — — 68 Amortization of unearned equity compensation — — 37 — 37 Changes in deferred income taxes and liability for uncertain tax benefits 218 (77 ) (213 ) — (72 ) Changes in nuclear decommissioning trust liability 1 — — — 1 Changes in derivative instruments 135 89 (44 ) — 180 Changes in collateral deposits supporting energy risk management activities (141 ) (39 ) — — (180 ) Gain on sale of emission allowances (6 ) — — — (6 ) Gain on postretirement benefits curtailment — (14 ) — — (14 ) Impairment losses 222 41 — — 263 Cash provided/(used) by changes in other working capital 1,048 (879 ) (702 ) 440 (93 ) Net Cash Provided/(Used) by Operating Activities 2,635 (314 ) (931 ) 2 1,392 Cash Flows from Investing Activities Acquisition of January 2015 Drop Down Assets, net of cash acquired — (489 ) — 489 — Dividends from NRG Yield, Inc. — — 52 (52 ) — Intercompany dividends — — 33 (33 ) — Acquisition of businesses, net of cash acquired — (31 ) — — (31 ) Capital expenditures (264 ) (595 ) (30 ) — (889 ) Increase in restricted cash, net (3 ) (38 ) — — (41 ) Decrease in restricted cash — U.S. DOE projects — 1 — — 1 Decrease in notes receivable — 10 — — 10 Purchases of emission allowances (40 ) — — — (40 ) Proceeds from sale of emission allowances 45 — — — 45 Investments in nuclear decommissioning trust fund securities (500 ) — — — (500 ) Proceeds from sales of nuclear decommissioning trust fund securities 499 — — — 499 Proceeds from renewable energy grants and state rebates — 62 — — 62 Proceeds from sale of assets, net of cash disposed of — — 1 — 1 Investments in unconsolidated affiliates 1 (317 ) (39 ) (2 ) (357 ) Other — 8 — — 8 Net Cash Used by Investing Activities (262 ) (1,389 ) 17 402 (1,232 ) Cash Flows from Financing Activities Proceeds from intercompany loans to subsidiaries (2,391 ) 1,178 1,213 — — Acquisition of January 2015 Drop Down Assets, net of cash acquired — — 489 (489 ) — Intercompany dividends — (33 ) — 33 — Payments of dividends from NRG Yield, Inc. — (52 ) — 52 — Payment of dividends to common and preferred stockholders — — (152 ) — (152 ) Payment for treasury stock — — (353 ) — (353 ) Net receipts for settlement of acquired derivatives that include financing elements — 138 — — 138 Proceeds from issuance of long-term debt — 635 44 — 679 Distributions from, net of contributions to, noncontrolling interest in subsidiaries — 651 — — 651 Proceeds from issuance of common stock — — 1 — 1 Payment of debt issuance costs — (14 ) — — (14 ) Payments for short and long-term debt — (938 ) (16 ) — (954 ) Other — (22 ) — — (22 ) Net Cash Provided by Financing Activities (2,391 ) 1,543 1,226 (404 ) (26 ) Effect of exchange rate changes on cash and cash equivalents — 15 — — 15 Net (Decrease)/Increase in Cash and Cash Equivalents (18 ) (145 ) 312 — 149 Cash and Cash Equivalents at Beginning of Period 18 1,455 643 — 2,116 Cash and Cash Equivalents at End of Period $ — $ 1,310 $ 955 $ — $ 2,265 (a) All significant intercompany transactions have been eliminated in consolidation.

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Policy)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Business Description and Basis of Presentation [Text Block]	NRG has one of the nation's largest and most diverse competitive generation portfolios balanced with a leading retail electricity platform. The Company owns and operates approximately 46,000 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 2015 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 September 30, 2016, and the results of operations, comprehensive income/(loss) and cash flows for the three and nine months ended September 30, 2016 and 2015.
Reclassification, Policy [Policy Text Block]	Reclassifications Certain prior year amounts have been reclassified for comparative purposes. The reclassifications did not affect results from operations, net assets or cash flows. The Company decreased accumulated depreciation and facilities and equipment within total property, plant and equipment by approximately $1 billion respectively, to adjust amounts previously presented as of December 31, 2015. This adjustment had no impact on net assets at December 31, 2015. Accordingly, the Company does not consider the adjustment to be material to the consolidated balance sheet. Consolidated operating income and net income for the three months and nine months ended September 30, 2016 were not impacted by the adjustment.
Use of Estimates (Policy)	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.
Cash Flow, Supplemental Disclosures [Text Block]	Other Cash Flow Information NRG’s investing activities exclude capital expenditures of $112 million which were accrued and unpaid at September 30, 2016
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Developments 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. The amendments of ASU No. 2016-16 were issued to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. 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 and do not require new disclosure requirements. The amendments of ASU No. 2016-16 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. 2016-16 should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company is currently evaluating the impact of the standard on the Company’s results of operations, cash flows and financial position. 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 amendments of ASU No. 2016-15 are effective for public entities for fiscal years beginning after December 15, 2017 and interim periods in those fiscal years. Early adoption is permitted, including adoption in an interim fiscal period with all amendments adopted in the same period. The adoption of ASU No. 2016-15 is required to be applied retrospectively. The Company is currently evaluating the impact of the standard on the Company's statement of cash flows. 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 of ASU No. 2016-09 were issued as part of the FASB's Simplification Initiative focused on improving areas of GAAP for which cost and complexity may be reduced while maintaining or improving the usefulness of information disclosed within the financial statements. 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 guidance in ASU No. 2016-09 is effective for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted. The Company does not expect the standard to have a material impact on its results of operations, cash flows and financial position. ASU 2016-07 — In March 2016, the FASB issued ASU No. 2016-07, Investments - Equity Method and Joint Ventures (Topic 323), or ASU No. 2016-07. The amendments of ASU No. 2016-07 eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting with no retroactive adjustment to the investment. In addition, ASU No. 2016-07 requires that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The guidance in ASU No. 2016-07 is effective for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. The adoption of ASU No. 2016-07 is required to be applied prospectively and early adoption is permitted. The Company does not expect the standard to have a material impact on its results of operations, cash flows and financial position. ASU 2016-02 — In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or ASU No. 2016-02. The amendments of ASU No. 2016-02 complete the joint effort between the FASB and the International Accounting Standards Board, or IASB, to develop a common leasing standard for GAAP and International Financial Reporting Standards, or IFRS, 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. The guidance in ASU No. 2016-02 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, ASU No. 2016-02 expands the required quantitative and qualitative disclosures with regards to lease arrangements. The guidance in ASU No. 2016-02 is effective for fiscal years beginning after December 15, 2018, and interim periods within those annual periods. The adoption of ASU No. 2016-02 is required to be applied using a modified retrospective approach for the earliest period presented and early adoption is permitted. The Company is currently working through an adoption plan which includes the evaluation of lease contracts compared to the new standard and evaluating the impact of ASU No. 2016-02 on the Company's results of operations, cash flows and financial position. ASU 2016-01 — In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, or ASU No. 2016-01. The amendments of ASU No. 2016-01 eliminate available-for-sale classification of equity investments and require that equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be generally measured at fair value with changes in fair value recognized in net income. Further, the amendments require that financial assets and financial liabilities to be presented separately in the notes to the financial statements, grouped by measurement category and form of financial asset. The guidance in ASU No. 2016-01 is effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within those annual periods. The Company is currently evaluating the impact of the standard on the Company's results of operations, cash flows and financial position. ASU 2015-16 — In September 2015, the FASB issued ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments , or ASU No. 2015-16. The amendments of ASU No. 2015-16 require that an acquirer recognize measurement period adjustments to the provisional amounts recognized in a business combination in the reporting period during which the adjustments are determined. Additionally, the amendments of ASU No. 2015-16 require the acquirer to record in the same period's financial statements the effect on earnings of changes in depreciation, amortization or other income effects, if any, as a result of the measurement period adjustment, calculated as if the accounting had been completed at the acquisition date as well as disclosing either on the face of the income statement or in the notes the portion of the amount recorded in current period earnings that would have been recorded in previous reporting periods. The guidance in ASU No. 2015-16 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. The amendments should be applied prospectively. The Company adopted ASU No. 2015-16 for the year ended December 31, 2016, and the adoption did not have a material impact on the Company's results of operations, cash flows and financial position. ASU 2014-09 — In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU No. 2014-09. The amendments of ASU No. 2014-09 complete the joint effort between the FASB and the IASB, to develop a common revenue standard for GAAP and IFRS, and to improve financial reporting. In addition to ASU No. 2014-09, the FASB has issued additional guidance which provides further clarification on Topic 606 including ASU No. 2016-08, ASU No. 2016-10 and ASU No. 2016-12. 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 four step process to be applied by an entity in evaluating its contracts with customers. In August 2015, the FASB issued ASU No. 2015-14, which formally deferred the effective date by one year to make the guidance of ASU No. 2014-09 effective for annual reporting periods beginning after December 15, 2017, including interim periods therein. Early adoption is permitted, but not prior to the original effective date, which was for annual reporting periods beginning after December 15, 2016. The Company is working through an adoption plan which includes the evaluation of revenue contracts compared to the new standard and evaluating the impact of Topic 606 on the Company's results of operations, cash flows and financial position.
Nuclear Decommissioning (Policy)	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 (Policy)	The Company's segment structure reflects how management currently makes financial decisions and allocates resources. The Company's businesses are segregated as follows: Generation (previously Generation/Business), which includes generation, international and business solutions; Retail Mass (previously NRG Home Retail); Renewables (previously NRG Renew), which includes solar and wind assets; NRG Yield; and corporate activities. The Company's corporate segment includes BETM, residential solar and electric vehicle services. Effective January 1, 2016, the Company began reporting the results of its residential solar business in its corporate segment. Effective April 1, 2016, the Company began reporting the results of its international business in its Generation segment. The financial information for the three months and nine months ended September 30, 2015 has been recast to reflect the change. 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 November 3, 2015, NRG Yield acquired 75% of the class B interests in NRG Wind TE Holdco, which owns a portfolio of 12 wind facilities, from the Company. 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. 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 Accoun26

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Supplemental Balance Sheet Disclosures [Text Block]	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. September 30, 2016 December 31, 2015 (In millions) Accounts receivable allowance for doubtful accounts $ 28 $ 26 Property plant and equipment accumulated depreciation 6,424 5,761 Intangible assets accumulated amortization 1,729 1,590 Out-of-market contracts accumulated amortization 740 639
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, 2015 $ 2,727 Distributions to noncontrolling interest (135 ) Dividends paid to NRG Yield, Inc. public shareholders (68 ) Comprehensive loss attributable to noncontrolling interest (45 ) Sale of assets to NRG Yield, Inc. (37 ) Redemption of noncontrolling interest (7 ) Contributions from noncontrolling interest 16 Balance as of September 30, 2016 $ 2,451
Redeemable Noncontrolling Interest [Table Text Block]	Redeemable Noncontrolling Interest The following table reflects the changes in the Company's redeemable noncontrolling interest balance: (In millions) Balance as of December 31, 2015 $ 29 Distributions to redeemable noncontrolling interest (46 ) Contributions from redeemable noncontrolling interest 61 Comprehensive loss attributable to redeemable noncontrolling interest (25 ) Balance as of September 30, 2016 $ 19

Fair Value of Financial Instr27

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value of Financial Instruments Disclosure [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 September 30, 2016 As of December 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable (a) $ 50 $ 50 $ 73 $ 73 Liabilities: Long-term debt, including current portion (b) 19,411 18,888 19,620 18,263 (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 September 30, 2016 and December 31, 2015: As of September 30, 2016 As of December 31, 2015 Level 2 Level 3 Level 2 Level 3 (In millions) Long-term debt, including current portion $ 11,767 $ 7,121 $ 11,028 $ 7,235
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 September 30, 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 Other (a) 10 — — 10 Nuclear trust fund investments: Cash and cash equivalents 24 — — 24 U.S. government and federal agency obligations 51 1 — 52 Federal agency mortgage-backed securities — 68 — 68 Commercial mortgage-backed securities — 17 — 17 Corporate debt securities — 87 — 87 Equity securities 301 — 54 355 Foreign government fixed income securities — 2 — 2 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 308 798 107 1,213 Interest rate contracts — 7 — 7 Total assets $ 705 $ 980 $ 178 $ 1,863 Derivative liabilities: Commodity contracts 375 773 133 1,281 Interest rate contracts — 163 — 163 Total liabilities $ 375 $ 936 $ 133 $ 1,444 (a) Consists primarily of mutual funds held in a Rabbi Trust for non-qualified deferred compensation plans for certain former employees. As of December 31, 2015 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 9 — — 9 Other (a) 14 — — 14 Nuclear trust fund investments: Cash and cash equivalents 6 — — 6 U.S. government and federal agency obligations 54 1 — 55 Federal agency mortgage-backed securities — 59 — 59 Commercial mortgage-backed securities — 25 — 25 Corporate debt securities — 81 — 81 Equity securities 280 — 54 334 Foreign government fixed income securities — 1 — 1 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 622 1,449 149 2,220 Total assets $ 986 $ 1,616 $ 220 $ 2,822 Derivative liabilities: Commodity contracts 868 1,036 182 2,086 Interest rate contracts — 128 — 128 Total liabilities $ 868 $ 1,164 $ 182 $ 2,214 (a) Primarily consists of mutual funds held in rabbi trusts for non-qualified deferred compensation plans for certain former employees and a total return swap that does not meet the definition of a derivative.
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 nine months ended September 30, 2016 , and 2015 , 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 September 30, 2016 Nine months ended September 30, 2016 (In millions) Debt Securities Trust Fund Investments Derivatives (a) Total Debt Securities Trust Fund Investments Derivatives (a) Total Beginning balance $ 16 $ 51 $ 7 $ 74 $ 17 $ 54 $ (33 ) $ 38 Total gains/(losses) — realized/unrealized: Included in earnings — — 2 2 — — 9 9 Included in OCI 1 — — 1 — — — — Included in nuclear decommissioning obligation — 3 — 3 — (1 ) — (1 ) Purchases — — (26 ) (26 ) — 1 3 4 Transfers into Level 3 (b) — — (12 ) (12 ) — — (5 ) (5 ) Transfers out of Level 3 (b) — — 3 3 — — — — Ending balance as of September 30, 2016 $ 17 $ 54 $ (26 ) $ 45 $ 17 $ 54 $ (26 ) $ 45 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 September 30, 2016 $ — $ — $ 1 $ 1 $ — $ — $ (14 ) $ (14 ) (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 September 30, 2015 Nine months ended September 30, 2015 (In millions) Debt Securities Other Trust Fund Investments Derivatives (a) Total Debt Securities Other Trust Fund Investments Derivatives (a) Total Beginning balance $ 18 $ — $ 55 $ 49 $ 122 $ 18 $ 11 $ 52 $ 80 $ 161 Total losses — realized/unrealized: Included in earnings — — — (17 ) (17 ) — (11 ) — (95 ) (106 ) Included in nuclear decommissioning obligations — — (6 ) — (6 ) — — (4 ) — (4 ) Purchases — — — 9 9 — — 1 44 45 Transfers into Level 3 (b) — — — (10 ) (10 ) — — — 1 1 Transfers out of Level 3 (b) — — — 2 2 — — — 3 3 Ending balance as of September 30, 2015 $ 18 $ — $ 49 $ 33 $ 100 $ 18 $ — $ 49 $ 33 $ 100 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 September 30, 2015 $ — $ — $ — $ (9 ) $ (9 ) $ — $ — $ — $ (37 ) $ (37 ) (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 Inputs, Assets, Quantitative Information [Table Text Block]	The following tables quantify the significant unobservable inputs used in developing the fair value of the Company's Level 3 positions as of September 30, 2016 and December 31, 2015 : Significant Unobservable Inputs September 30, 2016 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 53 $ 78 Discounted Cash Flow Forward Market Price (per MWh) $ 11 $ 81 $ 27 Coal Contracts — 5 Discounted Cash Flow Forward Market Price (per ton) 44 44 44 FTRs 54 50 Discounted Cash Flow Auction Prices (per MWh) (63 ) 55 — $ 107 $ 133 Significant Unobservable Inputs December 31, 2015 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 86 $ 100 Discounted Cash Flow Forward Market Price (per MWh) $ 10 $ 92 $ 27 Coal Contracts — 12 Discounted Cash Flow Forward Market Price (per ton) 28 45 35 FTRs 63 70 Discounted Cash Flow Auction Prices (per MWh) (98 ) 87 — $ 149 $ 182
Fair Value Inputs, Sensitivity Analysis [Table Text Block]	The following table provides sensitivity of fair value measurements to increases/(decreases) in significant unobservable inputs as of September 30, 2016 and December 31, 2015 : Significant Unobservable Input Position Change In Input Impact on Fair Value Measurement Forward Market Price Power/Coal Buy Increase/(Decrease) Higher/(Lower) Forward Market Price Power/Coal 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) Category by Industry Sector (% of Total) Financial institutions 33 % Utilities, energy merchants, marketers and other 42 ISOs 25 Total as of September 30, 2016 100 % Net Exposure (a) Category by Counterparty Credit Quality (% of Total) Investment grade 90 % Non-rated (b) 3 Non-investment grade 7 Total as of September 30, 2016 100 % (a) Counterparty credit exposure excludes uranium and coal transportation contracts because of the unavailability of market prices. (b) For non-rated counterparties, a significant portion are related to ISO and municipal public power entities, which are considered investment grade equivalent ratings based on NRG's internal credit ratings.

Nuclear Decommissioning Trust28

Nuclear Decommissioning Trust Fund (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 As of December 31, 2015 (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 $ 24 $ — $ — — $ 6 $ — $ — — U.S. government and federal agency obligations 52 4 — 11 55 1 — 11 Federal agency mortgage-backed securities 68 2 — 25 59 1 — 25 Commercial mortgage-backed securities 17 — 1 26 25 — 2 28 Corporate debt securities 87 3 1 11 81 1 1 10 Equity securities 355 213 — — 334 199 — — Foreign government fixed income securities 2 — — 9 1 — — 9 Total $ 605 $ 222 $ 2 $ 561 $ 202 $ 3
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. Nine months ended September 30, 2016 2015 (In millions) Realized gains $ 7 $ 14 Realized losses 3 10 Proceeds from sale of securities 354 499

Accounting for Derivative Ins29

Accounting for Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 and December 31, 2015 . 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 September 30, 2016 December 31, 2015 Category Units (In millions) Emissions Short Ton 1 1 Coal Short Ton 29 35 Natural Gas MMBtu 73 293 Oil Barrel — 1 Power MWh (35 ) (74 ) Capacity MW/Day (1 ) (1 ) Interest Dollars $ 3,219 $ 2,326 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 September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 (In millions) Derivatives designated as cash flow hedges: Interest rate contracts current $ — $ — $ 31 $ 42 Interest rate contracts long-term 1 — 99 68 Total derivatives designated as cash flow hedges 1 — 130 110 Derivatives not designated as cash flow hedges : Interest rate contracts current — — 8 5 Interest rate contracts long-term 6 — 25 13 Commodity contracts current 964 1,915 930 1,674 Commodity contracts long-term 249 305 351 412 Total derivatives not designated as cash flow hedges 1,219 2,220 1,314 2,104 Total derivatives $ 1,220 $ 2,220 $ 1,444 $ 2,214
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 September 30, 2016 (In millions) Commodity contracts: Derivative assets $ 1,213 $ (1,027 ) $ (23 ) $ 163 Derivative liabilities (1,281 ) 1,027 121 (133 ) Total commodity contracts (68 ) — 98 30 Interest rate contracts: Derivative assets 7 (4 ) — 3 Derivative liabilities (163 ) 4 — (159 ) Total interest rate contracts (156 ) — — (156 ) Total derivative instruments $ (224 ) $ — $ 98 $ (126 ) 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, 2015 (In millions) Commodity contracts: Derivative assets $ 2,220 $ (1,616 ) $ (113 ) $ 491 Derivative liabilities (2,086 ) 1,616 271 (199 ) Total commodity contracts 134 — 158 292 Interest rate contracts: Derivative liabilities (128 ) — — (128 ) Total derivative instruments $ 6 $ — $ 158 $ 164
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: Three months ended September 30, 2016 Nine months ended September 30, 2016 Energy Commodities Interest Rate Total Energy Commodities Interest Rate Total (In millions) Accumulated OCI beginning balance $ — $ (165 ) $ (165 ) $ — $ (101 ) $ (101 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts — 2 2 — 12 12 Mark-to-market of cash flow hedge accounting contracts — 32 32 — (42 ) (42 ) Accumulated OCI ending balance, net of $28 tax $ — $ (131 ) $ (131 ) $ — $ (131 ) $ (131 ) Losses expected to be realized from OCI during the next 12 months, net of $4 tax $ — $ 17 $ 17 $ — $ 17 $ 17 Three months ended September 30, 2015 Nine months ended September 30, 2015 Energy Commodities Interest Rate Total Energy Commodities Interest Rate Total (In millions) Accumulated OCI beginning balance $ (1 ) $ (62 ) $ (63 ) $ (1 ) $ (67 ) $ (68 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts 1 3 4 1 7 8 Mark-to-market of cash flow hedge accounting contracts — (33 ) (33 ) — (32 ) (32 ) Accumulated OCI ending balance, net of $54 tax $ — $ (92 ) $ (92 ) $ — $ (92 ) $ (92 )
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 September 30, Nine months ended September 30, 2016 2015 2016 2015 Unrealized mark-to-market results (In millions) Reversal of previously recognized unrealized gains on settled positions related to economic hedges $ (44 ) $ (29 ) $ (182 ) $ (179 ) Reversal of acquired gain positions related to economic hedges (19 ) (33 ) (47 ) (83 ) Net unrealized (losses)/gains on open positions related to economic hedges (121 ) 55 (19 ) (26 ) Total unrealized mark-to-market losses for economic hedging activities (184 ) (7 ) (248 ) (288 ) Reversal of previously recognized unrealized losses/(gains) on settled positions related to trading activity 3 2 13 (34 ) Reversal of acquired gain positions related to trading activity — (1 ) — (13 ) Net unrealized (losses)/gains on open positions related to trading activity (8 ) (2 ) 14 — Total unrealized mark-to-market (losses)/gains for trading activity (5 ) (1 ) 27 (47 ) Total unrealized losses $ (189 ) $ (8 ) $ (221 ) $ (335 ) Three months ended September 30, Nine months ended September 30, 2016 2015 2016 2015 (In millions) Unrealized (losses)/gains included in operating revenues $ (84 ) $ 34 $ (565 ) $ (212 ) Unrealized (losses)/gains included in cost of operations (105 ) (42 ) 344 (123 ) Total impact to statement of operations — energy commodities $ (189 ) $ (8 ) $ (221 ) $ (335 ) Total impact to statement of operations — interest rate contracts $ 9 $ (9 ) $ (9 ) $ 12

Debt and Capital Leases Debt an

Debt and Capital Leases Debt and Capital Leases (Tables)	9 Months Ended
	Sep. 30, 2016
Debt Instrument [Line Items]
Long-term debt and capital leases	Long-term debt and capital leases consisted of the following: (In millions, except rates) September 30, 2016 December 31, 2015 September 30, 2016 interest rate % (a) Recourse debt: Senior notes, due 2018 $ 584 $ 1,039 7.625 Senior notes, due 2020 — 1,058 8.250 Senior notes, due 2021 399 1,128 7.875 Senior notes, due 2022 992 1,100 6.250 Senior notes, due 2023 869 936 6.625 Senior notes, due 2024 733 904 6.250 Senior notes, due 2026 1,000 — 7.250 Senior notes, due 2027 1,250 — 6.625 Term loan facility, due 2018 — 1,964 L+2.00 Term loan facility, due 2023 1,886 — L+2.75 Tax-exempt bonds 455 455 4.125 - 6.00 Subtotal NRG recourse debt 8,168 8,584 Non-recourse debt: GenOn senior notes 1,922 1,956 7.875 - 9.875 GenOn Americas Generation senior notes 747 752 8.500 - 9.125 GenOn other 52 56 Subtotal GenOn debt (non-recourse to NRG) 2,721 2,764 NRG Yield Operating LLC Senior Notes, due 2024 500 500 5.375 NRG Yield Operating LLC Senior Notes, due 2026 350 — 5.000 NRG Yield LLC and Yield Operating LLC Revolving Credit Facility, due 2019 — 306 L+2.75 NRG Yield Inc. Convertible Senior Notes, due 2019 334 330 3.500 NRG Yield Inc. Convertible Senior Notes, due 2020 270 266 3.250 El Segundo Energy Center, due 2023 443 485 L+1.625 - L+2.25 Marsh Landing, due 2017 and 2023 385 418 L+1.175 - L+1.875 Alta Wind I - V lease financing arrangements, due 2034 and 2035 978 1,002 5.696 - 7.015 Walnut Creek, term loans due 2023 322 351 L+1.625 Tapestry, due 2021 175 181 L+1.625 CVSR, due 2037 771 793 2.339 - 3.775 CVSR HoldCo, due 2037 199 — 4.680 Alpine, due 2022 147 154 L+1.750 Energy Center Minneapolis, due 2017 and 2025 98 108 5.95 - 7.25 Viento, due 2023 183 189 L+2.75 NRG Yield - other 549 573 various Subtotal NRG Yield debt (non-recourse to NRG) 5,704 5,656 Ivanpah, due 2033 and 2038 1,135 1,149 2.285 - 4.256 Agua Caliente, due 2037 864 879 2.395 - 3.633 Dandan, due 2033 100 98 L+2.25 Peaker bonds, due 2019 — 72 L+1.07 Cedro Hill, due 2025 165 103 L+1.75 Midwest Generation, due 2019 234 — 4.390 NRG Other 320 315 various Subtotal other NRG non-recourse debt 2,818 2,616 Subtotal all non-recourse debt 11,243 11,036 Subtotal long-term debt (including current maturities) 19,411 19,620 Capital leases 11 16 various Subtotal long-term debt and capital leases (including current maturities) 19,422 19,636 Less current maturities 1,221 481 Less debt issuance costs 183 172 Total long-term debt and capital leases $ 18,018 $ 18,983 (a) As of September 30, 2016 , L+ equals 3 month LIBOR plus x%, with the exception of the Viento Funding II term loan, which is 6 month LIBOR plus x%, and the Alpine Term Loan, the NRG Marsh Landing term loan, the Walnut Creek term loan, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument Redemption [Table Text Block]	During the nine months ended September 30, 2016, the Company repurchased $2.6 billion in aggregate principal of its Senior Notes in the open market for $2.7 billion , which included accrued interest of $67 million . In connection with the repurchases, a $94 million loss on debt extinguishment was recorded, which included the write-off of previously deferred financing costs of $15 million . Principal Repurchased Cash Paid (a) Average Early Redemption Percentage Amount in millions, except rates 7.625% senior notes due 2018 $ 455 $ 502 107.95 % 8.250% senior notes due 2020 1,058 1,129 103.12 % 7.875% senior notes due 2021 729 771 104.02 % 6.250% senior notes due 2022 108 105 94.73 % 6.625% senior notes due 2023 67 64 94.13 % 6.250% senior notes due 2024 171 163 94.52 % Total at September 30, 2016 $ 2,588 $ 2,734 7.625% senior notes due 2018 (b) 186 204 107.75 % 7.875% senior notes due 2021 (b) 193 207 103.94 % Total at November 4, 2016 $ 2,967 $ 3,145 (a) Includes payment for accrued interest (b) Redemptions financed by cash on hand

Variable Interest Entities Summ

Variable Interest Entities Summarized Financial Information (Tables)	9 Months Ended
	Sep. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Additional Financial Information Disclosure [Text Block]	The summarized financial information for the Company's consolidated VIEs consisted of the following: (In millions) September 30, 2016 December 31, 2015 Current assets $ 76 $ 84 Net property, plant and equipment 1,742 1,807 Other long-term assets 945 863 Total assets 2,763 2,754 Current liabilities 59 56 Long-term debt 450 366 Other long-term liabilities 194 179 Total liabilities 703 601 Noncontrolling interests 562 493 Net assets less noncontrolling interests $ 1,498 $ 1,660

Changes in Capital Structure (T

Changes in Capital Structure (Tables)	9 Months Ended
	Sep. 30, 2016
Changes in Capital Structure Disclosure [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, 2015 416,939,950 (102,749,908 ) 314,190,042 Shares issued under LTIPs 643,642 — 643,642 Shares issued under ESPP — 609,094 609,094 Balance as of September 30, 2016 417,583,592 (102,140,814 ) 315,442,778
Schedule of dividends paid	The following table lists the dividends paid during the nine months ended September 30, 2016 : Third Quarter 2016 Second Quarter 2016 First Quarter 2016 Dividends per Common Share $ 0.030 $ 0.030 $ 0.145

Earnings_(Loss) Per Share (Tabl

Earnings/(Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Reconciliation of NRG's basic and diluted earnings per share	The reconciliation of NRG's basic and diluted earnings/(loss) per share is shown in the following table: Three months ended September 30, Nine months ended September 30, (In millions, except per share data) 2016 2015 2016 2015 Basic earnings/(loss) per share attributable to NRG Energy, Inc. common stockholders Net income/(loss) attributable to NRG Energy, Inc. $ 402 $ 66 $ 213 $ (68 ) Dividends for preferred shares — 5 5 15 Gain on redemption of 2.822% redeemable perpetual preferred stock — — (78 ) — Income/(loss) available for common stockholders $ 402 $ 61 $ 286 $ (83 ) Weighted average number of common shares outstanding - basic 316 331 315 334 Earnings/(Loss) per weighted average common share — basic $ 1.27 $ 0.18 $ 0.91 $ (0.25 ) Diluted earnings/(loss) per share attributable to NRG Energy, Inc. common stockholders Weighted average number of common shares outstanding 316 331 315 334 Incremental shares attributable to the issuance of equity compensation (treasury stock method) 1 1 1 — Total dilutive shares 317 332 316 334 Earnings/(loss) per weighted average common share — diluted $ 1.27 $ 0.18 $ 0.91 $ (0.25 )
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 September 30, Nine months ended September 30, (In millions of shares) 2016 2015 2016 2015 Equity compensation plans 2 3 3 6 Embedded derivative of 2.822% redeemable perpetual preferred stock — 16 — 16 Total 2 19 3 22

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting Disclosure [Abstract]
Schedule of segment reporting information, by segment	(In millions) Generation (a) Retail Mass (a) Renewables (a) NRG Yield (a) Corporate (a)(b) Eliminations Total Three months ended September 30, 2016 Operating revenues (a) $ 2,494 $ 1,619 $ 140 $ 272 $ 40 $ (613 ) $ 3,952 Depreciation and amortization 193 25 48 75 16 — 357 Impairment losses 8 — — — — — 8 Equity in earnings/(losses) of unconsolidated affiliates 6 — (4 ) 13 1 — 16 Gain on sale of assets 262 — — — 4 — 266 (Impairment loss)/gain on investment (5 ) — 1 — (4 ) — (8 ) Income/(loss) before income taxes 628 2 8 60 (252 ) (4 ) 442 Net Income/(Loss) 630 2 11 47 (293 ) (4 ) 393 Net Income/(Loss) attributable to NRG Energy, Inc. $ 630 $ 2 $ — $ 52 $ (317 ) $ 35 $ 402 Total assets as of September 30, 2016 $ 14,153 $ 1,601 $ 4,920 $ 8,482 $ 16,970 $ (14,635 ) 31,491 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 555 $ — $ 9 $ 2 $ 47 $ — $ 613 (b) Includes loss on debt extinguishment $ — $ — $ — $ — $ (50 ) $ — $ (50 ) (In millions) Generation (a) Retail Mass (a) Renewables (a) NRG Yield (a)(b) Corporate (a) Eliminations Total Three months ended September 30, 2015 Operating revenues (a) $ 2,726 $ 1,699 $ 124 $ 256 $ 1 $ (372 ) $ 4,434 Depreciation and amortization 220 30 46 69 17 — 382 Impairment losses 222 36 5 — — — 263 Equity in earnings/(loss) of unconsolidated affiliates 7 — (2 ) 12 1 6 24 Income/(Loss) before income taxes 166 197 (20 ) 40 (276 ) 7 114 Net Income/(Loss) 164 197 (16 ) 32 (317 ) 7 67 Net Income/(Loss) attributable to NRG Energy, Inc. $ 164 $ 197 $ (33 ) $ 20 $ (315 ) $ 33 $ 66 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 309 $ 2 $ (6 ) $ 18 $ 49 $ — $ 372 (b) Includes loss on debt extinguishment $ — $ — $ — $ 2 $ — $ — $ 2 (In millions) Generation (a) Retail Mass (a) Renewables (a) NRG Yield (a) Corporate (a)(b) Eliminations Total Nine months ended September 30, 2016 Operating revenues (a) $ 5,920 $ 3,868 $ 335 $ 789 $ 128 $ (1,221 ) $ 9,819 Depreciation and amortization 483 80 143 224 49 — 979 Impairment losses 84 — 26 — 13 — 123 Equity in earnings/(losses) of unconsolidated affiliates 1 — (13 ) 29 3 (7 ) 13 Gain/(loss) on sale of assets 293 — — — (78 ) — 215 (Impairment loss)/gain on investment (142 ) — 1 — (6 ) — (147 ) Income/(loss) before income taxes 417 644 (116 ) 136 (815 ) (7 ) 259 Net Income/(Loss) 418 644 (102 ) 111 (900 ) (7 ) 164 Net Income/(Loss) attributable to NRG Energy, Inc. $ 418 $ 644 $ (98 ) $ 108 $ (931 ) $ 72 $ 213 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 1,025 $ 2 $ 19 $ 6 $ 169 $ — $ 1,221 (b) Includes loss on debt extinguishment $ — $ — $ — $ — $ (119 ) $ — $ (119 ) (In millions) Generation (a) Retail Mass (a) Renewables (a) NRG Yield (a)(b) Corporate (a) Eliminations Total Nine months ended September 30, 2015 Operating revenues (a) $ 7,345 $ 4,308 $ 305 $ 729 $ 9 $ (1,033 ) $ 11,663 Depreciation and amortization 681 93 135 222 42 — 1,173 Impairment losses 222 36 5 — — — 263 Gain on postretirement benefits curtailment 14 — — — — — 14 Equity in earnings/(losses) of unconsolidated affiliates 9 — (2 ) 19 — 3 29 Income/(loss) before income taxes 216 523 (87 ) 61 (834 ) — (121 ) Net Income/(Loss) 213 523 (74 ) 53 (793 ) — (78 ) Net Income/(Loss) attributable to NRG Energy, Inc. $ 213 $ 523 $ (100 ) $ 29 $ (765 ) $ 32 $ (68 ) (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 853 $ 4 $ 18 $ 27 $ 131 $ — $ 1,033 (b) Includes loss on debt extinguishment $ — $ — $ — $ 9 $ — $ — $ 9

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The income tax provision consisted of the following: Three months ended September 30, Nine months ended September 30, (In millions except otherwise noted) 2016 2015 2016 2015 Income/(loss) before income taxes $ 442 $ 114 $ 259 $ (121 ) Income tax (benefit)/expense 49 47 95 (43 ) Effective tax rate 11.1 % 41.2 % 36.7 % 35.5 %

Condensed Consolidating Finan36

Condensed Consolidating Financial Information (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 2,424 $ 1,622 $ — $ (94 ) $ 3,952 Operating Costs and Expenses Cost of operations 1,718 1,158 11 (94 ) 2,793 Depreciation and amortization 147 203 7 — 357 Impairment losses 8 — — — 8 Selling, general and administrative 114 105 63 — 282 Acquisition-related transaction and integration costs — 1 (1 ) — — Development activity expenses — 12 11 — 23 Total operating costs and expenses 1,987 1,479 91 (94 ) 3,463 Loss on sale of assets — 262 4 — 266 Operating Income/(Loss) 437 405 (87 ) — 755 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (110 ) (13 ) 485 (362 ) — Equity in earnings/(losses) of unconsolidated affiliates 2 22 (2 ) (6 ) 16 Impairment loss on investment — (8 ) — — (8 ) Other income 1 8 — — 9 Loss on debt extinguishment — — (50 ) — (50 ) Interest expense (4 ) (148 ) (128 ) — (280 ) Total other (expense)/income (111 ) (139 ) 305 (368 ) (313 ) Income Before Income Taxes 326 266 218 (368 ) 442 Income tax expense/(benefit) 134 90 (218 ) 43 49 Net Income 192 176 436 (411 ) 393 Less: Net income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests — 6 34 (49 ) (9 ) Net Income Attributable to NRG Energy, Inc. $ 192 $ 170 $ 402 $ (362 ) $ 402 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Nine Months Ended September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 6,079 $ 3,907 $ — $ (167 ) $ 9,819 Operating Costs and Expenses Cost of operations 4,278 2,602 29 (171 ) 6,738 Depreciation and amortization 372 588 19 — 979 Impairment losses 8 115 — — 123 Selling, general and administrative 306 296 200 — 802 Acquisition-related transaction and integration costs — 1 6 — 7 Development activity expenses — 44 23 — 67 Total operating costs and expenses 4,964 3,646 277 (171 ) 8,716 Gain/(loss) on sale of assets — 294 (79 ) — 215 Operating Income/(Loss) 1,115 555 (356 ) 4 1,318 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (178 ) (36 ) 796 (582 ) — Equity in earnings/(losses) of unconsolidated affiliates 5 20 (2 ) (10 ) 13 Impairment loss on investment — (147 ) — — (147 ) Other income 3 31 2 (1 ) 35 Loss on debt extinguishment — (4 ) (115 ) — (119 ) Interest expense (11 ) (443 ) (387 ) — (841 ) Total other (expense)/income (181 ) (579 ) 294 (593 ) (1,059 ) Income/(Loss) Before Income Taxes 934 (24 ) (62 ) (589 ) 259 Income tax expense/(benefit) 367 (22 ) (345 ) 95 95 Net Income 567 (2 ) 283 (684 ) 164 Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests — (17 ) 70 (102 ) (49 ) Net Income Attributable to $ 567 $ 15 $ 213 $ (582 ) $ 213 (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 September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,132 $ 1,331 $ — $ (29 ) $ 4,434 Operating Costs and Expenses Cost of operations 2,276 792 14 (40 ) 3,042 Depreciation and amortization 190 187 5 — 382 Selling, general and administrative 136 91 100 — 327 Impairment losses 222 41 — — 263 Acquisition-related transaction and integration costs — 2 1 — 3 Development activity expenses — 17 21 — 38 Total operating costs and expenses 2,824 1,130 141 (40 ) 4,055 Operating Income/(Loss) 308 201 (141 ) 11 379 Other Income/(Expense) Equity in earnings of consolidated subsidiaries — 42 228 (270 ) — Equity in earnings of unconsolidated affiliates 3 27 1 (7 ) 24 Other income, net 2 3 1 (2 ) 4 Loss on debt extinguishment — (2 ) — — (2 ) Interest expense (4 ) (151 ) (136 ) — (291 ) Total other income/(expense) 1 (81 ) 94 (279 ) (265 ) Income/(Loss) Before Income Taxes 309 120 (47 ) (268 ) 114 Income tax expense/(benefit) 88 56 (130 ) 33 47 Net Income 221 64 83 (301 ) 67 Less: Net income attributable to noncontrolling interest and redeemable noncontrolling interest — 15 17 (31 ) 1 Net Income Attributable to NRG Energy, Inc. $ 221 $ 49 $ 66 $ (270 ) $ 66 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Nine Months Ended September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 7,959 $ 3,801 $ — $ (97 ) $ 11,663 Operating Costs and Expenses Cost of operations 6,083 2,554 10 (96 ) 8,551 Depreciation and amortization 590 568 15 — 1,173 Selling, general and administrative 351 280 247 — 878 Impairment losses 222 41 — — 263 Acquisition-related transaction and integration costs — 3 13 — 16 Development activity expenses — 43 66 — 109 Total operating costs and expenses 7,246 3,489 351 (96 ) 10,990 Gain on postretirement benefits curtailment — 14 — — 14 Operating Income/(Loss) 713 326 (351 ) (1 ) 687 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (35 ) (15 ) 432 (382 ) — Equity in earnings of unconsolidated affiliates 6 33 — (10 ) 29 Other income, net 3 23 3 (2 ) 27 Loss on debt extinguishment — (9 ) — — (9 ) Interest expense (13 ) (430 ) (412 ) — (855 ) Total other (expense)/income (39 ) (398 ) 23 (394 ) (808 ) Income/(Loss) Before Income Taxes 674 (72 ) (328 ) (395 ) (121 ) Income tax expense/(benefit) 225 (20 ) (281 ) 33 (43 ) Net Income/(Loss) 449 (52 ) (47 ) (428 ) (78 ) Less: Net income attributable to noncontrolling interest and redeemable noncontrolling interest — 15 21 (46 ) (10 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 449 $ (67 ) $ (68 ) $ (382 ) $ (68 ) (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 For the Three Months Ended September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 192 $ 176 $ 436 $ (411 ) $ 393 Other Comprehensive Income/(Loss), net of tax Unrealized gain on derivatives, net — 40 26 (39 ) 27 Foreign currency translation adjustments, net 2 2 4 (5 ) 3 Available-for-sale securities, net — — — — — Defined benefit plans, net 54 — (23 ) — 31 Other comprehensive income 56 42 7 (44 ) 61 Comprehensive Income 248 218 443 (455 ) 454 Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest — 13 34 (49 ) (2 ) Comprehensive Income Attributable to NRG Energy, Inc. 248 205 409 (406 ) 456 Comprehensive Income Available for Common Stockholders $ 248 $ 205 $ 409 $ (406 ) $ 456 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the Nine Months Ended September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 567 $ (2 ) $ 283 $ (684 ) $ 164 Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net — (15 ) 46 (39 ) (8 ) Foreign currency translation adjustments, net 4 4 6 (8 ) 6 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net 55 — (23 ) — 32 Other comprehensive income/(loss) 59 (11 ) 30 (47 ) 31 Comprehensive Income/(Loss) 626 (13 ) 313 (731 ) 195 Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (38 ) 70 (102 ) (70 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 626 25 243 (629 ) 265 Gain on redemption, net of dividends for preferred shares — — (73 ) — (73 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 626 $ 25 $ 316 $ (629 ) $ 338 (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 September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income $ 221 $ 64 $ 83 $ (301 ) $ 67 Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net (5 ) (24 ) 20 3 (6 ) Foreign currency translation adjustments, net — (6 ) (2 ) — (8 ) Available-for-sale securities, net — 12 (19 ) — (7 ) Defined benefit plans, net 4 (1 ) — — 3 Other comprehensive loss (1 ) (19 ) (1 ) 3 (18 ) Comprehensive Income 220 45 82 (298 ) 49 Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest — (3 ) 17 (31 ) (17 ) Comprehensive Income Attributable to NRG Energy, Inc. 220 48 65 (267 ) 66 Dividends for preferred shares — — 5 — 5 Comprehensive Income Available for Common Stockholders $ 220 $ 48 $ 60 $ (267 ) $ 61 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the Nine Months Ended September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 449 $ (52 ) $ (47 ) $ (428 ) $ (78 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net (10 ) (9 ) 29 (12 ) (2 ) Foreign currency translation adjustments, net — (6 ) (4 ) — (10 ) Available-for-sale securities, net — 11 (22 ) — (11 ) Defined benefit plans, net 1 (2 ) 10 — 9 Other comprehensive (loss)/income (9 ) (6 ) 13 (12 ) (14 ) Comprehensive Income/(Loss) 440 (58 ) (34 ) (440 ) (92 ) Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest — (9 ) 21 (46 ) (34 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 440 (49 ) (55 ) (394 ) (58 ) Dividends for preferred shares — — 15 — 15 Comprehensive Income/(Loss) Available for Common Stockholders $ 440 $ (49 ) $ (70 ) $ (394 ) $ (73 ) (a) All significant intercompany transactions have been eliminated in consolidation.
Condensed Consolidating Balance Sheets	NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS September 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ — $ 1,744 $ 691 $ — $ 2,435 Funds deposited by counterparties 6 10 — — 16 Restricted cash 10 470 — — 480 Accounts receivable - trade, net 880 482 — — 1,362 Accounts receivable - affiliate 308 (133 ) 173 (343 ) 5 Inventory 425 592 — — 1,017 Derivative instruments 700 384 — (120 ) 964 Cash collateral paid in support of energy risk management activities 206 131 — — 337 Renewable energy grant receivable, net — 34 — — 34 Prepayments and other current assets 70 237 57 — 364 Total current assets 2,605 3,951 921 (463 ) 7,014 Net property, plant and equipment 4,310 13,667 253 (27 ) 18,203 Other Assets Investment in subsidiaries 875 2,054 10,781 (13,710 ) — Equity investments in affiliates (14 ) 906 8 — 900 Notes receivable, less current portion — 21 — — 21 Goodwill 697 302 — — 999 Intangible assets, net 651 1,457 1 (3 ) 2,106 Nuclear decommissioning trust fund 605 — — — 605 Derivative instruments 231 80 6 (61 ) 256 Deferred income tax — 182 7 — 189 Other non-current assets 43 814 341 — 1,198 Total other assets 3,088 5,816 11,144 (13,774 ) 6,274 Total Assets $ 10,003 $ 23,434 $ 12,318 $ (14,264 ) $ 31,491 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 1,475 $ (254 ) $ — $ 1,221 Accounts payable 577 330 38 — 945 Accounts payable — affiliate 128 158 57 (343 ) — Derivative instruments 601 485 3 (120 ) 969 Cash collateral received in support of energy risk management activities 6 10 — — 16 Accrued expenses and other current liabilities 301 489 360 — 1,150 Total current liabilities 1,613 2,947 204 (463 ) 4,301 Other Liabilities Long-term debt and capital leases 244 10,011 7,763 — 18,018 Nuclear decommissioning reserve 284 — — — 284 Nuclear decommissioning trust liability 309 — — — 309 Deferred income taxes 1,068 (112 ) (909 ) — 47 Derivative instruments 233 303 — (61 ) 475 Out-of-market contracts, net 84 981 — — 1,065 Other non-current liabilities 361 787 332 — 1,480 Total non-current liabilities 2,583 11,970 7,186 (61 ) 21,678 Total liabilities 4,196 14,917 7,390 (524 ) 25,979 Redeemable noncontrolling interest in subsidiaries — 19 — — 19 Stockholders’ Equity 5,807 8,498 4,928 (13,740 ) 5,493 Total Liabilities and Stockholders’ Equity $ 10,003 $ 23,434 $ 12,318 $ (14,264 ) $ 31,491 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS December 31, 2015 Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ — $ 825 $ 693 $ — $ 1,518 Funds deposited by counterparties 55 51 — — 106 Restricted cash 5 409 — — 414 Accounts receivable - trade, net 851 304 2 — 1,157 Accounts receivable - affiliate 395 260 571 (1,222 ) 4 Inventory 570 682 — — 1,252 Derivative instruments 1,202 871 — (158 ) 1,915 Cash collateral paid in support of energy risk management activities 474 94 — — 568 Renewable energy grant receivable, net — 13 — — 13 Current assets held-for-sale — 6 — — 6 Prepayments and other current assets 93 274 71 — 438 Total current assets 3,645 3,789 1,337 (1,380 ) 7,391 Net Property, Plant and Equipment 4,767 13,773 219 (27 ) 18,732 Other Assets Investment in subsidiaries 842 2,244 11,039 (14,125 ) — Equity investments in affiliates (14 ) 1,160 1 (102 ) 1,045 Notes receivable, less current portion — 46 7 — 53 Goodwill 697 302 — — 999 Intangible assets, net 763 1,551 2 (6 ) 2,310 Nuclear decommissioning trust fund 561 — — — 561 Derivative instruments 153 184 — (32 ) 305 Deferred income taxes (6 ) 815 (642 ) — 167 Non-current assets held for sale — 105 — — 105 Other non-current assets 80 749 385 — 1,214 Total other assets 3,076 7,156 10,792 (14,265 ) 6,759 Total Assets $ 11,488 $ 24,718 $ 12,348 $ (15,672 ) $ 32,882 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ 2 $ 460 $ 19 $ — $ 481 Accounts payable 553 277 39 — 869 Accounts payable — affiliate 151 2,000 (929 ) (1,222 ) — Derivative instruments 1,130 749 — (158 ) 1,721 Cash collateral received in support of energy risk management activities 55 51 — — 106 Current liabilities held-for-sale — 2 — — 2 Accrued expenses and other current liabilities 319 429 449 (1 ) 1,196 Total current liabilities 2,210 3,968 (422 ) (1,381 ) 4,375 Other Liabilities Long-term debt and capital leases 302 10,496 8,185 — 18,983 Nuclear decommissioning reserve 326 — — — 326 Nuclear decommissioning trust liability 283 — — — 283 Deferred income taxes 179 (1,088 ) 928 — 19 Derivative instruments 301 224 — (32 ) 493 Out-of-market contracts, net 95 1,051 — — 1,146 Non-current liabilities held-for-sale — 4 — — 4 Other non-current liabilities 554 735 199 — 1,488 Total non-current liabilities 2,040 11,422 9,312 (32 ) 22,742 Total Liabilities 4,250 15,390 8,890 (1,413 ) 27,117 2.822% Preferred Stock — — 302 — 302 Redeemable noncontrolling interest in subsidiaries — 29 — — 29 Stockholders’ Equity 7,238 9,299 3,156 (14,259 ) 5,434 Total Liabilities and Stockholders’ Equity $ 11,488 $ 24,718 $ 12,348 $ (15,672 ) $ 32,882 (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 Nine Months Ended September 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 $ 567 $ (2 ) $ 283 $ (684 ) $ 164 Adjustments to reconcile net income/(loss) to net cash provided by operating activities: Distributions from unconsolidated affiliates — 65 — (8 ) 57 Equity in (earnings)/losses of unconsolidated affiliates (5 ) (20 ) 2 10 (13 ) Depreciation and amortization 372 588 19 — 979 Provision for bad debts 31 5 — — 36 Amortization of nuclear fuel 39 — — — 39 Amortization of financing costs and debt discount/premiums — (14 ) 17 — 3 Adjustment for debt extinguishment — 4 17 — 21 Amortization of intangibles and out-of-market contracts 32 41 — — 73 Amortization of unearned equity compensation — — 23 — 23 Impairment losses 8 262 — — 270 Changes in deferred income taxes and liability for uncertain tax benefits (134 ) (90 ) 253 — 29 Changes in nuclear decommissioning trust liability 24 — — — 24 Changes in derivative instruments (173 ) 258 (3 ) — 82 Changes in collateral deposits supporting energy risk management activities 268 (37 ) — — 231 Proceeds from sale of emission allowances 47 — — — 47 (Gain)/loss on sale of assets — (294 ) 70 (224 ) Cash (used)/provided by changes in other working capital (887 ) 305 (208 ) 682 (108 ) Net Cash Provided by Operating Activities 189 1,071 473 — 1,733 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. — — 59 (59 ) — Acquisition of September 2016 Drop Down Assets, net of cash acquired — (77 ) — 77 — Intercompany dividends — — 12 (12 ) — Acquisition of businesses, net of cash acquired — (18 ) — — (18 ) Capital expenditures (145 ) (713 ) (40 ) — (898 ) Increase in restricted cash, net (5 ) (25 ) — — (30 ) Increase in restricted cash — U.S. DOE funded projects — (36 ) — — (36 ) Decrease in notes receivable — 2 — — 2 Purchases of emission allowances (32 ) — — — (32 ) Proceeds from sale of emission allowances 47 — — — 47 Investments in nuclear decommissioning trust fund securities (378 ) — — — (378 ) Proceeds from sales of nuclear decommissioning trust fund securities 354 — — — 354 Proceeds from renewable energy grants and state rebates — 11 — — 11 Proceeds from sale of assets, net of cash disposed of — 619 17 — 636 Proceeds from (investments in) unconsolidated affiliates 2 (25 ) — — (23 ) Other 27 9 8 — 44 Net Cash (Used)/Provided by Investing Activities (130 ) (253 ) 56 6 (321 ) Cash Flows from Financing Activities Dividends from NRG Yield, Inc. — (59 ) — 59 — Payments (for)/from intercompany loans (2 ) (134 ) 136 — — Acquisition of September 2016 Drop Down Assets, net of cash acquired — — 77 (77 ) — Intercompany dividends (52 ) 40 — 12 — Payment of dividends to common and preferred stockholders — — (66 ) — (66 ) Payment for preferred shares — — (226 ) — (226 ) Net receipts from settlement of acquired derivatives that include financing elements — 129 — — 129 Proceeds from issuance of long-term debt — 1,097 4,140 — 5,237 Payments for short and long-term debt (2 ) (815 ) (4,540 ) — (5,357 ) Distributions from, net of contributions to, noncontrolling interest in subsidiaries — (127 ) — — (127 ) Proceeds from issuance of common stock — — 1 — 1 Payment of debt issuance costs — (17 ) (53 ) — (70 ) Other - contingent consideration (3 ) (7 ) — — (10 ) Net Cash (Used)/Provided by Financing Activities (59 ) 107 (531 ) (6 ) (489 ) Effect of exchange rate changes on cash and cash equivalents — (6 ) — — (6 ) Net Increase/(Decrease) in Cash and Cash Equivalents — 919 (2 ) — 917 Cash and Cash Equivalents at Beginning of Period — 825 693 — 1,518 Cash and Cash Equivalents at End of Period $ — $ 1,744 $ 691 $ — $ 2,435 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS For the Nine Months Ended September 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net Income/(Loss) $ 449 $ (52 ) $ (47 ) $ (428 ) $ (78 ) Adjustments to reconcile net loss to net cash provided by operating activities: Distributions from unconsolidated affiliates — 77 — (20 ) 57 Equity in earnings of unconsolidated affiliates (6 ) (33 ) — 10 (29 ) Depreciation and amortization 590 568 15 — 1,173 Provision for bad debts 46 — 3 — 49 Amortization of nuclear fuel 36 — — — 36 Amortization of financing costs and debt discount/premiums — (29 ) 20 (9 ) Adjustment for debt extinguishment — 9 — — 9 Amortization of intangibles and out-of-market contracts 43 25 — — 68 Amortization of unearned equity compensation — — 37 — 37 Changes in deferred income taxes and liability for uncertain tax benefits 218 (77 ) (213 ) — (72 ) Changes in nuclear decommissioning trust liability 1 — — — 1 Changes in derivative instruments 135 89 (44 ) — 180 Changes in collateral deposits supporting energy risk management activities (141 ) (39 ) — — (180 ) Gain on sale of emission allowances (6 ) — — — (6 ) Gain on postretirement benefits curtailment — (14 ) — — (14 ) Impairment losses 222 41 — — 263 Cash provided/(used) by changes in other working capital 1,048 (879 ) (702 ) 440 (93 ) Net Cash Provided/(Used) by Operating Activities 2,635 (314 ) (931 ) 2 1,392 Cash Flows from Investing Activities Acquisition of January 2015 Drop Down Assets, net of cash acquired — (489 ) — 489 — Dividends from NRG Yield, Inc. — — 52 (52 ) — Intercompany dividends — — 33 (33 ) — Acquisition of businesses, net of cash acquired — (31 ) — — (31 ) Capital expenditures (264 ) (595 ) (30 ) — (889 ) Increase in restricted cash, net (3 ) (38 ) — — (41 ) Decrease in restricted cash — U.S. DOE projects — 1 — — 1 Decrease in notes receivable — 10 — — 10 Purchases of emission allowances (40 ) — — — (40 ) Proceeds from sale of emission allowances 45 — — — 45 Investments in nuclear decommissioning trust fund securities (500 ) — — — (500 ) Proceeds from sales of nuclear decommissioning trust fund securities 499 — — — 499 Proceeds from renewable energy grants and state rebates — 62 — — 62 Proceeds from sale of assets, net of cash disposed of — — 1 — 1 Investments in unconsolidated affiliates 1 (317 ) (39 ) (2 ) (357 ) Other — 8 — — 8 Net Cash Used by Investing Activities (262 ) (1,389 ) 17 402 (1,232 ) Cash Flows from Financing Activities Proceeds from intercompany loans to subsidiaries (2,391 ) 1,178 1,213 — — Acquisition of January 2015 Drop Down Assets, net of cash acquired — — 489 (489 ) — Intercompany dividends — (33 ) — 33 — Payments of dividends from NRG Yield, Inc. — (52 ) — 52 — Payment of dividends to common and preferred stockholders — — (152 ) — (152 ) Payment for treasury stock — — (353 ) — (353 ) Net receipts for settlement of acquired derivatives that include financing elements — 138 — — 138 Proceeds from issuance of long-term debt — 635 44 — 679 Distributions from, net of contributions to, noncontrolling interest in subsidiaries — 651 — — 651 Proceeds from issuance of common stock — — 1 — 1 Payment of debt issuance costs — (14 ) — — (14 ) Payments for short and long-term debt — (938 ) (16 ) — (954 ) Other — (22 ) — — (22 ) Net Cash Provided by Financing Activities (2,391 ) 1,543 1,226 (404 ) (26 ) Effect of exchange rate changes on cash and cash equivalents — 15 — — 15 Net (Decrease)/Increase in Cash and Cash Equivalents (18 ) (145 ) 312 — 149 Cash and Cash Equivalents at Beginning of Period 18 1,455 643 — 2,116 Cash and Cash Equivalents at End of Period $ — $ 1,310 $ 955 $ — $ 2,265 (a) All significant intercompany transactions have been eliminated in consolidation.

Basis of Presentation Basis of

Basis of Presentation Basis of Presentation (Details) $ in Billions	12 Months Ended
	Dec. 31, 2015USD ($)	Sep. 30, 2016MW
Basis of Presentation [Abstract]
Power Generation Capacity, Megawatts | MW		46,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment, Period Increase (Decrease) | $	$ 1

Summary of Significant Accoun38

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Supplemental Info) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Allowance for Doubtful Accounts Receivable, Current	$ 28	$ 26
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	6,424	5,761
Finite-Lived Intangible Assets, Accumulated Amortization	1,729	1,590
Accumulated Amortization of Out of Market Contracts	740	$ 639
Capital expenditures accrued and unpaid	$ 112

Summary of Significant Accoun39

Summary of Significant Accounting Policies (NCI - Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Balance of Noncontrolling Interest	$ 2,451		$ 2,451		$ 2,727
Distributions to noncontrolling interest			(135)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	$ (2)	$ (17)	(70)	$ (34)
Redemption of noncontrolling interest			(7)
Contributions from noncontrolling interest			16
Noncontrolling Interest [Member]
Noncontrolling Interest [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest			(45)
NRG Yield, Inc. [Member]
Noncontrolling Interest [Line Items]
Distributions to noncontrolling interest			(68)
Noncontrolling Interest, Increase from Sale of Parent Equity Interest			$ (37)

Summary of Significant Accoun40

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Redeemable NCI - Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest in subsidiaries	$ 19		$ 19		$ 29
Redeemable Noncontrolling Interest, Distributions from Noncontrolling Interests			(46)
Contributions from redeemable noncontrolling interest			61
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	$ (2)	$ (17)	(70)	$ (34)
Redeemable noncontrolling interest [Member]
Noncontrolling Interest [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest			$ (25)

Business Acquisitions and Dis41

Business Acquisitions and Dispositions Business Acquisitions and Dispositions (Details 1 - Acquisitions) $ in Millions	Oct. 03, 2016USD ($)MW	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)MW	Sep. 30, 2015USD ($)	Jun. 30, 2015MW
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts			46,000
Desert Sunlight [Member]
Business Acquisition [Line Items]
Percentage of Ownership					25.00%
Power Generation Capacity, Megawatts					550
Payments to Acquire Businesses, Gross | $				$ 285
SunEdison Utility-Scale Solar and Wind [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross | $			$ 129
Business Combination, Contingent Consideration, Liability | $			$ 59
Mechanically-complete solar assets [Member] | SunEdison Utility-Scale Solar and Wind [Member]
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts			530
In-development solar and wind assets [Member] | SunEdison Utility-Scale Solar and Wind [Member]
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts			265
In-development wind assets [Member] | SunEdison Utility-Scale Solar and Wind [Member]
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts			937
Construction-ready solar facility [Member] | SunEdison Utility-Scale Solar and Wind [Member]
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts			154
Construction-ready and in-development solar assets [Member] | SunEdison Utility-Scale Solar and Wind [Member]
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts			182
Subsequent Event [Member] | SunEdison Hawaii Solar Assets [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross | $		$ 2
Subsequent Event [Member] | SunEdison Solar Distributed Generation [Member]
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts	29
Payments to Acquire Businesses, Gross | $	$ 68
Subsequent Event [Member] | In-development wind assets [Member] | SunEdison Utility-Scale Solar and Wind [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross | $		$ 111

Business Acquisitions and Dis42

Business Acquisitions and Dispositions Business Acquisitions and Dispositions (Details 2 - Dispositions)	Sep. 26, 2016USD ($)	Jul. 13, 2016USD ($)	Jun. 18, 2016USD ($)	May 13, 2016USD ($)	Mar. 02, 2016USD ($)	Feb. 03, 2016USD ($)	Nov. 25, 2015USD ($)	Nov. 10, 2015USD ($)	Sep. 30, 2016USD ($)MW	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)MW	Sep. 30, 2015USD ($)	Jul. 12, 2016USD ($)	Jun. 17, 2016USD ($)	May 12, 2016MW	Feb. 02, 2016USD ($)	Dec. 31, 2015USD ($)	Nov. 24, 2015MW	Nov. 09, 2015MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset Impairment Charges									$ 8,000,000			$ 263,000,000	$ 123,000,000	$ 263,000,000
Power Generation Capacity, Megawatts | MW									46,000				46,000
Disposal Group, Including Discontinued Operation, Other Assets, Current									$ 0				$ 0						$ 6,000,000
Disposal Group, Including Discontinued Operation, Liabilities, Current									0				0						2,000,000
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent									0				0						4,000,000
Gain (Loss) on Disposition of Assets														14,000,000
Long-term Debt									19,411,000,000				19,411,000,000						19,620,000,000
Gain on sale of assets and postretirement benefits curtailment, net									266,000,000			$ 0	215,000,000	$ 14,000,000
Equity investments in affiliates									900,000,000				$ 900,000,000						$ 1,045,000,000
Potrero LLC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property, Plant, and Equipment	$ 86,000,000
Gain (Loss) on Disposition of Assets									$ 74,000,000
EVgo [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses			$ 39,000,000
Capital Contributions From Partners in Equity Method Investment																$ 15,000,000
Future Capital Contributions From Partners in Equity Method Investment																$ 7,000,000
Future Revenue Rights			70,000,000
Gain on sale of assets and postretirement benefits curtailment, net										$ 78,000,000
Gain (Loss) on Sale of Equity Investments										27,000,000
Rockford [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of Ownership																	100.00%
Proceeds from Sale of Property, Plant, and Equipment		$ 56,000,000		$ 55,000,000
Base Residual Auction Results Adjustments															$ 1,000,000
Asset Impairment Charges										17,000,000
Power Generation Capacity, Megawatts | MW																	450
Aurora Generating Station [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property, Plant, and Equipment		$ 369,000,000		$ 365,000,000
Base Residual Auction Results Adjustments															$ 4,000,000
Power Generation Capacity, Megawatts | MW									878				878
Gain (Loss) on Disposition of Assets									$ 188,000,000
Seward Generating Station [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property, Plant, and Equipment						$ 75,000,000	$ 75,000,000
Disposal Group, Including Discontinued Operation, Cash																		$ 3,000,000
Amount of Continuing Cash Flow After Disposition						5,000,000
Power Generation Capacity, Megawatts | MW																				525
Shelby County Energy Center, LLC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property, Plant, and Equipment					$ 46,000,000			$ 46,000,000
Power Generation Capacity, Megawatts | MW																					352
Gain (Loss) on Disposition of Assets											$ 29,000,000
Future Revenue Rights											10,000,000
Receipt of Future Revenue Rights									7,000,000				$ 7,000,000
Robindale Energy Services, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term Purchase Commitment, Amount											$ 13,000,000
Annual [Member] | Seward Generating Station [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount of Continuing Cash Flow After Disposition						1,000,000
Environmental Testing [Member] | Seward Generating Station [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount of Continuing Cash Flow After Disposition						$ 2,500,000
Cash [Member] | Potrero LLC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property, Plant, and Equipment	74,000,000
Cash [Member] | EVgo [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses			17,000,000
Closing costs [Member] | Potrero LLC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property, Plant, and Equipment	8,000,000
Post-closing obligations [Member] | Potrero LLC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Property, Plant, and Equipment	$ 4,000,000
Working Capital Adjustment [Member] | EVgo [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses			$ 2,500,000
CPUC [Member] | EVgo [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Litigation Settlement, Amount													$ 102,500,000
Loss Contingency, Number of Fast Charge Stations to Be Installed in California													200
Loss Contingency, Number of Parking Spaces Required													10,000
Loss Contingency Accrual									$ 50,000,000	$ 56,000,000			$ 50,000,000
EVgo [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity Method Investment, Ownership Percentage									35.00%				35.00%
Equity investments in affiliates									$ 10,000,000				$ 10,000,000

Business Acquisitions and Dis43

Business Acquisitions and Dispositions Business Acquisitions and Dispositions (Details 3 - Transfer of Assets) (Details) $ in Millions	Sep. 30, 2016USD ($)MW	Sep. 01, 2016USD ($)	Dec. 31, 2015USD ($)	Nov. 02, 2015USD ($)facilityMW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term Debt	$ 19,411		$ 19,620
Power Generation Capacity, Megawatts | MW	46,000
CVSR [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of Ownership Sold of Subsidiary		51.05%
Consideration Paid for Sale of Assets Under Common Control		$ 78.5
ROFO Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of Ownership Sold of Subsidiary				75.00%
Consideration Paid for Sale of Assets Under Common Control				$ 209
Long-term Debt				$ 193
Number of Facilities | facility				12
Power Generation Capacity, Megawatts | MW				814
Consideration Paid for Sale of Assets Under Common Control, net of Working Capital Adjustments				$ 207
Financial Institutions [Member] | ROFO Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value				159
Working Capital Adjustment [Member] | ROFO Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration Paid for Sale of Assets Under Common Control				$ 2
NRG Yield, Inc. [Member] | CVSR [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term Debt		$ 496

Fair Value of Financial Instr44

Fair Value of Financial Instruments (Details 1 - Balance Sheet grouping) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion (b)		$ 19,411	$ 19,620
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes receivable	[1]	50	73
Long-term debt, including current portion (b)	[2]	19,411	19,620
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes receivable	[1]	50	73
Long-term debt, including current portion (b)	[2]	18,888	18,263
Fair Value, Inputs, Level 2 [Member] | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion (b)		11,767	11,028
Fair Value, Inputs, Level 3 [Member] | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion (b)		$ 7,121	$ 7,235
[1]	Includes the current portion of notes receivable which is recorded in prepayments and other current assets on the Company's consolidated balance sheets
[2]	Excludes deferred financing costs, which are recorded as a reduction to long-term debt on the Company's consolidated balance sheets.

Fair Value of Financial Instr45

Fair Value of Financial Instruments (Details 2 - Recurring FV) - USD ($) $ in Millions	Sep. 30, 2016		Dec. 31, 2015
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	$ 1,220		$ 2,220
Derivative Liabilities	1,444		2,214
Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	1,213		2,220
Derivative Liabilities	1,281		2,086
Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	7
Derivative Liabilities	163		128
Fair Value, Measurements, Recurring
Fair Value Assets and Liabilities, Measured on Recurring Basis
Debt securities	17		17
Available-for-sale securities	10		9
Other (a)	10	[1]	14	[2]
Total assets	1,863		2,822
Derivative Liabilities	1,444		2,214
Fair Value, Measurements, Recurring | Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	1,213		2,220
Derivative Liabilities	1,281		2,086
Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	7
Derivative Liabilities	163		128
Fair Value, Measurements, Recurring | Cash and cash equivalents
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	24		6
Fair Value, Measurements, Recurring | U.S. government and federal agency obligations
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	52		55
U.S. government and federal agency obligations	1		1
Fair Value, Measurements, Recurring | Federal agency mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	68		59
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	17		25
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	87		81
Fair Value, Measurements, Recurring | Equity securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	355		334
Fair Value, Measurements, Recurring | Foreign government fixed income securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	2		1
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring
Fair Value Assets and Liabilities, Measured on Recurring Basis
Debt securities	17		17
Available-for-sale securities	0		0
Other (a)	0	[1]	0	[2]
Total assets	178		220
Derivative Liabilities	133		182
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	107		149
Derivative Liabilities	133		182
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	0
Derivative Liabilities	0		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Cash and cash equivalents
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | U.S. government and federal agency obligations
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
U.S. government and federal agency obligations	0		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Federal agency mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Equity securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	54		54
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Foreign government fixed income securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring
Fair Value Assets and Liabilities, Measured on Recurring Basis
Debt securities	0		0
Available-for-sale securities	0		0
Other (a)	0	[1]	0	[2]
Total assets	980		1,616
Derivative Liabilities	936		1,164
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	798		1,449
Derivative Liabilities	773		1,036
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	7
Derivative Liabilities	163		128
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Cash and cash equivalents
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | U.S. government and federal agency obligations
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	1		1
U.S. government and federal agency obligations	0		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Federal agency mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	68		59
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	17		25
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	87		81
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Equity securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Foreign government fixed income securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	2		1
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring
Fair Value Assets and Liabilities, Measured on Recurring Basis
Debt securities	0		0
Available-for-sale securities	10		9
Other (a)	10	[1]	14	[2]
Total assets	705		986
Derivative Liabilities	375		868
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	308		622
Derivative Liabilities	375		868
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	0
Derivative Liabilities	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Cash and cash equivalents
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	24		6
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | U.S. government and federal agency obligations
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	51		54
U.S. government and federal agency obligations	1		1
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Federal agency mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Equity securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	301		280
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Foreign government fixed income securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	$ 0		$ 0
[1]	Consists primarily of mutual funds held in a Rabbi Trust for non-qualified deferred compensation plans for certain former employees.
[2]	Primarily consists of mutual funds held in rabbi trusts for non-qualified deferred compensation plans for certain former employees and a total return swap that does not meet the definition of a derivative.

Fair Value of Financial Instr46

Fair Value of Financial Instruments (Details 3 - Level 3 FV) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2016		Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015		Jun. 30, 2016		Dec. 31, 2015		Jun. 30, 2015		Dec. 31, 2014
Fair Value Asset and Liabilities, Measured on Recurring Basis Unobservable Input, Changes
No transfers from Level 1 to Level 2		$ 0		$ 0		$ 0		$ 0
No transfers from Level 2 to Level 1		0		0		0		0
Fair Value, Inputs, Level 3 [Member]
Reconciliation of the beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs		45		100		45		100		$ 74		$ 38		$ 122		$ 161
Total gains/(losses) - realized/unrealized:
Included in earnings		2		(17)		9		(106)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		1				0
Included in nuclear decommissioning obligation		3		(6)		(1)		(4)
Purchases		(26)		9		4		45
Transfers into Level 3 (b)		(12)	[1]	(10)	[2]	(5)	[1]	1	[2]
Transfers out of Level 3 (b)		3	[1]	2	[2]	0	[1]	3	[2]
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 September 30, 2015		1		(9)		(14)		(37)
Fair Value, Inputs, Level 3 [Member] | Debt Securities
Reconciliation of the beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs		17		18		17		18		16		17		18		18
Total gains/(losses) - realized/unrealized:
Included in earnings		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		1				0
Included in nuclear decommissioning obligation		0		0		0		0
Purchases		0		0		0		0
Transfers into Level 3 (b)		0	[1]	0	[2]	0	[1]	0	[2]
Transfers out of Level 3 (b)		0	[1]	0	[2]	0	[1]	0	[2]
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 September 30, 2015		0		0		0		0
Fair Value, Inputs, Level 3 [Member] | Other Financial Instrument [Member]
Reconciliation of the beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs				0				0						0		11
Total gains/(losses) - realized/unrealized:
Included in earnings				0				(11)
Included in nuclear decommissioning obligation				0				0
Purchases				0				0
Transfers into Level 3 (b)	[2]			0				0
Transfers out of Level 3 (b)	[2]			0				0
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 September 30, 2015				0				0
Fair Value, Inputs, Level 3 [Member] | Trust Fund Investments
Reconciliation of the beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs		54		49		54		49		51		54		55		52
Total gains/(losses) - realized/unrealized:
Included in earnings		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		0				0
Included in nuclear decommissioning obligation		3		(6)		(1)		(4)
Purchases		0		0		1		1
Transfers into Level 3 (b)		0	[1]	0	[2]	0	[1]	0	[2]
Transfers out of Level 3 (b)		0	[1]	0	[2]	0	[1]	0	[2]
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 September 30, 2015		0		0		0		0
Fair Value, Inputs, Level 3 [Member] | Derivatives(a)
Reconciliation of the beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs		(26)	[3]	33	[4]	(26)	[3]	33	[4]	$ 7	[3]	$ (33)	[3]	$ 49	[4]	$ 80	[4]
Total gains/(losses) - realized/unrealized:
Included in earnings		2	[3]	(17)	[4]	9	[3]	(95)	[4]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	[3]	0				0
Included in nuclear decommissioning obligation		0	[3]	0	[4]	0	[3]	0	[4]
Purchases		(26)	[3]	9	[4]	3	[3]	44	[4]
Transfers into Level 3 (b)		(12)	[1],[3]	(10)	[2],[4]	(5)	[1],[3]	1	[2],[4]
Transfers out of Level 3 (b)		3	[1],[3]	2	[2],[4]	0	[1],[3]	3	[2],[4]
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 September 30, 2015		$ 1	[3]	$ (9)	[4]	$ (14)	[3]	$ (37)	[4]
[1]	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.
[2]	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.
[3]	Consists of derivative assets and liabilities, net.
[4]	Consists of derivative assets and liabilities, net.

Fair Value of Financial Instr47

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details 4 - Derivative FV Measurements) $ / T in Millions, $ / MWh in Millions, $ in Millions	Sep. 30, 2016USD ($)$ / T$ / MWh	Dec. 31, 2015USD ($)$ / T$ / MWh	Sep. 30, 2015USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total derivative assets valued with prices provied by models and other valuation techniques (as a percent)	9.00%
Total derivative liabilities valued with prices provied by models and other valuation techniques (as a percent)	9.00%
Derivative Asset, Fair Value, Gross Asset	$ 1,220	$ 2,220
Derivative Liability, Fair Value, Gross Liability	1,444	2,214
Valuation Allowances and Reserves, Balance	2		$ 7
Increase in fair value as a result of the credit reserve, portion recorded in OCI	3		4
Increase in fair value as a result of the credit reserve, portion recorded in operating revenue and cost of operations	5		$ 3
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Gross Liability	1,444	2,214
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Gross Liability	133	182
Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,213	2,220
Derivative Liability, Fair Value, Gross Liability	1,281	2,086
Commodity contracts | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,213	2,220
Derivative Liability, Fair Value, Gross Liability	1,281	2,086
Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	107	149
Derivative Liability, Fair Value, Gross Liability	133	182
Power Contracts [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	53	86
Derivative Liability, Fair Value, Gross Liability	78	100
Coal Contract [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	5	12
Financial Transmission Rights [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	54	63
Derivative Liability, Fair Value, Gross Liability	$ 50	$ 70
Minimum [Member] | Power Contracts [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Forward Price | $ / MWh	11	10
Minimum [Member] | Coal Contract [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Forward Price | $ / T	44	28
Minimum [Member] | Financial Transmission Rights [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Auction Price | $ / MWh	63	98
Maximum [Member] | Power Contracts [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Forward Price | $ / MWh	81	92
Maximum [Member] | Coal Contract [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Forward Price | $ / T	44	45
Maximum [Member] | Financial Transmission Rights [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Auction Price | $ / MWh	55	87
Weighted Average [Member] | Power Contracts [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Forward Price | $ / MWh	27	27
Weighted Average [Member] | Coal Contract [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Forward Price | $ / T	44	35
Weighted Average [Member] | Financial Transmission Rights [Member] | Commodity contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Auction Price | $ / MWh	0	0

Fair Value of Financial Instr48

Fair Value of Financial Instruments (Details 5 - Credit Risk) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
Concentration of Credit Risk
Counterparty credit exposure to a portion of the Company's counterparties	$ 635
Collateral held (cash and letters of credit) against counterparty credit exposure to a portion of the Company's counterparties	45
Net counterparty credit exposure to a portion of the Company's counterparties	$ 607
Company's exposure before collateral is expected to roll off by the end of 2014 (as a percent)	79.00%
Net Exposure (as a percent)	100.00%	[1]
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	$ 295
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	$ 4,100
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)	90.00%	[1]
Non-rated (b)
Concentration of Credit Risk
Net Exposure (as a percent)	3.00%	[1],[2]
External Credit Rating, Non Investment Grade [Member]
Concentration of Credit Risk
Net Exposure (as a percent)	7.00%	[1]
Financial institutions
Concentration of Credit Risk
Net Exposure (as a percent)	33.00%	[1]
Utilities, energy merchants, marketers and other
Concentration of Credit Risk
Net Exposure (as a percent)	42.00%	[1]
ISOs
Concentration of Credit Risk
Net Exposure (as a percent)	25.00%	[1]
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	$ 2,600
[1]	Counterparty credit exposure excludes uranium and coal transportation contracts because of the unavailability of market prices.
[2]	For non-rated counterparties, a significant portion are related to ISO and municipal public power entities, which are considered investment grade equivalent ratings based on NRG's internal credit ratings.

Nuclear Decommissioning Trust49

Nuclear Decommissioning Trust Fund (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Nuclear decommissioning trust fund disclosure
Fair Value	$ 605		$ 561
Unrealized Gains	222		202
Unrealized Losses	2		3
Realized gains	7	$ 14
Realized losses	3	10
Proceeds from sale of securities	354	$ 499
Cash and Cash Equivalents [Member]
Nuclear decommissioning trust fund disclosure
Fair Value	24		6
Unrealized Gains	0		0
Unrealized Losses	$ 0		$ 0
Weighted-average Maturities (In years)	0 years		0 years
U.S. government and federal agency obligations
Nuclear decommissioning trust fund disclosure
Fair Value	$ 52		$ 55
Unrealized Gains	4		1
Unrealized Losses	$ 0		$ 0
Weighted-average Maturities (In years)	11 years		11 years
Federal agency mortgage-backed securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 68		$ 59
Unrealized Gains	2		1
Unrealized Losses	$ 0		$ 0
Weighted-average Maturities (In years)	25 years		25 years
Commercial mortgage-backed securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 17		$ 25
Unrealized Gains	0		0
Unrealized Losses	$ 1		$ 2
Weighted-average Maturities (In years)	26 years		28 years
Corporate debt securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 87		$ 81
Unrealized Gains	3		1
Unrealized Losses	$ 1		$ 1
Weighted-average Maturities (In years)	11 years		10 years
Equity securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 355		$ 334
Unrealized Gains	213		199
Unrealized Losses	$ 0		$ 0
Weighted-average Maturities (In years)	0 years		0 years
Foreign government fixed income securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 2		$ 1
Unrealized Gains	0		0
Unrealized Losses	$ 0		$ 0
Weighted-average Maturities (In years)	9 years		9 years

Accounting for Derivative Ins50

Accounting for Derivative Instruments and Hedging Activities (Details 1 - Underlying Derivatives and FV of Derivatives) shares in Millions, bbl in Millions, T in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016USD ($)MWhMMBTUTsharesbbl	Dec. 31, 2015USD ($)MWhMMBTUTsharesbbl
Fair Value of Derivative Instrument
Derivative Assets	$ 1,220	$ 2,220
Derivative Liabilities	1,444	2,214
Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	1	0
Derivative Liabilities	130	110
Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	1,219	2,220
Derivative Liabilities	1,314	2,104
Interest rate contracts current | Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	0	0
Derivative Liabilities	31	42
Interest rate contracts current | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	0	0
Derivative Liabilities	8	5
Interest rate contracts long-term | Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	1	0
Derivative Liabilities	99	68
Interest rate contracts long-term | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	6	0
Derivative Liabilities	25	13
Commodity contracts current | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	964	1,915
Derivative Liabilities	930	1,674
Commodity contracts long-term | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	249	305
Derivative Liabilities	$ 351	$ 412
Long [Member] | Emissions | Short Ton [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Mass | T	1	1
Long [Member] | Coal | Short Ton [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Mass | T	29	35
Long [Member] | Natural Gas | MMbtu [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	(73)	(293)
Long [Member] | Oil | Barrel [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Volume | bbl	0	1
Long [Member] | Interest | United States of America, Dollars
Volumetric Underlying Derivative Transactions
Derivative, Notional Amount	$ 3,219	$ 2,326
Long [Member] | Equity | Shares [Member]
Volumetric Underlying Derivative Transactions
Derivative, Non-monetary Notional Amount, Other | shares	1	1
Short [Member] | Power | M Wh [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Energy Measure | MWh	(35)	(74)
Short [Member] | Capacity | MW/Day [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Energy Measure | MWh	(1)	(1)

Accounting for Derivative Ins51

Accounting for Derivative Instruments and Hedging Activities (Details 2 - Offsetting Derivatives) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets	$ 1,220	$ 2,220
Cash Collateral (Held) / Posted	(16)	(106)
Gross Amounts of Recognized Derivative Liabilities	(1,444)	(2,214)
Cash Collateral Posted	337	568
Gross Amounts of Recognized Assets / Liabilities	(224)	6
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	98	158
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	(126)	164
Commodity contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets	1,213	2,220
Derivative Instruments	(1,027)	(1,616)
Cash Collateral (Held) / Posted	(23)	(113)
Net Amount	163	491
Gross Amounts of Recognized Derivative Liabilities	(1,281)	(2,086)
Derivative Instruments	1,027	1,616
Cash Collateral Posted	121	271
Derivative Liability, Fair Value, Amount Offset Against Collateral	(133)	(199)
Gross Amounts of Recognized Assets / Liabilities	(68)	134
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	98	158
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	30	292
Interest rate contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets	7
Derivative Instruments	(4)
Cash Collateral (Held) / Posted	0
Net Amount	3
Gross Amounts of Recognized Derivative Liabilities	(163)	(128)
Derivative Instruments	4	0
Cash Collateral Posted	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(159)	$ (128)
Gross Amounts of Recognized Assets / Liabilities	(156)
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0
Derivative, Collateral, Obligation to Return Cash Net Of Derivative, Collateral, Right to Reclaim Cash	0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	$ (156)

Accounting for Derivative Ins52

Accounting for Derivative Instruments and Hedging Activities (Details 3 - AOCI) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Effects of ASC 815 on NRG's Accumulated OCI Balance Attributable to Cash Flow Hedge Derivatives, net of tax
Accumulated OCI beginning balance	$ (165)	$ (63)	$ (101)	$ (68)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	2	4	12	8
Mark-to-market of cash flow hedge accounting contracts	32	(33)	(42)	(32)
Accumulated OCI ending balance, net of tax	(131)	(92)	(131)	(92)
Gains/(losses) expected to be realized from OCI during the next 12 months, net of tax	17		17
Accumulated OCI ending balance, tax	28	54	28	54
Gains/(losses) expected to be realized from OCI during the next 12 months, tax	4	0	4	0
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	0	0	0	0
Commodity contracts
Effects of ASC 815 on NRG's Accumulated OCI Balance Attributable to Cash Flow Hedge Derivatives, net of tax
Accumulated OCI beginning balance	0	(1)	0	(1)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	1	0	1
Mark-to-market of cash flow hedge accounting contracts	0	0	0	0
Accumulated OCI ending balance, net of tax	0	0	0	0
Gains/(losses) expected to be realized from OCI during the next 12 months, net of tax	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	(165)	(62)	(101)	(67)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	2	3	12	7
Mark-to-market of cash flow hedge accounting contracts	32	(33)	(42)	(32)
Accumulated OCI ending balance, net of tax	(131)	$ (92)	(131)	$ (92)
Gains/(losses) expected to be realized from OCI during the next 12 months, net of tax	$ 17		$ 17

Accounting for Derivative Ins53

Accounting for Derivative Instruments and Hedging Activities Accounting for Derivative Instruments and Hedging Activities (Details 4 - mark to market) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Unrealized mark-to-market results
Reversal of previously recognized unrealized gains on settled positions related to economic hedges	$ (44)		$ (29)	$ (182)	$ (179)
Reversal of acquired gain positions related to economic hedges	(19)		(33)	(47)	(83)
Net unrealized (losses)/gains on open positions related to economic hedges	(121)		55	(19)	(26)
Total unrealized mark-to-market losses for economic hedging activities	(184)		(7)	(248)	(288)
Reversal of previously recognized unrealized losses/(gains) on settled positions related to trading activity	3		2	13	(34)
Reversal of acquired gain positions related to trading activity	0		(1)	0	(13)
Net unrealized (losses)/gains on open positions related to trading activity	(8)		(2)	14	0
Total unrealized mark-to-market (losses)/gains for trading activity	(5)		(1)	27	(47)
Impact of derivative instruments on statement of operations
Total unrealized losses	(189)		(8)	(221)	(335)
Credit Risk Related Contingent Features
Derivative Liability, Fair Value of Collateral	73			73
Derivative, Net Liability Position, Collateral Required Contracts with Credit Rating Contingent Feature	42			42
Collateral due on net liability position that has not been called by a certain marginable agreement counterparty	10			10
Realized Gain [Member]
Impact of derivative instruments on statement of operations
Derivative Instruments Not Designated as Hedging Instruments, Gain	98	$ 38
Commodity contracts
Impact of derivative instruments on statement of operations
Total unrealized losses	(189)		(8)	(221)	(335)
Commodity contracts | Sales [Member]
Impact of derivative instruments on statement of operations
Total unrealized losses	(84)		34	(565)	(212)
Commodity contracts | Cost of Sales [Member]
Impact of derivative instruments on statement of operations
Total unrealized losses	(105)		(42)	344	(123)
Interest rate contracts
Impact of derivative instruments on statement of operations
Total unrealized losses	9		$ (9)	$ (9)	$ 12
2016 [Member] | Realized Gain [Member]
Impact of derivative instruments on statement of operations
Derivative Instruments Not Designated as Hedging Instruments, Gain		18
2017 [Member] | Realized Gain [Member]
Impact of derivative instruments on statement of operations
Derivative Instruments Not Designated as Hedging Instruments, Gain	82	19
2018 [Member] | Realized Gain [Member]
Impact of derivative instruments on statement of operations
Derivative Instruments Not Designated as Hedging Instruments, Gain	13	$ 1
2019 [Member] | Realized Gain [Member]
Impact of derivative instruments on statement of operations
Derivative Instruments Not Designated as Hedging Instruments, Gain	$ 3

Impairments (Details)

Impairments (Details) - USD ($) $ in Millions	Jul. 13, 2016	May 13, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	May 12, 2016
Asset Impairment Charges			$ 8			$ 263	$ 123	$ 263
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net			$ 8			$ 0	147	$ 0
Residential Solar [Member]
Asset Impairment Charges							$ 8
Petra Nova Parish Holdings [Member]
Equity Method Investment, Ownership Percentage			50.00%				50.00%
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net					$ 140
Rockford [Member]
Percentage of Ownership									100.00%
Proceeds from Sale of Property, Plant, and Equipment	$ 56	$ 55
Asset Impairment Charges				$ 17
Deferred Marketing Expenses [Member]
Asset Impairment Charges							$ 10
Mandalay operating unit [Member]
Asset Impairment Charges				16
Ormond Beach operating unit [Member]
Asset Impairment Charges				$ 43
Solar Panels [Member]
Asset Impairment Charges							$ 17

Debt and Capital Leases (Detail

Debt and Capital Leases (Details 1 - Debt Table) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Dec. 31, 2016	Jun. 30, 2016	Sep. 30, 2016		Nov. 04, 2016	Dec. 31, 2015
Debt and Capital Leases
Long-term Debt				$ 19,411			$ 19,620
Capital Lease Obligations				11			16
Subtotal				19,422			19,636
Less current maturities				1,221			481
Deferred Finance Costs, Net				183			172
Total long-term debt and capital leases				$ 18,018			18,983
Interest rate, variable basis				3 month LIBOR
Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 8,168			8,584
Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				11,243			11,036
Senior Notes Due In 2018 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased				455
Debt Instrument, Repurchase Amount	[1]			$ 502
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed				107.95%
Long-term Debt				$ 584			1,039
Debt Instrument, Interest Rate, Stated Percentage	[2]			7.625%
Senior Notes Due In 2020 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased				$ 1,058
Debt Instrument, Repurchase Amount	[1]			$ 1,129
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed				103.12%
Long-term Debt				$ 0			1,058
Debt Instrument, Interest Rate, Stated Percentage	[2]			8.25%
Senior Notes Due In 2021 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased				$ 729
Debt Instrument, Repurchase Amount	[1]			$ 771
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed				104.02%
Long-term Debt				$ 399			1,128
Debt Instrument, Interest Rate, Stated Percentage	[2]			7.875%
Senior Notes Due In 2022 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased				$ 108
Debt Instrument, Repurchase Amount	[1]			$ 105
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed				94.73%
Long-term Debt				$ 992			1,100
Debt Instrument, Interest Rate, Stated Percentage	[2]			6.25%
Senior Notes Due in 2023 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased				$ 67
Debt Instrument, Repurchase Amount	[1]			$ 64
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed				94.13%
Long-term Debt				$ 869			936
Debt Instrument, Interest Rate, Stated Percentage	[2]			6.625%
Senior Notes 2024 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased				$ 171
Debt Instrument, Repurchase Amount	[1]			$ 163
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed				94.52%
Long-term Debt				$ 733			904
Debt Instrument, Interest Rate, Stated Percentage	[2]			6.25%
Senior Notes due 2026 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 1,000			0
Debt Instrument, Interest Rate, Stated Percentage			7.25%	7.25%	[2]
Senior Notes due 2027 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 1,250			0
Debt Instrument, Interest Rate, Stated Percentage	[2]			6.625%
Senior Credit Facility Due 2018 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 0			1,964
Term Loan Facility Due 2023 [Member]
Debt and Capital Leases
Interest rate, variable basis				1 - month LIBOR
Term Loan Facility Due 2023 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 1,886			0
Tax-exempt Bonds [Member] | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 455			455
Indian River Power LLC, tax-exempt bonds, due 2040 | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			6.00%
Indian River Power LLC, tax-exempt bonds, due 2045 | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			5.375%
Dunkirk Power LLC, tax-exempt bonds, due 2042 | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			5.875%
Fort Bend County, tax-exempt bonds, due 2038 and 2042 | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			4.125%
GenOn Senior Notes [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 1,922			1,956
GenOn Senior Notes Due in 2017 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			7.875%
GenOn senior notes, due 2018 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			9.50%
GenOn senior notes, due 2020 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			9.875%
GenOn Americas Generation Senior Notes [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 747			752
GenOn Americas Generation Senior Notes Due in 2021 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			8.50%
GenOn Americas Generation senior notes, due in 2031 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			9.125%
GenOn Other [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 52			56
Genon [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				2,721			2,764
5.375% Senior Notes due in 2024 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 500			500
Debt Instrument, Interest Rate, Stated Percentage	[2]			5.375%
5.00% Senior Notes due in 2026 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 350			0
Debt Instrument, Interest Rate, Stated Percentage	[2]			5.00%
NRG Yield Revolving Credit Facility [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 0			306
3.5% Convertible Notes due 2019 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 334			330
Debt Instrument, Interest Rate, Stated Percentage	[2]			3.50%
3.25% Convertible Notes due 2020 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 270			266
Debt Instrument, Interest Rate, Stated Percentage	[2]			3.25%
West Holdings Credit Agreement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 443			485
Marsh Landing Term Loan Facility [Member]
Debt and Capital Leases
Interest rate, variable basis				1 - month LIBOR
Marsh Landing Term Loan Facility [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 385			418
Alta Wind I - V Lease financing arrangement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 978			1,002
Alta Wind I [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			7.015%
Alta Wind II [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			5.696%
Alta Wind III [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			6.067%
Alta Wind IV [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			5.938%
Alta Wind V [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			6.071%
Walnut Creek Energy, LLC, due in 2023 [Member]
Debt and Capital Leases
Interest rate, variable basis				1 - month LIBOR
Walnut Creek Energy, LLC, due in 2023 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 322			351
Interest rate, variable basis	[2]			LIBOR
Tapestry Wind LLC due in 2021 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 175			181
Interest rate, variable basis	[2]			LIBOR
CVSR due 2037 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 771			793
CVSR Holdco due 2037 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 199			0
Debt Instrument, Interest Rate, Stated Percentage	[2]			4.68%
NRG Solar Alpine LLC, due 2022
Debt and Capital Leases
Interest rate, variable basis				1 - month LIBOR
NRG Solar Alpine LLC, due 2022 | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 147			154
NRG Energy Center Minneapolis LLC, senior secured notes, due 2013, 2017, and 2025 | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 98			108
NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2025 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			5.95%
Viento Funding II, Inc., due in 2023 [Member]
Debt and Capital Leases
Interest rate, variable basis				6 - month LIBOR
Viento Funding II, Inc., due in 2023 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 183			189
Interest rate, variable basis	[2]			LIBOR
NRG Yield - Other [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 549			573
NRG Yield, Inc. | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				5,704			5,656
Ivanpah Financing, due 2014 and 2038 | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				1,135			1,149
Agua Caliente Solar LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				864			879
NRG Solar Dandan [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				100			98
NRG Peaker Finance Co. LLC Bonds Due 2019 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 0			72
Interest rate, variable basis	[2]			LIBOR
Cedro Hill Wind LLC, due in 2025 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 165			103
Interest rate, variable basis	[2]			LIBOR
Midwest Generation due 2019 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 234			0
Debt Instrument, Interest Rate, Stated Percentage	[2]			4.39%
Other (Non-recourse debt) | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				$ 320			315
NRG Energy [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt				2,818			$ 2,616
Senior Notes [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased				2,588
Debt Instrument, Repurchase Amount	[1]			2,734
Long-term Debt				$ 5,800
London Interbank Offered Rate (LIBOR) [Member] | Senior Credit Facility Due 2018 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Interest rate, variable basis	[2]			LIBOR
Interest rate, basis spread on variable rate	[2]			2.00%
London Interbank Offered Rate (LIBOR) [Member] | Term Loan Facility Due 2023 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Interest rate, variable basis	[2]		LIBOR	LIBOR
Interest rate, basis spread on variable rate	[2]		2.75%	2.75%
London Interbank Offered Rate (LIBOR) [Member] | NRG Yield Revolving Credit Facility [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, variable basis	[2]			LIBOR
Interest rate, basis spread on variable rate	[2]			2.75%
London Interbank Offered Rate (LIBOR) [Member] | West Holdings Credit Agreement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, variable basis	[2]			LIBOR
London Interbank Offered Rate (LIBOR) [Member] | Marsh Landing Term Loan Due 2017 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, variable basis	[2]			LIBOR
Interest rate, basis spread on variable rate	[2]			1.175%
London Interbank Offered Rate (LIBOR) [Member] | GenOn Marsh Landing term loan, due 2023 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, variable basis	[2]			LIBOR
Interest rate, basis spread on variable rate	[2]			1.875%
London Interbank Offered Rate (LIBOR) [Member] | Walnut Creek Energy, LLC, due in 2023 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, basis spread on variable rate	[2]			1.625%
London Interbank Offered Rate (LIBOR) [Member] | Tapestry Wind LLC due in 2021 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, basis spread on variable rate	[2]			1.625%
London Interbank Offered Rate (LIBOR) [Member] | NRG Solar Alpine LLC, due 2022 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, variable basis	[2]			LIBOR
Interest rate, basis spread on variable rate	[2]			1.75%
London Interbank Offered Rate (LIBOR) [Member] | Viento Funding II, Inc., due in 2023 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, basis spread on variable rate	[2]			2.75%
London Interbank Offered Rate (LIBOR) [Member] | NRG Solar Dandan [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, variable basis	[2]			LIBOR
Interest rate, basis spread on variable rate	[2]			2.25%
London Interbank Offered Rate (LIBOR) [Member] | NRG Peaker Finance Co. LLC Bonds Due 2019 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, basis spread on variable rate	[2]			1.07%
London Interbank Offered Rate (LIBOR) [Member] | Cedro Hill Wind LLC, due in 2025 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, basis spread on variable rate	[2]			1.75%
Minimum [Member] | CVSR due 2037 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			2.339%
Minimum [Member] | NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2017 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			7.12%
Minimum [Member] | Ivanpah Financing, due 2014 and 2038 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			2.285%
Minimum [Member] | Agua Caliente Solar LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			2.395%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | West Holdings Credit Agreement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			1.625%
Maximum [Member] | CVSR due 2037 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			3.775%
Maximum [Member] | NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2017 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			7.25%
Maximum [Member] | Ivanpah Financing, due 2014 and 2038 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			4.256%
Maximum [Member] | Agua Caliente Solar LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			3.633%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | West Holdings Credit Agreement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[2]			2.25%
Subsequent Event [Member] | Senior Notes Due In 2018 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased	[3]					$ 186
Debt Instrument, Repurchase Amount	[1],[3]					204
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	[3]	107.75%
Subsequent Event [Member] | Senior Notes Due In 2021 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased	[3]					193
Debt Instrument, Repurchase Amount	[1],[3]					207
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	[3]	103.94%
Subsequent Event [Member] | Senior Notes [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased						2,967
Debt Instrument, Repurchase Amount	[1]					$ 3,145
[1]	(a) Includes payment for accrued interest
[2]	As of September 30, 2016, L+ equals 3 month LIBOR plus x%, with the exception of the Viento Funding II term loan, which is 6 month LIBOR plus x%, and the Alpine Term Loan, the NRG Marsh Landing term loan, the Walnut Creek term loan, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.
[3]	Redemptions financed by cash on hand

Debt and Capital Leases Debt 56

Debt and Capital Leases Debt and Capital Leases (Details 2 - Recourse Debt - Issuance & Repurchases) - USD ($) $ in Millions		3 Months Ended					9 Months Ended
		Dec. 31, 2016	Sep. 30, 2016		Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015	Nov. 04, 2016
Debt and Capital Leases
Loss on debt extinguishment, net			$ (50)			$ (2)	$ (119)		$ (9)
Senior Notes [Member]
Debt and Capital Leases
Debt Instrument Repurchase, Accrued Interest							(67)
Loss on debt extinguishment, net							94
Deferred Financing Costs							$ 15
Recourse Debt [Member] | Senior Notes due 2026 [Member]
Debt and Capital Leases
Proceeds from Issuance of Senior Long-term Debt					$ 1,000
Debt Instrument, Interest Rate, Stated Percentage			7.25%	[1]	7.25%		7.25%	[1]
Recourse Debt [Member] | Senior Notes due 2027 [Member]
Debt and Capital Leases
Proceeds from Issuance of Senior Long-term Debt			$ 1,250
Debt Instrument, Interest Rate, Stated Percentage	[1]		6.625%				6.625%
Recourse Debt [Member] | Senior Notes Due In 2020 [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[1]		8.25%				8.25%
Debt Instrument, Principal Amount Repurchased			$ 1,058				$ 1,058
Debt Instrument, Repurchase Amount	[2]		$ 1,129				$ 1,129
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed							103.12%
Recourse Debt [Member] | Senior Notes Due In 2021 [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[1]		7.875%				7.875%
Debt Instrument, Principal Amount Repurchased			$ 729				$ 729
Debt Instrument, Repurchase Amount	[2]		$ 771				$ 771
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed							104.02%
Recourse Debt [Member] | Senior Notes Due In 2018 [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[1]		7.625%				7.625%
Debt Instrument, Principal Amount Repurchased			$ 455				$ 455
Debt Instrument, Repurchase Amount	[2]		$ 502				$ 502
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed							107.95%
Recourse Debt [Member] | Senior Notes Due in 2023 [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[1]		6.625%				6.625%
Debt Instrument, Principal Amount Repurchased			$ 67				$ 67
Debt Instrument, Repurchase Amount	[2]		$ 64				$ 64
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed							94.13%
Recourse Debt [Member] | Senior Notes Due In 2022 [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[1]		6.25%				6.25%
Debt Instrument, Principal Amount Repurchased			$ 108				$ 108
Debt Instrument, Repurchase Amount	[2]		$ 105				$ 105
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed							94.73%
Recourse Debt [Member] | Senior Notes 2024 [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage	[1]		6.25%				6.25%
Debt Instrument, Principal Amount Repurchased			$ 171				$ 171
Debt Instrument, Repurchase Amount	[2]		163				$ 163
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed							94.52%
Recourse Debt [Member] | Senior Notes [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased			2,588				$ 2,588
Debt Instrument, Repurchase Amount	[2]		$ 2,734				$ 2,734
Subsequent Event [Member] | Recourse Debt [Member] | Senior Notes Due In 2021 [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased	[3]									$ 193
Debt Instrument, Repurchase Amount	[2],[3]									207
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	[3]	103.94%
Subsequent Event [Member] | Recourse Debt [Member] | Senior Notes Due In 2018 [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased	[3]									186
Debt Instrument, Repurchase Amount	[2],[3]									204
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	[3]	107.75%
Subsequent Event [Member] | Recourse Debt [Member] | Senior Notes [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased										2,967
Debt Instrument, Repurchase Amount	[2]									$ 3,145
[1]	As of September 30, 2016, L+ equals 3 month LIBOR plus x%, with the exception of the Viento Funding II term loan, which is 6 month LIBOR plus x%, and the Alpine Term Loan, the NRG Marsh Landing term loan, the Walnut Creek term loan, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.
[2]	(a) Includes payment for accrued interest
[3]	Redemptions financed by cash on hand

Debt and Capital Leases Debt 57

Debt and Capital Leases Debt and Capital Leases (Details 3 - Sr Credit Facility & GenOn Sr Notes) $ in Millions		3 Months Ended					9 Months Ended
		Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)		Jun. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)		Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Debt and Capital Leases
Debt Instrument, Description of Variable Rate Basis							3 month LIBOR
Loss on debt extinguishment, net			$ (50)			$ (2)	$ (119)		$ (9)
Debt and Capital Lease Obligations			19,422				19,422			$ 19,636
Long-term Debt			19,411				$ 19,411			19,620
Term Loan Facility Due 2023 [Member]
Debt and Capital Leases
Debt Instrument, Description of Variable Rate Basis							1 - month LIBOR
NRG Yield Revolving Credit Facility [Member]
Debt and Capital Leases
Line of Credit Facility, Fair Value of Amount Outstanding			0				$ 0
Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt			8,168				8,168			8,584
Recourse Debt [Member] | Term Loan Facility Due 2023 [Member]
Debt and Capital Leases
Proceeds from Issuance of Senior Long-term Debt					$ 1,900
Percent of face value					99.50%
Debt Instrument, Periodic Payment, Percentage of Principal					0.0025
Loss on debt extinguishment, net					$ 21
Long-term Debt			$ 1,886				$ 1,886			0
Recourse Debt [Member] | Senior Notes due 2026 [Member]
Debt and Capital Leases
Proceeds from Issuance of Senior Long-term Debt					$ 1,000
Debt Instrument, Interest Rate, Stated Percentage			7.25%	[1]	7.25%		7.25%	[1]
Long-term Debt			$ 1,000				$ 1,000			0
Letter of Credit [Member] | NRG Yield Revolving Credit Facility [Member]
Debt and Capital Leases
Letters of Credit Outstanding, Amount			64				64
Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt			11,243				11,243			11,036
Non Recourse Debt [Member] | NRG Yield Revolving Credit Facility [Member]
Debt and Capital Leases
Long-term Debt			0				$ 0			$ 306
London Interbank Offered Rate (LIBOR) [Member] | Recourse Debt [Member] | Term Loan Facility Due 2023 [Member]
Debt and Capital Leases
Debt Instrument, Description of Variable Rate Basis	[1]				LIBOR		LIBOR
Debt Instrument, Basis Spread on Variable Rate	[1]				2.75%		2.75%
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member]
Debt and Capital Leases
Debt Instrument, Description of Variable Rate Basis	[1]				LIBOR
Line of Credit Facility, Maximum Borrowing Capacity					$ 0
London Interbank Offered Rate (LIBOR) [Member] | Non Recourse Debt [Member] | NRG Yield Revolving Credit Facility [Member]
Debt and Capital Leases
Debt Instrument, Description of Variable Rate Basis	[1]						LIBOR
Debt Instrument, Basis Spread on Variable Rate	[1]						2.75%
London Interbank Offered Rate (LIBOR) floor [Member] | Recourse Debt [Member] | Term Loan Facility Due 2023 [Member]
Debt and Capital Leases
Debt Instrument, Description of Variable Rate Basis	[1]				LIBOR
Debt Instrument, Basis Spread on Variable Rate	[1]				0.75%
Subsequent Event [Member] | Non Recourse Debt [Member] | NRG Energy Center Minneapolis Series D Notes [Member]
Debt and Capital Leases
Proceeds from Issuance of Debt		$ 125
Debt Instrument, Interest Rate, Stated Percentage		3.55%
Subsequent Event [Member] | Shelf Facility [Member] | NRG Energy Center Minneapolis Series D Notes [Member]
Debt and Capital Leases
Long-term Debt		$ 70
GenOn Energy, Inc. [Member] | Senior Notes [Member] | Senior Unsecured Notes 2017 [Member]
Debt and Capital Leases
Debt and Capital Lease Obligations			$ 703				$ 703
2016 Tranche B Revolving Credit Facility due 2021 [Member] [Member] | Revolving Credit Facility [Member]
Debt and Capital Leases
Line of Credit Facility, Maximum Borrowing Capacity					$ 2,200
2016 Tranche A Revolving Credit Facility due 2018 [Member] | Revolving Credit Facility [Member]
Debt and Capital Leases
Line of Credit Facility, Maximum Borrowing Capacity					$ 289
[1]	As of September 30, 2016, L+ equals 3 month LIBOR plus x%, with the exception of the Viento Funding II term loan, which is 6 month LIBOR plus x%, and the Alpine Term Loan, the NRG Marsh Landing term loan, the Walnut Creek term loan, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.

Debt and Capital Leases Debt 58

Debt and Capital Leases Debt and Capital Leases (Details 4 - Non Recourse Debt - Project Financings) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016	Jan. 29, 2016	Dec. 31, 2015	Dec. 31, 2013
Debt Instrument [Line Items]
Loss on debt extinguishment, net		$ (50)		$ (2)	$ (119)	$ (9)
Long-term Debt		19,411			19,411				$ 19,620
High Lonesome Mesa, LLC, due in 2017 [Member]
Debt Instrument [Line Items]
Percentage of Ownership							100.00%
Construction Loans [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Long-term Debt										$ 81
Letters of Credit Outstanding, Amount									5
Term Loan Facility [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Long-term Debt		77			77			$ 79
Letters of Credit, Issued Amount								4
Letters of Credit Outstanding, Amount		4			4
Cash Grant Loan [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Long-term Debt		23			23			$ 23		$ 23
Non Recourse Debt [Member]
Debt Instrument [Line Items]
Long-term Debt		11,243			11,243				11,036
Non Recourse Debt [Member] | NRG Peaker Finance Co. LLC Bonds Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchase Amount including fees			$ 85
Loss on debt extinguishment, net			3
Long-term Debt		0			0				72
Non Recourse Debt [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Long-term Debt		100			100				98
Non Recourse Debt [Member] | Midwest Generation due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 234			$ 234				0
Debt Instrument, Interest Rate, Stated Percentage	[1]	4.39%			4.39%
Non Recourse Debt [Member] | CVSR Financing Agreement [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.68%			4.68%
Proceeds from Issuance of Debt		$ 200
Proceeds from Debt, Net of Issuance Costs		199
Non Recourse Debt [Member] | 5.00% Senior Notes due in 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 350			$ 350				0
Debt Instrument, Interest Rate, Stated Percentage	[1]	5.00%			5.00%
Proceeds from Issuance of Senior Long-term Debt		$ 350
Recourse Debt [Member]
Debt Instrument [Line Items]
Long-term Debt		8,168			$ 8,168				$ 8,584
Midwest Generation [Member] | Non Recourse Debt [Member]
Debt Instrument [Line Items]
Proceeds from Sale of Other Assets	[1]		$ 253
Debt Instrument, Interest Rate, Stated Percentage	[1]		4.39%
Cedro Hill, Broken Bow, & Crofton Bluffs [Member]
Debt Instrument [Line Items]
Credit Facility, Maximum Borrowing Capacity, Amendment		312			$ 312
Proceeds from Lines of Credit		$ 87
[1]	As of September 30, 2016, L+ equals 3 month LIBOR plus x%, with the exception of the Viento Funding II term loan, which is 6 month LIBOR plus x%, and the Alpine Term Loan, the NRG Marsh Landing term loan, the Walnut Creek term loan, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.

Variable Interest Entities (Det

Variable Interest Entities (Details) $ in Millions	Sep. 30, 2016USD ($)facilityMW	Dec. 31, 2015USD ($)
Investments Accounted for by the Equity Method
Generation Capacity (in MW) | MW	46,000
Equity investments in affiliates	$ 900	$ 1,045
Deficit Restoration Obligation	44
Current assets	76	84
Net property, plant and equipment	1,742	1,807
Other long-term assets	945	863
Total assets	2,763	2,754
Current liabilities	59	56
Long-term debt	450	366
Other long-term liabilities	194	179
Total liabilities	703	601
Noncontrolling interests	562	493
Net assets less noncontrolling interests	$ 1,498	$ 1,660
GenConn Energy LLC
Investments Accounted for by the Equity Method
Economic interest in equity method investments (as a percent)	50.00%
Power generation units | facility	2
Generation Capacity (in MW) | MW	190
Equity investments in affiliates	$ 106
Sherbino I Wind Farm LLC
Investments Accounted for by the Equity Method
Economic interest in equity method investments (as a percent)	50.00%
Equity investments in affiliates	$ 72

Changes in Capital Structure (D

Changes in Capital Structure (Details) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016USD ($)shares	Jun. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)	Jun. 13, 2016USD ($)	May 24, 2016USD ($)	Dec. 31, 2015USD ($)shares
Capital Structure
Common stock, shares authorized	500,000,000			500,000,000				500,000,000
Common stock issued and outstanding
Shares issued, balance at the beginning of the year				416,939,950
Treasury shares, balance at the beginning of the year				(102,749,908)
Common Stock, Shares, Outstanding, beginning of year				314,190,042
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures				643,642
Stock Issued During Period, Shares, Employee Stock Purchase Plans				609,094
Shares issued, balance at the end of the year	417,583,592			417,583,592
Treasury shares, balance at the end of the year	(102,140,814)			(102,140,814)
Common Stock, Shares, Outstanding, end of year	315,442,778			315,442,778
Temporary Equity, Redemption Percentage						1	1
Temporary Equity, Liquidation Preference | $							$ 344.5
Preferred Stock Instrument, Interest Rate, Stated Percentage	2.822%			2.822%			2.822%	2.822%
Gain on Redemption of Redeemable Preferred Stock | $	$ 0	$ 78	$ 0	$ 78	$ 0
Payments for Repurchase of Redeemable Preferred Stock | $		$ 226		226	$ 0
2.822% convertible perpetual preferred stock | $	$ 0			$ 0		$ 304		$ 302
Common Stock, Capital Shares Reserved for Employee Stock Purchase Plan	667,819			667,819
Common Stock [Member]
Common stock issued and outstanding
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures				643,642
Stock Issued During Period, Shares, Employee Stock Purchase Plans				0
Treasury Stock [Member]
Common stock issued and outstanding
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures				0
Stock Issued During Period, Shares, Employee Stock Purchase Plans				609,094

Changes in Capital Structure Ch

Changes in Capital Structure Changes in Capital Structure (Details 2 - Dividends) - $ / shares	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016
Dividends Payable [Line Items]
Dividends per Common Share		$ 0.030	$ 0.030	$ 0.145
Subsequent Event [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared	Oct. 19, 2016
Common Stock, Dividends, Per Share, Declared	$ 0.03
Dividends Payable, Date to be Paid	Nov. 15, 2016
Dividends Payable, Date of Record	Nov. 1, 2016
Scenario, Plan [Member] | Subsequent Event [Member]
Dividends Payable [Line Items]
Common Stock, Dividends, Proposed Annual Amount, Per Share					$ 0.12

Earnings_(Loss) Per Share (Deta

Earnings/(Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	May 24, 2016	Dec. 31, 2015
Numerator:
Net income/(loss) attributable to NRG Energy, Inc.	$ 402		$ 66	$ 213	$ (68)
Gain on redemption, net of dividends for preferred shares	0		5	5	15
Gain on Redemption of Redeemable Preferred Stock	0	$ (78)	0	(78)	0
Income/(loss) available for common stockholders	$ 402		$ 61	$ 286	$ (83)
Denominator:
Weighted Average Number of Shares Outstanding, Basic	316		331	315	334
Basic earnings per share:
Earnings/(Loss) per Weighted Average Common Share — Basic	$ 1.27		$ 0.18	$ 0.91	$ (0.25)
Denominator (diluted earnings per share):
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	1		1	1	0
Total dilutive shares	317		332	316	334
Diluted earnings per share:
Earnings/(loss) per weighted average common share — diluted	$ 1.27		$ 0.18	$ 0.91	$ (0.25)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of diluted earnings per share, amount	2		19	3	22
Convertible perpetual preferred stock, interest rate (as a percentage)	2.822%			2.822%		2.822%	2.822%
Equity compensation plans
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of diluted earnings per share, amount	2		3	3	6
Embedded derivative of 3.625% redeemable perpetual preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of diluted earnings per share, amount	0		16	0	16

Segment Reporting (Details)

Segment Reporting (Details) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2016USD ($)		Sep. 30, 2015USD ($)		Sep. 30, 2016USD ($)		Sep. 30, 2015USD ($)		Sep. 01, 2016	Dec. 31, 2015USD ($)	Nov. 02, 2015facility
Segment Reporting Information
Operating revenues	$ 3,952	[1]	$ 4,434	[2]	$ 9,819	[1]	$ 11,663	[2]
Depreciation and amortization	357		382		979		1,173
Asset Impairment Charges	8		263		123		263
Equity in earnings/(losses) of unconsolidated affiliates	16		24		13		29
Gain on sale of assets and postretirement benefits curtailment, net	266		0		215		14
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	8		0		147		0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	442		114		259		(121)
Net Income/(Loss)	393		67		164		(78)
Net income/(loss) attributable to NRG Energy, Inc.	402		66		213		(68)
Total Assets	31,491				31,491					$ 32,882
Inter-Segment Sales	613		372		1,221		1,033
Loss on debt extinguishment	50		2		119		9
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							14
Generation/Business
Segment Reporting Information
Operating revenues	2,494	[1]	2,726	[2]	5,920	[1]	7,345	[2]
Depreciation and amortization	193		220		483		681
Asset Impairment Charges	8		222		84		222
Equity in earnings/(losses) of unconsolidated affiliates	6		7		1		9
Gain on sale of assets and postretirement benefits curtailment, net	262				293
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	5				142
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	628		166		417		216
Net Income/(Loss)	630		164		418		213
Net income/(loss) attributable to NRG Energy, Inc.	630		164		418		213
Total Assets	14,153				14,153
Inter-Segment Sales	555		309		1,025		853
Loss on debt extinguishment	0		0		0		0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							14
Retail Mass(a)
Segment Reporting Information
Operating revenues	1,619	[1]	1,699	[2]	3,868	[1]	4,308	[2]
Depreciation and amortization	25		30		80		93
Asset Impairment Charges	0		36		0		36
Equity in earnings/(losses) of unconsolidated affiliates	0		0		0		0
Gain on sale of assets and postretirement benefits curtailment, net	0				0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0				0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	2		197		644		523
Net Income/(Loss)	2		197		644		523
Net income/(loss) attributable to NRG Energy, Inc.	2		197		644		523
Total Assets	1,601				1,601
Inter-Segment Sales	0		2		2		4
Loss on debt extinguishment	0		0		0		0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							0
Renewables(a)
Segment Reporting Information
Operating revenues	140	[1]	124	[2]	335	[1]	305	[2]
Depreciation and amortization	48		46		143		135
Asset Impairment Charges	0		5		26		5
Equity in earnings/(losses) of unconsolidated affiliates	(4)		(2)		(13)		(2)
Gain on sale of assets and postretirement benefits curtailment, net	0				0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	1				1
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	8		(20)		(116)		(87)
Net Income/(Loss)	11		(16)		(102)		(74)
Net income/(loss) attributable to NRG Energy, Inc.	0		(33)		(98)		(100)
Total Assets	4,920				4,920
Inter-Segment Sales	9		(6)		19		18
Loss on debt extinguishment	0		0		0		0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							0
NRG Yield(a)
Segment Reporting Information
Operating revenues	272	[1]	256	[2]	789	[1]	729	[2]
Depreciation and amortization	75		69		224		222
Asset Impairment Charges	0		0		0		0
Equity in earnings/(losses) of unconsolidated affiliates	13		12		29		19
Gain on sale of assets and postretirement benefits curtailment, net	0				0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0				0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	60		40		136		61
Net Income/(Loss)	47		32		111		53
Net income/(loss) attributable to NRG Energy, Inc.	52		20		108		29
Total Assets	8,482				8,482
Inter-Segment Sales	2		18		6		27
Loss on debt extinguishment	0		(2)		0		(9)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							0
Corporate
Segment Reporting Information
Operating revenues	40	[1]	1	[2]	128	[1]	9	[2]
Depreciation and amortization	16		17		49		42
Asset Impairment Charges	0		0		13		0
Equity in earnings/(losses) of unconsolidated affiliates	1		1		3		0
Gain on sale of assets and postretirement benefits curtailment, net	4				(78)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	4				6
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(252)		(276)		(815)		(834)
Net Income/(Loss)	(293)		(317)		(900)		(793)
Net income/(loss) attributable to NRG Energy, Inc.	(317)		(315)		(931)		(765)
Total Assets	16,970				16,970
Inter-Segment Sales	47		49		169		131
Loss on debt extinguishment	50		0		119		0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							0
Elimination
Segment Reporting Information
Operating revenues	(613)	[1]	(372)	[2]	(1,221)	[1]	(1,033)	[2]
Depreciation and amortization	0		0		0		0
Asset Impairment Charges	0		0		0		0
Equity in earnings/(losses) of unconsolidated affiliates	0		6		(7)		3
Gain on sale of assets and postretirement benefits curtailment, net	0				0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0				0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(4)		7		(7)		0
Net Income/(Loss)	(4)		7		(7)		0
Net income/(loss) attributable to NRG Energy, Inc.	35		33		72		32
Total Assets	(14,635)				(14,635)
Inter-Segment Sales	0		0		0		0
Loss on debt extinguishment	$ 0		$ 0		$ 0		0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							$ 0
CVSR [Member]
Segment Reporting Information
Percentage of Ownership Sold of Subsidiary									51.05%
ROFO Assets [Member]
Segment Reporting Information
Percentage of Ownership Sold of Subsidiary											75.00%
Number of Facilities | facility											12
[1]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$555 $— $9 $2 $47 $— $613(b) Includes loss on debt extinguishment$— $— $— $— $(50) $— $(50)
[2]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$309 $2 $(6) $18 $49 $— $372(b) Includes loss on debt extinguishment$— $— $— $2 $— $— $2

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Effective Tax Rate
Income/(loss) before income taxes	$ 442	$ 114	$ 259	$ (121)
Income tax expense/(benefit)	$ 49	$ 47	$ 95	$ (43)
Effective tax rate	11.10%	41.20%	36.70%	35.50%
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	$ 44		$ 44
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued			1
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 4		$ 4

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2010	Sep. 30, 2016	Dec. 31, 2015
Loss Contingencies
Environmental Projects		$ 1,000,000
MD Department of Environment v. Chalk Point [Member]
Loss Contingencies
Civil Penalties		1,000,000
Midwest Generation New Source Review [Member]
Loss Contingencies
Civil Penalties	$ 37,500
Telephone Consumer Protection Act Purported Class Actions [Member]
Loss Contingencies
Loss Contingency, Damages Sought, Value		1,500
CDWR and SDGE v Sunrise Power [Member]
Loss Contingencies
Loss Contingency, Damages Sought, Value			$ 1,200,000
Remaining Term			70 months
Texas Westmoreland Coal Co. [Member] | Lignite Contract with Texas Westmoreland Coal Co. [Member]
Loss Contingencies
Third Party Bond Obligation		$ 95,500,000

Environmental Matters (Details)

Environmental Matters (Details) $ in Millions	Sep. 30, 2016USD ($)
Environmental capital expenditures [Line Items]
Environmental Capital Expenditures, Estimated	$ 328
Genon [Member]
Environmental capital expenditures [Line Items]
Environmental Capital Expenditures, Estimated	76
Midwest Generation [Member]
Environmental capital expenditures [Line Items]
Environmental Capital Expenditures, Estimated	$ 234

Condensed Consolidating Finan67

Condensed Consolidating Financial Information (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Debt Instrument
Long-term Debt	$ 19,411	$ 19,620
Recourse Debt [Member]
Debt Instrument
Long-term Debt	8,168	$ 8,584
Senior Notes [Member] | Recourse Debt [Member]
Debt Instrument
Long-term Debt	$ 5,800

Condensed Consolidating Finan68

Condensed Consolidating Financial Information (Details 2) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2016		Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015
Operating Revenues
Total operating revenues		$ 3,952	[1]	$ 4,434	[2]	$ 9,819	[1]	$ 11,663	[2]
Operating Costs and Expenses
Cost of operations		2,793		3,042		6,738		8,551
Depreciation and amortization		357		382		979		1,173
Asset Impairment Charges		8		263		123		263
Selling, general and administrative		282		327		802		878
Acquisition-related transaction and integration costs		0		3		7		16
Development activity expenses		23		38		67		109
Total operating costs and expenses		3,463		4,055		8,716		10,990
Gain on sale of assets and postretirement benefits curtailment, net		266		0		215		14
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments								14
Operating Income/(Loss)		755		379		1,318		687
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		0		0		0		0
Equity in earnings of unconsolidated affiliates		16		24		13		29
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		(8)		0		(147)		0
Other Nonoperating Income (Expense)		9		4		35		27
Loss on debt extinguishment, net		(50)		(2)		(119)		(9)
Interest Expense		(280)		(291)		(841)		(855)
Nonoperating Income (Expense)		(313)		(265)		(1,059)		(808)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		442		114		259		(121)
Income Tax Expense (Benefit)		49		47		95		(43)
Net Income/(Loss)		393		67		164		(78)
Net Income (Loss) Attributable to Noncontrolling Interest		(9)		1		(49)		(10)
Net Income (Loss) Attributable to Parent		402		66		213		(68)
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		27		(6)		(8)		(2)
Foreign currency translation adjustments, net		3		(8)		6		(10)
Available-for-sale securities, net		0		(7)		1		(11)
Defined benefit plans, net		31		3		32		9
Other comprehensive income		61		(18)		31		(14)
Comprehensive Income		454		49		195		(92)
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		(2)		(17)		(70)		(34)
Comprehensive Income Attributable to NRG Energy, Inc.		456		66		265		(58)
Gain on redemption, net of dividends for preferred shares		0		5		(73)		15
Comprehensive Income Available for Common Stockholders		456		61		338		(73)
Guarantor Subsidiaries
Operating Revenues
Total operating revenues		2,424		3,132		6,079		7,959
Operating Costs and Expenses
Cost of operations		1,718		2,276		4,278		6,083
Depreciation and amortization		147		190		372		590
Asset Impairment Charges		8		222		8		222
Selling, general and administrative		114		136		306		351
Acquisition-related transaction and integration costs		0		0		0		0
Development activity expenses		0		0		0		0
Total operating costs and expenses		1,987		2,824		4,964		7,246
Gain on sale of assets and postretirement benefits curtailment, net		0				0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments								0
Operating Income/(Loss)		437		308		1,115		713
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		(110)		0		(178)		(35)
Equity in earnings of unconsolidated affiliates		2		3		5		6
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		0				0
Other Nonoperating Income (Expense)		1		2		3		3
Loss on debt extinguishment, net		0		0		0		0
Interest Expense		(4)		(4)		(11)		(13)
Nonoperating Income (Expense)		(111)		1		(181)		(39)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		326		309		934		674
Income Tax Expense (Benefit)		134		88		367		225
Net Income/(Loss)		192		221		567		449
Net Income (Loss) Attributable to Noncontrolling Interest		0		0		0		0
Net Income (Loss) Attributable to Parent		192		221		567		449
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		0		(5)		0		(10)
Foreign currency translation adjustments, net		2		0		4		0
Available-for-sale securities, net		0		0		0		0
Defined benefit plans, net		(54)		(4)		(55)		(1)
Other comprehensive income		56		(1)		59		(9)
Comprehensive Income		248		220		626		440
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		0		0		0		0
Comprehensive Income Attributable to NRG Energy, Inc.		248		220		626		440
Gain on redemption, net of dividends for preferred shares				0		0		0
Comprehensive Income Available for Common Stockholders		248		220		626		440
Non-Guarantor Subsidiaries
Operating Revenues
Total operating revenues		1,622		1,331		3,907		3,801
Operating Costs and Expenses
Cost of operations		1,158		792		2,602		2,554
Depreciation and amortization		203		187		588		568
Asset Impairment Charges		0		41		115		41
Selling, general and administrative		105		91		296		280
Acquisition-related transaction and integration costs		1		2		1		3
Development activity expenses		12		17		44		43
Total operating costs and expenses		1,479		1,130		3,646		3,489
Gain on sale of assets and postretirement benefits curtailment, net		262				294
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments								14
Operating Income/(Loss)		405		201		555		326
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		(13)		42		(36)		(15)
Equity in earnings of unconsolidated affiliates		22		27		20		33
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		(8)				(147)
Other Nonoperating Income (Expense)		8		3		31		23
Loss on debt extinguishment, net		0		(2)		(4)		(9)
Interest Expense		(148)		(151)		(443)		(430)
Nonoperating Income (Expense)		(139)		(81)		(579)		(398)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		266		120		(24)		(72)
Income Tax Expense (Benefit)		90		56		(22)		(20)
Net Income/(Loss)		176		64		(2)		(52)
Net Income (Loss) Attributable to Noncontrolling Interest		6		15		(17)		15
Net Income (Loss) Attributable to Parent		170		49		15		(67)
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		40		(24)		(15)		(9)
Foreign currency translation adjustments, net		2		(6)		4		(6)
Available-for-sale securities, net		0		12		0		11
Defined benefit plans, net		0		1		0		2
Other comprehensive income		42		(19)		(11)		(6)
Comprehensive Income		218		45		(13)		(58)
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		13		(3)		(38)		(9)
Comprehensive Income Attributable to NRG Energy, Inc.		205		48		25		(49)
Gain on redemption, net of dividends for preferred shares				0		0		0
Comprehensive Income Available for Common Stockholders		205		48		25		(49)
NRG Energy, Inc.
Operating Revenues
Total operating revenues		0		0		0		0
Operating Costs and Expenses
Cost of operations		11		14		29		10
Depreciation and amortization		7		5		19		15
Asset Impairment Charges		0		0		0		0
Selling, general and administrative		63		100		200		247
Acquisition-related transaction and integration costs		(1)		1		6		13
Development activity expenses		11		21		23		66
Total operating costs and expenses		91		141		277		351
Gain on sale of assets and postretirement benefits curtailment, net		4				(79)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments								0
Operating Income/(Loss)		(87)		(141)		(356)		(351)
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		485		228		796		432
Equity in earnings of unconsolidated affiliates		(2)		1		(2)		0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		0				0
Other Nonoperating Income (Expense)		0		1		2		3
Loss on debt extinguishment, net		(50)		0		(115)		0
Interest Expense		(128)		(136)		(387)		(412)
Nonoperating Income (Expense)		305		94		294		23
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		218		(47)		(62)		(328)
Income Tax Expense (Benefit)		(218)		(130)		(345)		(281)
Net Income/(Loss)		436		83		283		(47)
Net Income (Loss) Attributable to Noncontrolling Interest		34		17		70		21
Net Income (Loss) Attributable to Parent		402		66		213		(68)
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		26		20		46		29
Foreign currency translation adjustments, net		4		(2)		6		(4)
Available-for-sale securities, net		0		(19)		1		(22)
Defined benefit plans, net		23		0		23		(10)
Other comprehensive income		7		(1)		30		13
Comprehensive Income		443		82		313		(34)
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		34		17		70		21
Comprehensive Income Attributable to NRG Energy, Inc.		409		65		243		(55)
Gain on redemption, net of dividends for preferred shares				5		(73)		15
Comprehensive Income Available for Common Stockholders		409		60		316		(70)
Consolidation, Eliminations [Member]
Operating Revenues
Total operating revenues		(94)	[3]	(29)	[4]	(167)	[5]	(97)	[6]
Operating Costs and Expenses
Cost of operations		(94)	[3]	(40)	[4]	(171)	[5]	(96)	[6]
Depreciation and amortization		0	[3]	0	[4]	0	[5],[7]	0	[6],[8]
Asset Impairment Charges		0	[3]	0	[5]	0	[5]	0	[5]
Selling, general and administrative		0	[3]	0	[4]	0	[5]	0	[6]
Acquisition-related transaction and integration costs		0	[3]	0	[4]	0	[5]	0	[6]
Development activity expenses		0	[3]	0	[4]	0	[5]	0	[6]
Total operating costs and expenses		(94)	[3]	(40)	[4]	(171)	[5]	(96)	[6]
Gain on sale of assets and postretirement benefits curtailment, net		0	[3]			0	[5]
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	[6]							0
Operating Income/(Loss)		0	[3]	11	[4]	4	[5]	(1)	[6]
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		(362)	[3]	(270)	[4]	(582)	[5]	(382)	[6]
Equity in earnings of unconsolidated affiliates		(6)	[3]	(7)	[4]	(10)	[5],[7]	(10)	[6],[7]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		0	[3]			0	[5]
Other Nonoperating Income (Expense)		0	[3]	(2)	[4]	(1)	[5]	(2)	[6]
Loss on debt extinguishment, net		0	[3]	0	[4]	0	[5]	0	[6]
Interest Expense		0	[3]	0	[4]	0	[5]	0	[6]
Nonoperating Income (Expense)		(368)	[3]	(279)	[4]	(593)	[5]	(394)	[6]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		(368)	[3]	(268)	[4]	(589)	[5]	(395)	[6]
Income Tax Expense (Benefit)		43	[3]	33	[4]	95	[5]	33	[6]
Net Income/(Loss)		(411)	[3]	(301)	[4]	(684)	[7]	(428)	[6],[8]
Net Income (Loss) Attributable to Noncontrolling Interest		(49)	[3]	(31)	[4]	(102)	[5]	(46)	[6]
Net Income (Loss) Attributable to Parent		(362)	[3]	(270)	[4]	(582)	[5]	(382)	[6]
Other Comprehensive Income/(Loss), net of tax
Unrealized gain on derivatives, net		(39)	[9]	3	[10]	(39)	[7]	(12)	[10]
Foreign currency translation adjustments, net		(5)	[9]	0	[10]	(8)	[7]	0	[10]
Available-for-sale securities, net		0	[9]	0	[10]	0	[7]	0	[10]
Defined benefit plans, net		0	[9]	0	[10]	0	[7]	0	[10]
Other comprehensive income		(44)	[9]	3	[10]	(47)	[7]	(12)	[10]
Comprehensive Income		(455)	[9]	(298)	[10]	(731)	[7]	(440)	[10]
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		(49)	[9]	(31)	[10]	(102)	[7]	(46)	[10]
Comprehensive Income Attributable to NRG Energy, Inc.		(406)	[9]	(267)	[10]	(629)	[7]	(394)	[10]
Gain on redemption, net of dividends for preferred shares				0	[10]	0	[7]	0	[10]
Comprehensive Income Available for Common Stockholders		$ (406)	[9]	$ (267)	[10]	$ (629)	[7]	$ (394)	[10]
[1]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$555 $— $9 $2 $47 $— $613(b) Includes loss on debt extinguishment$— $— $— $— $(50) $— $(50)
[2]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$309 $2 $(6) $18 $49 $— $372(b) Includes loss on debt extinguishment$— $— $— $2 $— $— $2
[3]	All significant intercompany transactions have been eliminated in consolidation.
[4]	(a)All significant intercompany transactions have been eliminated in consolidation.
[5]	All significant intercompany transactions have been eliminated in consolidation.
[6]	All significant intercompany transactions have been eliminated in consolidation.
[7]	All significant intercompany transactions have been eliminated in consolidation.
[8]	All significant intercompany transactions have been eliminated in consolidation.
[9]	All significant intercompany transactions have been eliminated in consolidation.
[10]	All significant intercompany transactions have been eliminated in consolidation.

Condensed Consolidating Finan69

Condensed Consolidating Financial Information (Details 3) - USD ($) $ in Millions		Sep. 30, 2016		Jun. 13, 2016	May 24, 2016	Dec. 31, 2015		Sep. 30, 2015		Dec. 31, 2014
Current Assets
Cash and cash equivalents		$ 2,435				$ 1,518		$ 2,265		$ 2,116
Funds deposited by counterparties		16				106
Restricted cash		480				414
Accounts receivable - trade, net		1,362				1,157
Accounts receivable - affiliate		5				4
Inventory		1,017				1,252
Derivative instruments		964				1,915
Cash collateral paid in support of energy risk management activities		337				568
Renewable energy grant receivable, net		34				13
Disposal Group, Including Discontinued Operation, Other Assets, Current		0				6
Prepayments and other current assets		364				438
Total current assets		7,014				7,391
Net property, plant and equipment		18,203				18,732
Other Assets
Investment in subsidiaries		0				0
Equity investments in affiliates		900				1,045
Notes receivable, less current portion		21				53
Goodwill		999				999
Intangible assets, net		2,106				2,310
Nuclear decommissioning trust fund		605				561
Derivative instruments		256				305
Deferred income taxes		189				167
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent		0				105
Other non-current assets		1,198				1,214
Total other assets		6,274				6,759
Total Assets		31,491				32,882
Current Liabilities
Current portion of long-term debt and capital leases		1,221				481
Accounts payable		945				869
Accounts payable — affiliate		0				0
Derivative instruments		969				1,721
Cash collateral received in support of energy risk management activities		16				106
Accrued expenses and other current liabilities		1,150				1,196
Disposal Group, Including Discontinued Operation, Liabilities, Current		0				2
Other Liabilities, Current						1,196
Total current liabilities		4,301				4,375
Other Liabilities
Long-term debt and capital leases		18,018				18,983
Nuclear decommissioning reserve		284				326
Nuclear decommissioning trust liability		309				283
Deferred income taxes		47				19
Derivative instruments		475				493
Out-of-market contracts, net of accumulated amortization of $639 and $562		1,065				1,146
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent		0				4
Other non-current liabilities		1,480				1,488
Total non-current liabilities		21,678				22,742
Total liabilities		25,979				27,117
2.822% convertible perpetual preferred stock		0		$ 304		302
Redeemable noncontrolling interest in subsidiaries		$ 19				$ 29
Convertible perpetual preferred stock, interest rate (as a percentage)		2.822%			2.822%	2.822%
Stockholders’ Equity		$ 5,493				$ 5,434
Total Liabilities and Stockholders’ Equity		31,491				32,882
Guarantor Subsidiaries
Current Assets
Cash and cash equivalents		0				0		0		18
Funds deposited by counterparties		6				55
Restricted cash		10				5
Accounts receivable - trade, net		880				851
Accounts receivable - affiliate		308				395
Inventory		425				570
Derivative instruments		700				1,202
Cash collateral paid in support of energy risk management activities		206				474
Renewable energy grant receivable, net		0				0
Disposal Group, Including Discontinued Operation, Other Assets, Current						0
Prepayments and other current assets		70				93
Total current assets		2,605				3,645
Net property, plant and equipment		4,310				4,767
Other Assets
Investment in subsidiaries		875				842
Equity investments in affiliates		(14)				(14)
Notes receivable, less current portion		0				0
Goodwill		697				697
Intangible assets, net		651				763
Nuclear decommissioning trust fund		605				561
Derivative instruments		231				153
Deferred income taxes		0				(6)
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent						0
Other non-current assets		43				80
Total other assets		3,088				3,076
Total Assets		10,003				11,488
Current Liabilities
Current portion of long-term debt and capital leases		0				2
Accounts payable		577				553
Accounts payable — affiliate		128				151
Derivative instruments		601				1,130
Cash collateral received in support of energy risk management activities		6				55
Accrued expenses and other current liabilities		301
Disposal Group, Including Discontinued Operation, Liabilities, Current						0
Other Liabilities, Current						319
Total current liabilities		1,613				2,210
Other Liabilities
Long-term debt and capital leases		244				302
Nuclear decommissioning reserve		284				326
Nuclear decommissioning trust liability		309				283
Deferred income taxes		1,068				179
Derivative instruments		233				301
Out-of-market contracts, net of accumulated amortization of $639 and $562		84				95
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent						0
Other non-current liabilities		361				554
Total non-current liabilities		2,583				2,040
Total liabilities		4,196				4,250
2.822% convertible perpetual preferred stock						0
Redeemable noncontrolling interest in subsidiaries		0				0
Stockholders’ Equity		5,807				7,238
Total Liabilities and Stockholders’ Equity		10,003				11,488
Non-Guarantor Subsidiaries
Current Assets
Cash and cash equivalents		1,744				825		1,310		1,455
Funds deposited by counterparties		10				51
Restricted cash		470				409
Accounts receivable - trade, net		482				304
Accounts receivable - affiliate		(133)				260
Inventory		592				682
Derivative instruments		384				871
Cash collateral paid in support of energy risk management activities		131				94
Renewable energy grant receivable, net		34				13
Disposal Group, Including Discontinued Operation, Other Assets, Current						6
Prepayments and other current assets		237				274
Total current assets		3,951				3,789
Net property, plant and equipment		13,667				13,773
Other Assets
Investment in subsidiaries		2,054				2,244
Equity investments in affiliates		906				1,160
Notes receivable, less current portion		21				46
Goodwill		302				302
Intangible assets, net		1,457				1,551
Nuclear decommissioning trust fund		0				0
Derivative instruments		80				184
Deferred income taxes		182				815
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent						105
Other non-current assets		814				749
Total other assets		5,816				7,156
Total Assets		23,434				24,718
Current Liabilities
Current portion of long-term debt and capital leases		1,475				460
Accounts payable		330				277
Accounts payable — affiliate		158				2,000
Derivative instruments		485				749
Cash collateral received in support of energy risk management activities		10				51
Accrued expenses and other current liabilities		489
Disposal Group, Including Discontinued Operation, Liabilities, Current						2
Other Liabilities, Current						429
Total current liabilities		2,947				3,968
Other Liabilities
Long-term debt and capital leases		10,011				10,496
Nuclear decommissioning reserve		0				0
Nuclear decommissioning trust liability		0				0
Deferred income taxes		(112)				(1,088)
Derivative instruments		303				224
Out-of-market contracts, net of accumulated amortization of $639 and $562		981				1,051
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent						4
Other non-current liabilities		787				735
Total non-current liabilities		11,970				11,422
Total liabilities		14,917				15,390
2.822% convertible perpetual preferred stock						0
Redeemable noncontrolling interest in subsidiaries		19				29
Stockholders’ Equity		8,498				9,299
Total Liabilities and Stockholders’ Equity		23,434				24,718
NRG Energy, Inc.
Current Assets
Cash and cash equivalents		691				693		955		643
Funds deposited by counterparties		0				0
Restricted cash		0				0
Accounts receivable - trade, net		0				2
Accounts receivable - affiliate		173				571
Inventory		0				0
Derivative instruments		0				0
Cash collateral paid in support of energy risk management activities		0				0
Renewable energy grant receivable, net		0				0
Disposal Group, Including Discontinued Operation, Other Assets, Current						0
Prepayments and other current assets		57				71
Total current assets		921				1,337
Net property, plant and equipment		253				219
Other Assets
Investment in subsidiaries		10,781				11,039
Equity investments in affiliates		8				1
Notes receivable, less current portion		0				7
Goodwill		0				0
Intangible assets, net		1				2
Nuclear decommissioning trust fund		0				0
Derivative instruments		6				0
Deferred income taxes		7				(642)
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent						0
Other non-current assets		341				385
Total other assets		11,144				10,792
Total Assets		12,318				12,348
Current Liabilities
Current portion of long-term debt and capital leases		(254)				19
Accounts payable		38				39
Accounts payable — affiliate		57				(929)
Derivative instruments		3				0
Cash collateral received in support of energy risk management activities		0				0
Accrued expenses and other current liabilities		360
Disposal Group, Including Discontinued Operation, Liabilities, Current						0
Other Liabilities, Current						449
Total current liabilities		204				(422)
Other Liabilities
Long-term debt and capital leases		7,763				8,185
Nuclear decommissioning reserve		0				0
Nuclear decommissioning trust liability		0				0
Deferred income taxes		(909)				928
Derivative instruments		0				0
Out-of-market contracts, net of accumulated amortization of $639 and $562		0				0
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent						0
Other non-current liabilities		332				199
Total non-current liabilities		7,186				9,312
Total liabilities		7,390				8,890
2.822% convertible perpetual preferred stock						302
Redeemable noncontrolling interest in subsidiaries		0				$ 0
Convertible perpetual preferred stock, interest rate (as a percentage)						2.822%
Stockholders’ Equity		4,928				$ 3,156
Total Liabilities and Stockholders’ Equity		12,318				12,348
Consolidation, Eliminations [Member]
Current Assets
Cash and cash equivalents		0	[1],[2]			0	[3]	$ 0	[4]	$ 0	[4]
Funds deposited by counterparties		0	[1]			0	[3]
Restricted cash		0	[1]			0	[3]
Accounts receivable - trade, net		0	[1]			0	[3]
Accounts receivable - affiliate		(343)	[1]			(1,222)	[3]
Inventory		0	[1]			0	[3]
Derivative instruments		(120)	[1]			(158)	[3]
Cash collateral paid in support of energy risk management activities		0	[1]			0	[3]
Renewable energy grant receivable, net		0	[1]			0	[3]
Disposal Group, Including Discontinued Operation, Other Assets, Current	[3]					0
Prepayments and other current assets		0	[1]			0	[3]
Total current assets		(463)	[1]			(1,380)	[3]
Net property, plant and equipment		(27)	[1]			(27)	[3]
Other Assets
Investment in subsidiaries		(13,710)	[1]			(14,125)	[3]
Equity investments in affiliates		0	[1]			(102)	[3]
Notes receivable, less current portion		0	[1]			0	[3]
Goodwill		0	[1]			0	[3]
Intangible assets, net		(3)	[1]			(6)	[3]
Nuclear decommissioning trust fund		0	[1]			0	[3]
Derivative instruments		(61)	[1]			(32)	[3]
Deferred income taxes		0	[1]			0	[3]
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent	[3]					0
Other non-current assets		0	[1]			0	[3]
Total other assets		(13,774)	[1]			(14,265)	[3]
Total Assets		(14,264)	[1]			(15,672)	[3]
Current Liabilities
Current portion of long-term debt and capital leases		0	[1]			0	[3]
Accounts payable		0	[1]			0	[3]
Accounts payable — affiliate		(343)	[1]			(1,222)	[3]
Derivative instruments		(120)	[1]			(158)	[3]
Cash collateral received in support of energy risk management activities		0	[1]			0	[3]
Accrued expenses and other current liabilities	[1]	0
Disposal Group, Including Discontinued Operation, Liabilities, Current	[3]					0
Other Liabilities, Current	[3]					(1)
Total current liabilities		(463)	[1]			(1,381)	[3]
Other Liabilities
Long-term debt and capital leases		0	[1]			0	[3]
Nuclear decommissioning reserve		0	[1]			0	[3]
Nuclear decommissioning trust liability		0	[1]			0	[3]
Deferred income taxes		0	[1]			0	[3]
Derivative instruments		(61)	[1]			(32)	[3]
Out-of-market contracts, net of accumulated amortization of $639 and $562		0	[1]			0	[3]
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	[3]					0
Other non-current liabilities		0	[1]			0	[3]
Total non-current liabilities		(61)	[1]			(32)	[3]
Total liabilities		(524)	[1]			(1,413)	[3]
2.822% convertible perpetual preferred stock	[3]					0
Redeemable noncontrolling interest in subsidiaries		0	[1]			0	[3]
Stockholders’ Equity		(13,740)	[1]			(14,259)	[3]
Total Liabilities and Stockholders’ Equity		$ (14,264)	[1]			$ (15,672)	[3]
[1]	All significant intercompany transactions have been eliminated in consolidation.
[2]	All significant intercompany transactions have been eliminated in consolidation.
[3]	All significant intercompany transactions have been eliminated in consolidation.
[4]	All significant intercompany transactions have been eliminated in consolidation.

Condensed Consolidating Finan70

Condensed Consolidating Financial Information (Details 4) - USD ($) $ in Millions		3 Months Ended					9 Months Ended
		Sep. 30, 2016		Jun. 30, 2016	Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015
Cash Flows from Operating Activities
Net Income/(Loss)		$ 393			$ 67		$ 164		$ (78)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries							(57)		(57)
Equity in earnings of unconsolidated affiliates		(16)			(24)		(13)		(29)
Depreciation and amortization		357			382		979		1,173
Provision for bad debts							36		49
Amortization of nuclear fuel							39		36
Amortization of financing costs and debt discount/premiums							3		(9)
Amortization of intangibles and out-of-market contracts							73		68
Amortization of unearned equity compensation							23		37
Changes in deferred income taxes and liability for uncertain tax benefits							29		(72)
Changes in nuclear decommissioning trust liability							24		1
Changes in derivative instruments							82		180
Changes in collateral deposits supporting energy risk management activities							231		(180)
Cash used by changes in other working capital							(108)		(93)
Proceeds from sale of emission allowances							47		(6)
Gain on sale of assets, net and postretirement benefits curtailment							(224)		(14)
Asset Impairment Charges		8			263		123		263
Impairment losses							270		263
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments									(14)
Gain on sale of assets and postretirement benefits curtailment									(14)
Adjustment to loss on debt extinguishment							21		9
Net Cash Provided by Operating Activities							1,733		1,392
Cash Flows from Investing Activities
Proceeds from Dividends Received							0		0
Payments to Acquire Business Two, Net of Cash Acquired							0		0
Acquisitions of businesses, net of cash acquired							(18)		(31)
Capital expenditures							(898)		(889)
Increase in restricted cash, net							(30)		(41)
Increase in restricted cash — U.S. DOE funded projects							(36)		1
Decrease in notes receivable							2		10
Investments in nuclear decommissioning trust fund securities							(378)		(500)
Proceeds from the sale of nuclear decommissioning trust fund securities							354		499
Proceeds from renewable energy grants and state rebates							11		62
Payments to Acquire Intangible Assets							(32)		(40)
Proceeds from Sale of Intangible Assets							(47)		(45)
Proceeds from sale of assets, net of cash disposed of							636		1
(Investments in) Proceeds From Sales of Unconsolidated Affiliates							23		357
Other							44		8
Net Cash (Used)/Provided by Investing Activities							(321)		(1,232)
Cash Flows from Financing Activities
Payments (for)/from intercompany loans							0		0
Payments to Acquire Business Three, Net of Cash Acquired							0		0
Intercompany Dividend Proceeds - Financing							0		0
Payment of dividends to common and preferred stockholders							(66)		(152)
Payment for treasury stock							0		(353)
Payments for Repurchase of Redeemable Preferred Stock				$ 226			226		0
Net receipts from settlement of acquired derivatives that include financing elements							129		138
Proceeds from issuance of long-term debt							5,237		679
Distributions from, net of contributions to, noncontrolling interest in subsidiaries							(127)		(651)
Proceeds from issuance of common stock							1		1
Payments of Debt Issuance Costs							70		14
Payments for short and long-term debt							(5,357)		(954)
Other - contingent consideration							(10)		(22)
Net Cash (Used)/Provided by Financing Activities							(489)		(26)
Effect of exchange rate changes on cash and cash equivalents							(6)		15
Net Increase/(Decrease) in Cash and Cash Equivalents							917		149
Cash and Cash Equivalents at Beginning of Period							1,518		2,116
Cash and Cash Equivalents at End of Period		2,435			2,265		2,435		2,265
Guarantor Subsidiaries
Cash Flows from Operating Activities
Net Income/(Loss)		192			221		567		449
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries							0		0
Equity in earnings of unconsolidated affiliates		(2)			(3)		(5)		(6)
Depreciation and amortization		147			190		372		590
Provision for bad debts							31		46
Amortization of nuclear fuel							39		36
Amortization of financing costs and debt discount/premiums							0		0
Amortization of intangibles and out-of-market contracts							32		43
Amortization of unearned equity compensation							0		0
Changes in deferred income taxes and liability for uncertain tax benefits							(134)		218
Changes in nuclear decommissioning trust liability							24		1
Changes in derivative instruments							(173)		135
Changes in collateral deposits supporting energy risk management activities							268		(141)
Cash used by changes in other working capital							(887)		1,048
Proceeds from sale of emission allowances							47		(6)
Gain on sale of assets, net and postretirement benefits curtailment							0
Asset Impairment Charges		8			222		8		222
Impairment losses							8		222
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments									0
Gain on sale of assets and postretirement benefits curtailment									0
Adjustment to loss on debt extinguishment							0		0
Net Cash Provided by Operating Activities							189		2,635
Cash Flows from Investing Activities
Proceeds from Dividends Received							0		0
Payments to Acquire Business Two, Net of Cash Acquired							0		0
Acquisitions of businesses, net of cash acquired							0		0
Capital expenditures							(145)		(264)
Increase in restricted cash, net							(5)		(3)
Increase in restricted cash — U.S. DOE funded projects							0		0
Decrease in notes receivable							0		0
Investments in nuclear decommissioning trust fund securities							(378)		(500)
Proceeds from the sale of nuclear decommissioning trust fund securities							354		499
Proceeds from renewable energy grants and state rebates							0		0
Payments to Acquire Intangible Assets							(32)		(40)
Proceeds from Sale of Intangible Assets							(47)		(45)
Proceeds from sale of assets, net of cash disposed of							0		0
(Investments in) Proceeds From Sales of Unconsolidated Affiliates							(2)		(1)
Other							27		0
Net Cash (Used)/Provided by Investing Activities							(130)		(262)
Cash Flows from Financing Activities
Payments (for)/from intercompany loans							(2)		(2,391)
Payments to Acquire Business Three, Net of Cash Acquired							0		0
Intercompany Dividend Proceeds - Financing							(52)		0
Payment of dividends to common and preferred stockholders							0		0
Payment for treasury stock									0
Payments for Repurchase of Redeemable Preferred Stock							0
Net receipts from settlement of acquired derivatives that include financing elements							0		0
Proceeds from issuance of long-term debt							0		0
Distributions from, net of contributions to, noncontrolling interest in subsidiaries							0		0
Proceeds from issuance of common stock							0		0
Payments of Debt Issuance Costs							0		0
Payments for short and long-term debt							(2)		0
Other - contingent consideration							(3)		0
Net Cash (Used)/Provided by Financing Activities							(59)		(2,391)
Effect of exchange rate changes on cash and cash equivalents							0		0
Net Increase/(Decrease) in Cash and Cash Equivalents							0		(18)
Cash and Cash Equivalents at Beginning of Period							0		18
Cash and Cash Equivalents at End of Period		0			0		0		0
Non-Guarantor Subsidiaries
Cash Flows from Operating Activities
Net Income/(Loss)		176			64		(2)		(52)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries							(65)		(77)
Equity in earnings of unconsolidated affiliates		(22)			(27)		(20)		(33)
Depreciation and amortization		203			187		588		568
Provision for bad debts							5		0
Amortization of nuclear fuel							0		0
Amortization of financing costs and debt discount/premiums							(14)		(29)
Amortization of intangibles and out-of-market contracts							41		25
Amortization of unearned equity compensation							0		0
Changes in deferred income taxes and liability for uncertain tax benefits							(90)		(77)
Changes in nuclear decommissioning trust liability							0		0
Changes in derivative instruments							258		89
Changes in collateral deposits supporting energy risk management activities							(37)		(39)
Cash used by changes in other working capital							305		(879)
Proceeds from sale of emission allowances							0		0
Gain on sale of assets, net and postretirement benefits curtailment							(294)
Asset Impairment Charges		0			41		115		41
Impairment losses							262		41
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments									(14)
Gain on sale of assets and postretirement benefits curtailment									(14)
Adjustment to loss on debt extinguishment							4		9
Net Cash Provided by Operating Activities							1,071		(314)
Cash Flows from Investing Activities
Proceeds from Dividends Received							0		0
Payments to Acquire Business Two, Net of Cash Acquired							(77)		(489)
Acquisitions of businesses, net of cash acquired							(18)		(31)
Capital expenditures							(713)		(595)
Increase in restricted cash, net							(25)		(38)
Increase in restricted cash — U.S. DOE funded projects							(36)		1
Decrease in notes receivable							2		10
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							11		62
Payments to Acquire Intangible Assets							0		0
Proceeds from Sale of Intangible Assets							0		0
Proceeds from sale of assets, net of cash disposed of							619		0
(Investments in) Proceeds From Sales of Unconsolidated Affiliates							25		317
Other							9		8
Net Cash (Used)/Provided by Investing Activities							(253)		(1,389)
Cash Flows from Financing Activities
Payments (for)/from intercompany loans							(134)		1,178
Payments to Acquire Business Three, Net of Cash Acquired							0		0
Intercompany Dividend Proceeds - Financing							40		(33)
Payment of dividends to common and preferred stockholders							0		0
Payment for treasury stock									0
Payments for Repurchase of Redeemable Preferred Stock							0
Net receipts from settlement of acquired derivatives that include financing elements							129		138
Proceeds from issuance of long-term debt							1,097		635
Distributions from, net of contributions to, noncontrolling interest in subsidiaries							127		(651)
Proceeds from issuance of common stock							0		0
Payments of Debt Issuance Costs							17		14
Payments for short and long-term debt							(815)		(938)
Other - contingent consideration							(7)		(22)
Net Cash (Used)/Provided by Financing Activities							107		1,543
Effect of exchange rate changes on cash and cash equivalents							(6)		15
Net Increase/(Decrease) in Cash and Cash Equivalents							919		(145)
Cash and Cash Equivalents at Beginning of Period							825		1,455
Cash and Cash Equivalents at End of Period		1,744			1,310		1,744		1,310
NRG Energy, Inc.
Cash Flows from Operating Activities
Net Income/(Loss)		436			83		283		(47)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries							0		0
Equity in earnings of unconsolidated affiliates		2			(1)		2		0
Depreciation and amortization		7			5		19		15
Provision for bad debts							0		3
Amortization of nuclear fuel							0		0
Amortization of financing costs and debt discount/premiums							17		20
Amortization of intangibles and out-of-market contracts							0		0
Amortization of unearned equity compensation							23		37
Changes in deferred income taxes and liability for uncertain tax benefits							253		(213)
Changes in nuclear decommissioning trust liability							0		0
Changes in derivative instruments							(3)		(44)
Changes in collateral deposits supporting energy risk management activities							0		0
Cash used by changes in other working capital							(208)		(702)
Proceeds from sale of emission allowances							0		0
Gain on sale of assets, net and postretirement benefits curtailment							70
Asset Impairment Charges		0			0		0		0
Impairment losses							0		0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments									0
Gain on sale of assets and postretirement benefits curtailment									0
Adjustment to loss on debt extinguishment							17		0
Net Cash Provided by Operating Activities							473		(931)
Cash Flows from Investing Activities
Proceeds from Dividends Received							12		33
Payments to Acquire Business Two, Net of Cash Acquired							0		0
Acquisitions of businesses, net of cash acquired							0		0
Capital expenditures							(40)		(30)
Increase in restricted cash, net							0		0
Increase in restricted cash — U.S. DOE funded projects							0		0
Decrease in notes receivable							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
Payments to Acquire Intangible Assets							0		0
Proceeds from Sale of Intangible Assets							0		0
Proceeds from sale of assets, net of cash disposed of							17		1
(Investments in) Proceeds From Sales of Unconsolidated Affiliates							0		39
Other							8		0
Net Cash (Used)/Provided by Investing Activities							56		17
Cash Flows from Financing Activities
Payments (for)/from intercompany loans							136		1,213
Payments to Acquire Business Three, Net of Cash Acquired							(77)		(489)
Intercompany Dividend Proceeds - Financing							0		0
Payment of dividends to common and preferred stockholders							(66)		(152)
Payment for treasury stock									(353)
Payments for Repurchase of Redeemable Preferred Stock							226
Net receipts from settlement of acquired derivatives that include financing elements							0		0
Proceeds from issuance of long-term debt							4,140		44
Distributions from, net of contributions to, noncontrolling interest in subsidiaries							0		0
Proceeds from issuance of common stock							1		1
Payments of Debt Issuance Costs							53		0
Payments for short and long-term debt							(4,540)		(16)
Other - contingent consideration							0		0
Net Cash (Used)/Provided by Financing Activities							(531)		1,226
Effect of exchange rate changes on cash and cash equivalents							0		0
Net Increase/(Decrease) in Cash and Cash Equivalents							(2)		312
Cash and Cash Equivalents at Beginning of Period							693		643
Cash and Cash Equivalents at End of Period		691			955		691		955
NRG Yield, Inc.
Cash Flows from Investing Activities
Proceeds from Dividends Received							0		0
Cash Flows from Financing Activities
Intercompany Dividend Proceeds - Financing							0		0
NRG Yield, Inc. | Guarantor Subsidiaries
Cash Flows from Investing Activities
Proceeds from Dividends Received							0		0
Cash Flows from Financing Activities
Intercompany Dividend Proceeds - Financing							0		0
NRG Yield, Inc. | Non-Guarantor Subsidiaries
Cash Flows from Investing Activities
Proceeds from Dividends Received							0		0
Cash Flows from Financing Activities
Intercompany Dividend Proceeds - Financing							(59)		(52)
NRG Yield, Inc. | NRG Energy, Inc.
Cash Flows from Investing Activities
Proceeds from Dividends Received							59		52
Cash Flows from Financing Activities
Intercompany Dividend Proceeds - Financing							0		0
Consolidation, Eliminations [Member]
Cash Flows from Operating Activities
Net Income/(Loss)		(411)	[1]		(301)	[2]	(684)	[3]	(428)	[4],[5]
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries	[3]						8		20
Equity in earnings of unconsolidated affiliates		6	[1]		7	[2]	10	[3],[6]	10	[3],[4]
Depreciation and amortization		0	[1]		0	[2]	0	[3],[6]	0	[4],[5]
Provision for bad debts							0	[3]	0	[5]
Amortization of nuclear fuel							0	[3]	0	[5]
Amortization of financing costs and debt discount/premiums							0	[3]		[5]
Amortization of intangibles and out-of-market contracts							0	[3]	0	[5]
Amortization of unearned equity compensation							0	[3]	0	[5]
Changes in deferred income taxes and liability for uncertain tax benefits							0	[3]	0	[5]
Changes in nuclear decommissioning trust liability							0	[3]	0	[5]
Changes in derivative instruments							0	[3]	0	[5]
Changes in collateral deposits supporting energy risk management activities							0	[3]	0	[5]
Cash used by changes in other working capital							682	[3]	440	[5]
Proceeds from sale of emission allowances							0	[3]	0	[5]
Gain on sale of assets, net and postretirement benefits curtailment	[3]
Asset Impairment Charges		0	[1]		0	[6]	0	[6]	0	[6]
Impairment losses							0	[3]	0	[5]
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	[4]								0
Gain on sale of assets and postretirement benefits curtailment	[5]								0
Adjustment to loss on debt extinguishment	[3]						0		0
Net Cash Provided by Operating Activities	[5]						0		2
Cash Flows from Investing Activities
Proceeds from Dividends Received	[3]						(12)		(33)
Payments to Acquire Business Two, Net of Cash Acquired							77	[3]	489	[5]
Acquisitions of businesses, net of cash acquired							0	[3]	0	[5]
Capital expenditures							0	[3]	0	[5]
Increase in restricted cash, net							0	[3]	0	[5]
Increase in restricted cash — U.S. DOE funded projects							0	[3]	0	[5]
Decrease in notes receivable							0	[3]	0	[5]
Investments in nuclear decommissioning trust fund securities							0	[3]	0	[5]
Proceeds from the sale of nuclear decommissioning trust fund securities							0	[3]	0	[5]
Proceeds from renewable energy grants and state rebates							0	[3]	0	[5]
Payments to Acquire Intangible Assets							0	[3]	0	[5]
Proceeds from Sale of Intangible Assets							0	[3]	0	[5]
Proceeds from sale of assets, net of cash disposed of							0	[3]	0	[5]
(Investments in) Proceeds From Sales of Unconsolidated Affiliates							0	[3]	2	[5]
Other							0	[3]	0	[5]
Net Cash (Used)/Provided by Investing Activities							6	[3]	402	[5]
Cash Flows from Financing Activities
Payments (for)/from intercompany loans							0	[3]	0	[5]
Payments to Acquire Business Three, Net of Cash Acquired	[3]						77		489
Intercompany Dividend Proceeds - Financing	[3]						12		33
Payment of dividends to common and preferred stockholders							0	[3]	0	[5]
Payment for treasury stock	[5]								0
Payments for Repurchase of Redeemable Preferred Stock	[3]						0
Net receipts from settlement of acquired derivatives that include financing elements							0	[3]	0	[5]
Proceeds from issuance of long-term debt							0	[3]	0	[5]
Distributions from, net of contributions to, noncontrolling interest in subsidiaries							0	[3]	0	[5]
Proceeds from issuance of common stock							0	[3]	0	[5]
Payments of Debt Issuance Costs							0	[3]	0	[5]
Payments for short and long-term debt							0	[3]	0	[5]
Other - contingent consideration							0	[3]	0	[5]
Net Cash (Used)/Provided by Financing Activities							(6)	[3]	(404)	[5]
Effect of exchange rate changes on cash and cash equivalents							0	[3]	0	[5]
Net Increase/(Decrease) in Cash and Cash Equivalents							0	[3]	0	[5]
Cash and Cash Equivalents at Beginning of Period							0	[7]	0	[5]
Cash and Cash Equivalents at End of Period		$ 0	[3],[8]		$ 0	[5]	0	[3],[8]	0	[5]
Consolidation, Eliminations [Member] | NRG Yield, Inc.
Cash Flows from Investing Activities
Proceeds from Dividends Received	[3]						(59)		(52)
Cash Flows from Financing Activities
Intercompany Dividend Proceeds - Financing	[3]						$ 59		$ 52
[1]	All significant intercompany transactions have been eliminated in consolidation.
[2]	(a)All significant intercompany transactions have been eliminated in consolidation.
[3]	All significant intercompany transactions have been eliminated in consolidation.
[4]	All significant intercompany transactions have been eliminated in consolidation.
[5]	All significant intercompany transactions have been eliminated in consolidation.
[6]	All significant intercompany transactions have been eliminated in consolidation.
[7]	All significant intercompany transactions have been eliminated in consolidation.
[8]	All significant intercompany transactions have been eliminated in consolidation.