NRG Energy (NRG) 10-Q 9 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 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	Jun. 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		315,280,157
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
Operating Revenues
Total operating revenues	$ 2,638	[1]	$ 3,400	[2]	$ 5,867	[1]	$ 7,229	[2]
Operating Costs and Expenses
Cost of operations	1,756		2,436		3,945		5,509
Depreciation and amortization	309		396		622		791
Asset Impairment Charges	115		0		115		0
Selling, general and administrative	265		296		520		551
Acquisition-related transaction and integration costs	5		3		7		13
Development activity expenses	18		37		44		71
Total operating costs and expenses	2,468		3,168		5,253		6,935
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0		0		0		14
Loss on sale of assets, net of gains	(83)		0		(51)		0
Operating Income	87		232		563		308
Other Income/(Expense)
Equity in earnings/(losses) of unconsolidated affiliates	4		8		(3)		5
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	7		0		(139)		0
Other income, net	8		4		26		23
Loss on debt extinguishment	(80)		(7)		(69)		(7)
Interest expense	(277)		(263)		(561)		(564)
Total other expense	(338)		(258)		(746)		(543)
Loss Before Income Taxes	(251)		(26)		(183)		(235)
Income tax expense/(benefit)	25		(17)		46		(90)
Net Loss	(276)		(9)		(229)		(145)
Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests	(5)		5		(40)		(11)
Net Loss Attributable to NRG Energy, Inc.	(271)		(14)		(189)		(134)
Gain on redemption, net of dividends for preferred shares	(78)		5		(73)		10
Loss Available for Common Stockholders	$ (193)		$ (19)		$ (116)		$ (144)
Loss per Share Attributable to NRG Energy, Inc. Common Stockholders
Weighted average number of common shares outstanding - basic and diluted	315		333		315		335
Loss per Weighted Average Common Share — Basic and Diluted	$ (0.61)		$ (0.06)		$ (0.37)		$ (0.43)
Weighted average number of common shares outstanding — diluted	315		333		315		335
Loss per Weighted Average Common Share — Diluted	$ (0.67)		$ (0.06)		$ (0.42)		$ (0.43)
Dividends Per Common Share	$ 0.03		$ 0.14		$ 0.18		$ 0.29
[1]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$218 $3 $5 $— $55 $— $281(b) Includes loss on sale of assets$— $— $— $— $(83) $— $(83)(c) Includes loss on debt extinguishment$— $— $— $— $(80) $— $(80)
[2]	(e) Operating revenues include inter-segment sales and net derivative gains and losses of:$297 $4 $23 $9 $48 $— $381

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income/(Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Loss	$ (276)	$ (9)	$ (229)	$ (145)
Other Comprehensive (Loss)/Income, net of tax
Unrealized (loss)/gains on derivatives, net of income tax expense of $1, $12, $2 and $6	(3)	16	(35)	4
Foreign currency translation adjustments, net of income tax expense/(benefit) of $0 , $6, $0 and $(1)	(3)	9	3	(2)
Available-for-sale securities, net of income tax benefit of $0, $3, $0 and $7	(2)	(3)	1	(4)
Defined benefit plans, net of tax expense of $0, $0, $0 and $4	0	(1)	1	6
Other comprehensive (loss)/income	(8)	21	(30)	4
Comprehensive (Loss)/Income	(284)	12	(259)	(141)
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests	(16)	12	(68)	(17)
Comprehensive Loss Attributable to NRG Energy, Inc.	(268)	0	(191)	(124)
Gain on redemption, net of dividends for preferred shares	(78)	5	(73)	10
Comprehensive Loss Available for Common Stockholders	$ (190)	$ (5)	$ (118)	$ (134)

Condensed Consolidated Stateme4

Condensed Consolidated Statement of Comprehensive Loss Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Unrealized gain/loss on derivatives, income tax benefit	$ 1	$ 12	$ 2	$ 6
Foreign currency translation adjustments, income tax benefit	0	6	0	(1)
Available-for-sale securities, income tax expense	0	3	0	7
Defined benefit plans, income tax expense	$ 0	$ 0	$ 0	$ 4

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 1,389	$ 1,518
Funds deposited by counterparties	44	106
Restricted cash	413	414
Accounts receivable — trade, less allowance for doubtful accounts of $20 and $21	1,251	1,157
Inventory	1,124	1,252
Derivative instruments	1,470	1,915
Cash collateral paid in support of energy risk management activities	218	568
Renewable energy grant receivable, net	36	13
Disposal Group, Including Discontinued Operation, Other Assets, Current	13	6
Prepayments and other current assets	406	442
Total current assets	6,364	7,391
Property, plant and equipment, net of accumulated depreciation of $6,107 and $5,761	18,382	18,732
Other Assets
Equity investments in affiliates	882	1,045
Notes receivable, less current portion	25	53
Goodwill	999	999
Intangible assets, net of accumulated amortization of $1,650 and $1,525	2,180	2,310
Nuclear decommissioning trust fund	599	561
Derivative instruments	348	305
Deferred income taxes	175	167
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent	229	105
Other non-current assets	1,239	1,214
Total other assets	6,676	6,759
Total Assets	31,422	32,882
Current Liabilities
Current portion of long-term debt and capital leases	1,215	481
Accounts payable	898	869
Derivative instruments	1,373	1,721
Cash collateral received in support of energy risk management activities	44	106
Disposal Group, Including Discontinued Operation, Liabilities, Current	2	2
Accrued expenses and other current liabilities	982	1,196
Total current liabilities	4,514	4,375
Other Liabilities
Long-term debt and capital leases	17,893	18,983
Nuclear decommissioning reserve	334	326
Nuclear decommissioning trust liability	309	283
Deferred income taxes	42	19
Derivative instruments	539	493
Off-market Lease, Unfavorable	1,093	1,146
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	0	4
Other non-current liabilities	1,554	1,488
Total non-current liabilities	21,764	22,742
Total Liabilities	26,278	27,117
2.822% convertible perpetual preferred stock	0	302
Redeemable noncontrolling interest in subsidiaries	23	29
Stockholders’ Equity
Common stock	4	4
Additional paid-in capital	8,306	8,296
Retained deficit	(3,179)	(3,007)
Less treasury stock, at cost — 102,450,781 and 102,749,908 shares, respectively	(2,406)	(2,413)
Accumulated other comprehensive loss	(203)	(173)
Noncontrolling interest	2,599	2,727
Total Stockholders’ Equity	5,121	5,434
Total Liabilities and Stockholders’ Equity	$ 31,422	$ 32,882

Condensed Consolidated Balance6

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Accounts receivable - trade, allowance for doubtful accounts	$ 20	$ 21
Property, plant and equipment, accumulated depreciation	6,107	5,761
Intangible assets, accumulated amortization	1,650	1,525
Accumulated Amortization of Out of Market Contracts	$ 712	$ 664
Convertible perpetual preferred stock, interest rate (as a percentage)	2.822%	2.822%
Treasury stock, shares (in shares)	102,450,781	102,749,908

Condensed Consolidated Stateme7

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash Flows from Operating Activities
Net Loss	$ (229)	$ (145)
Adjustments to reconcile net loss to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates	32	40
Depreciation and amortization	622	791
Provision for bad debts	20	29
Amortization of nuclear fuel	26	23
Amortization of financing costs and debt discount/premiums	3	(7)
Adjustment to loss on debt extinguishment	14	7
Amortization of intangibles and out-of-market contracts	41	32
Amortization of unearned equity compensation	16	24
Impairment losses	254	0
Changes in deferred income taxes and liability for uncertain tax benefits	1	(98)
Changes in nuclear decommissioning trust liability	13	(4)
Changes in derivative instruments	(25)	186
Changes in collateral deposits supporting energy risk management activities	350	(112)
Proceeds from sale of emission allowances	47	0
Loss/(gain) on sale of assets and postretirement benefits curtailment	43	(14)
Cash used by changes in other working capital	(355)	(294)
Net Cash Provided by Operating Activities	873	458
Cash Flows from Investing Activities
Acquisitions of businesses, net of cash acquired	(17)	(30)
Capital expenditures	(622)	(583)
Decrease/(increase) in restricted cash, net	29	(3)
(Increase)/decrease in restricted cash to support equity requirements for U.S. DOE funded projects	(28)	27
(Increase)/decrease in notes receivable	(3)	7
Purchases of emission allowances	27	0
Proceeds from sale of emission allowances	25	0
Investments in nuclear decommissioning trust fund securities	(280)	(354)
Proceeds from the sale of nuclear decommissioning trust fund securities	267	358
Proceeds from renewable energy grants and state rebates	10	61
Proceeds from sale of assets, net of cash disposed of	145	1
Investments in unconsolidated affiliates	0	(353)
Other	32	9
Net Cash Used by Investing Activities	(469)	(860)
Cash Flows from Financing Activities
Payment of dividends to common and preferred stockholders	(57)	(102)
Payment for treasury stock	0	(186)
Payment for preferred shares	(226)	0
Net receipts from settlement of acquired derivatives that include financing elements	103	91
Proceeds from issuance of long-term debt	3,223	629
Distributions from, net of contributions to, noncontrolling interest in subsidiaries	(21)	670
Proceeds from issuance of common stock	0	1
Payments of Debt Issuance Costs	35	12
Payments for short and long-term debt	(3,507)	(662)
Other - contingent consideration	(10)	0
Net Cash (Used)/Provided by Financing Activities	(530)	429
Effect of exchange rate changes on cash and cash equivalents	(3)	3
Net (Decrease)/Increase in Cash and Cash Equivalents	(129)	30
Cash and Cash Equivalents at Beginning of Period	1,518	2,116
Cash and Cash Equivalents at End of Period	$ 1,389	$ 2,146

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 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, which produces, sells and delivers energy and energy products and services in major competitive power markets in the U.S. while positioning itself as a leader in the way residential, industrial and commercial consumers use energy products and services. NRG has one of the nation's largest and most diverse competitive power generation portfolios balanced with a leading retail electricity platform. The Company owns and operates approximately 48,000 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 June 30, 2016, and the results of operations, comprehensive income/(loss) and cash flows for the three and six months ended June 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 loss for the three months and six months ended June 30, 2016 were not impacted by the adjustment.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Other Cash Flow Information NRG’s investing activities exclude capital expenditures of $96 million which were accrued and unpaid at June 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 (82 ) Contributions from noncontrolling interest 13 Redemption of noncontrolling interest (8 ) Comprehensive loss attributable to noncontrolling interest (51 ) Balance as of June 30, 2016 $ 2,599 Redeemable Noncontrolling Interest The following table reflects the changes in the Company's redeemable noncontrolling interest balance for the six months ended June 30, 2016 : (In millions) Balance as of December 31, 2015 $ 29 Distributions to redeemable noncontrolling interest (1 ) Contributions from redeemable noncontrolling interest 12 Comprehensive loss attributable to redeemable noncontrolling interest (17 ) Balance as of June 30, 2016 $ 23 Recent Accounting Developments ASU 2016-09 — In March 2016, the FASB issued ASU 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 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 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 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 evaluating the impact of the standard 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. The guidance in ASU No. 2014-09 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 the following steps to be applied by an entity: (1) identify the contract with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies the performance obligation. 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. In addition to ASU No. 2014-09, the FASB has issued additional guidance which provides further clarification on Topic 606. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606), or ASU No. 2016-08. The amendments of ASU No. 2016-08 clarify how to apply the implementation guidance on principal versus agent considerations related to the sale of goods or services to a customer as updated by ASU No. 2014-09. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606), or ASU No. 2016-10. The amendments of ASU No. 2016-10 provide further clarification on contract revenue recognition as updated by ASU No. 2014-09, specifically related to the identification of separately identifiable performance obligations and the implementation of licensing contracts. In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606), or ASU No. 2016-12. The amendments of ASU No. 2016-12 provide further clarification on contract revenue recognition as updated by ASU No. 2014-09, specifically related to collectibility, the presentation of tax collected from customers, and non-cash consideration, as well as offering practical expedients. 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	6 Months Ended
	Jun. 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 Yield Operating, 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. Dispositions Disposition of Majority Interest in EVgo On June 17, 2016, the Company completed the sale of a majority interest in its EVgo business to Vision Ridge Partners for total consideration of approximately $39 million , including $17 million in cash received, which is net of $2.5 million in working capital adjustments, $15 million contributed as capital to the EVgo business and $7 million of future contributions by Vision Ridge Partners. all of which were determined based on forecasted cash requirements to operate the business in future periods. In addition, the Company has future earnout potential of up to $70 million based on future profitability targets. NRG will retain its original financial obligation of $102.5 million under its agreement with the CPUC whereby EVgo will build at least 200 public fast charging Freedom Station sites and perform the associated work to prepare 10,000 commercial and multi-family parking spaces for electric vehicle charging in California. As part of the sale, NRG has contracted with EVgo to continue to build the remaining required Freedom Stations and commercial and multi-family parking spaces for electric vehicle charging required under this obligation and will be directly reimbursed by NRG for the costs. As a result of the sale, the Company recorded a loss on sale of $83 million during the second quarter of 2016, which reflects the loss on the sale of the equity interest of $27 million and the accrual of NRG's remaining obligation under its agreement with the CPUC of $56 million . At June 30, 2016, the Company's remaining 35% interest in EVgo was accounted for as an equity-method investment at its fair value of $10 million . Rockford Disposition On May 12, 2016, the Company entered into an agreement with RA Generation, LLC to sell 100% of its interests in the Rockford I and Rockford II generating stations, or Rockford, for cash consideration of $55 million , subject to adjustments for working capital and the results of the PJM 2019/2020 base residual auction. Rockford is a 450 MW natural gas facility located in Rockford, Illinois. The transaction triggered an indicator of impairment as the sales price was less than the carrying amount of the assets, and, as a result the assets were considered to be impaired. The Company measured the impairment loss as the difference between the carrying amount of the assets and the agreed-upon sales price. The Company recorded an impairment loss of $17 million during the quarter ended June 30, 2016 to reduce the carrying amount of the assets held for sale to the fair market value. At June 30, 2016, the Company had $2 million of current assets and $54 million of non-current assets classified as held for sale for Rockford on its balance sheet. On July 12, 2016, the Company completed the sale of Rockford for cash proceeds of $56 million , including $1 million in adjustments for the PJM base residual auction results. For further discussion on this impairment, refer to Note 7 , Impairments . 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. At June 30, 2016, GenOn had $2 million of current assets, $175 million of non-current assets and $2 million of current liabilities classified as held for sale for Aurora on its balance sheet. 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 sale will result in a gain of approximately $189 million to be recognized within GenOn's consolidated results of operations during the third quarter of 2016. Seward Disposition On November 24, 2015, GenOn entered into an agreement with an affiliate of Robindale Energy Services, Inc. to sell 100% of its interest in the Seward generating station, a 525 MW coal-fired facility in Pennsylvania, for cash consideration of $75 million . At December 31, 2015, GenOn had $5 million of current assets, $83 million of non-current assets, $1 million of current liabilities and $4 million of non-current liabilities classified as held for sale for Seward on its balance sheet. 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 future environmental testing. 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 100% of its interest in 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 $1 million of current assets, $22 million of non-current assets, and $1 million of current liabilities classified as held for sale for Shelby on its balance sheet. 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 within the consolidated results of operations during the first quarter of 2016. In addition, GenOn retained $10 million related to future revenue rights retained as part of the agreement. Transfer of Assets under Common Control On August 8, 2016, the Company entered into an agreement to sell the remaining 51.05% interest in the CVSR project to NRG Yield, Inc. for total expected consideration of $78.5 million plus assumed debt and working capital adjustments to be calculated at close. The sale is subject to customary closing conditions and is expected to close during the third quarter of 2016. 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 . On January 2, 2015, the Company sold the following facilities to NRG Yield, Inc.: Walnut Creek, the Tapestry projects (Buffalo Bear, Pinnacle and Taloga) and Laredo Ridge. NRG Yield, Inc. paid total cash consideration of $489 million , including $9 million of working capital adjustments, plus assumed project level debt of $737 million .

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 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 June 30, 2016 As of December 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable (a) $ 54 $ 54 $ 73 $ 73 Liabilities: Long-term debt, including current portion (b) 19,253 18,593 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. Recurring Fair Value Measurements Debt securities, equity securities, and trust fund investments, which are comprised of various U.S. debt and equity securities, and derivative assets and liabilities, are carried at fair market value. The following tables present assets and liabilities measured and recorded at fair value on the Company's condensed consolidated balance sheets on a recurring basis and their level within the fair value hierarchy: As of June 30, 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 $ — $ — $ 16 $ 16 Available-for-sale securities 11 — — 11 Other (a) 11 — — 11 Nuclear trust fund investments: Cash and cash equivalents 33 — — 33 U.S. government and federal agency obligations 55 1 — 56 Federal agency mortgage-backed securities — 69 — 69 Commercial mortgage-backed securities — 19 — 19 Corporate debt securities — 81 — 81 Equity securities 289 — 51 340 Foreign government fixed income securities — 1 — 1 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 595 1,007 216 1,818 Total assets $ 995 $ 1,178 $ 283 $ 2,456 Derivative liabilities: Commodity contracts 529 974 209 1,712 Interest rate contracts — 200 — 200 Total liabilities $ 529 $ 1,174 $ 209 $ 1,912 (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 six months ended June 30, 2016 , and 2015 between Levels 1 and 2. The following tables reconcile, for the three and six months ended June 30, 2016 , and 2015 , the beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements, at least annually, using significant unobservable inputs: Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Three months ended June 30, 2016 Six months ended June 30, 2016 (In millions) Debt Securities Trust Fund Investments Derivatives (a) Total Debt Securities Trust Fund Investments Derivatives (a) Total Beginning balance $ 17 $ 52 $ (17 ) $ 52 $ 17 $ 54 $ (33 ) $ 38 Total gains/(losses) — realized/unrealized: Included in earnings — — 24 24 — — 7 7 Included in OCI (1 ) — — (1 ) (1 ) — — (1 ) Included in nuclear decommissioning obligation — (1 ) — (1 ) — (4 ) — (4 ) Purchases — — 24 24 — 1 29 30 Transfers into Level 3 (b) — — (20 ) (20 ) — — 7 7 Transfers out of Level 3 (b) — — (4 ) (4 ) — — (3 ) (3 ) Ending balance as of June 30, 2016 $ 16 $ 51 $ 7 $ 74 $ 16 $ 51 $ 7 $ 74 Gains/(losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of June 30, 2016 $ — $ — $ 9 $ 9 $ — $ — $ (15 ) $ (15 ) (a) Consists of derivative assets and liabilities, net. (b) Transfers into/out of Level 3 are related to the availability of external broker quotes and are valued as of the end of the reporting period. All transfers in/out are with Level 2. Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Three months ended June 30, 2015 Six months ended June 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 $ 11 $ 54 $ 34 $ 117 $ 18 $ 11 $ 52 $ 80 $ 161 Total gains/(losses) — realized/unrealized: Included in earnings — (11 ) — (23 ) (34 ) — (11 ) — (78 ) (89 ) Included in nuclear decommissioning obligations — — — — — — — 2 — 2 Purchases — — 1 39 40 — — 1 35 36 Transfers into Level 3 (b) — — — (4 ) (4 ) — — — 11 11 Transfers out of Level 3 (b) — — — 3 3 — — — 1 1 Ending balance as of June 30, 2015 $ 18 $ — $ 55 $ 49 $ 122 $ 18 $ — $ 55 $ 49 $ 122 Losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of June 30, 2015 $ — $ — $ — $ (8 ) $ (8 ) $ — $ — $ — $ (28 ) $ (28 ) (a) Consists of derivative assets and liabilities, net. (b) Transfers into/out of Level 3 are related to the availability of external broker quotes and are valued as of the end of the reporting period. All transfers in/out are with Level 2. Derivative Fair Value Measurements A portion of NRG's contracts are exchange-traded contracts with readily available quoted market prices. A majority of NRG's contracts are non-exchange-traded contracts valued using prices provided by external sources, primarily price quotations available through brokers or over-the-counter and on-line exchanges. The remainder of the assets and liabilities represent contracts for which external sources or observable market quotes are not available for the whole term or for certain delivery months or the contracts are retail and load following power contracts. These contracts are valued using various valuation techniques including but not limited to internal models that apply fundamental analysis of the market and corroboration with similar markets. As of June 30, 2016 , contracts valued with prices provided by models and other valuation techniques make up 12% of the total derivative assets and 11% of the total derivative liabilities. NRG's significant positions classified as Level 3 include physical and financial power and physical coal executed in illiquid markets as well as financial transmission rights, or FTRs. The significant unobservable inputs used in developing fair value include illiquid power and coal location pricing which is derived as a basis to liquid locations. The basis spread is based on observable market data when available or derived from historic prices and forward market prices from similar observable markets when not available. For FTRs, NRG uses the most recent auction prices to derive the fair value. The following tables quantify the significant unobservable inputs used in developing the fair value of the Company's Level 3 positions as of June 30, 2016 and December 31, 2015 : Significant Unobservable Inputs June 30, 2016 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 165 $ 146 Discounted Cash Flow Forward Market Price (per MWh) $ 10 $ 108 $ 38 Coal Contracts — 13 Discounted Cash Flow Forward Market Price (per ton) 28 38 33 FTRs 51 50 Discounted Cash Flow Auction Prices (per MWh) (97 ) 29 — $ 216 $ 209 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 June 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 June 30, 2016 , the credit reserve resulted in a $6 million increase in fair value, which is composed of a $4 million gain in OCI and a $2 million gain in operating revenue and cost of operations. As of June 30, 2015 , the credit reserve resulted in a $3 million increase in fair value, which was composed of a $1 million gain in OCI and a $2 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 June 30, 2016 , counterparty credit exposure, excluding credit risk exposure under certain long term agreements, was $678 million and NRG held collateral (cash and letters of credit) against those positions of $53 million , resulting in a net exposure of $646 million . Approximately 87% 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 (% of Total) Financial institutions 53 % Utilities, energy merchants, marketers and other 29 ISOs 18 Total as of June 30, 2016 100 % Net Exposure (a) Category (% of Total) Investment grade 97 % Non-rated (b) 2 Non-investment grade 1 Total as of June 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 $296 million as of June 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 June 30, 2016 , aggregate credit risk exposure managed by NRG to these counterparties was approximately $4.1 billion , including $2.5 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 June 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	6 Months Ended
	Jun. 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 June 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 $ 33 $ — $ — — $ 6 $ — $ — — U.S. government and federal agency obligations 56 5 — 12 55 1 — 11 Federal agency mortgage-backed securities 69 2 — 24 59 1 — 25 Commercial mortgage-backed securities 19 — 1 27 25 — 2 28 Corporate debt securities 81 3 — 11 81 1 1 10 Equity securities 340 202 — — 334 199 — — Foreign government fixed income securities 1 — — 8 1 — — 9 Total $ 599 $ 212 $ 1 $ 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. Six months ended June 30, 2016 2015 (In millions) Realized gains $ 3 $ 9 Realized losses 2 5 Proceeds from sale of securities 267 358

Accounting for Derivative Instr

Accounting for Derivative Instruments and Hedging Activities	6 Months Ended
	Jun. 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 June 30, 2016 , NRG had energy-related derivative instruments extending through 2027 . The Company marks these derivatives to market through the income statement. Interest Rate Swaps NRG is exposed to changes in interest rates through the Company's issuance of variable rate debt. In order to manage the Company's interest rate risk, NRG enters into interest rate swap agreements. As of June 30, 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 June 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 June 30, 2016 December 31, 2015 Category Units (In millions) Emissions Short Ton — 1 Coal Short Ton 27 35 Natural Gas MMBtu 136 293 Oil Barrel 1 1 Power MWh (45 ) (74 ) Capacity MW/Day (1 ) (1 ) Interest Dollars $ 3,184 $ 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 June 30, 2016 December 31, 2015 June 30, 2016 December 31, 2015 (In millions) Derivatives designated as cash flow hedges: Interest rate contracts current $ — $ — $ 39 $ 42 Interest rate contracts long-term — — 124 68 Total derivatives designated as cash flow hedges — — 163 110 Derivatives not designated as cash flow hedges : Interest rate contracts current — — 9 5 Interest rate contracts long-term — — 28 13 Commodity contracts current 1,470 1,915 1,325 1,674 Commodity contracts long-term 348 305 387 412 Total derivatives not designated as cash flow hedges 1,818 2,220 1,749 2,104 Total derivatives $ 1,818 $ 2,220 $ 1,912 $ 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 June 30, 2016 (In millions) Commodity contracts: Derivative assets $ 1,818 $ (1,525 ) $ (53 ) $ 240 Derivative liabilities (1,712 ) 1,525 17 (170 ) Total commodity contracts 106 — (36 ) 70 Interest rate contracts: Derivative liabilities (200 ) — — (200 ) Total derivative instruments $ (94 ) $ — $ (36 ) $ (130 ) 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 June 30, 2016 Six months ended June 30, 2016 Energy Commodities Interest Rate Total Energy Commodities Interest Rate Total (In millions) Accumulated OCI beginning balance $ — $ (150 ) $ (150 ) $ — $ (101 ) $ (101 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts — 7 7 — 10 10 Mark-to-market of cash flow hedge accounting contracts — (22 ) (22 ) — (74 ) (74 ) Accumulated OCI ending balance, net of $26 tax $ — $ (165 ) $ (165 ) $ — $ (165 ) $ (165 ) Losses expected to be realized from OCI during the next 12 months, net of $3 tax $ — $ 22 $ 22 $ — $ 22 $ 22 Three months ended June 30, 2015 Six months ended June 30, 2015 Energy Commodities Interest Rate Total Energy Commodities Interest Rate Total (In millions) Accumulated OCI beginning balance $ (1 ) $ (83 ) $ (84 ) $ (1 ) $ (67 ) $ (68 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts — 2 2 — 4 4 Mark-to-market of cash flow hedge accounting contracts — 19 19 — 1 1 Accumulated OCI ending balance, net of $37 tax $ (1 ) $ (62 ) $ (63 ) $ (1 ) $ (62 ) $ (63 ) 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 six months ended June 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 earnings. The following table summarizes the pre-tax effects of economic hedges that have not been designated as cash flow hedges, ineffectiveness on cash flow hedges and trading activity on the Company's statement of operations. The effect of energy commodity contracts is included within operating revenues and cost of operations and the effect of interest rate contracts is included in interest expense. Three months ended June 30, Six months ended June 30, 2016 2015 2016 2015 Unrealized mark-to-market results (In millions) Reversal of previously recognized unrealized gains on settled positions related to economic hedges $ (51 ) $ (36 ) $ (137 ) $ (150 ) Reversal of acquired gain positions related to economic hedges (15 ) (24 ) (28 ) (50 ) Net unrealized (losses)/gains on open positions related to economic hedges (32 ) 57 102 (81 ) Total unrealized mark-to-market losses for economic hedging activities (98 ) (3 ) (63 ) (281 ) Reversal of previously recognized unrealized losses/(gains) on settled positions related to trading activity 2 (15 ) 10 (36 ) Reversal of acquired gain positions related to trading activity — (5 ) — (12 ) Net unrealized gains/(losses) on open positions related to trading activity 11 (4 ) 22 2 Total unrealized mark-to-market gains/(losses) for trading activity 13 (24 ) 32 (46 ) Total unrealized losses $ (85 ) $ (27 ) $ (31 ) $ (327 ) Three months ended June 30, Six months ended June 30, 2016 2015 2016 2015 (In millions) Unrealized losses included in operating revenues $ (526 ) $ (137 ) $ (481 ) $ (246 ) Unrealized gains/(losses) included in cost of operations 441 110 450 (81 ) Total impact to statement of operations — energy commodities $ (85 ) $ (27 ) $ (31 ) $ (327 ) Total impact to statement of operations — interest rate contracts $ (7 ) $ 35 $ (18 ) $ 21 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 revenue or cost of operations during the same period. For the six months ended June 30, 2016 , the $102 million unrealized gain from open economic hedge positions was primarily the result of an increase in value of forward purchases of ERCOT electricity and natural gas due to increases in ERCOT power and natural gas prices, partially offset by a decrease in value of forward sales of PJM electricity due to decreases in PJM power prices. For the six months ended June 30, 2015 , the $81 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. As discussed above, GenOn realized approximately $38 million due to the closure and financial settlement of all open positions with one of GenOn's counterparties during the three months ended June 30, 2016. GenOn expects to close out and financially settle certain open positions with an additional counterparty during the third quarter of 2016. These positions had a fair market value of $80 million as of June 30, 2016. As of July 31, 2016, GenOn has realized $98 million due to the closure and financial settlement of these positions which would have otherwise been realized in 2017 through 2019. Credit Risk Related Contingent Features Certain of the Company's hedging agreements contain provisions that require the Company to post additional collateral if the counterparty determines that there has been deterioration in credit quality, generally termed “adequate assurance” under the agreements, or requires the Company to post additional collateral if there were a one notch downgrade in the Company's credit rating. The collateral required for contracts with adequate assurance clauses that are in a net liability position as of June 30, 2016 , was $80 million . The collateral required for contracts with credit rating contingent features as of June 30, 2016 , was $15 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 $9 million as of June 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	6 Months Ended
	Jun. 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 occurring 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. Petra Nova Parish Holdings — During the first quarter of 2016, management changed its plans with respect to its future capital commitments driven in part by the continued decline in oil prices. As a result, the Company reviewed its 50% interest in Petra Nova Parish Holdings for impairment utilizing the other-than-temporary impairment model. In determining fair value, the Company utilized an income approach and considered project specific assumptions for the future project cash flows. The carrying amount of the Company's equity method investment exceeded the fair value of the investment and the Company concluded that the decline is considered to be other than temporary. As a result, the Company measured the impairment loss as the difference between the carrying amount and the fair value of the investment and recorded an impairment loss of $140 million .

Debt and Capital Leases

Debt and Capital Leases	6 Months Ended
	Jun. 30, 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) June 30, 2016 December 31, 2015 June 30, 2016 interest rate % (a) Recourse debt: Senior notes, due 2018 $ 587 $ 1,039 7.625 Senior notes, due 2020 818 1,058 8.250 Senior notes, due 2021 889 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 734 904 6.250 Senior notes, due 2026 1,000 — 7.250 Term loan facility, due 2018 — 1,964 L+2.00 Term loan facility, due 2023 1,890 — L+2.75 Tax-exempt bonds 455 455 4.125 - 6.00 Subtotal NRG recourse debt 8,234 8,584 Non-recourse debt: GenOn senior notes 1,934 1,956 7.875 - 9.875 GenOn Americas Generation senior notes 748 752 8.500 - 9.125 GenOn Other 53 56 Subtotal GenOn debt (non-recourse to NRG) 2,735 2,764 Yield Operating LLC Senior Notes, due 2024 500 500 5.375 Yield LLC and Yield Operating LLC Revolving Credit Facility, due 2019 318 306 L+2.75 Yield Inc. Convertible Senior Notes, due 2019 333 330 3.500 Yield Inc. Convertible Senior Notes, due 2020 268 266 3.250 El Segundo Energy Center, due 2023 457 485 L+1.625 - L+2.25 Marsh Landing, due 2017 and 2023 410 418 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 341 351 L+1.625 Tapestry, due 2021 176 181 L+1.625 Laredo Ridge, due 2028 102 104 L+1.875 Alpine, due 2022 151 154 L+1.750 Energy Center Minneapolis, due 2017 and 2025 100 108 5.95 - 7.25 Viento, due 2023 183 189 L+2.75 NRG Yield - other 455 469 various Subtotal NRG Yield debt (non-recourse to NRG) 4,772 4,863 Ivanpah, due 2033 and 2038 1,141 1,149 2.285 - 4.256 Agua Caliente, due 2037 874 879 2.395 - 3.633 CVSR, due 2037 780 793 2.339 - 3.775 Dandan, due 2033 101 98 L+2.25 Peaker bonds, due 2019 — 72 L+1.07 Cedro Hill, due 2025 100 103 L+3.125 Midwest Generation, due 2019 249 — 4.390 NRG Other 267 315 various Subtotal other NRG non-recourse debt 3,512 3,409 Subtotal all non-recourse debt 11,019 11,036 Subtotal long-term debt (including current maturities) 19,253 19,620 Capital leases: Capital leases 13 13 various Other 2 3 various Subtotal long-term debt and capital leases (including current maturities) 19,268 19,636 Less current maturities 1,215 481 Less debt issuance costs 160 172 Total long-term debt and capital leases $ 17,893 $ 18,983 (a) As of June 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 NRG Marsh Landing term loan, Walnut Creek term loan, and NRG Yield Operating LLC revolving credit facility, 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 will be 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. 2016 Senior Notes Repurchases During the six months ended June 30, 2016, the Company repurchased $1.3 billion in aggregate principal of its Senior Notes in the open market for $1.3 billion , which included accrued interest of $21 million . In connection with the repurchases, a $45 million loss on debt extinguishment was recorded, which included the write-off of previously deferred financing costs of $7 million . Principal Repurchased Cash Paid (a) Average Early Redemption Percentage Amount in millions, except rates 7.625% senior notes due 2018 $ 451 $ 499 107.95 % 7.875% senior notes due 2021 240 250 104.19 % 6.625% senior notes due 2023 67 64 94.13 % 6.250% senior notes due 2022 108 105 94.73 % 6.250% senior notes due 2024 171 163 94.52 % 8.250% senior notes due 2020 239 254 104.38 % Total $ 1,276 $ 1,335 (a) Includes accrued interest. 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, 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 and 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 and 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 June 30, 2016, $707 million of GenOn's senior unsecured notes outstanding are classified as current within the consolidated balance sheet as they mature on June 15, 2017. GenOn is not expected to generate sufficient cash, exclusive of cash subject to the restrictions under the GenOn Mid-Atlantic and REMA operating leases, during the subsequent twelve months to make this principal payment as it becomes due. There is no assurance GenOn will continue as a going concern. GenOn is currently considering all options available to it, including negotiations with creditors, refinancing the senior unsecured notes, potential sales of certain generating assets as well as the possibility for 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. 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. 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. The construction loans have interest rates of LIBOR plus an applicable margin of 2.25% or base rate plus 1.25% and the cash grant loans have an interest rate of LIBOR plus an applicable margin of 1.75% . The term loan has an interest rate of LIBOR plus an applicable margin of 2.25% , which escalates 0.25% on the fifth, tenth, and fifteenth anniversary of the term conversion. The term loan, which is secured by all the assets of Dandan, matures January 2033, and amortizes based upon a predetermined schedule. The Dandan Financing Agreement also includes a letter of credit facility on behalf of Dandan of up to $5 million . Dandan pays an availability fee of 2.25% from the closing date until the fifth anniversary of the term conversion date and 2.50% from the fifth anniversary of the term conversion date on issued letters of credit. 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 June 30, 2016, $78 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 June 30, 2016, $249 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 In July, 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.

Variable Interest Entities

Variable Interest Entities	6 Months Ended
	Jun. 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, Yield Operating, 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 $108 million as of June 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 $73 million as of June 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 $38 million as of June 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) June 30, 2016 December 31, 2015 Current assets $ 78 $ 84 Net property, plant and equipment 1,754 1,807 Other long-term assets 926 863 Total assets 2,758 2,754 Current liabilities 57 56 Long-term debt 350 366 Other long-term liabilities 192 179 Total liabilities 599 601 Noncontrolling interests 703 493 Net assets less noncontrolling interests $ 1,456 $ 1,660

Changes in Capital Structure

Changes in Capital Structure	6 Months Ended
	Jun. 30, 2016
Changes in Capital Structure Disclosure [Abstract]
Changes in Capital Structure	Changes in Capital Structure As of June 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 457,135 — 457,135 Shares issued under ESPP — 299,127 299,127 Balance as of June 30, 2016 417,397,085 (102,450,781 ) 314,946,304 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 June 30, 2016 , there were 977,786 shares of treasury stock available for issuance under the ESPP. In July 2016, 309,967 shares of NRG common stock were issued to employee accounts from treasury stock under the ESPP. NRG Common Stock Dividends The following table lists the dividends paid during the six months ended June 30, 2016 : Second Quarter 2016 First Quarter 2016 Dividends per Common Share $ 0.030 $ 0.145 On July 13, 2016 , NRG declared a quarterly dividend on the Company's common stock of $0.03 per share, payable August 15, 2016 , to stockholders of record as of August 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	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
Earnings Per Share	Loss Per Share Basic loss per common share is computed by dividing net 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 loss per share is computed in a manner consistent with that of basic 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 loss per share is shown in the following table: Three months ended June 30, Six months ended June 30, (In millions, except per share data) 2016 2015 2016 2015 Basic and diluted loss per share attributable to NRG Energy, Inc. common stockholders Net loss attributable to NRG Energy, Inc. $ (271 ) $ (14 ) $ (189 ) $ (134 ) Dividends for preferred shares — 5 5 10 Gain on redemption of 2.822% redeemable perpetual preferred stock (78 ) — (78 ) — Loss available for common stockholders $ (193 ) $ (19 ) $ (116 ) $ (144 ) Weighted average number of common shares outstanding - basic and diluted 315 333 315 335 Loss per weighted average common share — basic and diluted $ (0.61 ) $ (0.06 ) $ (0.37 ) $ (0.43 ) The following table summarizes NRG’s outstanding equity instruments that are anti-dilutive and were not included in the computation of the Company’s diluted loss per share: Three months ended June 30, Six months ended June 30, (In millions of shares) 2016 2015 2016 2015 Equity compensation plans 3 7 3 7 Embedded derivative of 2.822% redeemable perpetual preferred stock — 16 — 16 Total 3 23 3 23

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 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, excluding those in the NRG Yield segment; 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 six months ended June 30, 2015 has been recast to reflect the change. Intersegment sales are accounted for at market. 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. The acquisition was treated as a transfer of entities under common control and accordingly the financial information for the three and six months ended June 30, 2015 has been recast to reflect this change. 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)(b) Retail Mass (a) Renewables (a) NRG Yield (a) Corporate (a)(c) Eliminations Total Three months ended June 30, 2016 Operating revenues (a) $ 1,306 $ 1,201 $ 125 $ 258 $ 29 $ (281 ) $ 2,638 Depreciation and amortization 144 27 55 67 16 — 309 Impairment losses 76 — 26 — 13 — 115 Equity in (losses)/earnings of unconsolidated affiliates — — (4 ) 18 1 (11 ) 4 Gain on investment — — — — 7 — 7 (Loss)/income before income taxes (371 ) 496 (63 ) 70 (371 ) (12 ) (251 ) Net (Loss)/Income (371 ) 496 (58 ) 58 (389 ) (12 ) (276 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (371 ) $ 496 $ (53 ) $ 42 $ (409 ) $ 24 $ (271 ) Total assets as of June 30, 2016 $ 14,445 $ 2,169 $ 5,730 $ 7,609 $ 16,799 $ (15,330 ) $ 31,422 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 218 $ 3 $ 5 $ — $ 55 $ — $ 281 (b) Includes loss on sale of assets $ — $ — $ — $ — $ (83 ) $ — $ (83 ) (c) Includes loss on debt extinguishment $ — $ — $ — $ — $ (80 ) $ — $ (80 ) (In millions) Generation (e) Retail Mass (e) Renewables (e) NRG Yield (e) Corporate (e) Eliminations Total Three months ended June 30, 2015 Operating revenues (a) $ 2,110 $ 1,298 $ 128 $ 235 $ 10 $ (381 ) $ 3,400 Depreciation and amortization 228 33 53 70 12 — 396 Equity in earnings/(loss) of unconsolidated affiliates 6 — (2 ) 8 — (4 ) 8 Income/(Loss) before income taxes 4 217 (9 ) 42 (272 ) (8 ) (26 ) Net Income/(Loss) 3 217 (6 ) 38 (253 ) (8 ) (9 ) Net Income/(Loss) attributable to NRG Energy, Inc. $ 3 $ 217 $ (20 ) $ 21 $ (239 ) $ 4 $ (14 ) (e) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 297 $ 4 $ 23 $ 9 $ 48 $ — $ 381 (In millions) Generation (h)(i) Retail Mass (h) Renewables (h) NRG Yield (h) Corporate (h)(i)(j) Eliminations Total Six months ended June 30, 2016 Operating revenues (a) $ 3,426 $ 2,249 $ 234 $ 478 $ 88 $ (608 ) $ 5,867 Depreciation and amortization 290 55 111 133 33 — 622 Impairment losses 76 — 26 — 13 — 115 Equity in (losses)/earnings of unconsolidated affiliates (5 ) — (8 ) 20 2 (12 ) (3 ) Impairment loss on investment (137 ) — — — (2 ) — (139 ) (Loss)/Income before income taxes (211 ) 642 (114 ) 72 (563 ) (9 ) (183 ) Net (Loss)/Income (212 ) 642 (103 ) 60 (607 ) (9 ) (229 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (212 ) $ 642 $ (88 ) $ 52 $ (614 ) $ 31 $ (189 ) (h) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 469 $ 4 $ 10 $ 4 $ 121 $ — $ 608 (i) Includes gain/(loss) on sale of assets $ 32 $ — $ — $ — $ (83 ) $ — $ (51 ) (j) Includes loss on debt extinguishment $ — $ — $ — $ — $ (69 ) $ — $ (69 ) (In millions) Generation (l)(m) Retail Mass (l) Renewables (l) NRG Yield (l) Corporate (l) Eliminations Total Six months ended June 30, 2015 Operating revenues (a) $ 4,619 $ 2,609 $ 219 $ 435 $ 8 $ (661 ) $ 7,229 Depreciation and amortization 461 63 105 137 25 — 791 Equity in earnings/(losses) of unconsolidated affiliates 2 — (3 ) 10 (1 ) (3 ) 5 Income/(Loss) before income taxes 33 321 (66 ) 18 (534 ) (7 ) (235 ) Net Income/(Loss) 32 321 (57 ) 18 (452 ) (7 ) (145 ) Net Income/(Loss) attributable to NRG Energy, Inc. $ 32 $ 321 $ (66 ) $ 6 $ (426 ) $ (1 ) $ (134 ) (l) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 544 $ 4 $ 23 $ 9 $ 81 $ — $ 661 (m) Includes gain on postretirement benefits curtailment $ 14 $ — $ — $ — $ — $ — $ 14

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Tax Rate The income tax provision consisted of the following: Three months ended June 30, Six months ended June 30, (In millions except otherwise noted) 2016 2015 2016 2015 Loss before income taxes $ (251 ) $ (26 ) $ (183 ) $ (235 ) Income tax expense/(benefit) 25 (17 ) 46 (90 ) Effective tax rate (10.0 )% 65.4 % (25.1 )% 38.3 % For the three and six months ended June 30, 2016 , NRG's overall effective tax rate was different than the statutory rate of 35% primarily due to tax expense resulting from the change in the valuation allowance, amortization of indefinite lived assets, inclusion of consolidated partnerships and the impact of state income taxes. For the three and six months ended June 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 our wind assets partially offset by tax expense attributable to consolidated partnerships. Uncertain Tax Benefits As of June 30, 2016 , NRG has recorded a non-current tax liability of $43 million for uncertain tax benefits from positions taken on various state income tax returns, including accrued interest. For the six months ended June 30, 2016 , NRG accrued an insignificant amount of interest relating to the uncertain tax benefits. As of June 30, 2016 , NRG had cumulative interest and penalties related to these uncertain tax benefits of $3 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 2011. 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	6 Months Ended
	Jun. 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 June 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. Subsequent to the close of the second quarter of 2016, each of Ivanpah's unit 1 and unit 3 satisfied their respective production requirements for the initial six-month measurement period under the forbearance agreements. Lignite Contract with Texas Westmoreland Coal Co. — The lignite used to fuel the Gulf Coast region's Limestone facility is 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 based on a cost-plus arrangement with incentives and penalties to ensure proper management of the mine. NRG has the flexibility to increase or decrease lignite purchases from the mine within certain ranges, including the ability to suspend or terminate lignite purchases with adequate notice. The mining period extends through 2018 with an option to further extend the mining period by two five -year intervals. TWCC is responsible for performing ongoing reclamation activities at the mine until all lignite reserves have been produced. When production is completed at the mine, NRG will be responsible for final mine reclamation obligations and maintains an appropriate ARO. The Railroad Commission of Texas has imposed a bond obligation of $107.5 million on TWCC for the reclamation of this lignite mine. Pursuant to the contract with TWCC, NRG supports this obligation as follows: $12 million is guaranteed by NRG, and $95.5 million is supported by surety bonds posted by NRG, of which $64 million were issued during the second quarter of 2016. Additionally, NRG is required to provide additional performance assurance over TWCC's current bond obligations 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. On July 29, 2016, MC Asset Recovery filed its appeal with the Fifth Circuit. 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 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 is responding to this second subpoena. The Company does not expect the resolution of this matter to have a material impact on the Company's consolidated financial position, results of operations, or cash flows. 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 July 2016, the parties signed a consent decree, which will settle the matter, subject to approval by the court. The consent decree requires: (1) improving the wastewater treatment systems at the Chalk Point and Dickerson facilities; (2) completing supplemental environmental projects worth $1 million ; and (3) paying a 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. The Company is vigorously defending against these lawsuits. On July 8, 2016, NRG filed a Rule 11 Motion seeking dismissal of NRG from the California case. 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. Braun v. NRG Yield, Inc. — On April 19, 2016, plaintiffs filed a purported class action lawsuit against NRG Yield, Inc. and against each current and former member of its board of directors individually 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 provides that the plaintiffs will file an amended complaint by August 19, 2016. The Defendants need to file a responsive pleading by October 18, 2016.

Regulatory Matters

Regulatory Matters	6 Months Ended
	Jun. 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. This case governs capacity revenues already received by the Company, as well as the revenues for forward periods. 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. The matter is pending at FERC.

Environmental Matters

Environmental Matters	6 Months Ended
	Jun. 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 operations. 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. The EPA is currently reviewing the decision. In December 2015, the EPA proposed the CSAPR Update Rule using the 2008 Ozone NAAQS, which would reduce the total amount of ozone season NO x as compared with the previously utilized 1997 Ozone NAAQS. If finalized, this proposal would reduce future NO x allocations and/or current banked allowances. While NRG cannot predict the final outcome of this rulemaking, 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 its results of operations, financial condition and cash flows and has accrued its environmental and asset retirement obligations under the rule based on current estimates as of June 30, 2016. Environmental Capital Expenditures NRG estimates that environmental capital expenditures from 2016 through 2020 required to comply with environmental laws will be approximately $322 million , which includes $61 million for GenOn and $247 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	6 Months Ended
	Jun. 30, 2016
Condensed Consolidating Financial Information Disclosure [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information As of June 30, 2016 , the Company had outstanding $5.9 billion of Senior Notes due from 2018 - 2026, 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 June 30, 2016 : Ace Energy, Inc. 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 LLC 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. New Genco GP, LLC NRG Norwalk Harbor Operations Inc. NRG conducts much of its business through and derives much of its income from its subsidiaries. Therefore, the Company's ability to make required payments with respect to its indebtedness and other obligations depends on the financial results and condition of its subsidiaries and NRG's ability to receive funds from its subsidiaries. There are no restrictions on the ability of any of the guarantor subsidiaries to transfer funds to NRG. However, there may be restrictions for certain non-guarantor subsidiaries. The following condensed consolidating financial information presents the financial information of NRG Energy, Inc., the guarantor subsidiaries and the non-guarantor subsidiaries in accordance with Rule 3-10 under the SEC Regulation S-X. The financial information may not necessarily be indicative of results of operations or financial position had the guarantor subsidiaries or non-guarantor subsidiaries operated as independent entities. In this presentation, NRG Energy, Inc. consists of parent company operations. Guarantor subsidiaries and non-guarantor subsidiaries of NRG are reported on an equity basis. For companies acquired, the fair values of the assets and liabilities acquired have been presented on a push-down accounting basis. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Three Months Ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 1,699 $ 986 $ — $ (47 ) $ 2,638 Operating Costs and Expenses Cost of operations 1,110 685 8 (47 ) 1,756 Depreciation and amortization 108 195 6 — 309 Impairment losses — 115 — — 115 Selling, general and administrative 94 92 79 — 265 Acquisition-related transaction and integration costs — — 5 — 5 Development activity expenses — 13 5 — 18 Total operating costs and expenses 1,312 1,100 103 (47 ) 2,468 Loss on sale of assets — — (83 ) — (83 ) Operating Income/(Loss) 387 (114 ) (186 ) — 87 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (44 ) (27 ) 98 (27 ) — Equity in earnings of unconsolidated affiliates 3 6 — (5 ) 4 Gain on investment — 1 6 — 7 Other income 2 3 4 (1 ) 8 Loss on debt extinguishment — (4 ) (76 ) — (80 ) Interest expense (2 ) (145 ) (130 ) — (277 ) Total other expense (41 ) (166 ) (98 ) (33 ) (338 ) Income/(Loss) Before Income Taxes 346 (280 ) (284 ) (33 ) (251 ) Income tax expense/(benefit) 133 (104 ) (44 ) 40 25 Net Income/(Loss) 213 (176 ) (240 ) (73 ) (276 ) Less: Net income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests — 10 31 (46 ) (5 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 213 $ (186 ) $ (271 ) $ (27 ) $ (271 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the Three Months Ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 213 $ (176 ) $ (240 ) $ (73 ) $ (276 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net — (5 ) (4 ) 6 (3 ) Foreign currency translation adjustments, net (2 ) (2 ) (4 ) 5 (3 ) Available-for-sale securities, net — — (2 ) — (2 ) Defined benefit plans, net — — — — — Other comprehensive loss (2 ) (7 ) (10 ) 11 (8 ) Comprehensive Income/(Loss) 211 (183 ) (250 ) (62 ) (284 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (1 ) 31 (46 ) (16 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 211 (182 ) (281 ) (16 ) (268 ) Gain on redemption of preferred shares — — (78 ) — (78 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 211 $ (182 ) $ (203 ) $ (16 ) $ (190 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the Six Months Ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) 375 (178 ) (153 ) (273 ) (229 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net — (55 ) 20 — (35 ) Foreign currency translation adjustments, net 2 2 2 (3 ) 3 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net 1 — — — 1 Other comprehensive income/(loss) 3 (53 ) 23 (3 ) (30 ) Comprehensive Income/(Loss) 378 (231 ) (130 ) (276 ) (259 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (51 ) 36 (53 ) (68 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 378 (180 ) (166 ) (223 ) (191 ) Gain on redemption, net of dividends for preferred shares — — (73 ) — (73 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 378 $ (180 ) $ (93 ) $ (223 ) $ (118 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS June 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 $ — $ 1,039 $ 350 $ — $ 1,389 Funds deposited by counterparties — 44 — — 44 Restricted cash 10 403 — — 413 Accounts receivable - trade, net 911 338 2 — 1,251 Accounts receivable - affiliate 325 41 191 (553 ) 4 Inventory 475 649 — — 1,124 Derivative instruments 991 574 — (95 ) 1,470 Cash collateral paid in support of energy risk management activities 130 88 — — 218 Renewable energy grant receivable, net — 36 — — 36 Current assets held-for-sale — 13 — — 13 Prepayments and other current assets 106 237 59 — 402 Total current assets 2,948 3,462 602 (648 ) 6,364 Net property, plant and equipment 4,483 13,678 248 (27 ) 18,382 Other Assets Investment in subsidiaries 1,080 2,031 10,771 (13,882 ) — Equity investments in affiliates (17 ) 984 10 (95 ) 882 Notes receivable, less current portion — 24 (2 ) 3 25 Goodwill 697 302 — — 999 Intangible assets, net 691 1,491 1 (3 ) 2,180 Nuclear decommissioning trust fund 599 — — — 599 Derivative instruments 210 164 — (26 ) 348 Deferred income tax 30 590 (445 ) — 175 Non-current assets held-for-sale — 229 — — 229 Other non-current assets 53 833 353 — 1,239 Total other assets 3,343 6,648 10,688 (14,003 ) 6,676 Total Assets $ 10,774 $ 23,788 $ 11,538 $ (14,678 ) $ 31,422 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 1,375 $ (163 ) $ 3 $ 1,215 Accounts payable 588 270 40 — 898 Accounts payable — affiliate 242 269 42 (553 ) — Derivative instruments 915 550 3 (95 ) 1,373 Cash collateral received in support of energy risk management activities — 44 — — 44 Current liabilities held-for-sale — 2 — — 2 Accrued expenses and other current liabilities 301 338 343 — 982 Total current liabilities 2,046 2,848 265 (645 ) 4,514 Other Liabilities Long-term debt and capital leases 245 9,810 7,838 — 17,893 Nuclear decommissioning reserve 334 — — — 334 Nuclear decommissioning trust liability 309 — — — 309 Deferred income taxes 958 255 (1,171 ) — 42 Derivative instruments 298 267 — (26 ) 539 Out-of-market contracts, net 88 1,005 — — 1,093 Other non-current liabilities 411 781 362 — 1,554 Total non-current liabilities 2,643 12,118 7,029 (26 ) 21,764 Total liabilities 4,689 14,966 7,294 (671 ) 26,278 Redeemable noncontrolling interest in subsidiaries — 23 — — 23 Stockholders’ Equity 6,085 8,799 4,244 (14,007 ) 5,121 Total Liabilities and Stockholders’ Equity $ 10,774 $ 23,788 $ 11,538 $ (14,678 ) $ 31,422 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS For the Six Months Ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net Income/(Loss) $ 375 $ (178 ) $ (153 ) $ (273 ) $ (229 ) Adjustments to reconcile net income/(loss) to net cash provided by operating activities: Distributions from unconsolidated affiliates — 40 — (11 ) 29 Equity in (earnings)/losses of unconsolidated affiliates (3 ) 2 — 4 3 Depreciation and amortization 225 385 12 — 622 Provision for bad debts 16 4 — — 20 Amortization of nuclear fuel 26 — — — 26 Amortization of financing costs and debt discount/premiums — (10 ) 13 — 3 Adjustment for debt extinguishment — 4 10 — 14 Amortization of intangibles and out-of-market contracts 20 21 — — 41 Amortization of unearned equity compensation — — 16 — 16 Impairment losses — 254 — — 254 Changes in deferred income taxes and liability for uncertain tax benefits 233 (112 ) (120 ) — 1 Changes in nuclear decommissioning trust liability 13 — — — 13 Changes in derivative instruments (64 ) 36 3 — (25 ) Changes in collateral deposits supporting energy risk management activities 344 6 — — 350 Proceeds from sale of emission allowances 47 — — — 47 (Gain)/loss on sale of assets — (32 ) 75 — 43 Cash (used)/provided by changes in other working capital (935 ) 24 276 280 (355 ) Net Cash Provided by Operating Activities 297 444 132 — 873 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. — — 39 (39 ) — Intercompany dividends — 12 (12 ) — Acquisition of businesses, net of cash acquired — (17 ) — — (17 ) Capital expenditures (80 ) (509 ) (33 ) — (622 ) Decrease in restricted cash, net 4 25 — — 29 Decrease/(increase) in restricted cash — U.S. DOE funded projects 1 (29 ) — — (28 ) Increase in notes receivable — (3 ) — — (3 ) Purchases of emission allowances (27 ) — — — (27 ) Proceeds from sale of emission allowances 25 — — — 25 Investments in nuclear decommissioning trust fund securities (280 ) — — — (280 ) Proceeds from sales of nuclear decommissioning trust fund securities 267 — — — 267 Proceeds from renewable energy grants and state rebates — 10 — — 10 Proceeds from sale of assets, net of cash disposed of — 120 25 — 145 Other 28 4 — — 32 Net Cash (Used)/Provided by Investing Activities (62 ) (399 ) 43 (51 ) (469 ) Cash Flows from Financing Activities Payments (for)/from intercompany loans (179 ) 45 134 — — Payment of dividends NRG Yield, Inc. — (39 ) — 39 — Intercompany dividends (52 ) 40 — 12 — Payment of dividends to common and preferred stockholders — — (57 ) — (57 ) Payment for preferred shares — — (226 ) — (226 ) Net receipts from settlement of acquired derivatives that include financing elements — 103 — — 103 Proceeds from issuance of long-term debt — 332 2,891 — 3,223 Distributions from, net of contributions to, noncontrolling interest in subsidiaries — (21 ) — — (21 ) Payment of debt issuance costs — — (35 ) — (35 ) Payments for short and long-term debt (1 ) (281 ) (3,225 ) — (3,507 ) Other (3 ) (7 ) — — (10 ) Net Cash (Used)/Provided by Financing Activities (235 ) 172 (518 ) 51 (530 ) Effect of exchange rate changes on cash and cash equivalents — (3 ) — — (3 ) Net Increase/(Decrease) in Cash and Cash Equivalents — 214 (343 ) — (129 ) Cash and Cash Equivalents at Beginning of Period — 825 693 — 1,518 Cash and Cash Equivalents at End of Period $ — $ 1,039 $ 350 $ — $ 1,389 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Three Months Ended June 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 2,267 $ 1,161 $ — $ (28 ) $ 3,400 Operating Costs and Expenses Cost of operations 1,703 756 (16 ) (7 ) 2,436 Depreciation and amortization 196 195 5 — 396 Selling, general and administrative 116 93 87 — 296 Acquisition-related transaction and integration costs — (1 ) 4 — 3 Development activity expenses — 11 26 — 37 Total operating costs and expenses 2,015 1,054 106 (7 ) 3,168 Operating Income/(Loss) 252 107 (106 ) (21 ) 232 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (22 ) (49 ) 154 (83 ) — Equity in earnings of unconsolidated affiliates 3 10 — (5 ) 8 Other income, net — 3 1 — 4 Loss on debt extinguishment — (7 ) — — (7 ) Interest expense (5 ) (121 ) (137 ) — (263 ) Total other expense (24 ) (164 ) 18 (88 ) (258 ) Income/(Loss) Before Income Taxes 228 (57 ) (88 ) (109 ) (26 ) Income tax expense/(benefit) 83 (16 ) (84 ) — (17 ) Net Income/(Loss) 145 (41 ) (4 ) (109 ) (9 ) Less: Net income attributable to noncontrolling interest and redeemable noncontrolling interest — 21 10 (26 ) 5 Net Income/(Loss) Attributable to NRG Energy, Inc. $ 145 $ (62 ) $ (14 ) $ (83 ) $ (14 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Six Months Ended June 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 4,833 $ 2,464 $ — $ (68 ) $ 7,229 Operating Costs and Expenses Cost of operations 3,807 1,762 (4 ) (56 ) 5,509 Depreciation and amortization 400 381 10 — 791 Selling, general and administrative 221 183 147 — 551 Acquisition-related transaction and integration costs — 1 12 — 13 Development activity expenses — 26 45 — 71 Total operating costs and expenses 4,428 2,353 210 (56 ) 6,935 Gain on postretirement benefits curtailment — 14 — — 14 Operating Income/(Loss) 405 125 (210 ) (12 ) 308 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (35 ) (57 ) 204 (112 ) — Equity in earnings/(losses) of unconsolidated affiliates 3 6 (1 ) (3 ) 5 Other income, net 1 20 2 — 23 Loss on debt extinguishment — (7 ) — — (7 ) Interest expense (9 ) (279 ) (276 ) — (564 ) Total other expense (40 ) (317 ) (71 ) (115 ) (543 ) Income/(Loss) Before Income Taxes 365 (192 ) (281 ) (127 ) (235 ) Income tax expense/(benefit) 137 (76 ) (151 ) — (90 ) Net Income/(Loss) 228 (116 ) (130 ) (127 ) (145 ) Less: Net income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest — — 4 (15 ) (11 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 228 $ (116 ) $ (134 ) $ (112 ) $ (134 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the Three Months Ended June 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 145 $ (41 ) $ (4 ) $ (109 ) $ (9 ) Other Comprehensive Income/(Loss), net of tax Unrealized gain on derivatives, net 2 4 25 (15 ) 16 Foreign currency translation adjustments, net — 9 — — 9 Available-for-sale securities, net — — (3 ) — (3 ) Defined benefit plans, net — — (1 ) — (1 ) Other comprehensive income 2 13 21 (15 ) 21 Comprehensive Income/(Loss) 147 (28 ) 17 (124 ) 12 Less: Comprehensive income attributable to noncontrolling interest and redeemable noncontrolling interest — 28 10 (26 ) 12 Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 147 (56 ) 7 (98 ) — Dividends for preferred shares — — 5 — 5 Comprehensive Income/(Loss) Available for Common Stockholders $ 147 $ (56 ) $ 2 $ (98 ) $ (5 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the Six Months Ended June 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) 228 (116 ) (130 ) (127 ) (145 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net (5 ) 15 9 (15 ) 4 Foreign currency translation adjustments, net — — (2 ) — (2 ) Available-for-sale securities, net — (1 ) (3 ) — (4 ) Defined benefit plans, net (3 ) (1 ) 10 — 6 Other comprehensive (loss)/income (8 ) 13 14 (15 ) 4 Comprehensive Income/(Loss) 220 (103 ) (116 ) (142 ) (141 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (6 ) 4 (15 ) (17 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 220 (97 ) (120 ) (127 ) (124 ) Dividends for preferred shares — — 10 — 10 Comprehensive Income/(Loss) Available for Common Stockholders $ 220 $ (97 ) $ (130 ) $ (127 ) $ (134 ) (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 Six Months Ended June 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) $ 228 $ (116 ) $ (130 ) $ (127 ) $ (145 ) Adjustments to reconcile net loss to net cash provided by operating activities: Distributions from unconsolidated affiliates 6 50 — (11 ) 45 Equity in (earnings)/losses of unconsolidated affiliates (3 ) (6 ) 1 3 (5 ) Depreciation and amortization 400 381 10 — 791 Provision for bad debts 26 — 3 — 29 Amortization of nuclear fuel 23 — — — 23 Amortization of financing costs and debt discount/premiums — (20 ) 13 — (7 ) Adjustment for debt extinguishment — 7 — — 7 Amortization of intangibles and out-of-market contracts 24 8 — — 32 Amortization of unearned equity compensation — — 24 — 24 Changes in deferred income taxes and liability for uncertain tax benefits 137 (76 ) (159 ) — (98 ) Changes in nuclear decommissioning trust liability (4 ) — — — (4 ) Changes in derivative instruments 63 121 2 — 186 Changes in collateral deposits supporting energy risk management activities (82 ) (30 ) — — (112 ) Gain on postretirement benefits curtailment — (14 ) — — (14 ) Cash provided/(used) by changes in other working capital 710 (771 ) (368 ) 135 (294 ) Net Cash Provided/(Used) by Operating Activities 1,528 (466 ) (604 ) — 458 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. — — 34 (34 ) — Intercompany dividends — — 33 (33 ) — Acquisition of businesses, net of cash acquired — (30 ) — — (30 ) Capital expenditures (177 ) (388 ) (18 ) — (583 ) Increase in restricted cash, net — (3 ) — — (3 ) Decrease in restricted cash — U.S. DOE projects — 27 — — 27 Decrease in notes receivable — 7 — — 7 Investments in nuclear decommissioning trust fund securities (354 ) — — — (354 ) Proceeds from sales of nuclear decommissioning trust fund securities 358 — — — 358 Proceeds from renewable energy grants and state rebates — 61 — — 61 Proceeds from sale of assets, net of cash disposed of — — 1 — 1 Investments in unconsolidated affiliates — (304 ) (49 ) — (353 ) Other 5 4 — — 9 Net Cash (Used)/Provided by Investing Activities (168 ) (626 ) 1 (67 ) (860 ) Cash Flows from Financing Activities Payments (for)/from intercompany loans (1,368 ) 440 928 — — Intercompany dividends — (33 ) — 33 — Payments of dividends from NRG Yield, Inc. — (34 ) — 34 — Payment of dividends to common and preferred stockholders — — (102 ) — (102 ) Payment for treasury stock — — (186 ) — (186 ) Net receipts for settlement of acquired derivatives that include financing elements — 91 — — 91 Proceeds from issuance of long-term debt — 601 28 — 629 Distributions from, net of contributions to, noncontrolling interest in subsidiaries — 670 — — 670 Proceeds from issuance of common stock — — 1 — 1 Payment of debt issuance costs — (12 ) — — (12 ) Payments for short and long-term debt — (652 ) (10 ) — (662 ) Net Cash (Used)/Provided by Financing Activities (1,368 ) 1,071 659 67 429 Effect of exchange rate changes on cash and cash equivalents — 3 — — 3 Net (Decrease)/Increase in Cash and Cash Equivalents (8 ) (18 ) 56 — 30 Cash and Cash Equivalents at Beginning of Period 18 1,455 643 — 2,116 Cash and Cash Equivalents at End of Period $ 10 $ 1,437 $ 699 $ — $ 2,146 (a) All significant intercompany transactions have been eliminated in consolidation.

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Policy)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Business Description and Basis of Presentation [Text Block]	NRG Energy, Inc., or NRG or the Company, is an integrated competitive power company, which produces, sells and delivers energy and energy products and services in major competitive power markets in the U.S. while positioning itself as a leader in the way residential, industrial and commercial consumers use energy products and services. NRG has one of the nation's largest and most diverse competitive power generation portfolios balanced with a leading retail electricity platform. The Company owns and operates approximately 48,000 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 June 30, 2016, and the results of operations, comprehensive income/(loss) and cash flows for the three and six months ended June 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 loss for the three months and six months ended June 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 $96 million which were accrued and unpaid at June 30, 2016
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Developments ASU 2016-09 — In March 2016, the FASB issued ASU 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 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 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 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 evaluating the impact of the standard 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. The guidance in ASU No. 2014-09 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 the following steps to be applied by an entity: (1) identify the contract with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies the performance obligation. 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. In addition to ASU No. 2014-09, the FASB has issued additional guidance which provides further clarification on Topic 606. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606), or ASU No. 2016-08. The amendments of ASU No. 2016-08 clarify how to apply the implementation guidance on principal versus agent considerations related to the sale of goods or services to a customer as updated by ASU No. 2014-09. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606), or ASU No. 2016-10. The amendments of ASU No. 2016-10 provide further clarification on contract revenue recognition as updated by ASU No. 2014-09, specifically related to the identification of separately identifiable performance obligations and the implementation of licensing contracts. In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606), or ASU No. 2016-12. The amendments of ASU No. 2016-12 provide further clarification on contract revenue recognition as updated by ASU No. 2014-09, specifically related to collectibility, the presentation of tax collected from customers, and non-cash consideration, as well as offering practical expedients. 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, excluding those in the NRG Yield segment; 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

Summary of Significant Accoun26

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
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 (82 ) Contributions from noncontrolling interest 13 Redemption of noncontrolling interest (8 ) Comprehensive loss attributable to noncontrolling interest (51 ) Balance as of June 30, 2016 $ 2,599
Redeemable Noncontrolling Interest [Table Text Block]	Redeemable Noncontrolling Interest The following table reflects the changes in the Company's redeemable noncontrolling interest balance for the six months ended June 30, 2016 : (In millions) Balance as of December 31, 2015 $ 29 Distributions to redeemable noncontrolling interest (1 ) Contributions from redeemable noncontrolling interest 12 Comprehensive loss attributable to redeemable noncontrolling interest (17 ) Balance as of June 30, 2016 $ 23

Fair Value of Financial Instr27

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 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 June 30, 2016 As of December 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable (a) $ 54 $ 54 $ 73 $ 73 Liabilities: Long-term debt, including current portion (b) 19,253 18,593 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.
Assets and liabilities measured and recorded at fair value on the consolidated balance sheets on a recurring basis	The following tables present assets and liabilities measured and recorded at fair value on the Company's condensed consolidated balance sheets on a recurring basis and their level within the fair value hierarchy: As of June 30, 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 $ — $ — $ 16 $ 16 Available-for-sale securities 11 — — 11 Other (a) 11 — — 11 Nuclear trust fund investments: Cash and cash equivalents 33 — — 33 U.S. government and federal agency obligations 55 1 — 56 Federal agency mortgage-backed securities — 69 — 69 Commercial mortgage-backed securities — 19 — 19 Corporate debt securities — 81 — 81 Equity securities 289 — 51 340 Foreign government fixed income securities — 1 — 1 Other trust fund investments: U.S. government and federal agency obligations 1 — — 1 Derivative assets: Commodity contracts 595 1,007 216 1,818 Total assets $ 995 $ 1,178 $ 283 $ 2,456 Derivative liabilities: Commodity contracts 529 974 209 1,712 Interest rate contracts — 200 — 200 Total liabilities $ 529 $ 1,174 $ 209 $ 1,912 (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 six months ended June 30, 2016 , and 2015 , the beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements, at least annually, using significant unobservable inputs: Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Three months ended June 30, 2016 Six months ended June 30, 2016 (In millions) Debt Securities Trust Fund Investments Derivatives (a) Total Debt Securities Trust Fund Investments Derivatives (a) Total Beginning balance $ 17 $ 52 $ (17 ) $ 52 $ 17 $ 54 $ (33 ) $ 38 Total gains/(losses) — realized/unrealized: Included in earnings — — 24 24 — — 7 7 Included in OCI (1 ) — — (1 ) (1 ) — — (1 ) Included in nuclear decommissioning obligation — (1 ) — (1 ) — (4 ) — (4 ) Purchases — — 24 24 — 1 29 30 Transfers into Level 3 (b) — — (20 ) (20 ) — — 7 7 Transfers out of Level 3 (b) — — (4 ) (4 ) — — (3 ) (3 ) Ending balance as of June 30, 2016 $ 16 $ 51 $ 7 $ 74 $ 16 $ 51 $ 7 $ 74 Gains/(losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of June 30, 2016 $ — $ — $ 9 $ 9 $ — $ — $ (15 ) $ (15 ) (a) Consists of derivative assets and liabilities, net. (b) Transfers into/out of Level 3 are related to the availability of external broker quotes and are valued as of the end of the reporting period. All transfers in/out are with Level 2. Fair Value Measurement Using Significant Unobservable Inputs (Level 3) Three months ended June 30, 2015 Six months ended June 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 $ 11 $ 54 $ 34 $ 117 $ 18 $ 11 $ 52 $ 80 $ 161 Total gains/(losses) — realized/unrealized: Included in earnings — (11 ) — (23 ) (34 ) — (11 ) — (78 ) (89 ) Included in nuclear decommissioning obligations — — — — — — — 2 — 2 Purchases — — 1 39 40 — — 1 35 36 Transfers into Level 3 (b) — — — (4 ) (4 ) — — — 11 11 Transfers out of Level 3 (b) — — — 3 3 — — — 1 1 Ending balance as of June 30, 2015 $ 18 $ — $ 55 $ 49 $ 122 $ 18 $ — $ 55 $ 49 $ 122 Losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets or liabilities still held as of June 30, 2015 $ — $ — $ — $ (8 ) $ (8 ) $ — $ — $ — $ (28 ) $ (28 ) (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 June 30, 2016 and December 31, 2015 : Significant Unobservable Inputs June 30, 2016 Fair Value Input/Range Assets Liabilities Valuation Technique Significant Unobservable Input Low High Weighted Average (In millions) Power Contracts $ 165 $ 146 Discounted Cash Flow Forward Market Price (per MWh) $ 10 $ 108 $ 38 Coal Contracts — 13 Discounted Cash Flow Forward Market Price (per ton) 28 38 33 FTRs 51 50 Discounted Cash Flow Auction Prices (per MWh) (97 ) 29 — $ 216 $ 209 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 June 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 (% of Total) Financial institutions 53 % Utilities, energy merchants, marketers and other 29 ISOs 18 Total as of June 30, 2016 100 % Net Exposure (a) Category (% of Total) Investment grade 97 % Non-rated (b) 2 Non-investment grade 1 Total as of June 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)	6 Months Ended
	Jun. 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 June 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 $ 33 $ — $ — — $ 6 $ — $ — — U.S. government and federal agency obligations 56 5 — 12 55 1 — 11 Federal agency mortgage-backed securities 69 2 — 24 59 1 — 25 Commercial mortgage-backed securities 19 — 1 27 25 — 2 28 Corporate debt securities 81 3 — 11 81 1 1 10 Equity securities 340 202 — — 334 199 — — Foreign government fixed income securities 1 — — 8 1 — — 9 Total $ 599 $ 212 $ 1 $ 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. Six months ended June 30, 2016 2015 (In millions) Realized gains $ 3 $ 9 Realized losses 2 5 Proceeds from sale of securities 267 358

Accounting for Derivative Ins29

Accounting for Derivative Instruments and Hedging Activities (Tables)	6 Months Ended
	Jun. 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 June 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 June 30, 2016 December 31, 2015 Category Units (In millions) Emissions Short Ton — 1 Coal Short Ton 27 35 Natural Gas MMBtu 136 293 Oil Barrel 1 1 Power MWh (45 ) (74 ) Capacity MW/Day (1 ) (1 ) Interest Dollars $ 3,184 $ 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 June 30, 2016 December 31, 2015 June 30, 2016 December 31, 2015 (In millions) Derivatives designated as cash flow hedges: Interest rate contracts current $ — $ — $ 39 $ 42 Interest rate contracts long-term — — 124 68 Total derivatives designated as cash flow hedges — — 163 110 Derivatives not designated as cash flow hedges : Interest rate contracts current — — 9 5 Interest rate contracts long-term — — 28 13 Commodity contracts current 1,470 1,915 1,325 1,674 Commodity contracts long-term 348 305 387 412 Total derivatives not designated as cash flow hedges 1,818 2,220 1,749 2,104 Total derivatives $ 1,818 $ 2,220 $ 1,912 $ 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 June 30, 2016 (In millions) Commodity contracts: Derivative assets $ 1,818 $ (1,525 ) $ (53 ) $ 240 Derivative liabilities (1,712 ) 1,525 17 (170 ) Total commodity contracts 106 — (36 ) 70 Interest rate contracts: Derivative liabilities (200 ) — — (200 ) Total derivative instruments $ (94 ) $ — $ (36 ) $ (130 ) 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 June 30, 2016 Six months ended June 30, 2016 Energy Commodities Interest Rate Total Energy Commodities Interest Rate Total (In millions) Accumulated OCI beginning balance $ — $ (150 ) $ (150 ) $ — $ (101 ) $ (101 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts — 7 7 — 10 10 Mark-to-market of cash flow hedge accounting contracts — (22 ) (22 ) — (74 ) (74 ) Accumulated OCI ending balance, net of $26 tax $ — $ (165 ) $ (165 ) $ — $ (165 ) $ (165 ) Losses expected to be realized from OCI during the next 12 months, net of $3 tax $ — $ 22 $ 22 $ — $ 22 $ 22 Three months ended June 30, 2015 Six months ended June 30, 2015 Energy Commodities Interest Rate Total Energy Commodities Interest Rate Total (In millions) Accumulated OCI beginning balance $ (1 ) $ (83 ) $ (84 ) $ (1 ) $ (67 ) $ (68 ) Reclassified from accumulated OCI to income: Due to realization of previously deferred amounts — 2 2 — 4 4 Mark-to-market of cash flow hedge accounting contracts — 19 19 — 1 1 Accumulated OCI ending balance, net of $37 tax $ (1 ) $ (62 ) $ (63 ) $ (1 ) $ (62 ) $ (63 )
Pre-tax effects of economic hedges that have not been designated as cash flow hedges, ineffectiveness on cash flow hedges and trading activity on the Company's statement of operations	The following table summarizes the pre-tax effects of economic hedges that have not been designated as cash flow hedges, ineffectiveness on cash flow hedges and trading activity on the Company's statement of operations. The effect of energy commodity contracts is included within operating revenues and cost of operations and the effect of interest rate contracts is included in interest expense. Three months ended June 30, Six months ended June 30, 2016 2015 2016 2015 Unrealized mark-to-market results (In millions) Reversal of previously recognized unrealized gains on settled positions related to economic hedges $ (51 ) $ (36 ) $ (137 ) $ (150 ) Reversal of acquired gain positions related to economic hedges (15 ) (24 ) (28 ) (50 ) Net unrealized (losses)/gains on open positions related to economic hedges (32 ) 57 102 (81 ) Total unrealized mark-to-market losses for economic hedging activities (98 ) (3 ) (63 ) (281 ) Reversal of previously recognized unrealized losses/(gains) on settled positions related to trading activity 2 (15 ) 10 (36 ) Reversal of acquired gain positions related to trading activity — (5 ) — (12 ) Net unrealized gains/(losses) on open positions related to trading activity 11 (4 ) 22 2 Total unrealized mark-to-market gains/(losses) for trading activity 13 (24 ) 32 (46 ) Total unrealized losses $ (85 ) $ (27 ) $ (31 ) $ (327 ) Three months ended June 30, Six months ended June 30, 2016 2015 2016 2015 (In millions) Unrealized losses included in operating revenues $ (526 ) $ (137 ) $ (481 ) $ (246 ) Unrealized gains/(losses) included in cost of operations 441 110 450 (81 ) Total impact to statement of operations — energy commodities $ (85 ) $ (27 ) $ (31 ) $ (327 ) Total impact to statement of operations — interest rate contracts $ (7 ) $ 35 $ (18 ) $ 21

Debt and Capital Leases Debt an

Debt and Capital Leases Debt and Capital Leases (Tables)	6 Months Ended
	Jun. 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) June 30, 2016 December 31, 2015 June 30, 2016 interest rate % (a) Recourse debt: Senior notes, due 2018 $ 587 $ 1,039 7.625 Senior notes, due 2020 818 1,058 8.250 Senior notes, due 2021 889 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 734 904 6.250 Senior notes, due 2026 1,000 — 7.250 Term loan facility, due 2018 — 1,964 L+2.00 Term loan facility, due 2023 1,890 — L+2.75 Tax-exempt bonds 455 455 4.125 - 6.00 Subtotal NRG recourse debt 8,234 8,584 Non-recourse debt: GenOn senior notes 1,934 1,956 7.875 - 9.875 GenOn Americas Generation senior notes 748 752 8.500 - 9.125 GenOn Other 53 56 Subtotal GenOn debt (non-recourse to NRG) 2,735 2,764 Yield Operating LLC Senior Notes, due 2024 500 500 5.375 Yield LLC and Yield Operating LLC Revolving Credit Facility, due 2019 318 306 L+2.75 Yield Inc. Convertible Senior Notes, due 2019 333 330 3.500 Yield Inc. Convertible Senior Notes, due 2020 268 266 3.250 El Segundo Energy Center, due 2023 457 485 L+1.625 - L+2.25 Marsh Landing, due 2017 and 2023 410 418 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 341 351 L+1.625 Tapestry, due 2021 176 181 L+1.625 Laredo Ridge, due 2028 102 104 L+1.875 Alpine, due 2022 151 154 L+1.750 Energy Center Minneapolis, due 2017 and 2025 100 108 5.95 - 7.25 Viento, due 2023 183 189 L+2.75 NRG Yield - other 455 469 various Subtotal NRG Yield debt (non-recourse to NRG) 4,772 4,863 Ivanpah, due 2033 and 2038 1,141 1,149 2.285 - 4.256 Agua Caliente, due 2037 874 879 2.395 - 3.633 CVSR, due 2037 780 793 2.339 - 3.775 Dandan, due 2033 101 98 L+2.25 Peaker bonds, due 2019 — 72 L+1.07 Cedro Hill, due 2025 100 103 L+3.125 Midwest Generation, due 2019 249 — 4.390 NRG Other 267 315 various Subtotal other NRG non-recourse debt 3,512 3,409 Subtotal all non-recourse debt 11,019 11,036 Subtotal long-term debt (including current maturities) 19,253 19,620 Capital leases: Capital leases 13 13 various Other 2 3 various Subtotal long-term debt and capital leases (including current maturities) 19,268 19,636 Less current maturities 1,215 481 Less debt issuance costs 160 172 Total long-term debt and capital leases $ 17,893 $ 18,983 (a) As of June 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 NRG Marsh Landing term loan, Walnut Creek term loan, and NRG Yield Operating LLC revolving credit facility, 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 six months ended June 30, 2016, the Company repurchased $1.3 billion in aggregate principal of its Senior Notes in the open market for $1.3 billion , which included accrued interest of $21 million . In connection with the repurchases, a $45 million loss on debt extinguishment was recorded, which included the write-off of previously deferred financing costs of $7 million . Principal Repurchased Cash Paid (a) Average Early Redemption Percentage Amount in millions, except rates 7.625% senior notes due 2018 $ 451 $ 499 107.95 % 7.875% senior notes due 2021 240 250 104.19 % 6.625% senior notes due 2023 67 64 94.13 % 6.250% senior notes due 2022 108 105 94.73 % 6.250% senior notes due 2024 171 163 94.52 % 8.250% senior notes due 2020 239 254 104.38 % Total $ 1,276 $ 1,335 (a) Includes accrued interest.

Variable Interest Entities Summ

Variable Interest Entities Summarized Financial Information (Tables)	6 Months Ended
	Jun. 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) June 30, 2016 December 31, 2015 Current assets $ 78 $ 84 Net property, plant and equipment 1,754 1,807 Other long-term assets 926 863 Total assets 2,758 2,754 Current liabilities 57 56 Long-term debt 350 366 Other long-term liabilities 192 179 Total liabilities 599 601 Noncontrolling interests 703 493 Net assets less noncontrolling interests $ 1,456 $ 1,660

Changes in Capital Structure (T

Changes in Capital Structure (Tables)	6 Months Ended
	Jun. 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 457,135 — 457,135 Shares issued under ESPP — 299,127 299,127 Balance as of June 30, 2016 417,397,085 (102,450,781 ) 314,946,304
Schedule of dividends paid	The following table lists the dividends paid during the six months ended June 30, 2016 : Second Quarter 2016 First Quarter 2016 Dividends per Common Share $ 0.030 $ 0.145

Earnings_(Loss) Per Share (Tabl

Earnings/(Loss) Per Share (Tables)	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
Reconciliation of NRG's basic and diluted earnings per share	The reconciliation of NRG's basic and diluted loss per share is shown in the following table: Three months ended June 30, Six months ended June 30, (In millions, except per share data) 2016 2015 2016 2015 Basic and diluted loss per share attributable to NRG Energy, Inc. common stockholders Net loss attributable to NRG Energy, Inc. $ (271 ) $ (14 ) $ (189 ) $ (134 ) Dividends for preferred shares — 5 5 10 Gain on redemption of 2.822% redeemable perpetual preferred stock (78 ) — (78 ) — Loss available for common stockholders $ (193 ) $ (19 ) $ (116 ) $ (144 ) Weighted average number of common shares outstanding - basic and diluted 315 333 315 335 Loss per weighted average common share — basic and diluted $ (0.61 ) $ (0.06 ) $ (0.37 ) $ (0.43 )
Summary of NRG's outstanding equity instruments that are anti-dilutive and were not included in the computation of the Company's diluted earnings per share	The following table summarizes NRG’s outstanding equity instruments that are anti-dilutive and were not included in the computation of the Company’s diluted loss per share: Three months ended June 30, Six months ended June 30, (In millions of shares) 2016 2015 2016 2015 Equity compensation plans 3 7 3 7 Embedded derivative of 2.822% redeemable perpetual preferred stock — 16 — 16 Total 3 23 3 23

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2016
Segment Reporting Disclosure [Abstract]
Schedule of segment reporting information, by segment	(In millions) Generation (a)(b) Retail Mass (a) Renewables (a) NRG Yield (a) Corporate (a)(c) Eliminations Total Three months ended June 30, 2016 Operating revenues (a) $ 1,306 $ 1,201 $ 125 $ 258 $ 29 $ (281 ) $ 2,638 Depreciation and amortization 144 27 55 67 16 — 309 Impairment losses 76 — 26 — 13 — 115 Equity in (losses)/earnings of unconsolidated affiliates — — (4 ) 18 1 (11 ) 4 Gain on investment — — — — 7 — 7 (Loss)/income before income taxes (371 ) 496 (63 ) 70 (371 ) (12 ) (251 ) Net (Loss)/Income (371 ) 496 (58 ) 58 (389 ) (12 ) (276 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (371 ) $ 496 $ (53 ) $ 42 $ (409 ) $ 24 $ (271 ) Total assets as of June 30, 2016 $ 14,445 $ 2,169 $ 5,730 $ 7,609 $ 16,799 $ (15,330 ) $ 31,422 (a) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 218 $ 3 $ 5 $ — $ 55 $ — $ 281 (b) Includes loss on sale of assets $ — $ — $ — $ — $ (83 ) $ — $ (83 ) (c) Includes loss on debt extinguishment $ — $ — $ — $ — $ (80 ) $ — $ (80 ) (In millions) Generation (e) Retail Mass (e) Renewables (e) NRG Yield (e) Corporate (e) Eliminations Total Three months ended June 30, 2015 Operating revenues (a) $ 2,110 $ 1,298 $ 128 $ 235 $ 10 $ (381 ) $ 3,400 Depreciation and amortization 228 33 53 70 12 — 396 Equity in earnings/(loss) of unconsolidated affiliates 6 — (2 ) 8 — (4 ) 8 Income/(Loss) before income taxes 4 217 (9 ) 42 (272 ) (8 ) (26 ) Net Income/(Loss) 3 217 (6 ) 38 (253 ) (8 ) (9 ) Net Income/(Loss) attributable to NRG Energy, Inc. $ 3 $ 217 $ (20 ) $ 21 $ (239 ) $ 4 $ (14 ) (e) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 297 $ 4 $ 23 $ 9 $ 48 $ — $ 381 (In millions) Generation (h)(i) Retail Mass (h) Renewables (h) NRG Yield (h) Corporate (h)(i)(j) Eliminations Total Six months ended June 30, 2016 Operating revenues (a) $ 3,426 $ 2,249 $ 234 $ 478 $ 88 $ (608 ) $ 5,867 Depreciation and amortization 290 55 111 133 33 — 622 Impairment losses 76 — 26 — 13 — 115 Equity in (losses)/earnings of unconsolidated affiliates (5 ) — (8 ) 20 2 (12 ) (3 ) Impairment loss on investment (137 ) — — — (2 ) — (139 ) (Loss)/Income before income taxes (211 ) 642 (114 ) 72 (563 ) (9 ) (183 ) Net (Loss)/Income (212 ) 642 (103 ) 60 (607 ) (9 ) (229 ) Net (Loss)/Income attributable to NRG Energy, Inc. $ (212 ) $ 642 $ (88 ) $ 52 $ (614 ) $ 31 $ (189 ) (h) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 469 $ 4 $ 10 $ 4 $ 121 $ — $ 608 (i) Includes gain/(loss) on sale of assets $ 32 $ — $ — $ — $ (83 ) $ — $ (51 ) (j) Includes loss on debt extinguishment $ — $ — $ — $ — $ (69 ) $ — $ (69 ) (In millions) Generation (l)(m) Retail Mass (l) Renewables (l) NRG Yield (l) Corporate (l) Eliminations Total Six months ended June 30, 2015 Operating revenues (a) $ 4,619 $ 2,609 $ 219 $ 435 $ 8 $ (661 ) $ 7,229 Depreciation and amortization 461 63 105 137 25 — 791 Equity in earnings/(losses) of unconsolidated affiliates 2 — (3 ) 10 (1 ) (3 ) 5 Income/(Loss) before income taxes 33 321 (66 ) 18 (534 ) (7 ) (235 ) Net Income/(Loss) 32 321 (57 ) 18 (452 ) (7 ) (145 ) Net Income/(Loss) attributable to NRG Energy, Inc. $ 32 $ 321 $ (66 ) $ 6 $ (426 ) $ (1 ) $ (134 ) (l) Operating revenues include inter-segment sales and net derivative gains and losses of: $ 544 $ 4 $ 23 $ 9 $ 81 $ — $ 661 (m) Includes gain on postretirement benefits curtailment $ 14 $ — $ — $ — $ — $ — $ 14

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The income tax provision consisted of the following: Three months ended June 30, Six months ended June 30, (In millions except otherwise noted) 2016 2015 2016 2015 Loss before income taxes $ (251 ) $ (26 ) $ (183 ) $ (235 ) Income tax expense/(benefit) 25 (17 ) 46 (90 ) Effective tax rate (10.0 )% 65.4 % (25.1 )% 38.3 %

Condensed Consolidating Finan36

Condensed Consolidating Financial Information (Tables)	6 Months Ended
	Jun. 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 June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 1,699 $ 986 $ — $ (47 ) $ 2,638 Operating Costs and Expenses Cost of operations 1,110 685 8 (47 ) 1,756 Depreciation and amortization 108 195 6 — 309 Impairment losses — 115 — — 115 Selling, general and administrative 94 92 79 — 265 Acquisition-related transaction and integration costs — — 5 — 5 Development activity expenses — 13 5 — 18 Total operating costs and expenses 1,312 1,100 103 (47 ) 2,468 Loss on sale of assets — — (83 ) — (83 ) Operating Income/(Loss) 387 (114 ) (186 ) — 87 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (44 ) (27 ) 98 (27 ) — Equity in earnings of unconsolidated affiliates 3 6 — (5 ) 4 Gain on investment — 1 6 — 7 Other income 2 3 4 (1 ) 8 Loss on debt extinguishment — (4 ) (76 ) — (80 ) Interest expense (2 ) (145 ) (130 ) — (277 ) Total other expense (41 ) (166 ) (98 ) (33 ) (338 ) Income/(Loss) Before Income Taxes 346 (280 ) (284 ) (33 ) (251 ) Income tax expense/(benefit) 133 (104 ) (44 ) 40 25 Net Income/(Loss) 213 (176 ) (240 ) (73 ) (276 ) Less: Net income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests — 10 31 (46 ) (5 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 213 $ (186 ) $ (271 ) $ (27 ) $ (271 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Six Months Ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 3,655 $ 2,285 $ — $ (73 ) $ 5,867 Operating Costs and Expenses Cost of operations 2,560 1,444 18 (77 ) 3,945 Depreciation and amortization 225 385 12 — 622 Impairment losses — 115 — — 115 Selling, general and administrative 192 191 137 — 520 Acquisition-related transaction and integration costs — — 7 — 7 Development activity expenses — 32 12 — 44 Total operating costs and expenses 2,977 2,167 186 (77 ) 5,253 Gain/(loss) on sale of assets — 32 (83 ) — (51 ) Operating Income/(Loss) 678 150 (269 ) 4 563 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (68 ) (23 ) 311 (220 ) — Equity in earnings/(losses) of unconsolidated affiliates 3 (2 ) — (4 ) (3 ) Impairment loss on investment — (139 ) — — (139 ) Other income 2 23 2 (1 ) 26 Loss on debt extinguishment — (4 ) (65 ) — (69 ) Interest expense (7 ) (295 ) (259 ) — (561 ) Total other expense (70 ) (440 ) (11 ) (225 ) (746 ) Income/(Loss) Before Income Taxes 608 (290 ) (280 ) (221 ) (183 ) Income tax expense/(benefit) 233 (112 ) (127 ) 52 46 Net Income/(Loss) 375 (178 ) (153 ) (273 ) (229 ) Less: Net (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interests — (23 ) 36 (53 ) (40 ) Net Income/(Loss) Attributable to $ 375 $ (155 ) $ (189 ) $ (220 ) $ (189 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Three Months Ended June 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 2,267 $ 1,161 $ — $ (28 ) $ 3,400 Operating Costs and Expenses Cost of operations 1,703 756 (16 ) (7 ) 2,436 Depreciation and amortization 196 195 5 — 396 Selling, general and administrative 116 93 87 — 296 Acquisition-related transaction and integration costs — (1 ) 4 — 3 Development activity expenses — 11 26 — 37 Total operating costs and expenses 2,015 1,054 106 (7 ) 3,168 Operating Income/(Loss) 252 107 (106 ) (21 ) 232 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (22 ) (49 ) 154 (83 ) — Equity in earnings of unconsolidated affiliates 3 10 — (5 ) 8 Other income, net — 3 1 — 4 Loss on debt extinguishment — (7 ) — — (7 ) Interest expense (5 ) (121 ) (137 ) — (263 ) Total other expense (24 ) (164 ) 18 (88 ) (258 ) Income/(Loss) Before Income Taxes 228 (57 ) (88 ) (109 ) (26 ) Income tax expense/(benefit) 83 (16 ) (84 ) — (17 ) Net Income/(Loss) 145 (41 ) (4 ) (109 ) (9 ) Less: Net income attributable to noncontrolling interest and redeemable noncontrolling interest — 21 10 (26 ) 5 Net Income/(Loss) Attributable to NRG Energy, Inc. $ 145 $ (62 ) $ (14 ) $ (83 ) $ (14 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS For the Six Months Ended June 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Operating Revenues Total operating revenues $ 4,833 $ 2,464 $ — $ (68 ) $ 7,229 Operating Costs and Expenses Cost of operations 3,807 1,762 (4 ) (56 ) 5,509 Depreciation and amortization 400 381 10 — 791 Selling, general and administrative 221 183 147 — 551 Acquisition-related transaction and integration costs — 1 12 — 13 Development activity expenses — 26 45 — 71 Total operating costs and expenses 4,428 2,353 210 (56 ) 6,935 Gain on postretirement benefits curtailment — 14 — — 14 Operating Income/(Loss) 405 125 (210 ) (12 ) 308 Other Income/(Expense) Equity in (losses)/earnings of consolidated subsidiaries (35 ) (57 ) 204 (112 ) — Equity in earnings/(losses) of unconsolidated affiliates 3 6 (1 ) (3 ) 5 Other income, net 1 20 2 — 23 Loss on debt extinguishment — (7 ) — — (7 ) Interest expense (9 ) (279 ) (276 ) — (564 ) Total other expense (40 ) (317 ) (71 ) (115 ) (543 ) Income/(Loss) Before Income Taxes 365 (192 ) (281 ) (127 ) (235 ) Income tax expense/(benefit) 137 (76 ) (151 ) — (90 ) Net Income/(Loss) 228 (116 ) (130 ) (127 ) (145 ) Less: Net income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interest — — 4 (15 ) (11 ) Net Income/(Loss) Attributable to NRG Energy, Inc. $ 228 $ (116 ) $ (134 ) $ (112 ) $ (134 ) (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 June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 213 $ (176 ) $ (240 ) $ (73 ) $ (276 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net — (5 ) (4 ) 6 (3 ) Foreign currency translation adjustments, net (2 ) (2 ) (4 ) 5 (3 ) Available-for-sale securities, net — — (2 ) — (2 ) Defined benefit plans, net — — — — — Other comprehensive loss (2 ) (7 ) (10 ) 11 (8 ) Comprehensive Income/(Loss) 211 (183 ) (250 ) (62 ) (284 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (1 ) 31 (46 ) (16 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 211 (182 ) (281 ) (16 ) (268 ) Gain on redemption of preferred shares — — (78 ) — (78 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 211 $ (182 ) $ (203 ) $ (16 ) $ (190 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME For the Six Months Ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) 375 (178 ) (153 ) (273 ) (229 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net — (55 ) 20 — (35 ) Foreign currency translation adjustments, net 2 2 2 (3 ) 3 Available-for-sale securities, net — — 1 — 1 Defined benefit plans, net 1 — — — 1 Other comprehensive income/(loss) 3 (53 ) 23 (3 ) (30 ) Comprehensive Income/(Loss) 378 (231 ) (130 ) (276 ) (259 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (51 ) 36 (53 ) (68 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 378 (180 ) (166 ) (223 ) (191 ) Gain on redemption, net of dividends for preferred shares — — (73 ) — (73 ) Comprehensive Income/(Loss) Available for Common Stockholders $ 378 $ (180 ) $ (93 ) $ (223 ) $ (118 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the Three Months Ended June 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Net Income/(Loss) $ 145 $ (41 ) $ (4 ) $ (109 ) $ (9 ) Other Comprehensive Income/(Loss), net of tax Unrealized gain on derivatives, net 2 4 25 (15 ) 16 Foreign currency translation adjustments, net — 9 — — 9 Available-for-sale securities, net — — (3 ) — (3 ) Defined benefit plans, net — — (1 ) — (1 ) Other comprehensive income 2 13 21 (15 ) 21 Comprehensive Income/(Loss) 147 (28 ) 17 (124 ) 12 Less: Comprehensive income attributable to noncontrolling interest and redeemable noncontrolling interest — 28 10 (26 ) 12 Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 147 (56 ) 7 (98 ) — Dividends for preferred shares — — 5 — 5 Comprehensive Income/(Loss) Available for Common Stockholders $ 147 $ (56 ) $ 2 $ (98 ) $ (5 ) (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) For the Six Months Ended June 30, 2015 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. Eliminations (a) Consolidated (In millions) Net Income/(Loss) 228 (116 ) (130 ) (127 ) (145 ) Other Comprehensive Income/(Loss), net of tax Unrealized (loss)/gain on derivatives, net (5 ) 15 9 (15 ) 4 Foreign currency translation adjustments, net — — (2 ) — (2 ) Available-for-sale securities, net — (1 ) (3 ) — (4 ) Defined benefit plans, net (3 ) (1 ) 10 — 6 Other comprehensive (loss)/income (8 ) 13 14 (15 ) 4 Comprehensive Income/(Loss) 220 (103 ) (116 ) (142 ) (141 ) Less: Comprehensive (loss)/income attributable to noncontrolling interest and redeemable noncontrolling interest — (6 ) 4 (15 ) (17 ) Comprehensive Income/(Loss) Attributable to NRG Energy, Inc. 220 (97 ) (120 ) (127 ) (124 ) Dividends for preferred shares — — 10 — 10 Comprehensive Income/(Loss) Available for Common Stockholders $ 220 $ (97 ) $ (130 ) $ (127 ) $ (134 ) (a) All significant intercompany transactions have been eliminated in consolidation.
Condensed Consolidating Balance Sheets	NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated ASSETS (In millions) Current Assets Cash and cash equivalents $ — $ 1,039 $ 350 $ — $ 1,389 Funds deposited by counterparties — 44 — — 44 Restricted cash 10 403 — — 413 Accounts receivable - trade, net 911 338 2 — 1,251 Accounts receivable - affiliate 325 41 191 (553 ) 4 Inventory 475 649 — — 1,124 Derivative instruments 991 574 — (95 ) 1,470 Cash collateral paid in support of energy risk management activities 130 88 — — 218 Renewable energy grant receivable, net — 36 — — 36 Current assets held-for-sale — 13 — — 13 Prepayments and other current assets 106 237 59 — 402 Total current assets 2,948 3,462 602 (648 ) 6,364 Net property, plant and equipment 4,483 13,678 248 (27 ) 18,382 Other Assets Investment in subsidiaries 1,080 2,031 10,771 (13,882 ) — Equity investments in affiliates (17 ) 984 10 (95 ) 882 Notes receivable, less current portion — 24 (2 ) 3 25 Goodwill 697 302 — — 999 Intangible assets, net 691 1,491 1 (3 ) 2,180 Nuclear decommissioning trust fund 599 — — — 599 Derivative instruments 210 164 — (26 ) 348 Deferred income tax 30 590 (445 ) — 175 Non-current assets held-for-sale — 229 — — 229 Other non-current assets 53 833 353 — 1,239 Total other assets 3,343 6,648 10,688 (14,003 ) 6,676 Total Assets $ 10,774 $ 23,788 $ 11,538 $ (14,678 ) $ 31,422 LIABILITIES AND STOCKHOLDERS’ EQUITY Current Liabilities Current portion of long-term debt and capital leases $ — $ 1,375 $ (163 ) $ 3 $ 1,215 Accounts payable 588 270 40 — 898 Accounts payable — affiliate 242 269 42 (553 ) — Derivative instruments 915 550 3 (95 ) 1,373 Cash collateral received in support of energy risk management activities — 44 — — 44 Current liabilities held-for-sale — 2 — — 2 Accrued expenses and other current liabilities 301 338 343 — 982 Total current liabilities 2,046 2,848 265 (645 ) 4,514 Other Liabilities Long-term debt and capital leases 245 9,810 7,838 — 17,893 Nuclear decommissioning reserve 334 — — — 334 Nuclear decommissioning trust liability 309 — — — 309 Deferred income taxes 958 255 (1,171 ) — 42 Derivative instruments 298 267 — (26 ) 539 Out-of-market contracts, net 88 1,005 — — 1,093 Other non-current liabilities 411 781 362 — 1,554 Total non-current liabilities 2,643 12,118 7,029 (26 ) 21,764 Total liabilities 4,689 14,966 7,294 (671 ) 26,278 Redeemable noncontrolling interest in subsidiaries — 23 — — 23 Stockholders’ Equity 6,085 8,799 4,244 (14,007 ) 5,121 Total Liabilities and Stockholders’ Equity $ 10,774 $ 23,788 $ 11,538 $ (14,678 ) $ 31,422 (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 Six Months Ended June 30, 2016 (Unaudited) Guarantor Subsidiaries Non-Guarantor Subsidiaries NRG Energy, Inc. (Note Issuer) Eliminations (a) Consolidated (In millions) Cash Flows from Operating Activities Net Income/(Loss) $ 375 $ (178 ) $ (153 ) $ (273 ) $ (229 ) Adjustments to reconcile net income/(loss) to net cash provided by operating activities: Distributions from unconsolidated affiliates — 40 — (11 ) 29 Equity in (earnings)/losses of unconsolidated affiliates (3 ) 2 — 4 3 Depreciation and amortization 225 385 12 — 622 Provision for bad debts 16 4 — — 20 Amortization of nuclear fuel 26 — — — 26 Amortization of financing costs and debt discount/premiums — (10 ) 13 — 3 Adjustment for debt extinguishment — 4 10 — 14 Amortization of intangibles and out-of-market contracts 20 21 — — 41 Amortization of unearned equity compensation — — 16 — 16 Impairment losses — 254 — — 254 Changes in deferred income taxes and liability for uncertain tax benefits 233 (112 ) (120 ) — 1 Changes in nuclear decommissioning trust liability 13 — — — 13 Changes in derivative instruments (64 ) 36 3 — (25 ) Changes in collateral deposits supporting energy risk management activities 344 6 — — 350 Proceeds from sale of emission allowances 47 — — — 47 (Gain)/loss on sale of assets — (32 ) 75 — 43 Cash (used)/provided by changes in other working capital (935 ) 24 276 280 (355 ) Net Cash Provided by Operating Activities 297 444 132 — 873 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. — — 39 (39 ) — Intercompany dividends — 12 (12 ) — Acquisition of businesses, net of cash acquired — (17 ) — — (17 ) Capital expenditures (80 ) (509 ) (33 ) — (622 ) Decrease in restricted cash, net 4 25 — — 29 Decrease/(increase) in restricted cash — U.S. DOE funded projects 1 (29 ) — — (28 ) Increase in notes receivable — (3 ) — — (3 ) Purchases of emission allowances (27 ) — — — (27 ) Proceeds from sale of emission allowances 25 — — — 25 Investments in nuclear decommissioning trust fund securities (280 ) — — — (280 ) Proceeds from sales of nuclear decommissioning trust fund securities 267 — — — 267 Proceeds from renewable energy grants and state rebates — 10 — — 10 Proceeds from sale of assets, net of cash disposed of — 120 25 — 145 Other 28 4 — — 32 Net Cash (Used)/Provided by Investing Activities (62 ) (399 ) 43 (51 ) (469 ) Cash Flows from Financing Activities Payments (for)/from intercompany loans (179 ) 45 134 — — Payment of dividends NRG Yield, Inc. — (39 ) — 39 — Intercompany dividends (52 ) 40 — 12 — Payment of dividends to common and preferred stockholders — — (57 ) — (57 ) Payment for preferred shares — — (226 ) — (226 ) Net receipts from settlement of acquired derivatives that include financing elements — 103 — — 103 Proceeds from issuance of long-term debt — 332 2,891 — 3,223 Distributions from, net of contributions to, noncontrolling interest in subsidiaries — (21 ) — — (21 ) Payment of debt issuance costs — — (35 ) — (35 ) Payments for short and long-term debt (1 ) (281 ) (3,225 ) — (3,507 ) Other (3 ) (7 ) — — (10 ) Net Cash (Used)/Provided by Financing Activities (235 ) 172 (518 ) 51 (530 ) Effect of exchange rate changes on cash and cash equivalents — (3 ) — — (3 ) Net Increase/(Decrease) in Cash and Cash Equivalents — 214 (343 ) — (129 ) Cash and Cash Equivalents at Beginning of Period — 825 693 — 1,518 Cash and Cash Equivalents at End of Period $ — $ 1,039 $ 350 $ — $ 1,389 (a) All significant intercompany transactions have been eliminated in consolidation. NRG ENERGY, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS For the Six Months Ended June 30, 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) $ 228 $ (116 ) $ (130 ) $ (127 ) $ (145 ) Adjustments to reconcile net loss to net cash provided by operating activities: Distributions from unconsolidated affiliates 6 50 — (11 ) 45 Equity in (earnings)/losses of unconsolidated affiliates (3 ) (6 ) 1 3 (5 ) Depreciation and amortization 400 381 10 — 791 Provision for bad debts 26 — 3 — 29 Amortization of nuclear fuel 23 — — — 23 Amortization of financing costs and debt discount/premiums — (20 ) 13 — (7 ) Adjustment for debt extinguishment — 7 — — 7 Amortization of intangibles and out-of-market contracts 24 8 — — 32 Amortization of unearned equity compensation — — 24 — 24 Changes in deferred income taxes and liability for uncertain tax benefits 137 (76 ) (159 ) — (98 ) Changes in nuclear decommissioning trust liability (4 ) — — — (4 ) Changes in derivative instruments 63 121 2 — 186 Changes in collateral deposits supporting energy risk management activities (82 ) (30 ) — — (112 ) Gain on postretirement benefits curtailment — (14 ) — — (14 ) Cash provided/(used) by changes in other working capital 710 (771 ) (368 ) 135 (294 ) Net Cash Provided/(Used) by Operating Activities 1,528 (466 ) (604 ) — 458 Cash Flows from Investing Activities Dividends from NRG Yield, Inc. — — 34 (34 ) — Intercompany dividends — — 33 (33 ) — Acquisition of businesses, net of cash acquired — (30 ) — — (30 ) Capital expenditures (177 ) (388 ) (18 ) — (583 ) Increase in restricted cash, net — (3 ) — — (3 ) Decrease in restricted cash — U.S. DOE projects — 27 — — 27 Decrease in notes receivable — 7 — — 7 Investments in nuclear decommissioning trust fund securities (354 ) — — — (354 ) Proceeds from sales of nuclear decommissioning trust fund securities 358 — — — 358 Proceeds from renewable energy grants and state rebates — 61 — — 61 Proceeds from sale of assets, net of cash disposed of — — 1 — 1 Investments in unconsolidated affiliates — (304 ) (49 ) — (353 ) Other 5 4 — — 9 Net Cash (Used)/Provided by Investing Activities (168 ) (626 ) 1 (67 ) (860 ) Cash Flows from Financing Activities Payments (for)/from intercompany loans (1,368 ) 440 928 — — Intercompany dividends — (33 ) — 33 — Payments of dividends from NRG Yield, Inc. — (34 ) — 34 — Payment of dividends to common and preferred stockholders — — (102 ) — (102 ) Payment for treasury stock — — (186 ) — (186 ) Net receipts for settlement of acquired derivatives that include financing elements — 91 — — 91 Proceeds from issuance of long-term debt — 601 28 — 629 Distributions from, net of contributions to, noncontrolling interest in subsidiaries — 670 — — 670 Proceeds from issuance of common stock — — 1 — 1 Payment of debt issuance costs — (12 ) — — (12 ) Payments for short and long-term debt — (652 ) (10 ) — (662 ) Net Cash (Used)/Provided by Financing Activities (1,368 ) 1,071 659 67 429 Effect of exchange rate changes on cash and cash equivalents — 3 — — 3 Net (Decrease)/Increase in Cash and Cash Equivalents (8 ) (18 ) 56 — 30 Cash and Cash Equivalents at Beginning of Period 18 1,455 643 — 2,116 Cash and Cash Equivalents at End of Period $ 10 $ 1,437 $ 699 $ — $ 2,146 (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 ($)	Jun. 30, 2016MW
Basis of Presentation [Abstract]
Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment, Period Increase (Decrease) | $	$ 1
Power Generation Capacity, Megawatts | MW		48,000

Summary of Significant Accoun38

Summary of Significant Accounting Policies (NCI - Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Capital expenditures accrued and unpaid			$ 96
Balance as of December 31, 2015	$ 2,599		2,599		$ 2,727
Distributions to noncontrolling interest			(82)
Contributions from noncontrolling interest			13
Noncontrolling Interest, Change in Redemption Value			(8)
Less: Comprehensive loss attributable to noncontrolling interest and redeemable noncontrolling interest	$ (16)	$ 12	(68)	$ (17)
Noncontrolling Interest [Member]
Noncontrolling Interest [Line Items]
Less: Comprehensive loss attributable to noncontrolling interest and redeemable noncontrolling interest			$ (51)

Summary of Significant Accoun39

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Redeemable NCI - Details 3) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest in subsidiaries	$ 23		$ 23		$ 29
Redeemable Noncontrolling Interest, Distributions from Noncontrolling Interests			(1)
Contributions from redeemable noncontrolling interest			12
Less: Comprehensive loss attributable to noncontrolling interest and redeemable noncontrolling interest	$ (16)	$ 12	(68)	$ (17)
Redeemable noncontrolling interest [Member]
Noncontrolling Interest [Line Items]
Less: Comprehensive loss attributable to noncontrolling interest and redeemable noncontrolling interest			$ (17)

Business Acquisitions and Dis40

Business Acquisitions and Dispositions Business Acquisitions and Dispositions (Details 1 - Acquisitions) $ in Millions	3 Months Ended
	Jun. 30, 2015USD ($)MW	Jun. 30, 2016MW
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts		48,000
Desert Sunlight [Member]
Business Acquisition [Line Items]
Percentage of Ownership	25.00%
Power Generation Capacity, Megawatts	550
Payments to Acquire Businesses, Gross | $	$ 285

Business Acquisitions and Dis41

Business Acquisitions and Dispositions Business Acquisitions and Dispositions (Details 2 - Dispositions)	Jul. 13, 2016USD ($)	Jun. 18, 2016USD ($)	May 13, 2016USD ($)	Mar. 02, 2016USD ($)	Feb. 03, 2016USD ($)	Nov. 25, 2015USD ($)	Nov. 10, 2015USD ($)	Jun. 30, 2016USD ($)MW	Mar. 31, 2016USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2012USD ($)	Jun. 30, 2016USD ($)MW	Jun. 30, 2015USD ($)	Jul. 12, 2016USD ($)	Jun. 17, 2016USD ($)	May 12, 2016	Feb. 02, 2016USD ($)	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								$ 115,000,000		$ 0		$ 115,000,000	$ 0
Power Generation Capacity, Megawatts | MW								48,000				48,000
Disposal Group, Including Discontinued Operation, Other Assets, Current								$ 13,000,000				$ 13,000,000						$ 6,000,000
Disposal Group, Including Discontinued Operation, Liabilities, Current								2,000,000				2,000,000						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								19,253,000,000				19,253,000,000						19,620,000,000
Loss on sale of assets, net of gains								(83,000,000)		$ 0		(51,000,000)	$ 0
Equity investments in affiliates								882,000,000				882,000,000						1,045,000,000
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 Revenue Rights		70,000,000
Loss on sale of assets, net of gains								83,000,000
Gain (Loss) on Sale of Equity Investments								$ 27,000,000
Seward Generating Station [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					$ 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
Disposal Group, Including Discontinued Operation, Other Assets, Current																		5,000,000
Disposal Group, Including Discontinued Operation, Assets, Noncurrent																		83,000,000
Disposal Group, Including Discontinued Operation, Liabilities, Current																		1,000,000
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent																		4,000,000
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				450
Disposal Group, Including Discontinued Operation, Other Assets, Current								$ 2,000,000				$ 2,000,000
Disposal Group, Including Discontinued Operation, Assets, Noncurrent								$ 54,000,000				$ 54,000,000
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
Disposal Group, Including Discontinued Operation, Other Assets, Current								$ 2,000,000				$ 2,000,000
Disposal Group, Including Discontinued Operation, Assets, Noncurrent								175,000,000				175,000,000
Disposal Group, Including Discontinued Operation, Liabilities, Current								2,000,000				2,000,000
Gain (Loss) on Disposition of Assets	$ 189,000,000
Shelby County Energy Center, LLC [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				$ 46,000,000			$ 46,000,000
Power Generation Capacity, Megawatts | MW																				352
Disposal Group, Including Discontinued Operation, Other Assets, Current																		1,000,000
Disposal Group, Including Discontinued Operation, Assets, Noncurrent																		22,000,000
Disposal Group, Including Discontinued Operation, Liabilities, Current																		$ 1,000,000
Gain (Loss) on Disposition of Assets									$ 29,000,000
Future Revenue Rights									10,000,000
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] | 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
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
Scenario, Forecast [Member] | EVgo [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Capital Contributions From Partners in Equity Method Investment															$ 7,000,000
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								$ 56,000,000				$ 56,000,000
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 Dis42

Business Acquisitions and Dispositions Business Acquisitions and Dispositions (Details 3 - Transfer of Assets) (Details)	Aug. 05, 2016USD ($)	Jun. 30, 2016USD ($)MW	Dec. 31, 2015USD ($)	Nov. 02, 2015USD ($)facilityMW	Jan. 02, 2015USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Power Generation Capacity, Megawatts | MW		48,000
Long-term Debt		$ 19,253,000,000	$ 19,620,000,000
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				$ 209,000,000	$ 489,000,000
Consideration Paid for Sale of Assets Under Common Control, net of Working Capital Adjustments				$ 207,000,000
Percentage of Ownership Sold of Subsidiary				75.00%
Number of Facilities				12
Power Generation Capacity, Megawatts | MW				814
Long-term Debt				$ 193,000,000	737,000,000
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			$ 159,000,000
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				$ 2,000,000	$ 9,000,000
Subsequent Event [Member] | CVSR [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	$ 79,000,000
Percentage of Ownership Sold of Subsidiary	51.05%

Fair Value of Financial Instr43

Fair Value of Financial Instruments (Details 1 - Balance Sheet grouping) - USD ($) $ in Millions		Jun. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Long-term debt, including current portion (b)		$ 19,253	$ 19,620
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes receivable	[1]	54	73
Long-term debt, including current portion (b)	[2]	19,253	19,620
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes receivable	[1]	54	73
Long-term debt, including current portion (b)	[2]	$ 18,593	$ 18,263
[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 Instr44

Fair Value of Financial Instruments (Details 2 - Recurring FV) - USD ($) $ in Millions	Jun. 30, 2016		Dec. 31, 2015
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	$ 1,818		$ 2,220
Derivative Liabilities	1,912		2,214
Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	1,818		2,220
Derivative Liabilities	1,712		2,086
Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Liabilities	200		128
Fair Value, Measurements, Recurring
Fair Value Assets and Liabilities, Measured on Recurring Basis
Debt securities	16		17
Available-for-sale securities	11		9
Other (a)	11	[1]	14	[2]
Total assets	2,456		2,822
Total liabilities	1,912		2,214
Fair Value, Measurements, Recurring | Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	1,818		2,220
Derivative Liabilities	1,712		2,086
Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Liabilities	200		128
Fair Value, Measurements, Recurring | Cash and cash equivalents
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	33		6
Fair Value, Measurements, Recurring | U.S. government and federal agency obligations
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	56		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	69		59
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	19		25
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	81		81
Fair Value, Measurements, Recurring | Equity securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	340		334
Fair Value, Measurements, Recurring | Foreign government fixed income securities
Fair Value Assets and Liabilities, Measured on Recurring Basis
Decommissioning Fund Investments	1		1
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring
Fair Value Assets and Liabilities, Measured on Recurring Basis
Debt securities	16		17
Available-for-sale securities	0		0
Other (a)	0	[1]	0	[2]
Total assets	283		220
Total liabilities	209		182
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	216		149
Derivative Liabilities	209		182
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
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	51		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	1,178		1,616
Total liabilities	1,174		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	1,007		1,449
Derivative Liabilities	974		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 Liabilities	200		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	69		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	19		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	81		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	1		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	11		9
Other (a)	11	[1]	14	[2]
Total assets	995		986
Total liabilities	529		868
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Commodity contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
Derivative Assets	595		622
Derivative Liabilities	529		868
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Interest rate contracts
Fair Value Assets and Liabilities, Measured on Recurring Basis
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	33		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	55		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	289		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 Instr45

Fair Value of Financial Instruments (Details 3 - Level 3 FV) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015		Mar. 31, 2016		Dec. 31, 2015		Mar. 31, 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		74		122		74		122		$ 52		$ 38		$ 117		$ 161
Total gains/(losses) - realized/unrealized:
Included in earnings		24		(34)		7		(89)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		(1)				(1)
Included in nuclear decommissioning obligation		(1)		0		(4)		2
Purchases		24		40		30		36
Transfers into Level 3 (b)		(20)	[1]	(4)	[2]	7	[1]	11	[2]
Transfers out of Level 3 (b)		(4)	[1]	3	[2]	(3)	[1]	1	[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 June 30, 2015		9		(8)		(15)		(28)
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		16		18		16		18		17		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)				(1)
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 June 30, 2015		0		0		0		0
Fair Value, Inputs, Level 3 [Member] | Other
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						11		11
Total gains/(losses) - realized/unrealized:
Included in earnings				(11)				(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 June 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		51		55		51		55		52		54		54		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		(1)		0		(4)		2
Purchases		0		1		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 June 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		7	[3]	49	[4]	7	[3]	49	[4]	$ (17)	[3]	$ (33)	[3]	$ 34	[4]	$ 80	[4]
Total gains/(losses) - realized/unrealized:
Included in earnings		24	[3]	(23)	[4]	7	[3]	(78)	[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		24	[3]	39	[4]	29	[3]	35	[4]
Transfers into Level 3 (b)		(20)	[1],[3]	(4)	[2],[4]	7	[1],[3]	11	[2],[4]
Transfers out of Level 3 (b)		(4)	[1],[3]	3	[2],[4]	(3)	[1],[3]	1	[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 June 30, 2015		$ 9	[3]	$ (8)	[4]	$ (15)	[3]	$ (28)	[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 Instr46

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details 4 - Derivative FV Measurements) $ / T in Millions, $ / MWh in Millions, $ in Millions	Jun. 30, 2016USD ($)$ / T$ / MWh	Dec. 31, 2015USD ($)$ / T$ / MWh	Jun. 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)	12.00%
Total derivative liabilities valued with prices provied by models and other valuation techniques (as a percent)	11.00%
Derivative Asset, Fair Value, Gross Asset	$ 1,818	$ 2,220
Derivative Liability, Fair Value, Gross Liability	1,912	2,214
Valuation Allowances and Reserves, Balance	6		$ 3
Increase in fair value as a result of the credit reserve, portion recorded in OCI	4		1
Increase in fair value as a result of the credit reserve, portion recorded in operating revenue and cost of operations	2		$ 2
Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,818	2,220
Derivative Liability, Fair Value, Gross Liability	1,712	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	1,818	2,220
Derivative Liability, Fair Value, Gross Liability	1,712	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	216	149
Derivative Liability, Fair Value, Gross Liability	209	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	165	86
Derivative Liability, Fair Value, Gross Liability	146	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	13	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	51	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	10	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	28	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	(97)	(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	108	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	38	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	29	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	38	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	33	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 Instr47

Fair Value of Financial Instruments (Details 5 - Credit Risk) $ in Millions	6 Months Ended
	Jun. 30, 2016USD ($)
Concentration of Credit Risk
Counterparty credit exposure to a portion of the Company's counterparties	$ 678
Collateral held (cash and letters of credit) against counterparty credit exposure to a portion of the Company's counterparties	53
Net counterparty credit exposure to a portion of the Company's counterparties	$ 646
Company's exposure before collateral is expected to roll off by the end of 2014 (as a percent)	87.00%
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	$ 296
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)	97.00%	[1]
Non-rated (b)
Concentration of Credit Risk
Net Exposure (as a percent)	2.00%	[1],[2]
External Credit Rating, Non Investment Grade [Member]
Concentration of Credit Risk
Net Exposure (as a percent)	1.00%	[1]
Financial institutions
Concentration of Credit Risk
Net Exposure (as a percent)	53.00%	[1]
Utilities, energy merchants, marketers and other
Concentration of Credit Risk
Net Exposure (as a percent)	29.00%	[1]
ISOs
Concentration of Credit Risk
Net Exposure (as a percent)	18.00%	[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	$ 2,500
[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 Trust48

Nuclear Decommissioning Trust Fund (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Nuclear decommissioning trust fund disclosure
Fair Value	$ 599		$ 561
Unrealized Gains	212		202
Unrealized Losses	1		3
Realized gains	3	$ 9
Realized losses	2	5
Proceeds from sale of securities	267	$ 358
Cash and Cash Equivalents [Member]
Nuclear decommissioning trust fund disclosure
Fair Value	33		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	$ 56		$ 55
Unrealized Gains	5		1
Unrealized Losses	$ 0		$ 0
Weighted-average Maturities (In years)	12 years		11 years
Federal agency mortgage-backed securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 69		$ 59
Unrealized Gains	2		1
Unrealized Losses	$ 0		$ 0
Weighted-average Maturities (In years)	24 years		25 years
Commercial mortgage-backed securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 19		$ 25
Unrealized Gains	0		0
Unrealized Losses	$ 1		$ 2
Weighted-average Maturities (In years)	27 years		28 years
Corporate debt securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 81		$ 81
Unrealized Gains	3		1
Unrealized Losses	$ 0		$ 1
Weighted-average Maturities (In years)	11 years		10 years
Equity securities
Nuclear decommissioning trust fund disclosure
Fair Value	$ 340		$ 334
Unrealized Gains	202		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	$ 1		$ 1
Unrealized Gains	0		0
Unrealized Losses	$ 0		$ 0
Weighted-average Maturities (In years)	8 years		9 years

Accounting for Derivative Ins49

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	6 Months Ended	12 Months Ended
	Jun. 30, 2016USD ($)MWhMMBTUTsharesbbl	Dec. 31, 2015USD ($)MWhMMBTUTsharesbbl
Fair Value of Derivative Instrument
Derivative Assets	$ 1,818	$ 2,220
Derivative Liabilities	1,912	2,214
Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	0	0
Derivative Liabilities	163	110
Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	1,818	2,220
Derivative Liabilities	1,749	2,104
Interest rate contracts current | Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	0	0
Derivative Liabilities	39	42
Interest rate contracts current | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	0	0
Derivative Liabilities	9	5
Interest rate contracts long-term | Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	0	0
Derivative Liabilities	124	68
Interest rate contracts long-term | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	0	0
Derivative Liabilities	28	13
Commodity contracts current | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	1,470	1,915
Derivative Liabilities	1,325	1,674
Commodity contracts long-term | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instrument
Derivative Assets	348	305
Derivative Liabilities	$ 387	$ 412
Long [Member] | Emissions | Short Ton [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Mass | T	0	1
Long [Member] | Coal | Short Ton [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Mass | T	27	35
Long [Member] | Natural Gas | MMbtu [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	136	293
Long [Member] | Oil | Barrel [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Volume | bbl	1	1
Long [Member] | Interest | United States of America, Dollars
Volumetric Underlying Derivative Transactions
Derivative, Notional Amount	$ 3,184	$ 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	(45)	(74)
Short [Member] | Capacity | MW/Day [Member]
Volumetric Underlying Derivative Transactions
Derivative, Nonmonetary Notional Amount, Energy Measure | MWh	(1)	(1)

Accounting for Derivative Ins50

Accounting for Derivative Instruments and Hedging Activities (Details 2 - Offsetting Derivatives) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets	$ 1,818	$ 2,220
Cash Collateral (Held) / Posted	(44)	(106)
Gross Amounts of Recognized Derivative Liabilities	(1,912)	(2,214)
Cash Collateral Posted	218	568
Gross Amounts of Recognized Assets / Liabilities	(94)	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	(36)	158
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	(130)	164
Commodity contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets	1,818	2,220
Derivative Instruments	(1,525)	(1,616)
Cash Collateral (Held) / Posted	(53)	(113)
Net Amount	240	491
Gross Amounts of Recognized Derivative Liabilities	(1,712)	(2,086)
Derivative Instruments	1,525	1,616
Cash Collateral Posted	17	271
Derivative Liability, Fair Value, Amount Offset Against Collateral	(170)	(199)
Gross Amounts of Recognized Assets / Liabilities	106	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	(36)	158
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	70	292
Interest rate contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Gross Amounts of Recognized Derivative Liabilities	(200)	(128)
Derivative Instruments	0	0
Cash Collateral Posted	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ (200)	$ (128)

Accounting for Derivative Ins51

Accounting for Derivative Instruments and Hedging Activities (Details 3 - AOCI) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 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	$ (150)	$ (84)	$ (101)	$ (68)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	7	2	10	4
Mark-to-market of cash flow hedge accounting contracts	(22)	19	(74)	1
Accumulated OCI ending balance, net of tax	(165)	(63)	(165)	(63)
Gains/(losses) expected to be realized from OCI during the next 12 months, net of tax	22		22
Accumulated OCI ending balance, tax	26	37	26	37
Gains/(losses) expected to be realized from OCI during the next 12 months, tax	3	0	3	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	0	0	0
Mark-to-market of cash flow hedge accounting contracts	0	0	0	0
Accumulated OCI ending balance, net of tax	0	(1)	0	(1)
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	(150)	(83)	(101)	(67)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	7	2	10	4
Mark-to-market of cash flow hedge accounting contracts	(22)	19	(74)	1
Accumulated OCI ending balance, net of tax	(165)	$ (62)	(165)	$ (62)
Gains/(losses) expected to be realized from OCI during the next 12 months, net of tax	$ 22		$ 22

Accounting for Derivative Ins52

Accounting for Derivative Instruments and Hedging Activities Accounting for Derivative Instruments and Hedging Activities (Details 4 - mark to market) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Unrealized mark-to-market results
Reversal of previously recognized unrealized gains on settled positions related to economic hedges		$ (51)	$ (36)	$ (137)	$ (150)
Reversal of acquired gain positions related to economic hedges		(15)	(24)	(28)	(50)
Net unrealized (losses)/gains on open positions related to economic hedges		(32)	57	102	(81)
Total unrealized mark-to-market losses for economic hedging activities		(98)	(3)	(63)	(281)
Reversal of previously recognized unrealized losses/(gains) on settled positions related to trading activity		2	(15)	10	(36)
Reversal of acquired gain positions related to trading activity		0	(5)	0	(12)
Net unrealized gains/(losses) on open positions related to trading activity		11	(4)	22	2
Total unrealized mark-to-market gains/(losses) for trading activity		13	(24)	32	(46)
Impact of derivative instruments on statement of operations
Total unrealized losses		(85)	(27)	(31)	(327)
Derivative Instruments Not Designated as Hedging Instruments, Gain	$ 98
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value		80		80
Credit Risk Related Contingent Features
Derivative Liability, Fair Value of Collateral		80		80
Derivative, Net Liability Position, Collateral Required Contracts with Credit Rating Contingent Feature		15		15
Collateral due on net liability position that has not been called by a certain marginable agreement counterparty		9		9
Realized Gain [Member]
Impact of derivative instruments on statement of operations
Derivative Instruments Not Designated as Hedging Instruments, Gain		38
Commodity contracts
Impact of derivative instruments on statement of operations
Total unrealized losses		(85)	(27)	(31)	(327)
Commodity contracts | Sales [Member]
Impact of derivative instruments on statement of operations
Total unrealized losses		(526)	(137)	(481)	(246)
Commodity contracts | Cost of Sales [Member]
Impact of derivative instruments on statement of operations
Total unrealized losses		441	110	450	(81)
Interest rate contracts
Impact of derivative instruments on statement of operations
Total unrealized losses		$ (7)	$ 35	$ (18)	$ 21

Impairments (Details)

Impairments (Details) - USD ($) $ in Millions	Jul. 13, 2016	May 13, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	May 12, 2016
Asset Impairment Charges			$ 115	$ 0	$ 115	$ 0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net			$ (7)	$ 0	139	$ 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	6 Months Ended
		Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Debt and Capital Leases
Long-term Debt		$ 19,253	$ 19,253	$ 19,620
Capital Lease Obligations		13	13	13
Subtotal		19,268	19,268	19,636
Less current maturities		1,215	1,215	481
Deferred Finance Costs, Net		160	160	172
Total long-term debt and capital leases		17,893	$ 17,893	18,983
Interest rate, variable basis			3 month LIBOR
Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		8,234	$ 8,234	8,584
Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		11,019	$ 11,019	11,036
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		410	$ 410	418
Senior Notes Due In 2018 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased		451	451
Debt Instrument, Repurchase Amount	[1]	$ 499	499
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		107.95%
Long-term Debt		$ 587	$ 587	1,039
Interest rate, stated rate	[2]	7.625%	7.625%
Senior Notes Due In 2020 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased		$ 239	$ 239
Debt Instrument, Repurchase Amount	[1]	$ 254	254
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		104.38%
Long-term Debt		$ 818	$ 818	1,058
Interest rate, stated rate	[2]	8.25%	8.25%
Senior Notes Due In 2021 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased		$ 240	$ 240
Debt Instrument, Repurchase Amount	[1]	$ 250	250
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		104.19%
Long-term Debt		$ 889	$ 889	1,128
Interest rate, stated rate	[2]	7.875%	7.875%
Senior Notes Due In 2022 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased		$ 108	$ 108
Debt Instrument, Repurchase Amount	[1]	$ 105	105
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		94.73%
Long-term Debt		$ 992	$ 992	1,100
Interest rate, stated rate	[2]	6.25%	6.25%
Senior Notes Due in 2023 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased		$ 67	$ 67
Debt Instrument, Repurchase Amount	[1]	$ 64	64
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		94.13%
Long-term Debt		$ 869	$ 869	936
Interest rate, stated rate	[2]	6.625%	6.625%
Senior Notes 2024 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased		$ 171	$ 171
Debt Instrument, Repurchase Amount	[1]	$ 163	163
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		94.52%
Long-term Debt		$ 734	$ 734	904
Interest rate, stated rate	[2]	6.25%	6.25%
Senior Notes due 2026 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 1,000	$ 1,000	0
Interest rate, stated rate	[2]	7.25%	7.25%
Term loan facility, due 2018 | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 0	$ 0	1,964
Term Loan Facility Due 2023 [Member] | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		1,890	1,890	0
Tax-exempt Bonds [Member] | Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 455	$ 455	455
Indian River Power LLC, tax-exempt bonds, due 2040 | Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	6.00%	6.00%
Indian River Power LLC, tax-exempt bonds, due 2045 | Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	5.375%	5.375%
Dunkirk Power LLC, tax-exempt bonds, due 2042 | Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	5.875%	5.875%
Fort Bend County, tax-exempt bonds, due 2038 and 2042 | Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	4.125%	4.125%
GenOn Senior Notes [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 1,934	$ 1,934	1,956
GenOn Senior Notes Due in 2017 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	7.875%	7.875%
GenOn senior notes, due 2018 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	9.50%	9.50%
GenOn senior notes, due 2020 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	9.875%	9.875%
GenOn Americas Generation Senior Notes [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 748	$ 748	752
GenOn Americas Generation Senior Notes Due in 2021 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	8.50%	8.50%
GenOn Americas Generation senior notes, due in 2031 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	9.125%	9.125%
GenOn Other [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 53	$ 53	56
Genon [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		2,735	2,735	2,764
5.375% Senior Notes due in 2024 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 500	$ 500	500
Interest rate, stated rate	[2]	5.375%	5.375%
NRG Yield Revolving Credit Facility [Member]
Debt and Capital Leases
Interest rate, variable basis			1 - month LIBOR
NRG Yield Revolving Credit Facility [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 318	$ 318	306
3.5% Convertible Notes due 2019 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 333	$ 333	330
Interest rate, stated rate	[2]	3.50%	3.50%
3.25% Convertible Notes due 2020 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 268	$ 268	266
Interest rate, stated rate	[2]	3.25%	3.25%
West Holdings Credit Agreement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 457	$ 457	485
Alta Wind I - V Lease financing arrangement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		$ 978	$ 978	1,002
Alta Wind I [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	7.015%	7.015%
Alta Wind II [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	5.696%	5.696%
Alta Wind III [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	6.067%	6.067%
Alta Wind IV [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	5.938%	5.938%
Alta Wind V [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	6.071%	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		$ 341	$ 341	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		176	$ 176	181
Interest rate, variable basis	[2]		LIBOR
Laredo Ridge Wind, LLC, due in 2026 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		102	$ 102	104
Interest rate, variable basis	[2]		LIBOR
NRG Solar Alpine LLC, due 2022 | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		151	$ 151	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		$ 100	$ 100	108
NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2025 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	5.95%	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	$ 183	189
Interest rate, variable basis	[2]		LIBOR
NRG Yield - Other [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		455	$ 455	469
NRG Yield, Inc. | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		4,772	4,772	4,863
Ivanpah Financing, due 2014 and 2038 | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		1,141	1,141	1,149
Agua Caliente Solar LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		874	874	879
CVSR - High Plains Ranch II LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		780	780	793
NRG Solar Dandan [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		101	101	98
NRG Peaker Finance Co. LLC Bonds Due 2019 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		0	$ 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		100	$ 100	103
Interest rate, variable basis	[2]		LIBOR
Midwest Generation due 2019 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		249	$ 249	0
Other (Non-recourse debt) | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		267	267	315
NRG Energy [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		3,512	3,512	3,409
Other (Capital leases)
Debt and Capital Leases
Capital Lease Obligations		$ 2	$ 2	$ 3
London Interbank Offered Rate (LIBOR) [Member] | Term loan facility, due 2018 | 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
Interest rate, basis spread on variable rate	[2]		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]		1.75%
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] | Laredo Ridge Wind, LLC, due in 2026 [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, basis spread on variable rate	[2]		1.875%
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]		3.125%
Minimum [Member] | NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2017 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	7.12%	7.12%
Minimum [Member] | Ivanpah Financing, due 2014 and 2038 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	2.285%	2.285%
Minimum [Member] | Agua Caliente Solar LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	2.395%	2.395%
Minimum [Member] | CVSR - High Plains Ranch II LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	2.339%	2.339%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | West Holdings Credit Agreement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	1.625%	1.625%
Maximum [Member] | NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2017 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	7.25%	7.25%
Maximum [Member] | Ivanpah Financing, due 2014 and 2038 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	4.256%	4.256%
Maximum [Member] | Agua Caliente Solar LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	3.633%	3.633%
Maximum [Member] | CVSR - High Plains Ranch II LLC, due 2037 | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	3.775%	3.775%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | West Holdings Credit Agreement [Member] | Non Recourse Debt [Member]
Debt and Capital Leases
Interest rate, stated rate	[2]	2.25%	2.25%
[1]	(a) Includes accrued interest.
[2]	As of June 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 NRG Marsh Landing term loan, Walnut Creek term loan, and NRG Yield Operating LLC revolving credit facility, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.

Debt and Capital Leases Debt 55

Debt and Capital Leases Debt and Capital Leases (Details 2 - Recourse Debt - Issuance & Repurchases) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Debt and Capital Leases
Loss on debt extinguishment			$ (80)	$ (7)	$ (69)	$ (7)
Senior Notes [Member]
Debt and Capital Leases
Debt Instrument, Principal Amount Repurchased			1,300		1,300
Debt Instrument, Repurchase Amount			1,300		1,300
Debt Instrument Repurchase, Accrued Interest					21
Loss on debt extinguishment					45
Deferred Financing Costs					$ 7
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	[1]		7.25%		7.25%
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			$ 239		$ 239
Debt Instrument, Repurchase Amount	[2]		$ 254		$ 254
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed			(104.38%)
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			$ 240		$ 240
Debt Instrument, Repurchase Amount	[2]		$ 250		$ 250
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed			(104.19%)
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			$ 451		$ 451
Debt Instrument, Repurchase Amount	[2]		$ 499		$ 499
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			$ 1,276		1,276
Debt Instrument, Repurchase Amount	[2]		$ 1,335		$ 1,335
Subsequent Event [Member] | 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		6.625%
Subsequent Event [Member] | Recourse Debt [Member] | Senior Notes Due In 2020 [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage		8.25%
Subsequent Event [Member] | Recourse Debt [Member] | Senior Notes Due In 2021 [Member]
Debt and Capital Leases
Debt Instrument, Interest Rate, Stated Percentage		7.875%
[1]	As of June 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 NRG Marsh Landing term loan, Walnut Creek term loan, and NRG Yield Operating LLC revolving credit facility, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.
[2]	(a) Includes accrued interest.

Debt and Capital Leases Debt 56

Debt and Capital Leases Debt and Capital Leases (Details 3 - Sr Credit Facility & GenOn Sr Notes) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Debt and Capital Leases
Long-term Debt		$ 19,253		$ 19,253		$ 19,620
Debt Instrument, Description of Variable Rate Basis				3 month LIBOR
Loss on debt extinguishment		(80)	$ (7)	$ (69)	$ (7)
Debt and Capital Lease Obligations		19,268		$ 19,268		19,636
NRG Yield Revolving Credit Facility [Member]
Debt and Capital Leases
Debt Instrument, Description of Variable Rate Basis				1 - month LIBOR
Recourse Debt [Member]
Debt and Capital Leases
Long-term Debt		8,234		$ 8,234		8,584
Recourse Debt [Member] | Term Loan Facility Due 2023 [Member]
Debt and Capital Leases
Long-term Debt		$ 1,890		$ 1,890		$ 0
Percent of face value		99.50%		99.50%
Debt Instrument, Periodic Payment, Percentage of Principal		0.0025
Loss on debt extinguishment		$ 21
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
Debt Instrument, Basis Spread on Variable Rate	[1]			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		$ 0
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%
GenOn Energy, Inc. [Member] | Senior Notes [Member] | Senior Unsecured Notes 2017 [Member]
Debt and Capital Leases
Debt and Capital Lease Obligations		707		$ 707
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		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		$ 289
[1]	As of June 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 NRG Marsh Landing term loan, Walnut Creek term loan, and NRG Yield Operating LLC revolving credit facility, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.

Debt and Capital Leases Debt 57

Debt and Capital Leases Debt and Capital Leases (Details 4 - Non Recourse Debt - Project Financings) - USD ($) $ in Millions		3 Months Ended			6 Months Ended		12 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2013	Jan. 29, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Loss on debt extinguishment			$ (80)	$ (7)	$ (69)	$ (7)
Long-term Debt			$ 19,253		$ 19,253				$ 19,620
Debt Instrument, Description of Variable Rate Basis					3 month LIBOR
High Lonesome Mesa, LLC, due in 2017 [Member]
Debt Instrument [Line Items]
Percentage of Ownership			100.00%		100.00%
Construction Loans [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Long-term Debt							$ 81
Debt Instrument, Interest Rate, Stated Percentage							1.25%
Letters of Credit, Issued Amount							$ 5
Letters of Credit Outstanding, Amount									5
Term Loan Facility [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Long-term Debt			$ 78		$ 78			$ 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			11,019		11,019				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		85
Loss on debt extinguishment			3
Long-term Debt			0		$ 0				72
Debt Instrument, Description of Variable Rate Basis	[1]				LIBOR
Non Recourse Debt [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Long-term Debt			101		$ 101				98
Non Recourse Debt [Member] | Midwest Generation due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt			249		249				0
Non Recourse Debt [Member] | CVSR Financing Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt			780		780				793
Recourse Debt [Member]
Debt Instrument [Line Items]
Long-term Debt			$ 8,234		$ 8,234				$ 8,584
London Interbank Offered Rate (LIBOR) [Member] | Construction Loans [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	[1]						LIBOR
Debt Instrument, Basis Spread on Variable Rate							2.25%
Debt Instrument, Interest Rate, Increase (Decrease)							0.25%
London Interbank Offered Rate (LIBOR) [Member] | Cash Grant Loan [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	[1]						LIBOR
Debt Instrument, Basis Spread on Variable Rate							1.75%
London Interbank Offered Rate (LIBOR) [Member] | Non Recourse Debt [Member] | NRG Peaker Finance Co. LLC Bonds Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	[1]				1.07%
London Interbank Offered Rate (LIBOR) [Member] | Non Recourse Debt [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	[1]				LIBOR
Debt Instrument, Basis Spread on Variable Rate	[1]				2.25%
Until 5th anniversary of term conversion date [Member] | Construction Loans [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Letters Of Credit, Availability Fee, Percentage Of Applicable Margin							2.25%
From 5th anniversary of term conversion date [Member] | Construction Loans [Member] | NRG Solar Dandan [Member]
Debt Instrument [Line Items]
Letters Of Credit, Availability Fee, Percentage Of Applicable Margin							2.50%
Subsequent Event [Member] | Non Recourse Debt [Member] | CVSR Financing Agreement [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.68%
Proceeds from Issuance of Debt		$ 200
Proceeds from Debt, Net of Issuance Costs		199
Midwest Generation [Member] | Non Recourse Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[1]		4.39%		4.39%
Proceeds from Sale of Other Assets	[1]		$ 253
Cedro Hill, Broken Bow, & Crofton Bluffs [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Credit Facility, Maximum Borrowing Capacity, Amendment			$ 312		$ 312
Proceeds from Lines of Credit		$ 87
[1]	As of June 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 NRG Marsh Landing term loan, Walnut Creek term loan, and NRG Yield Operating LLC revolving credit facility, and 2016 Term Loan Facility, which are 1 month LIBOR plus x%.

Variable Interest Entities (Det

Variable Interest Entities (Details) $ in Millions	Jun. 30, 2016USD ($)facilityMW	Dec. 31, 2015USD ($)
Investments Accounted for by the Equity Method
Generation Capacity (in MW) | MW	48,000
Equity investments in affiliates	$ 882	$ 1,045
Deficit Restoration Obligation	38
Current assets	78	84
Net property, plant and equipment	1,754	1,807
Other long-term assets	926	863
Total assets	2,758	2,754
Current liabilities	57	56
Long-term debt	350	366
Other long-term liabilities	192	179
Total liabilities	599	601
Noncontrolling interests	703	493
Net assets less noncontrolling interests	$ 1,456	$ 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	$ 108
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	$ 73

Changes in Capital Structure (D

Changes in Capital Structure (Details) $ in Millions	3 Months Ended			6 Months Ended
	Sep. 30, 2016shares	Jun. 30, 2016USD ($)shares	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)shares	Jun. 30, 2015USD ($)	Jun. 13, 2016USD ($)	May 24, 2016USD ($)	Dec. 31, 2015USD ($)shares
Capital Structure
Temporary Equity, Redemption Percentage						1	1
Gain on Redemption of Redeemable Preferred Stock | $		$ 78	$ 0	$ 78	$ 0
Temporary Equity, Liquidation Preference | $							$ 344.5
Common stock authorized (in shares)
Common stock, shares authorized		500,000,000		500,000,000				500,000,000
Shares issued, balance at the beginning of the year	417,397,085			416,939,950
Treasury shares, balance at the beginning of the year	(102,450,781)			(102,749,908)
Common Stock, Shares, Outstanding, beginning of year	314,946,304			314,190,042
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures				457,135
Stock Issued During Period, Shares, Employee Stock Purchase Plans				299,127
Shares issued, balance at the end of the year		417,397,085		417,397,085
Treasury shares, balance at the end of the year		(102,450,781)		(102,450,781)
Common Stock, Shares, Outstanding, end of year		314,946,304		314,946,304
Common Stock, Capital Shares Reserved for Employee Stock Purchase Plan		977,786		977,786
Preferred Stock Instrument, Interest Rate, Stated Percentage		2.822%	2.822%	2.822%	2.822%		2.822%	2.822%
Payments for Repurchase of Redeemable Preferred Stock | $		$ 226		$ 226	$ 0
2.822% convertible perpetual preferred stock | $		$ 0		$ 0		$ 304		$ 302
Common Stock [Member]
Common stock authorized (in shares)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures				457,135
Stock Issued During Period, Shares, Employee Stock Purchase Plans				0
Treasury Stock [Member]
Common stock authorized (in shares)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures				0
Stock Issued During Period, Shares, Employee Stock Purchase Plans				299,127
Subsequent Event [Member] | Treasury Stock [Member]
Common stock authorized (in shares)
Stock Issued During Period, Shares, Employee Stock Purchase Plans	309,967

Changes in Capital Structure Ch

Changes in Capital Structure Changes in Capital Structure (Details 2 - Dividends) - $ / shares	3 Months Ended			12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016
Dividends Payable [Line Items]
Dividends per Common Share		$ 0.030	$ 0.145
Subsequent Event [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared	Jul. 13, 2016
Common Stock, Dividends, Per Share, Declared	$ 0.03
Dividends Payable, Date to be Paid	Aug. 15, 2016
Dividends Payable, Date of Record	Aug. 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		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	May 24, 2016	Dec. 31, 2015
Numerator:
Net loss attributable to NRG Energy, Inc.	$ (271)	$ (14)	$ (189)	$ (134)
Gain on redemption, net of dividends for preferred shares	0	5	5	10
Gain on Redemption of Redeemable Preferred Stock	(78)	0	(78)	0
Loss available for common stockholders	$ (193)	$ (19)	$ (116)	$ (144)
Denominator:
Weighted Average Number of Shares Outstanding, Basic	315	333	315	335
Basic earnings per share:
Loss per Weighted Average Common Share — Basic and Diluted	$ (0.61)	$ (0.06)	$ (0.37)	$ (0.43)
Denominator (diluted earnings per share):
Total dilutive shares	315	333	315	335
Diluted earnings per share:
Earnings/(loss) per weighted average common share — diluted	$ (0.67)	$ (0.06)	$ (0.42)	$ (0.43)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of diluted earnings per share, amount	3	23	3	23
Convertible perpetual preferred stock, interest rate (as a percentage)	2.822%	2.822%	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	3	7	3	7
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)	3 Months Ended				6 Months Ended
	Jun. 30, 2016USD ($)		Jun. 30, 2015USD ($)		Jun. 30, 2016USD ($)		Jun. 30, 2015USD ($)		Dec. 31, 2015USD ($)	Nov. 02, 2015	Nov. 02, 2015USD ($)	Nov. 02, 2015facility
Segment Reporting Information
Operating revenues	$ 2,638,000,000	[1]	$ 3,400,000,000	[2]	$ 5,867,000,000	[1]	$ 7,229,000,000	[2]
Depreciation and amortization	309,000,000		396,000,000		622,000,000		791,000,000
Asset Impairment Charges	115,000,000		0		115,000,000		0
Equity in earnings/(losses) of unconsolidated affiliates	4,000,000		8,000,000		(3,000,000)		5,000,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	7,000,000		0		(139,000,000)		0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(251,000,000)		(26,000,000)		(183,000,000)		(235,000,000)
Net Loss	(276,000,000)		(9,000,000)		(229,000,000)		(145,000,000)
Net loss attributable to NRG Energy, Inc.	(271,000,000)		(14,000,000)		(189,000,000)		(134,000,000)
Total Assets	31,422,000,000				31,422,000,000				$ 32,882,000,000
Inter-Segment Sales	281,000,000		381,000,000		608,000,000		661,000,000
Loss on sale of assets, net of gains	(83,000,000)		0		(51,000,000)		0
Loss on debt extinguishment	80,000,000		7,000,000		69,000,000		7,000,000
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0		0		0		14,000,000
Generation/Business
Segment Reporting Information
Operating revenues	1,306,000,000	[1]	2,110,000,000	[2]	3,426,000,000	[1]	4,619,000,000	[2]
Depreciation and amortization	144,000,000		228,000,000		290,000,000		461,000,000
Asset Impairment Charges	76,000,000				76,000,000
Equity in earnings/(losses) of unconsolidated affiliates	0		6,000,000		(5,000,000)		2,000,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0				(137,000,000)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(371,000,000)		4,000,000		(211,000,000)		33,000,000
Net Loss	(371,000,000)		3,000,000		(212,000,000)		32,000,000
Net loss attributable to NRG Energy, Inc.	(371,000,000)		3,000,000		(212,000,000)		32,000,000
Total Assets	14,445,000,000				14,445,000,000
Inter-Segment Sales	218,000,000		297,000,000		469,000,000		544,000,000
Loss on sale of assets, net of gains	0				32,000,000
Loss on debt extinguishment	0				0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							14,000,000
Retail Mass(a)
Segment Reporting Information
Operating revenues	1,201,000,000	[1]	1,298,000,000	[2]	2,249,000,000	[1]	2,609,000,000	[2]
Depreciation and amortization	27,000,000		33,000,000		55,000,000		63,000,000
Asset Impairment Charges	0				0
Equity in earnings/(losses) of unconsolidated affiliates	0		0		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	496,000,000		217,000,000		642,000,000		321,000,000
Net Loss	496,000,000		217,000,000		642,000,000		321,000,000
Net loss attributable to NRG Energy, Inc.	496,000,000		217,000,000		642,000,000		321,000,000
Total Assets	2,169,000,000				2,169,000,000
Inter-Segment Sales	3,000,000		4,000,000		4,000,000		4,000,000
Loss on sale of assets, net of gains	0				0
Loss on debt extinguishment	0				0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							0
Renewables(a)
Segment Reporting Information
Operating revenues	125,000,000	[1]	128,000,000	[2]	234,000,000	[1]	219,000,000	[2]
Depreciation and amortization	55,000,000		53,000,000		111,000,000		105,000,000
Asset Impairment Charges	26,000,000				26,000,000
Equity in earnings/(losses) of unconsolidated affiliates	(4,000,000)		(2,000,000)		(8,000,000)		(3,000,000)
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	(63,000,000)		(9,000,000)		(114,000,000)		(66,000,000)
Net Loss	(58,000,000)		(6,000,000)		(103,000,000)		(57,000,000)
Net loss attributable to NRG Energy, Inc.	(53,000,000)		(20,000,000)		(88,000,000)		(66,000,000)
Total Assets	5,730,000,000				5,730,000,000
Inter-Segment Sales	5,000,000		23,000,000		10,000,000		23,000,000
Loss on sale of assets, net of gains	0				0
Loss on debt extinguishment	0				0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							0
NRG Yield(a)
Segment Reporting Information
Operating revenues	258,000,000	[1]	235,000,000	[2]	478,000,000	[1]	435,000,000	[2]
Depreciation and amortization	67,000,000		70,000,000		133,000,000		137,000,000
Asset Impairment Charges	0				0
Equity in earnings/(losses) of unconsolidated affiliates	18,000,000		8,000,000		20,000,000		10,000,000
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	70,000,000		42,000,000		72,000,000		18,000,000
Net Loss	58,000,000		38,000,000		60,000,000		18,000,000
Net loss attributable to NRG Energy, Inc.	42,000,000		21,000,000		52,000,000		6,000,000
Total Assets	7,609,000,000				7,609,000,000
Inter-Segment Sales	0		9,000,000		4,000,000		9,000,000
Loss on sale of assets, net of gains	0				0
Loss on debt extinguishment	0				0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							0
Corporate
Segment Reporting Information
Operating revenues	29,000,000	[1]	10,000,000	[2]	88,000,000	[1]	8,000,000	[2]
Depreciation and amortization	16,000,000		12,000,000		33,000,000		25,000,000
Asset Impairment Charges	13,000,000				13,000,000
Equity in earnings/(losses) of unconsolidated affiliates	1,000,000		0		2,000,000		(1,000,000)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	7,000,000				(2,000,000)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(371,000,000)		(272,000,000)		(563,000,000)		(534,000,000)
Net Loss	(389,000,000)		(253,000,000)		(607,000,000)		(452,000,000)
Net loss attributable to NRG Energy, Inc.	(409,000,000)		(239,000,000)		(614,000,000)		(426,000,000)
Total Assets	16,799,000,000				16,799,000,000
Inter-Segment Sales	55,000,000		48,000,000		121,000,000		81,000,000
Loss on sale of assets, net of gains	(83,000,000)				(83,000,000)
Loss on debt extinguishment	80,000,000				69,000,000
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							0
Elimination
Segment Reporting Information
Operating revenues	(281,000,000)	[1]	(381,000,000)	[2]	(608,000,000)	[1]	(661,000,000)	[2]
Depreciation and amortization	0		0		0		0
Asset Impairment Charges	0				0
Equity in earnings/(losses) of unconsolidated affiliates	(11,000,000)		(4,000,000)		(12,000,000)		(3,000,000)
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	(12,000,000)		(8,000,000)		(9,000,000)		(7,000,000)
Net Loss	(12,000,000)		(8,000,000)		(9,000,000)		(7,000,000)
Net loss attributable to NRG Energy, Inc.	24,000,000		4,000,000		31,000,000		(1,000,000)
Total Assets	(15,330,000,000)				(15,330,000,000)
Inter-Segment Sales	0		$ 0		0		0
Loss on sale of assets, net of gains	0				0
Loss on debt extinguishment	$ 0				$ 0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments							$ 0
ROFO Assets [Member]
Segment Reporting Information
Percentage of Ownership Sold of Subsidiary										75.00%
Number of Facilities											12	12
[1]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$218 $3 $5 $— $55 $— $281(b) Includes loss on sale of assets$— $— $— $— $(83) $— $(83)(c) Includes loss on debt extinguishment$— $— $— $— $(80) $— $(80)
[2]	(e) Operating revenues include inter-segment sales and net derivative gains and losses of:$297 $4 $23 $9 $48 $— $381

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Effective Tax Rate
Loss before income taxes	$ (251)	$ (26)	$ (183)	$ (235)
Income tax expense/(benefit)	$ 25	$ (17)	$ 46	$ (90)
Effective tax rate	(10.00%)	65.40%	(25.10%)	38.30%
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	$ 43		$ 43
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued			0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 3		$ 3

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2016	Sep. 30, 2010	Jun. 30, 2016	Dec. 31, 2015
Loss Contingencies
Environmental Projects	$ 1,000,000		$ 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			1,500
CDWR and SDGE v Sunrise Power [Member]
Loss Contingencies
Loss Contingency, Damages Sought				1.2
Remaining Term				70 months
Lignite Contract with Texas Westmoreland Coal Co. [Member] | Guarantee of Indebtedness of Others [Member]
Loss Contingencies
Guarantor Obligations, Maximum Exposure, Undiscounted	12,000,000		$ 12,000,000
Lignite Contract with Texas Westmoreland Coal Co. [Member] | Surety Bond [Member]
Loss Contingencies
Surety Bonds in Support of Guarantee	95,500,000		$ 95,500,000
Surety Bonds Issued	64,000,000
Texas Westmoreland Coal Co. [Member] | Lignite Contract with Texas Westmoreland Coal Co. [Member]
Loss Contingencies
Long-term Purchase Commitment Mining Time Period Option to Extend			5 years
Third Party Bond Obligation	$ 107,500,000		$ 107,500,000

Environmental Matters (Details)

Environmental Matters (Details) $ in Millions	Jun. 30, 2016USD ($)
Environmental capital expenditures [Line Items]
Environmental Capital Expenditures, Estimated	$ 322
Genon [Member]
Environmental capital expenditures [Line Items]
Environmental Capital Expenditures, Estimated	61
Midwest Generation [Member]
Environmental capital expenditures [Line Items]
Environmental Capital Expenditures, Estimated	$ 247

Condensed Consolidating Finan66

Condensed Consolidating Financial Information (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument
Long-term Debt	$ 19,253	$ 19,620
Recourse Debt [Member]
Debt Instrument
Long-term Debt	8,234	$ 8,584
Senior Notes [Member] | Recourse Debt [Member]
Debt Instrument
Long-term Debt	$ 5,900

Condensed Consolidating Finan67

Condensed Consolidating Financial Information (Details 2) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
Operating Revenues
Total operating revenues		$ 2,638	[1]	$ 3,400	[2]	$ 5,867	[1]	$ 7,229	[2]
Operating Costs and Expenses
Cost of operations		1,756		2,436		3,945		5,509
Depreciation and amortization		309		396		622		791
Asset Impairment Charges		115		0		115		0
Selling, general and administrative		265		296		520		551
Acquisition-related transaction and integration costs		5		3		7		13
Development activity expenses		18		37		44		71
Total operating costs and expenses		2,468		3,168		5,253		6,935
Loss on sale of assets, net of gains		(83)		0		(51)		0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments		0		0		0		14
Operating Income/(Loss)		87		232		563		308
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		0		0		0		0
Equity in earnings/(losses) of unconsolidated affiliates		4		8		(3)		5
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		7		0		(139)		0
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net		(3)		16		(35)		4
Foreign currency translation adjustments, net		(3)		9		3		(2)
Available-for-sale securities, net		(2)		(3)		1		(4)
Defined benefit plans, net		0		(1)		1		6
Other comprehensive loss		(8)		21		(30)		4
Comprehensive Income/(Loss)		(284)		12		(259)		(141)
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		(16)		12		(68)		(17)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.		(268)		0		(191)		(124)
Gain on redemption of preferred shares		78		(5)		73		(10)
Comprehensive Income/(Loss) Available for Common Stockholders		(190)		(5)		(118)		(134)
Net Loss		(276)		(9)		(229)		(145)
Other Nonoperating Income (Expense)		8		4		26		23
Loss on debt extinguishment		(80)		(7)		(69)		(7)
Interest Expense		(277)		(263)		(561)		(564)
Nonoperating Income (Expense)		(338)		(258)		(746)		(543)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		(251)		(26)		(183)		(235)
Income Tax Expense (Benefit)		25		(17)		46		(90)
Net Income (Loss) Attributable to Noncontrolling Interest		(5)		5		(40)		(11)
Net Income (Loss) Attributable to Parent		(271)		(14)		(189)		(134)
Guarantor Subsidiaries
Operating Revenues
Total operating revenues		1,699		2,267		3,655		4,833
Operating Costs and Expenses
Cost of operations		1,110		1,703		2,560		3,807
Depreciation and amortization		108		196		225		400
Asset Impairment Charges		0				0
Selling, general and administrative		94		116		192		221
Acquisition-related transaction and integration costs		0		0		0		0
Development activity expenses		0		0		0		0
Total operating costs and expenses		1,312		2,015		2,977		4,428
Loss on sale of assets, net of gains		0				0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments								0
Operating Income/(Loss)		387		252		678		405
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		(44)		(22)		(68)		(35)
Equity in earnings/(losses) of unconsolidated affiliates		3		3		3		3
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		0				0
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net		0		2		0		(5)
Foreign currency translation adjustments, net		(2)		0		2		0
Available-for-sale securities, net		0		0		0		0
Defined benefit plans, net		0		0		(1)		3
Other comprehensive loss		(2)		2		3		(8)
Comprehensive Income/(Loss)		211		147		378		220
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		0		0		0		0
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.		211		147		378		220
Gain on redemption of preferred shares		0		0		0		0
Comprehensive Income/(Loss) Available for Common Stockholders		211		147		378		220
Net Loss		213		145		375		228
Other Nonoperating Income (Expense)		2		0		2		1
Loss on debt extinguishment		0		0		0		0
Interest Expense		(2)		(5)		(7)		(9)
Nonoperating Income (Expense)		(41)		(24)		(70)		(40)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		346		228		608		365
Income Tax Expense (Benefit)		133		83		233		137
Net Income (Loss) Attributable to Noncontrolling Interest		0		0		0		0
Net Income (Loss) Attributable to Parent		213		145		375		228
Non-Guarantor Subsidiaries
Operating Revenues
Total operating revenues		986		1,161		2,285		2,464
Operating Costs and Expenses
Cost of operations		685		756		1,444		1,762
Depreciation and amortization		195		195		385		381
Asset Impairment Charges		115				115
Selling, general and administrative		92		93		191		183
Acquisition-related transaction and integration costs		0		(1)		0		1
Development activity expenses		13		11		32		26
Total operating costs and expenses		1,100		1,054		2,167		2,353
Loss on sale of assets, net of gains		0				32
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments								14
Operating Income/(Loss)		(114)		107		150		125
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		(27)		(49)		(23)		(57)
Equity in earnings/(losses) of unconsolidated affiliates		6		10		(2)		6
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		1				(139)
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net		(5)		4		(55)		15
Foreign currency translation adjustments, net		(2)		9		2		0
Available-for-sale securities, net		0		0		0		(1)
Defined benefit plans, net		0		0		0		1
Other comprehensive loss		(7)		13		(53)		13
Comprehensive Income/(Loss)		(183)		(28)		(231)		(103)
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		(1)		28		(51)		(6)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.		(182)		(56)		(180)		(97)
Gain on redemption of preferred shares		0		0		0		0
Comprehensive Income/(Loss) Available for Common Stockholders		(182)		(56)		(180)		(97)
Net Loss		(176)		(41)		(178)		(116)
Other Nonoperating Income (Expense)		3		3		23		20
Loss on debt extinguishment		(4)		(7)		(4)		(7)
Interest Expense		(145)		(121)		(295)		(279)
Nonoperating Income (Expense)		(166)		(164)		(440)		(317)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		(280)		(57)		(290)		(192)
Income Tax Expense (Benefit)		(104)		(16)		(112)		(76)
Net Income (Loss) Attributable to Noncontrolling Interest		10		21		(23)		0
Net Income (Loss) Attributable to Parent		(186)		(62)		(155)		(116)
NRG Energy, Inc.
Operating Revenues
Total operating revenues		0		0		0		0
Operating Costs and Expenses
Cost of operations		8		(16)		18		(4)
Depreciation and amortization		6		5		12		10
Asset Impairment Charges		0				0
Selling, general and administrative		79		87		137		147
Acquisition-related transaction and integration costs		5		4		7		12
Development activity expenses		5		26		12		45
Total operating costs and expenses		103		106		186		210
Loss on sale of assets, net of gains		(83)				(83)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments								0
Operating Income/(Loss)		(186)		(106)		(269)		(210)
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		98		154		311		204
Equity in earnings/(losses) of unconsolidated affiliates		0		0		0		(1)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		6				0
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net		(4)		25		20		9
Foreign currency translation adjustments, net		(4)		0		2		(2)
Available-for-sale securities, net		(2)		(3)		1		(3)
Defined benefit plans, net		0		1		0		(10)
Other comprehensive loss		(10)		21		23		14
Comprehensive Income/(Loss)		(250)		17		(130)		(116)
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		31		10		36		4
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.		(281)		7		(166)		(120)
Gain on redemption of preferred shares		78		(5)		73		(10)
Comprehensive Income/(Loss) Available for Common Stockholders		(203)		2		(93)		(130)
Net Loss		(240)		(4)		(153)		(130)
Other Nonoperating Income (Expense)		4		1		2		2
Loss on debt extinguishment		(76)		0		(65)		0
Interest Expense		(130)		(137)		(259)		(276)
Nonoperating Income (Expense)		(98)		18		(11)		(71)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		(284)		(88)		(280)		(281)
Income Tax Expense (Benefit)		(44)		(84)		(127)		(151)
Net Income (Loss) Attributable to Noncontrolling Interest		31		10		36		4
Net Income (Loss) Attributable to Parent		(271)		(14)		(189)		(134)
Eliminations
Operating Revenues
Total operating revenues		(47)	[3]	(28)	[4]	(73)	[5]	(68)	[6]
Operating Costs and Expenses
Cost of operations		(47)	[3]	(7)	[4]	(77)	[5]	(56)	[6]
Depreciation and amortization		0	[3]	0	[4]	0	[5],[7]	0	[6],[8]
Asset Impairment Charges		0	[3]			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		(47)	[3]	(7)	[4]	(77)	[5]	(56)	[6]
Loss on sale of assets, net of gains		0	[3]			0	[5]
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	[6]							0
Operating Income/(Loss)		0	[3]	(21)	[4]	4	[5]	(12)	[6]
Other Income/(Expense)
Equity in (losses)/earnings of consolidated subsidiaries		(27)	[3]	(83)	[4]	(220)	[5]	(112)	[6]
Equity in earnings/(losses) of unconsolidated affiliates		(5)	[3]	(5)	[4]	(4)	[5],[7]	(3)	[6],[7]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		0	[3]			0	[5]
Other Comprehensive Income/(Loss), net of tax
Unrealized (loss)/gain on derivatives, net		6	[9]	(15)	[10]	0	[7]	(15)	[10]
Foreign currency translation adjustments, net		5	[9]	0	[10]	(3)	[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 loss		11	[9]	(15)	[10]	(3)	[7]	(15)	[10]
Comprehensive Income/(Loss)		(62)	[9]	(124)	[10]	(276)	[7]	(142)	[10]
Less: Comprehensive income/(loss) attributable to noncontrolling interest and redeemable noncontrolling interests		(46)	[9]	(26)	[10]	(53)	[7]	(15)	[10]
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.		(16)	[9]	(98)	[10]	(223)	[7]	(127)	[10]
Gain on redemption of preferred shares		0	[9]	0	[10]	0	[7]	0	[10]
Comprehensive Income/(Loss) Available for Common Stockholders		(16)	[9]	(98)	[10]	(223)	[7]	(127)	[10]
Net Loss		(73)	[3]	(109)	[4]	(273)	[7]	(127)	[6],[8]
Other Nonoperating Income (Expense)		(1)	[3]	0	[4]	(1)	[5]	0	[6]
Loss on debt extinguishment		0	[3]	0	[4]	0	[5]	0	[6]
Interest Expense		0	[3]	0	[4]	0	[5]	0	[6]
Nonoperating Income (Expense)		(33)	[3]	(88)	[4]	(225)	[5]	(115)	[6]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest		(33)	[3]	(109)	[4]	(221)	[5]	(127)	[6]
Income Tax Expense (Benefit)		40	[3]	0	[4]	52	[5]	0	[6]
Net Income (Loss) Attributable to Noncontrolling Interest		(46)	[3]	(26)	[4]	(53)	[5]	(15)	[6]
Net Income (Loss) Attributable to Parent		$ (27)	[3]	$ (83)	[4]	$ (220)	[5]	$ (112)	[6]
[1]	(a) Operating revenues include inter-segment sales and net derivative gains and losses of:$218 $3 $5 $— $55 $— $281(b) Includes loss on sale of assets$— $— $— $— $(83) $— $(83)(c) Includes loss on debt extinguishment$— $— $— $— $(80) $— $(80)
[2]	(e) Operating revenues include inter-segment sales and net derivative gains and losses of:$297 $4 $23 $9 $48 $— $381
[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 Finan68

Condensed Consolidating Financial Information (Details 3) - USD ($) $ in Millions		Jun. 30, 2016		Jun. 13, 2016	May 24, 2016	Dec. 31, 2015		Jun. 30, 2015		Dec. 31, 2014
Current Assets
Cash and cash equivalents		$ 1,389				$ 1,518		$ 2,146		$ 2,116
Funds deposited by counterparties		44				106
Restricted cash		413				414
Accounts receivable - trade, net		1,251				1,157
Accounts receivable - affiliate		4				4
Inventory		1,124				1,252
Derivative instruments		1,470				1,915
Cash collateral paid in support of energy risk management activities		218				568
Renewable energy grant receivable, net		36				13
Disposal Group, Including Discontinued Operation, Other Assets, Current		13				6
Prepayments and other current assets		402				438
Total current assets		6,364				7,391
Net property, plant and equipment		18,382				18,732
Other Assets
Investment in subsidiaries		0				0
Equity investments in affiliates		882				1,045
Notes receivable, less current portion		25				53
Goodwill		999				999
Intangible assets, net		2,180				2,310
Nuclear decommissioning trust fund		599				561
Derivative instruments		348				305
Deferred income taxes		175				167
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent		229				105
Other non-current assets		1,239				1,214
Total other assets		6,676				6,759
Total Assets		31,422				32,882
Current Liabilities
Current portion of long-term debt and capital leases		1,215				481
Accounts payable		898				869
Accounts payable — affiliate		0				0
Derivative instruments		1,373				1,721
Cash collateral received in support of energy risk management activities		44				106
Disposal Group, Including Discontinued Operation, Other Liabilities, Current		2
Accrued expenses and other current liabilities		982				1,196
Disposal Group, Including Discontinued Operation, Liabilities, Current		2				2
Other Liabilities, Current						1,196
Total current liabilities		4,514				4,375
Other Liabilities
Long-term debt and capital leases		17,893				18,983
Nuclear decommissioning reserve		334				326
Nuclear decommissioning trust liability		309				283
Deferred income taxes		42				19
Derivative instruments		539				493
Out-of-market contracts, net of accumulated amortization of $639 and $562		1,093				1,146
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent		0				4
Other non-current liabilities		1,554				1,488
Total non-current liabilities		21,764				22,742
Total liabilities		26,278				27,117
2.822% convertible perpetual preferred stock		0		$ 304		302
Redeemable noncontrolling interest in subsidiaries		$ 23				$ 29
Convertible perpetual preferred stock, interest rate (as a percentage)		2.822%			2.822%	2.822%		2.822%
Stockholders’ Equity		$ 5,121				$ 5,434
Total Liabilities and Stockholders’ Equity		31,422				32,882
Guarantor Subsidiaries
Current Assets
Cash and cash equivalents		0				0		$ 10		18
Funds deposited by counterparties		0				55
Restricted cash		10				5
Accounts receivable - trade, net		911				851
Accounts receivable - affiliate		325				395
Inventory		475				570
Derivative instruments		991				1,202
Cash collateral paid in support of energy risk management activities		130				474
Renewable energy grant receivable, net		0				0
Disposal Group, Including Discontinued Operation, Other Assets, Current		0				0
Prepayments and other current assets		106				93
Total current assets		2,948				3,645
Net property, plant and equipment		4,483				4,767
Other Assets
Investment in subsidiaries		1,080				842
Equity investments in affiliates		(17)				(14)
Notes receivable, less current portion		0				0
Goodwill		697				697
Intangible assets, net		691				763
Nuclear decommissioning trust fund		599				561
Derivative instruments		210				153
Deferred income taxes		30				(6)
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent		0				0
Other non-current assets		53				80
Total other assets		3,343				3,076
Total Assets		10,774				11,488
Current Liabilities
Current portion of long-term debt and capital leases		0				2
Accounts payable		588				553
Accounts payable — affiliate		242				151
Derivative instruments		915				1,130
Cash collateral received in support of energy risk management activities		0				55
Disposal Group, Including Discontinued Operation, Other Liabilities, Current		0
Accrued expenses and other current liabilities		301
Disposal Group, Including Discontinued Operation, Liabilities, Current						0
Other Liabilities, Current						319
Total current liabilities		2,046				2,210
Other Liabilities
Long-term debt and capital leases		245				302
Nuclear decommissioning reserve		334				326
Nuclear decommissioning trust liability		309				283
Deferred income taxes		958				179
Derivative instruments		298				301
Out-of-market contracts, net of accumulated amortization of $639 and $562		88				95
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent						0
Other non-current liabilities		411				554
Total non-current liabilities		2,643				2,040
Total liabilities		4,689				4,250
2.822% convertible perpetual preferred stock						0
Redeemable noncontrolling interest in subsidiaries		0				0
Stockholders’ Equity		6,085				7,238
Total Liabilities and Stockholders’ Equity		10,774				11,488
Non-Guarantor Subsidiaries
Current Assets
Cash and cash equivalents		1,039				825		1,437		1,455
Funds deposited by counterparties		44				51
Restricted cash		403				409
Accounts receivable - trade, net		338				304
Accounts receivable - affiliate		41				260
Inventory		649				682
Derivative instruments		574				871
Cash collateral paid in support of energy risk management activities		88				94
Renewable energy grant receivable, net		36				13
Disposal Group, Including Discontinued Operation, Other Assets, Current		13				6
Prepayments and other current assets		237				274
Total current assets		3,462				3,789
Net property, plant and equipment		13,678				13,773
Other Assets
Investment in subsidiaries		2,031				2,244
Equity investments in affiliates		984				1,160
Notes receivable, less current portion		24				46
Goodwill		302				302
Intangible assets, net		1,491				1,551
Nuclear decommissioning trust fund		0				0
Derivative instruments		164				184
Deferred income taxes		590				815
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent		229				105
Other non-current assets		833				749
Total other assets		6,648				7,156
Total Assets		23,788				24,718
Current Liabilities
Current portion of long-term debt and capital leases		1,375				460
Accounts payable		270				277
Accounts payable — affiliate		269				2,000
Derivative instruments		550				749
Cash collateral received in support of energy risk management activities		44				51
Disposal Group, Including Discontinued Operation, Other Liabilities, Current		2
Accrued expenses and other current liabilities		338
Disposal Group, Including Discontinued Operation, Liabilities, Current						2
Other Liabilities, Current						429
Total current liabilities		2,848				3,968
Other Liabilities
Long-term debt and capital leases		9,810				10,496
Nuclear decommissioning reserve		0				0
Nuclear decommissioning trust liability		0				0
Deferred income taxes		255				(1,088)
Derivative instruments		267				224
Out-of-market contracts, net of accumulated amortization of $639 and $562		1,005				1,051
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent						4
Other non-current liabilities		781				735
Total non-current liabilities		12,118				11,422
Total liabilities		14,966				15,390
2.822% convertible perpetual preferred stock						0
Redeemable noncontrolling interest in subsidiaries		23				29
Stockholders’ Equity		8,799				9,299
Total Liabilities and Stockholders’ Equity		23,788				24,718
NRG Energy, Inc.
Current Assets
Cash and cash equivalents		350				693		699		643
Funds deposited by counterparties		0				0
Restricted cash		0				0
Accounts receivable - trade, net		2				2
Accounts receivable - affiliate		191				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				0
Prepayments and other current assets		59				71
Total current assets		602				1,337
Net property, plant and equipment		248				219
Other Assets
Investment in subsidiaries		10,771				11,039
Equity investments in affiliates		10				1
Notes receivable, less current portion		(2)				7
Goodwill		0				0
Intangible assets, net		1				2
Nuclear decommissioning trust fund		0				0
Derivative instruments		0				0
Deferred income taxes		(445)				(642)
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent		0				0
Other non-current assets		353				385
Total other assets		10,688				10,792
Total Assets		11,538				12,348
Current Liabilities
Current portion of long-term debt and capital leases		(163)				19
Accounts payable		40				39
Accounts payable — affiliate		42				(929)
Derivative instruments		3				0
Cash collateral received in support of energy risk management activities		0				0
Disposal Group, Including Discontinued Operation, Other Liabilities, Current		0
Accrued expenses and other current liabilities		343
Disposal Group, Including Discontinued Operation, Liabilities, Current						0
Other Liabilities, Current						449
Total current liabilities		265				(422)
Other Liabilities
Long-term debt and capital leases		7,838				8,185
Nuclear decommissioning reserve		0				0
Nuclear decommissioning trust liability		0				0
Deferred income taxes		(1,171)				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		362				199
Total non-current liabilities		7,029				9,312
Total liabilities		7,294				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		4,244				$ 3,156
Total Liabilities and Stockholders’ Equity		11,538				12,348
Eliminations
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		(553)	[1]			(1,222)	[3]
Inventory		0	[1]			0	[3]
Derivative instruments		(95)	[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		0	[1]			0	[3]
Prepayments and other current assets		0	[1]			0	[3]
Total current assets		(648)	[1]			(1,380)	[3]
Net property, plant and equipment		(27)	[1]			(27)	[3]
Other Assets
Investment in subsidiaries		(13,882)	[1]			(14,125)	[3]
Equity investments in affiliates		(95)	[1]			(102)	[3]
Notes receivable, less current portion		3	[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		(26)	[1]			(32)	[3]
Deferred income taxes		0	[1]			0	[3]
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent		0	[1]			0	[3]
Other non-current assets		0	[1]			0	[3]
Total other assets		(14,003)	[1]			(14,265)	[3]
Total Assets		(14,678)	[1]			(15,672)	[3]
Current Liabilities
Current portion of long-term debt and capital leases		3	[1]			0	[3]
Accounts payable		0	[1]			0	[3]
Accounts payable — affiliate		(553)	[1]			(1,222)	[3]
Derivative instruments		(95)	[1]			(158)	[3]
Cash collateral received in support of energy risk management activities		0	[1]			0	[3]
Disposal Group, Including Discontinued Operation, Other Liabilities, Current	[1]	0
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		(645)	[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		(26)	[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		(26)	[1]			(32)	[3]
Total liabilities		(671)	[1]			(1,413)	[3]
2.822% convertible perpetual preferred stock	[3]					0
Redeemable noncontrolling interest in subsidiaries		0	[1]			0	[3]
Stockholders’ Equity		(14,007)	[1]			(14,259)	[3]
Total Liabilities and Stockholders’ Equity		$ (14,678)	[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 Finan69

Condensed Consolidating Financial Information (Details 4) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
Cash Flows from Operating Activities
Net Loss		$ (276)		$ (9)		$ (229)		$ (145)
Adjustments to reconcile net loss to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries						(29)		(45)
Equity in earnings of unconsolidated affiliates		(4)		(8)		3		(5)
Depreciation and amortization		309		396		622		791
Provision for bad debts						20		29
Amortization of nuclear fuel						26		23
Amortization of financing costs and debt discount/premiums						3		(7)
Amortization of intangibles and out-of-market contracts						41		32
Amortization of unearned equity compensation						16		24
Changes in deferred income taxes and liability for uncertain tax benefits						1		(98)
Changes in nuclear decommissioning trust liability						13		(4)
Changes in derivative instruments						(25)		186
Changes in collateral deposits supporting energy risk management activities						350		(112)
Cash used by changes in other working capital						(355)		(294)
Proceeds from sale of emission allowances						47		0
Loss/(gain) on sale of assets and postretirement benefits curtailment						43		(14)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		115		0		115		0
Impairment losses						254		0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments		0		0		0		(14)
Gain on sale of assets and postretirement benefits curtailment								(14)
Adjustment to loss on debt extinguishment						14		7
Net Cash Provided by Operating Activities						873		458
Cash Flows from Investing Activities
Proceeds from Dividends Received						0		0
Acquisitions of businesses, net of cash acquired						(17)		(30)
Capital expenditures						(622)		(583)
Decrease/(increase) in restricted cash, net						29		(3)
Decrease/(increase) in restricted cash — U.S. DOE funded projects						(28)		27
Increase in notes receivable						(3)		7
Investments in nuclear decommissioning trust fund securities						(280)		(354)
Proceeds from the sale of nuclear decommissioning trust fund securities						267		358
Proceeds from renewable energy grants and state rebates						10		61
Payments to Acquire Intangible Assets						(27)		0
Proceeds from Sale of Intangible Assets						(25)		0
Proceeds from sale of assets, net of cash disposed of						145		1
(Investments in) Proceeds From Sales of Unconsolidated Affiliates						0		(353)
Other						32		9
Net Cash Used by Investing Activities						(469)		(860)
Cash Flows from Financing Activities
Proceeds from intercompany loans						0		0
Intercompany Dividend Proceeds - Financing						0		0
Payment of dividends to common and preferred stockholders						(57)		(102)
Payment for treasury stock						0		(186)
Payments for Repurchase of Redeemable Preferred Stock		226				226		0
Net receipts from settlement of acquired derivatives that include financing elements						103		91
Proceeds from issuance of long-term debt						3,223		629
Distributions from, net of contributions to, noncontrolling interest in subsidiaries						21		(670)
Proceeds from issuance of common stock						0		1
Payments of Debt Issuance Costs						35		12
Payments for short and long-term debt						(3,507)		(662)
Other - contingent consideration						(10)		0
Net Cash (Used)/Provided by Financing Activities						(530)		429
Effect of exchange rate changes on cash and cash equivalents						(3)		3
Net Increase/(Decrease) in Cash and Cash Equivalents						(129)		30
Cash and Cash Equivalents at Beginning of Period						1,518		2,116
Cash and Cash Equivalents at End of Period		1,389		2,146		1,389		2,146
Guarantor Subsidiaries
Cash Flows from Operating Activities
Net Loss		213		145		375		228
Adjustments to reconcile net loss to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries						0		(6)
Equity in earnings of unconsolidated affiliates		(3)		(3)		(3)		(3)
Depreciation and amortization		108		196		225		400
Provision for bad debts						16		26
Amortization of nuclear fuel						26		23
Amortization of financing costs and debt discount/premiums						0		0
Amortization of intangibles and out-of-market contracts						20		24
Amortization of unearned equity compensation						0		0
Changes in deferred income taxes and liability for uncertain tax benefits						233		137
Changes in nuclear decommissioning trust liability						13		(4)
Changes in derivative instruments						(64)		63
Changes in collateral deposits supporting energy risk management activities						344		(82)
Cash used by changes in other working capital						(935)		710
Proceeds from sale of emission allowances						47
Loss/(gain) on sale of assets and postretirement benefits curtailment						0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		0				0
Impairment losses						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						0		0
Net Cash Provided by Operating Activities						297		1,528
Cash Flows from Investing Activities
Proceeds from Dividends Received						0		0
Acquisitions of businesses, net of cash acquired						0		0
Capital expenditures						(80)		(177)
Decrease/(increase) in restricted cash, net						4		0
Decrease/(increase) in restricted cash — U.S. DOE funded projects						1		0
Increase in notes receivable						0		0
Investments in nuclear decommissioning trust fund securities						(280)		(354)
Proceeds from the sale of nuclear decommissioning trust fund securities						267		358
Proceeds from renewable energy grants and state rebates						0		0
Payments to Acquire Intangible Assets						(27)
Proceeds from Sale of Intangible Assets						(25)
Proceeds from sale of assets, net of cash disposed of						0		0
(Investments in) Proceeds From Sales of Unconsolidated Affiliates								0
Other						28		5
Net Cash Used by Investing Activities						(62)		(168)
Cash Flows from Financing Activities
Proceeds from intercompany loans						(179)		(1,368)
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
Payments of Debt Issuance Costs						0		0
Payments for short and long-term debt						(1)		0
Other - contingent consideration						(3)
Net Cash (Used)/Provided by Financing Activities						(235)		(1,368)
Effect of exchange rate changes on cash and cash equivalents						0		0
Net Increase/(Decrease) in Cash and Cash Equivalents						0		(8)
Cash and Cash Equivalents at Beginning of Period						0		18
Cash and Cash Equivalents at End of Period		0		10		0		10
Non-Guarantor Subsidiaries
Cash Flows from Operating Activities
Net Loss		(176)		(41)		(178)		(116)
Adjustments to reconcile net loss to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries						(40)		(50)
Equity in earnings of unconsolidated affiliates		(6)		(10)		2		(6)
Depreciation and amortization		195		195		385		381
Provision for bad debts						4		0
Amortization of nuclear fuel						0		0
Amortization of financing costs and debt discount/premiums						(10)		(20)
Amortization of intangibles and out-of-market contracts						21		8
Amortization of unearned equity compensation						0		0
Changes in deferred income taxes and liability for uncertain tax benefits						(112)		(76)
Changes in nuclear decommissioning trust liability						0		0
Changes in derivative instruments						36		121
Changes in collateral deposits supporting energy risk management activities						6		(30)
Cash used by changes in other working capital						24		(771)
Proceeds from sale of emission allowances						0
Loss/(gain) on sale of assets and postretirement benefits curtailment						(32)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		115				115
Impairment losses						254
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		7
Net Cash Provided by Operating Activities						444		(466)
Cash Flows from Investing Activities
Proceeds from Dividends Received								0
Acquisitions of businesses, net of cash acquired						(17)		(30)
Capital expenditures						(509)		(388)
Decrease/(increase) in restricted cash, net						25		(3)
Decrease/(increase) in restricted cash — U.S. DOE funded projects						(29)		27
Increase in notes receivable						(3)		7
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						10		61
Payments to Acquire Intangible Assets						0
Proceeds from Sale of Intangible Assets						0
Proceeds from sale of assets, net of cash disposed of						120		0
(Investments in) Proceeds From Sales of Unconsolidated Affiliates								(304)
Other						4		4
Net Cash Used by Investing Activities						(399)		(626)
Cash Flows from Financing Activities
Proceeds from intercompany loans						45		440
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						103		91
Proceeds from issuance of long-term debt						332		601
Distributions from, net of contributions to, noncontrolling interest in subsidiaries						21		(670)
Proceeds from issuance of common stock								0
Payments of Debt Issuance Costs						0		12
Payments for short and long-term debt						(281)		(652)
Other - contingent consideration						(7)
Net Cash (Used)/Provided by Financing Activities						172		1,071
Effect of exchange rate changes on cash and cash equivalents						(3)		3
Net Increase/(Decrease) in Cash and Cash Equivalents						214		(18)
Cash and Cash Equivalents at Beginning of Period						825		1,455
Cash and Cash Equivalents at End of Period		1,039		1,437		1,039		1,437
NRG Energy, Inc.
Cash Flows from Operating Activities
Net Loss		(240)		(4)		(153)		(130)
Adjustments to reconcile net 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		0		0		0		1
Depreciation and amortization		6		5		12		10
Provision for bad debts						0		3
Amortization of nuclear fuel						0		0
Amortization of financing costs and debt discount/premiums						13		13
Amortization of intangibles and out-of-market contracts						0		0
Amortization of unearned equity compensation						16		24
Changes in deferred income taxes and liability for uncertain tax benefits						(120)		(159)
Changes in nuclear decommissioning trust liability						0		0
Changes in derivative instruments						3		2
Changes in collateral deposits supporting energy risk management activities						0		0
Cash used by changes in other working capital						276		(368)
Proceeds from sale of emission allowances						0
Loss/(gain) on sale of assets and postretirement benefits curtailment						75
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		0				0
Impairment losses						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						10		0
Net Cash Provided by Operating Activities						132		(604)
Cash Flows from Investing Activities
Proceeds from Dividends Received						12		33
Acquisitions of businesses, net of cash acquired						0		0
Capital expenditures						(33)		(18)
Decrease/(increase) in restricted cash, net						0		0
Decrease/(increase) in restricted cash — U.S. DOE funded projects						0		0
Increase 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
Proceeds from Sale of Intangible Assets						0
Proceeds from sale of assets, net of cash disposed of						25		1
(Investments in) Proceeds From Sales of Unconsolidated Affiliates								(49)
Other						0		0
Net Cash Used by Investing Activities						43		1
Cash Flows from Financing Activities
Proceeds from intercompany loans						134		928
Intercompany Dividend Proceeds - Financing						0		0
Payment of dividends to common and preferred stockholders						(57)		(102)
Payment for treasury stock								(186)
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						2,891		28
Distributions from, net of contributions to, noncontrolling interest in subsidiaries						0		0
Proceeds from issuance of common stock								1
Payments of Debt Issuance Costs						35		0
Payments for short and long-term debt						(3,225)		(10)
Other - contingent consideration						0
Net Cash (Used)/Provided by Financing Activities						(518)		659
Effect of exchange rate changes on cash and cash equivalents						0		0
Net Increase/(Decrease) in Cash and Cash Equivalents						(343)		56
Cash and Cash Equivalents at Beginning of Period						693		643
Cash and Cash Equivalents at End of Period		350		699		350		699
Eliminations
Cash Flows from Operating Activities
Net Loss		(73)	[1]	(109)	[2]	(273)	[3]	(127)	[4],[5]
Adjustments to reconcile net loss to net cash provided by operating activities:
Distributions and equity in (earnings)/losses of unconsolidated affiliates and consolidated subsidiaries	[3]					11		11
Equity in earnings of unconsolidated affiliates		5	[1]	5	[2]	4	[3],[6]	3	[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]	0	[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						280	[3]	135	[5]
Proceeds from sale of emission allowances	[3]					0
Loss/(gain) on sale of assets and postretirement benefits curtailment	[3]					0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		0	[1]			0	[6]
Impairment losses	[3]					0
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		0
Cash Flows from Investing Activities
Proceeds from Dividends Received	[3]					(12)		(33)
Acquisitions of businesses, net of cash acquired						0	[3]	0	[5]
Capital expenditures						0	[3]	0	[5]
Decrease/(increase) in restricted cash, net						0	[3]	0	[5]
Decrease/(increase) in restricted cash — U.S. DOE funded projects						0	[3]	0	[5]
Increase 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	[3]					0
Proceeds from Sale of Intangible Assets	[3]					0
Proceeds from sale of assets, net of cash disposed of						0	[3]	0	[5]
(Investments in) Proceeds From Sales of Unconsolidated Affiliates	[5]							0
Other						0	[3]	0	[5]
Net Cash Used by Investing Activities						(51)	[3]	(67)	[5]
Cash Flows from Financing Activities
Proceeds from intercompany loans						0	[3]	0	[5]
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	[5]							0
Payments of Debt Issuance Costs						0	[3]	0	[5]
Payments for short and long-term debt						0	[3]	0	[5]
Other - contingent consideration	[3]					0
Net Cash (Used)/Provided by Financing Activities						51	[3]	67	[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]
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						(39)		(34)
NRG Yield, Inc. | NRG Energy, Inc.
Cash Flows from Investing Activities
Proceeds from Dividends Received						39		34
Cash Flows from Financing Activities
Intercompany Dividend Proceeds - Financing						0		0
NRG Yield, Inc. | Eliminations
Cash Flows from Investing Activities
Proceeds from Dividends Received	[3]					(39)		(34)
Cash Flows from Financing Activities
Intercompany Dividend Proceeds - Financing	[3]					$ 39		$ 34
[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.