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

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 31, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	NRG Yield, Inc.
Entity Central Index Key	1,567,683
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Common Class A [Member]
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		34,586,250
Common Class B [Member]
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		42,738,750
Common Class C [Member]
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		63,729,360
Common Class D [Member]
Class of Stock [Line Items]
Entity Common Stock, Shares Outstanding		42,738,750

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
Operating Revenues
Total operating revenues		$ 284	$ 283	[1]	$ 502	$ 517	[1]
Operating Costs and Expenses
Cost of operations		77	77	[1]	161	162	[1]
Depreciation and amortization		78	75	[1]	153	149	[1]
General and administrative		6	3	[1]	10	6	[1]
Acquisition-related transaction and integration costs		1	0	[1]	2	0	[1]
Total operating costs and expenses		162	155	[1]	326	317	[1]
Operating Income		122	128	[1]	176	200	[1]
Other Income (Expense)
Equity in earnings of unconsolidated affiliates		16	14	[1]	35	18	[1]
Other income, net		1	2	[1]	2	2	[1]
Interest expense		(86)	(68)	[1]	(162)	(142)	[1]
Total other expense, net		(69)	(52)	[1]	(125)	(122)	[1]
Income Before Income Taxes		53	76	[1]	51	78	[1]
Income tax expense		8	12	[1]	7	12	[1]
Net Income		45	64	[1],[2]	44	66	[1],[2]
Less: Pre-acquisition net income of Drop Down Assets		0	6	[2]	12	6	[1],[2]
Net Income Excluding Pre-acquisition Net Income of Drop Down Assets		45	58	[1]	32	60	[1]
Less: Net Income attributable to noncontrolling interests		17	26	[1]	7	23	[1]
Net Income Attributable to NRG Yield, Inc.		$ 28	32	[1]	$ 25	$ 37	[1]
Earnings Per Share Attributable to NRG Yield, Inc. Class A and Class C Common Stockholders
Dividends Per Common Share, Cash Paid		$ 0.27
Common Class C [Member]
Other Income (Expense)
Net Income Attributable to NRG Yield, Inc.	[3]	$ 18	$ 21
Earnings Per Share Attributable to NRG Yield, Inc. Class A and Class C Common Stockholders
Weighted Average Number of Shares Outstanding, Basic	[3]	63	63
Weighted Average Number of Shares Outstanding, Basic and Diluted	[3]				63	63
Weighted average number of Class A common shares outstanding - diluted	[3]	74	73
Earnings Per Share, Basic	[3]	$ 0.29	$ 0.33		$ (0.03)	$ 0.38
Earnings Per Share, Basic and Diluted	[3]				0.26	0.38
Earnings per Weighted Average Class A Common Share - Diluted	[3]	0.28	0.31
Dividends Per Common Share, Cash Paid		$ 0.27	$ 0.23	[1]	$ 0.53	$ 0.455	[1]
Common Class A [Member]
Other Income (Expense)
Net Income Attributable to NRG Yield, Inc.	[3]	$ 10	$ 11
Earnings Per Share Attributable to NRG Yield, Inc. Class A and Class C Common Stockholders
Weighted Average Number of Shares Outstanding, Basic	[3]	35	35
Weighted Average Number of Shares Outstanding, Basic and Diluted	[3]				35	35
Weighted average number of Class A common shares outstanding - diluted	[3]	49	49
Earnings Per Share, Basic	[3]	$ 0.29	$ 0.33
Earnings Per Share, Basic and Diluted	[3]				$ 0.26	$ 0.38
Earnings per Weighted Average Class A Common Share - Diluted	[3]	0.26	0.29
Dividends Per Common Share, Cash Paid		$ 0.27	$ 0.23	[1]	$ 0.53	$ 0.455	[1]
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[3]	(a) Basic and diluted earnings per share might not recalculate due to presenting values in millions rather than whole dollars.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	[2]	Jun. 30, 2017	Jun. 30, 2016	[2]
Net income	$ 45	$ 64	[1]	$ 44	$ 66	[1]
Other Comprehensive Loss, net of tax
Unrealized loss on derivatives, net of income tax benefit of $1, $3, $0 and $12	(6)	(16)		0	(57)
Other comprehensive loss	(6)	(16)		0	(57)
Comprehensive Income	39	48		44	9
Less: Pre-acquisition net income of Drop Down Assets	0	6		12	6	[1]
Less: Comprehensive income (loss) attributable to noncontrolling interests	14	13		7	(14)
Comprehensive Income Attributable to NRG Yield, Inc.	$ 25	$ 29		$ 25	$ 17
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Unrealized gain/loss on derivatives, income tax expense /(benefit)	$ (1)	$ (3)	$ 0	$ (12)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 181,000,000	$ 322,000,000
Restricted cash	114,000,000	165,000,000
Accounts receivable — trade	119,000,000	92,000,000
Inventory	41,000,000	39,000,000
Derivative instruments	1,000,000	2,000,000
Notes receivable	14,000,000	16,000,000
Prepayments and other current assets	21,000,000	20,000,000
Total current assets	491,000,000	656,000,000
Property, plant and equipment, net	5,322,000,000	5,460,000,000
Other Assets
Equity investments in affiliates	1,161,000,000	1,152,000,000
Notes receivable	7,000,000	14,000,000
Intangible assets, net	1,251,000,000	1,286,000,000
Derivative instruments	0	1,000,000
Deferred income taxes	207,000,000	216,000,000
Other non-current assets	74,000,000	51,000,000
Total other assets	2,700,000,000	2,720,000,000
Total Assets	8,513,000,000	8,836,000,000
Current Liabilities
Current portion of long-term debt	298,000,000	291,000,000
Accounts payable — trade	23,000,000	23,000,000
Accounts payable — affiliate	31,000,000	40,000,000
Derivative instruments	26,000,000	32,000,000
Accrued expenses and other current liabilities	60,000,000	86,000,000
Total current liabilities	438,000,000	472,000,000
Other Liabilities
Long-term debt	5,597,000,000	5,696,000,000
Due to Related Parties, Noncurrent	9,000,000	9,000,000
Derivative instruments	54,000,000	44,000,000
Other non-current liabilities	79,000,000	76,000,000
Total non-current liabilities	5,739,000,000	5,825,000,000
Total Liabilities	6,177,000,000	6,297,000,000
Commitments and Contingencies	0	0
Stockholders' Equity
Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued	0	0
Class A, Class B, Class C and Class D common stock, $0.01 par value; 3,000,000,000 shares authorized (Class A 500,000,000, Class B 500,000,000, Class C 1,000,000,000, Class D 1,000,000,000); 183,793,110 shares issued and outstanding (Class A 34,586,250, Class B 42,738,750, Class C 63,729,360, Class D 42,738,750) at June 30, 2017 and 182,848,000 shares issued and outstanding (Class A 34,586,250, Class B 42,738,750, Class C 62,784,250, Class D 42,738,750) at December 31, 2016	1,000,000	1,000,000
Additional paid-in capital	1,842,000,000	1,879,000,000
Retained earnings	23,000,000	(2,000,000)
Accumulated other comprehensive loss	(28,000,000)	(28,000,000)
Noncontrolling interest	498,000,000	689,000,000
Total Stockholders' Equity	2,336,000,000	2,539,000,000
Total Liabilities and Stockholders' Equity	$ 8,513,000,000	$ 8,836,000,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Common Stock, Par or Stated Value Per Share	$ 0.01
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	0	0
Commitments and Contingencies	$ 0	$ 0
Common Class A [Member]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	34,586,250	34,586,250
Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Class B [Member]
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	42,738,750	42,738,750
Common Class C [Member]
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common Stock, Shares, Issued	63,729,360	62,784,250
Common Class D [Member]
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common Stock, Shares, Issued	42,738,750	42,738,750

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows from Operating Activities
Net income	$ 44	$ 66	[1],[2]
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in earnings of unconsolidated affiliates	(35)	(18)	[1]
Distributions from unconsolidated affiliates	29	25	[3]
Depreciation and amortization	153	149	[3]
Amortization of financing costs and debt discounts	11	10	[3]
Amortization of intangibles and out-of-market contracts	34	40	[3]
Changes in deferred income taxes	7	12	[3]
Changes in derivative instruments	4	(1)	[3]
Loss on disposal of asset components	4	3	[3]
Changes in prepaid and accrued liabilities for tolling agreements	(64)	(65)	[3]
Changes in other working capital	(16)	(3)	[3]
Net Cash Provided by Operating Activities	171	218	[3]
Cash Flows from Investing Activities
Acquisition of Drop Down Assets	131	0	[3]
Capital expenditures	(13)	(11)	[3]
Cash receipts from notes receivable	9	9	[3]
Return of investment from unconsolidated affiliates	25	18	[3]
Investments in unconsolidated affiliates	(33)	(59)	[3]
Other	0	(2)	[3]
Net Cash Used in Investing Activities	(143)	(41)	[3]
Cash Flows from Financing Activities
Net contributions from noncontrolling interests	15	8	[3]
Net distributions and return of capital to NRG prior to the acquisition of Drop Down Assets	(42)	(15)	[3]
Proceeds from the issuance of common stock	16	0	[3]
Payments of dividends and distributions	(104)	(89)	[3]
Payments of debt issuance costs	4	0	[3]
Proceeds from the revolving credit facility	0	60	[3]
Payments for the revolving credit facility	0	48	[3]
Proceeds from the issuance of long-term debt	41	0	[3]
Payments for long-term debt	(142)	(122)	[3]
Net Cash Used in Financing Activities	(220)	(206)	[3]
Net Decrease in Cash, Cash Equivalents and Restricted Cash	(192)	(29)	[3]
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	487	242	[3]
Cash, Cash Equivalents and Restricted Cash at End of Period	$ 295	$ 213	[3]
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[3]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Nature of Business

Nature of Business	6 Months Ended
	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business NRG Yield, Inc., together with its consolidated subsidiaries, or the Company, is a dividend growth-oriented company formed to serve as the primary vehicle through which NRG owns, operates and acquires contracted renewable and conventional generation and thermal infrastructure assets. The Company believes it is well positioned to be a premier company for investors seeking stable and growing dividend income from a diversified portfolio of lower-risk, high-quality assets. NRG Yield, Inc. owns 100% of the Class A units and Class C units of NRG Yield LLC, including a controlling interest through its position as managing member. The Company owns a diversified portfolio of contracted renewable and conventional generation and thermal infrastructure assets in the U.S. The Company’s contracted generation portfolio collectively represents 4,879 net MW as of June 30, 2017 . Each of these assets sells substantially all of its output pursuant to long-term offtake agreements with creditworthy counterparties. The weighted average remaining contract duration of these offtake agreements was approximately 16 years as of June 30, 2017 based on CAFD. The Company also owns thermal infrastructure assets with an aggregate steam and chilled water capacity of 1,319 net MWt and electric generation capacity of 123 net MW. These thermal infrastructure assets provide steam, hot and/or chilled water, and, in some instances, electricity to commercial businesses, universities, hospitals and governmental units in multiple locations, principally through long-term contracts or pursuant to rates regulated by state utility commissions. NRG Yield, Inc. consolidates the results of NRG Yield LLC through its controlling interest, with NRG's interest shown as noncontrolling interest in the financial statements. The holders of NRG Yield, Inc.'s outstanding shares of Class A and Class C common stock are entitled to dividends as declared. NRG receives its distributions from NRG Yield LLC through its ownership of NRG Yield LLC Class B and Class D units. The following table represents the structure of the Company as of June 30, 2017 : On July 12, 2017, NRG announced that it had adopted and initiated a three-year, three-part improvement plan, or the NRG Transformation Plan. As part of the NRG Transformation Plan, NRG announced that it is exploring strategic alternatives for its renewables platform and its interest in the Company. NRG, through its holdings of Class B common stock and Class D common stock, has a 55.1% voting interest in the Company and receives distributions from NRG Yield LLC through its ownership of Class B units and Class D units. NRG stated that the strategic alternatives span a variety of ownership structures and partnership types, including the potential partial or full monetization of NRG's renewables platform and NRG's interest in the Company. NRG is the Company's controlling stockholder and the Company has been highly dependent on NRG for, among other things, growth opportunities and management and administration services. See Part I, Item 1A, Risk Factors in the Company's 2016 Form 10-K as well as Part II, Item 1A, Risk Factors in this report, for risks related to the NRG Transformation Plan and the Company's relationship with NRG. As of June 30, 2017 , the Company's operating assets are comprised of the following projects: Projects Percentage Ownership Net Capacity (MW) (a) Offtake Counterparty Expiration Conventional El Segundo 100 % 550 Southern California Edison 2023 GenConn Devon 50 % 95 Connecticut Light & Power 2040 GenConn Middletown 50 % 95 Connecticut Light & Power 2041 Marsh Landing 100 % 720 Pacific Gas and Electric 2023 Walnut Creek 100 % 485 Southern California Edison 2023 1,945 Utility Scale Solar Agua Caliente 16 % 46 Pacific Gas and Electric 2039 Alpine 100 % 66 Pacific Gas and Electric 2033 Avenal 50 % 23 Pacific Gas and Electric 2031 Avra Valley 100 % 26 Tucson Electric Power 2032 Blythe 100 % 21 Southern California Edison 2029 Borrego 100 % 26 San Diego Gas and Electric 2038 CVSR 100 % 250 Pacific Gas and Electric 2038 Desert Sunlight 250 25 % 63 Southern California Edison 2035 Desert Sunlight 300 25 % 75 Pacific Gas and Electric 2040 Kansas South 100 % 20 Pacific Gas and Electric 2033 Roadrunner 100 % 20 El Paso Electric 2031 TA High Desert 100 % 20 Southern California Edison 2033 Utah Solar Portfolio (e) 50 % 265 PacifiCorp 2036 921 Distributed Solar Apple I LLC Projects 100 % 9 Various 2032 AZ DG Solar Projects 100 % 5 Various 2025 - 2033 14 Wind Alta I 100 % 150 Southern California Edison 2035 Alta II 100 % 150 Southern California Edison 2035 Alta III 100 % 150 Southern California Edison 2035 Alta IV 100 % 102 Southern California Edison 2035 Alta V 100 % 168 Southern California Edison 2035 Alta X (b) 100 % 137 Southern California Edison 2038 Alta XI (b) 100 % 90 Southern California Edison 2038 Buffalo Bear 100 % 19 Western Farmers Electric Co-operative 2033 Crosswinds (b) (f) 74.3 % 16 Corn Belt Power Cooperative 2027 Elbow Creek (b) (f) 75 % 92 NRG Power Marketing LLC 2022 Elkhorn Ridge (b) (f) 50.3 % 41 Nebraska Public Power District 2029 Forward (b) (f) 75 % 22 Constellation NewEnergy, Inc. 2017 Goat Wind (b) (f) 74.9 % 113 Dow Pipeline Company 2025 Hardin (b) (f) 74.3 % 11 Interstate Power and Light Company 2027 Laredo Ridge 100 % 80 Nebraska Public Power District 2031 Lookout (b) (f) 75 % 29 Southern Maryland Electric Cooperative 2030 Projects Percentage Ownership Net Capacity (MW) (a) Offtake Counterparty Expiration Odin (b) (f) 74.9 % 15 Missouri River Energy Services 2028 Pinnacle 100 % 55 Maryland Department of General Services and University System of Maryland 2031 San Juan Mesa (b) (f) 56.3 % 68 Southwestern Public Service Company 2025 Sleeping Bear (b) (f) 75 % 71 Public Service Company of Oklahoma 2032 South Trent 100 % 101 AEP Energy Partners 2029 Spanish Fork (b) (f) 75 % 14 PacifiCorp 2028 Spring Canyon II (b) 90.1 % 29 Platte River Power Authority 2039 Spring Canyon III (b) 90.1 % 25 Platte River Power Authority 2039 Taloga 100 % 130 Oklahoma Gas & Electric 2031 Wildorado (b) (f) 74.9 % 121 Southwestern Public Service Company 2027 1,999 Thermal NRG Dover Energy Center LLC 100 % 103 NRG Power Marketing LLC 2018 Thermal generation 100 % 20 Various Various 123 Total net generation capacity (c) 5,002 Thermal equivalent MWt (d) 100 % 1,319 Various Various (a) Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of June 30, 2017 . (b) Projects are part of tax equity arrangements. (c) The Company's total generation capacity is net of 6 MWs for noncontrolling interest for Spring Canyon II and III. The Company's generation capacity including this noncontrolling interest was 5,008 MWs. (d) For thermal energy, net capacity represents MWt for steam or chilled water and excludes 134 MWt available under the right-to-use provisions contained in agreements between two of the Company's thermal facilities and certain of its customers. (e) Represents interests in Four Brothers Solar, LLC, Granite Mountain Holdings, LLC, and Iron Springs Holdings, LLC, all acquired as part of the March 2017 Drop Down Assets (ownership percentage is based upon cash to be distributed). (f) Projects are part of NRG Wind TE Holdco portfolio. In addition to the facilities owned or leased in the table above, the Company entered into partnerships to own or purchase solar power generation projects, as well as other ancillary related assets from a related party via intermediate funds. The Company does not consolidate these partnerships and accounts for them as equity method investments. The Company's net interest in these projects is 190 MW based on cash to be distributed as of June 30, 2017 . For further discussions, refer to Note 5 , Investments Accounted for by the Equity Method and Variable Interest Entities to the consolidated financial statements for the year ended December 31, 2016 included in the Company's May 9, 2017 Form 8-K. Substantially all of the Company's generation assets are under long-term contractual arrangements for the output or capacity from these assets. The thermal assets are comprised of district energy systems and combined heat and power plants that produce steam, hot water and/or chilled water and, in some instances, electricity at a central plant. Certain district energy systems are subject to rate regulation by state public utility commissions (although they may negotiate certain rates) while the other district energy systems have rates determined by negotiated bilateral contracts. As further described in Note 3 , Business Acquisitions , on March 27, 2017, the Company acquired the following interests from NRG, referred to as the March 2017 Drop Down Assets: (i) Agua Caliente Borrower 2 LLC, which owns a 16% interest in the Agua Caliente solar farm, one of the ROFO assets and (ii) NRG's interests in seven utility-scale solar farms located in Utah that were part of NRG's November 2, 2016 acquisition of projects from SunEdison, or the Utah Solar Portfolio. The Company paid total cash consideration of $130 million , plus a $1 million working capital adjustment, and assumed non-recourse debt of $ 328 million , which is consolidated, as well as its pro-rata share of non-recourse project-level debt of $135 million . The acquisition was funded with cash on hand. The acquisition of the March 2017 Drop Down Assets was accounted for as a transfer of entities under common control. The accounting guidance requires retrospective combination of the entities for all periods presented as if the combination had been in effect from the beginning of the financial statement period or from the date the entities were under common control (if later than the beginning of the financial statement period). Accordingly, in connection with the retrospective adjustment of prior periods, the Company adjusted its financial statements to reflect its results of operations, financial position and cash flows as if it recorded its interests in the Agua Caliente Borrower 2 LLC on January 1, 2016, and its interests in the Utah Solar Portfolio on November 2, 2016. The recast for the March 2017 Drop Down Assets did not affect the historical net income attributable to NRG Yield, Inc.'s weighted average number of shares outstanding, earnings per share or dividends. In connection with the acquisition of the March 2017 Drop Down Assets, the Company filed the May 9, 2017 Form 8-K to recast the financial statements include in its 2016 Form 10-K for all periods presented in the following sections: Part II, Item 6. Selected Financial Data, Part II, Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations, and Part IV, Item 15. Exhibits, Financial Statement Schedules. The accompanying unaudited interim 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 GAAP 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 for the year ended December 31, 2016 included in the Company's May 9, 2017 Form 8-K. Interim results are not necessarily indicative of results for a full year. In the opinion of management, the accompanying unaudited interim consolidated financial statements contain all material adjustments consisting of normal and recurring accruals necessary to present fairly the Company's consolidated financial position as of June 30, 2017 , and the results of operations, comprehensive income (loss) and cash flows for the three and six months ended June 30, 2017 and 2016 .

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The preparation of consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions. These estimates and assumptions impact the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities as of the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could be different from these estimates. Accumulated Depreciation, Accumulated Amortization The following table presents the accumulated depreciation included in the property, plant and equipment, net, and accumulated amortization included in intangible assets, net, respectively, as of June 30, 2017 and December 31, 2016: June 30, 2017 December 31, 2016 (In millions) Property, Plant and Equipment Accumulated Depreciation $ 1,102 $ 951 Intangible Assets Accumulated Amortization 198 163 Noncontrolling Interests Stockholders' equity represents the equity associated with the Class A and Class C common stockholders, the equity associated with the Class B and Class D common stockholder, NRG, and the third-party interests under certain tax equity arrangements are classified as noncontrolling interests. The following table reflects the changes in the Company's noncontrolling interest balance: (In millions) Balance as of December 31, 2016 689 Capital contributions from tax equity investors, net of distributions 13 Payment for March 2017 Drop Down Assets (131 ) Pre-acquisition net income of Drop Down Assets 12 Comprehensive income 7 Distributions to NRG for Drop Down Assets, net of contributions (47 ) NRG Yield LLC distributions to NRG (45 ) Balance as of June 30, 2017 $ 498 Distributions and Contributions to and from NRG for Drop Down Assets Distributions and contributions to and from NRG for Drop Down Assets relate primarily to NRG's interests in the March 2017 Drop Down Assets prior to the acquisition by the Company, as well as NRG's 25% interest in the November 2015 Drop Down Assets. This amount includes cash and non-cash distributions and includes a distribution to NRG from Agua Caliente Borrower 2 LLC following the issuance of the Agua Caliente Holdco financing, as described in Note 7 , Long-term Debt . NRG Yield LLC Distributions to NRG The following table lists the distributions paid to NRG on NRG Yield LLC's Class B and D units during the six months ended June 30, 2017 : Second Quarter 2017 First Quarter 2017 Distributions per Class B Unit $ 0.27 $ 0.26 Distributions per Class D Unit $ 0.27 $ 0.26 On July 25, 2017 , NRG Yield LLC declared a distribution on its Class A, Class B, Class C and Class D units of $0.28 per unit payable on September 15, 2017 to unit holders of record as of September 1, 2017 . Income Taxes NRG Yield, Inc. is included in certain NRG consolidated unitary state tax return filings which is reflected in NRG Yield, Inc.'s state effective tax rate. If NRG Yield, Inc. filed under a separate standalone methodology, there would be an additional state tax expense of approximately $1 million as of June 30, 2017 due to a change in the NRG Yield, Inc. state effective tax rate. Reclassifications Certain prior-year amounts have been reclassified for comparative purposes. Recent Accounting Developments ASU 2016-18 — In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230) , Restricted Cash, or ASU No. 2016-18. The amendments of ASU No. 2016-18 require an entity to include amounts generally described as restricted cash and restricted cash equivalents with cash and cash equivalents when reconciling the beginning of period and end of period total amounts on the statement of cash flows. The amendments of ASU No. 2016-18 are effective for annual reporting periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted and the adoption of ASU No. 2016-18 will be applied retrospectively. The Company early adopted ASU No. 2016-18 during the second quarter of 2017. Net cash flows used in investing activities for the six months ended June 30, 2016 increased by $7 million. The sum of Company's cash and cash equivalents and restricted cash reported within the consolidated balance sheet as of December 31, 2016 equals the beginning balances of cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows for the six months ended June 30, 2017. The sum of Company's cash and cash equivalents and restricted cash reported within the consolidated balance sheet as of June 30, 2017 equals to the ending balances of cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows for the six months ended June 30, 2017. ASU 2016-02 — In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or Topic 842, with the objective to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and to improve financial reporting by expanding the related disclosures. The guidance in Topic 842 provides that a lessee that may have previously accounted for a lease as an operating lease under current GAAP should recognize the assets and liabilities that arise from a lease on the balance sheet. In addition, Topic 842 expands the required quantitative and qualitative disclosures with regards to lease arrangements. The Company expects to adopt the standard effective January 1, 2019 utilizing the required modified retrospective approach for the earliest period presented. The Company expects to elect certain of the practical expedients permitted, including the expedient that permits the Company to retain its existing lease assessment and classification. The Company is currently working through an adoption plan and evaluating the anticipated impact on the Company's results of operations, cash flows and financial position. While the Company is currently evaluating the impact the new guidance will have on its financial position and results of operations, the Company expects to recognize lease liabilities and right of use assets. The extent of the increase to assets and liabilities associated with these amounts remains to be determined pending the Company’s review of its existing lease contracts and service contracts which may contain embedded leases. While this review is still in process, the Company believes the adoption of Topic 842 may be material to its financial statements. 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, which was further amended through various updates issued by the FASB thereafter. The amendments of ASU No. 2014-09 completed the joint effort between the FASB and the IASB, to develop a common revenue standard for GAAP and IFRS, and to improve financial reporting. The guidance under Topic 606 provides that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for the goods or services provided and establishes a five step model to be applied by an entity in evaluating its contracts with customers. The Company expects to adopt the standard effective January 1, 2018 and apply the guidance retrospectively to contracts at the date of adoption. The Company will recognize the cumulative effect of applying Topic 606 at the date of initial application, as prescribed under the modified retrospective transition method. The Company also expects to elect the practical expedient available under Topic 606 for measuring progress toward complete satisfaction of a performance obligation and for disclosure requirements of remaining performance obligations. The practical expedient allows an entity to recognize revenue in the amount to which the entity has the right to invoice such that the entity has a right to the consideration in an amount that corresponds directly with the value to the customer for performance completed to date by the entity. The majority of the Company's revenues are obtained through PPAs, which are currently accounted for as operating leases. In connection with the implementation of Topic 842, as described above, the Company expects to elect certain of the practical expedients permitted, including the expedient that permits the Company to retain its existing lease assessment and classification. As leases are excluded from the scope of Topic 606, the Company expects the standard to have an immaterial impact on the Company's results of operations, cash flows and financial position; however, the Company continues to assess the impact in connection with its plan of adoption.

Business Acquisitions Business

Business Acquisitions Business Acquisitions (Notes)	6 Months Ended
	Jun. 30, 2017
Business Acquisitions [Abstract]
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	Business Acquisitions 2017 Acquisitions August 2017 Drop Down Assets — On August 1, 2017, the Company acquired the remaining 25% interest in NRG Wind TE Holdco, a portfolio of 12 wind projects, from NRG for total cash consideration of $ 41.5 million , excluding working capital adjustments. The transaction also includes potential additional payments to NRG dependent upon actual energy prices for merchant periods beginning in 2027. March 2017 Drop Down Assets — On March 27, 2017, the Company acquired the following interests from NRG: (i) Agua Caliente Borrower 2 LLC, which owns a 16% interest (approximately 31% of NRG's 51% interest) in the Agua Caliente solar farm, one of the ROFO Assets, representing ownership of approximately 46 net MW of capacity and (ii) NRG's interests in the Utah Solar Portfolio. Agua Caliente is located in Yuma County, AZ and sells power subject to a 25 -year PPA with Pacific Gas and Electric, with 22 years remaining on that contract. The seven utility-scale solar farms in the Utah Solar Portfolio are owned by the following entities: Four Brothers Capital, LLC, Iron Springs Capital, LLC, and Granite Mountain Capital, LLC. These utility-scale solar farms achieved commercial operations in 2016, sell power subject to 20 -year PPAs with PacifiCorp, a subsidiary of Berkshire Hathaway and are part of a tax equity structure with Dominion Solar Projects III, Inc., or Dominion, through which the Company is entitled to receive 50% of cash to be distributed, as further described below. The Company paid cash consideration of $130 million , plus $1 million of working capital. The acquisition of the March 2017 Drop Down Assets was funded with cash on hand. The Company recorded the acquired interests as equity method investments. The Company also assumed non-recourse debt of $41 million and $287 million on Agua Caliente Borrower 2 LLC and the Utah Solar Portfolio, respectively, as further described in Note 7 , Long-term Debt , as well as its pro-rata share of non-recourse project-level debt of Agua Caliente Solar LLC, as further described in Note 4 , Investments Accounted for by the Equity Method and Variable Interest Entities . The assets and liabilities transferred to the Company relate to interests under common control by NRG and were recorded at historical cost in accordance with ASC 805-50, Business Combination - Related Issues. The difference between the cash paid and the historical value of the entities' equity of $8 million was recorded as an adjustment to NRG's noncontrolling interest. Since the transaction constituted a transfer of entities under common control, the accounting guidance requires retrospective combination of the entities for all periods presented as if the combination has been in effect from the beginning of the financial statement period or from the date the entities were under common control (if later than the beginning of the financial statement period). The following is a summary of assets and liabilities transferred in connection with the acquisition of the March 2017 Drop Down Assets as of March 27, 2017: (In millions) Assets: Cash $ 6 Equity investment in projects 456 Total assets acquired 462 Liabilities: Debt (Current and non-current) (a) 320 Other current and non-current liabilities 3 Total liabilities assumed 323 Net assets acquired $ 139 (a) Net of $8 million of debt issuance costs. The following tables present a summary of the Company's historical information combining the financial information for the March 2017 Drop Down Assets transferred in connection with the acquisition: Three months ended June 30, 2016 Six months ended June 30, 2016 As Previously Reported (a) March 2017 Drop Down Assets As Currently Reported As Previously Reported (a) March 2017 Drop Down Assets As Currently Reported (In millions) Total operating revenues $ 283 $ — $ 283 $ 517 $ — $ 517 Operating income 128 — 128 200 — 200 Net income 63 1 64 64 2 66 (a) As previously reported in the Form 8-K filed with the SEC on September 6, 2016 in connection with the CVSR Drop Down completed on September 1, 2016. 2016 Acquisitions CVSR Drop Down — Prior to September 1, 2016, the Company had a 48.95% interest in CVSR, which was accounted for as an equity method investment. On September 1, 2016, the Company acquired from NRG the remaining 51.05% interest of CVSR Holdco LLC, which indirectly owns the CVSR solar facility, for total cash consideration of $78.5 million plus an immaterial working capital adjustment. The Company also assumed additional debt of $496 million , which represents 51.05% of the CVSR project level debt and 51.05% of the notes issued under the CVSR Holdco Financing Agreement, as of the closing date, as further described in Note 10 , Long-term Debt , to the consolidated financial statements for the year ended December 31, 2016 included in the Company's May 9, 2017 Form 8-K. The acquisition was funded with cash on hand. The assets and liabilities transferred to the Company relate to interests under common control by NRG and were recorded at historical cost in accordance with ASC 805-50, Business Combinations - Related Issues . The difference between the cash paid and historical value of the CVSR Drop Down of $112 million , as well as $6 million of AOCL, was recorded as a distribution to NRG with the offset to noncontrolling interest. Because the transaction constituted a transfer of net assets under common control, the guidance requires retrospective combination of the entities for all periods presented as if the combination has been in effect since the inception of common control. In connection with the retrospective adjustment of prior periods, the Company now consolidates CVSR and 100% of its debt, consisting of $771 million of project level debt and $200 million of notes issued under the CVSR Holdco Financing Agreement as of September 1, 2016. In connection with the retrospective adjustment of prior periods, the Company has removed the equity method investment from all prior periods and adjusted its financial statements to reflect its results of operations, financial position and cash flows as if it had consolidated CVSR from the beginning of the financial statement period.

Variable Interest Entities

Variable Interest Entities	6 Months Ended
	Jun. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Investments Accounted for by the Equity Method and Variable Interest Entities	Investments Accounted for by the Equity Method and Variable Interest Entities Entities that are Consolidated The Company has a controlling financial interest in certain entities which have been identified as VIEs under ASC 810, Consolidations, or ASC 810. These arrangements are primarily related to tax equity arrangements entered into with third parties in order to monetize certain tax credits associated with wind facilities, as further described in Note 5 , Investments Accounted for by the Equity Method and Variable Interest Entities , to the consolidated financial statements for the year ended December 31, 2016 included in the Company's May 9, 2017 Form 8-K. Summarized financial information for the Company's consolidated VIEs consisted of the following as of June 30, 2017 : (In millions) NRG Wind TE Holdco Alta Wind TE Holdco Spring Canyon Other current and non-current assets $ 184 $ 22 $ 3 Property, plant and equipment 428 449 98 Intangible assets 2 268 — Total assets 614 739 101 Current and non-current liabilities 203 8 6 Total liabilities 203 8 6 Noncontrolling interest 125 102 64 Net assets less noncontrolling interests $ 286 $ 629 $ 31 Entities that are not Consolidated The Company has interests in entities that are considered VIEs under ASC 810, but for which it is not considered the primary beneficiary. The Company accounts for its interests in these entities under the equity method of accounting, as further described in Note 5 , Investments Accounted for by the Equity Method and Variable Interest Entities , to the consolidated financial statements for the year ended December 31, 2016 included in the Company's May 9, 2017 Form 8-K. The Company's maximum exposure to loss as of June 30, 2017 is limited to its equity investment in the unconsolidated entities, as further summarized in the table below: (In millions) Maximum exposure to loss Four Brothers Solar, LLC $ 226 Granite Mountain Holdings, LLC 82 Iron Springs Holdings, LLC 57 GenConn Energy LLC 104 NRG DGPV Holdco 1 LLC 73 NRG RPV Holdco 1 LLC 67 NRG DGPV Holdco 2 LLC 44 Utah Solar Portfolio — As described in Note 3 , Business Acquisitions , on March 27, 2017, as part of the March 2017 Drop Down Assets acquisition, the Company acquired from NRG 100% of the Class A equity interests in the Utah Solar Portfolio, comprised of Four Brothers Solar, LLC, Granite Mountain Holdings, LLC, and Iron Springs Holdings, LLC. The Class B interests of the Utah Solar Portfolio are owned by a tax equity investor, or TE Investor, who receives 99% of allocations of taxable income and other items until the flip point, which occurs when the TE Investor obtains a specified return on its initial investment, at which time the allocations to the TE Investor change to 50% . The Company generally receives 50% of distributable cash throughout the term of the tax-equity arrangements. The three entities comprising the Utah Solar Portfolio are VIEs. As the Company is not the primary beneficiary, the Company uses the equity method of accounting to account for its interests in the Utah Solar Portfolio. The Company utilizes the HLBV method to determine its share of the income or losses in the investees. The following tables present summarized financial information for the Company's significant equity method investments: Three months ended June 30, Six months ended June 30, (In millions) 2017 2016 2017 2016 Income Statement Data: Utah Solar Portfolio Operating revenues $ 24 $ — $ 37 $ — Operating income 10 — 8 — Net income 10 — 8 — June 30, 2017 December 31, 2016 Balance Sheet Data: (In millions) Utah Solar Portfolio Current assets $ 29 $ 20 Non-current assets 1,101 1,105 Current liabilities 9 14 Non-current liabilities 26 38 NRG DGPV Holdco 2 LLC — On February 29, 2016, the Company and NRG entered into an additional partnership by forming NRG DGPV Holdco 2 LLC, or DGPV Holdco 2, to purchase solar power generation projects as well as other ancillary related assets from NRG Renew LLC or its subsidiaries. The Company contributed $ 26 million into the partnership during the six months ended June 30, 2017 , of which $9 million remained due to NRG in accounts payable — affiliate as of June 30, 2017 . Non-recourse project-level debt of unconsolidated affiliates Agua Caliente Financing — As described above, the Company acquired a 16% interest in the Agua Caliente solar facility through its acquisition of Agua Caliente Borrower 2 LLC. As of June 30, 2017 , Agua Caliente Solar LLC, the direct owner of the Agua Caliente solar facility, had $843 million outstanding under the Agua Caliente financing agreement with the Federal Financing Bank, or FFB, borrowed to finance the costs of constructing the facility. The Company's pro-rata share of the Agua Caliente financing arrangement was $135 million as of June 30, 2017 . Amounts borrowed under the Agua Caliente financing agreement accrue interest at a fixed rate based on U.S. Treasury rates plus a spread of 0.375% , mature in 2037 and are secured by the assets of Agua Caliente Solar LLC. The loans provided by the FFB are guaranteed by the U.S. DOE.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair Value Accounting under ASC 820 ASC 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three levels as follows: • Level 1—quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access as of the measurement date. • Level 2—inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data. • Level 3—unobservable inputs for the asset or liability only used when there is little, if any, market activity for the asset or liability at the measurement date. In accordance with ASC 820, the Company determines the level in the fair value hierarchy within which each fair value measurement in its entirety falls, based on the lowest level input that is significant to the fair value measurement. For cash and cash equivalents, restricted cash, accounts receivable, accounts receivable — affiliate, accounts payable, current portion of the accounts payable — affiliates, accrued expenses and other liabilities, the carrying amounts approximate 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 the Company’s recorded financial instruments not carried at fair market value are as follows: As of June 30, 2017 As of December 31, 2016 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable, including current portion $ 21 $ 21 $ 30 $ 30 Liabilities: Long-term debt, including current portion $ 5,961 $ 6,017 $ 6,057 $ 6,056 The fair value of the Company's publicly-traded long-term debt is based on quoted market prices and is classified as Level 2 within the fair value hierarchy. The fair value of debt securities, non-publicly traded long-term debt and certain notes receivable of the Company are based on expected future cash flows discounted at market interest rates, or current interest rates for similar instruments with equivalent credit quality and are classified as Level 3 within the fair value hierarchy. The following table presents the level within the fair value hierarchy for long-term debt, including current portion as of June 30, 2017 and December 31, 2016 : As of June 30, 2017 As of December 31, 2016 Level 2 Level 3 Level 2 Level 3 (In millions) Long-term debt, including current portion $ 1,516 $ 4,501 $ 1,455 $ 4,601 Recurring Fair Value Measurements The Company records its derivative assets and liabilities at fair value on its consolidated balance sheet. The following table presents assets and liabilities measured and recorded at fair value on the Company's consolidated balance sheets on a recurring basis and their level within the fair value hierarchy: As of June 30, 2017 As of December 31, 2016 Fair Value (a) Fair Value (a) Fair Value (a) (In millions) Level 2 Level 1 Level 2 Derivative assets: Commodity contracts $ 1 $ 1 $ 1 Interest rate contracts — — 1 Total assets 1 1 2 Derivative liabilities: Commodity contracts 2 — 1 Interest rate contracts 78 — 75 Total liabilities $ 80 $ — $ 76 (a) There were no derivative assets or liabilities classified as Level 1 as of June 30, 2017 . There were no derivative assets or liabilities classified as Level 3 as of June 30, 2017 and December 31, 2016 . Derivative Fair Value Measurements The Company's contracts are non-exchange-traded and valued using prices provided by external sources. For the Company’s energy markets, management receives quotes from multiple sources. To the extent that multiple quotes are received, the prices reflect the average of the bid-ask mid-point prices obtained from all sources believed to provide the most liquid market for the commodity. The fair value of each contract is discounted using a risk free interest rate. In addition, a credit reserve is applied to reflect credit risk, which is, for interest rate swaps, calculated based on credit default swaps using the bilateral method. For commodities, to the extent that the net exposure under a specific master agreement is an asset, the Company uses the counterparty’s default swap rate. If the net exposure under a specific master agreement is a liability, the Company uses NRG's default swap rate. For interest rate swaps and commodities, the credit reserve is added to the discounted fair value to reflect the exit price that a market participant would be willing to receive to assume the liabilities or that a market participant would be willing to pay for the assets. As of June 30, 2017 , the credit reserve resulted in a $1 million increase in fair value in interest expense. It is possible that future market prices could vary from those used in recording assets and liabilities and such variations could be material. Concentration of Credit Risk In addition to the credit risk discussion in Note 2 , Summary of Significant Accounting Policies , to the consolidated financial statements for the year ended December 31, 2016 included in the Company's May 9, 2017 Form 8-K, the following is a discussion of the concentration of credit risk for the Company's financial instruments. Credit risk relates to the risk of loss resulting from non-performance or non-payment by counterparties pursuant to the terms of their contractual obligations. The Company monitors and manages credit risk through credit policies that include: (i) an established credit approval process; (ii) daily monitoring of counterparties' credit limits; (iii) the use of credit mitigation measures such as margin, collateral, prepayment arrangements, or volumetric limits; (iv) the use of payment netting agreements; and (v) the use of master netting agreements that allow for the netting of positive and negative exposures of various contracts associated with a single counterparty. Risks surrounding counterparty performance and credit could ultimately impact the amount and timing of expected cash flows. The Company seeks to mitigate counterparty risk by having a diversified portfolio of counterparties. Counterparty credit exposure includes credit risk exposure under certain long-term agreements, including solar and other PPAs. As external sources or observable market quotes are not available to estimate such exposure, the Company estimates the exposure related to these contracts based on various techniques including, but not limited to, internal models based on a fundamental analysis of the market and extrapolation of observable market data with similar characteristics. Based on these valuation techniques, as of June 30, 2017 , credit risk exposure to these counterparties attributable to the Company's ownership interests was approximately $2.9 billion for the next five years . The majority of these power contracts are with utilities 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, which the Company is unable to predict.

Accounting for Derivative Instr

Accounting for Derivative Instruments and Hedging Activities	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Accounting for Derivative Instruments and Hedging Activities	Accounting for Derivative Instruments and Hedging Activities This footnote should be read in conjunction with the complete description under Note 7 , Accounting for Derivative Instruments and Hedging Activities , to the consolidated financial statements for the year ended December 31, 2016 included in the Company's May 9, 2017 Form 8-K. Energy-Related Commodities As of June 30, 2017 , the Company had energy-related derivative instruments extending through 2020. At June 30, 2017 , these contracts were not designated as cash flow or fair value hedges. Interest Rate Swaps As of June 30, 2017 , the Company had interest rate derivative instruments on non-recourse debt extending through 2036, most of which are designated as cash flow hedges. Volumetric Underlying Derivative Transactions The following table summarizes the net notional volume buy of the Company's open derivative transactions broken out by commodity: Total Volume June 30, 2017 December 31, 2016 Commodity Units (In millions) Natural Gas MMBtu 2 3 Interest Dollars $ 2,045 $ 2,070 Fair Value of Derivative Instruments The following table summarizes the fair value within the derivative instrument valuation on the balance sheet: Fair Value Derivative Assets Derivative Liabilities June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 (In millions) Derivatives Designated as Cash Flow Hedges: Interest rate contracts current $ — $ — $ 8 $ 26 Interest rate contracts long-term — 1 16 39 Total Derivatives Designated as Cash Flow Hedges — 1 24 65 Derivatives Not Designated as Cash Flow Hedges: Interest rate contracts current — — 17 5 Interest rate contracts long-term — — 37 5 Commodity contracts current 1 2 1 1 Commodity contracts long-term — — 1 — Total Derivatives Not Designated as Cash Flow Hedges 1 2 56 11 Total Derivatives $ 1 $ 3 $ 80 $ 76 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. As of June 30, 2017 and December 31, 2016 , there was no outstanding collateral paid or received. The following tables summarize the offsetting of derivatives by the counterparty master agreement level as of June 30, 2017 and December 31, 2016 : As of June 30, 2017 Gross Amounts of Recognized Assets/Liabilities Derivative Instruments Net Amount Commodity contracts: (In millions) Derivative assets $ 1 $ (1 ) $ — Derivative liabilities (2 ) 1 (1 ) Total commodity contracts (1 ) — (1 ) Interest rate contracts: Derivative liabilities (78 ) — (78 ) Total interest rate contracts (78 ) — (78 ) Total derivative instruments $ (79 ) $ — $ (79 ) As of December 31, 2016 Gross Amounts of Recognized Assets/Liabilities Derivative Instruments Net Amount Commodity contracts: (In millions) Derivative assets $ 2 $ — $ 2 Derivative liabilities (1 ) — (1 ) Total commodity contracts 1 — 1 Interest rate contracts: Derivative assets 1 (1 ) — Derivative liabilities (75 ) 1 (74 ) Total interest rate contracts (74 ) — (74 ) Total derivative instruments $ (73 ) $ — $ (73 ) Accumulated Other Comprehensive Loss The following table summarizes the effects on the Company’s accumulated OCL balance attributable to interest rate swaps designated as cash flow hedge derivatives, net of tax: Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions) Accumulated OCL beginning balance $ (64 ) $ (124 ) $ (70 ) $ (83 ) Reclassified from accumulated OCL to income due to realization of previously deferred amounts 2 3 6 6 Mark-to-market of cash flow hedge accounting contracts (8 ) (19 ) (6 ) (63 ) Accumulated OCL ending balance, net of income tax benefit of $16 and $28, respectively (70 ) (140 ) (70 ) (140 ) Accumulated OCL attributable to noncontrolling interests (42 ) (93 ) (42 ) (93 ) Accumulated OCL attributable to NRG Yield, Inc. $ (28 ) $ (47 ) $ (28 ) $ (47 ) Losses expected to be realized from OCL during the next 12 months, net of income tax benefit of $4 $ 14 $ 14 Amounts reclassified from accumulated OCL into income and amounts recognized in income from the ineffective portion of cash flow hedges are recorded to interest expense. There was no ineffectiveness for the six months ended June 30, 2017 and 2016 . Accounting guidelines require a high degree of correlation between the derivative and the hedged item throughout the period in order to qualify as a cash flow hedge. As of December 31, 2016, the Company's regression analysis for Viento Funding II interest rate swaps, while positively correlated, did not meet the required threshold for cash flow hedge accounting. As a result, the Company de-designated the Viento Funding II cash flow hedges as of December 31, 2016, and will prospectively mark these derivatives to market through the income statement. The Company's regression analysis for Marsh Landing, Walnut Creek and Avra Valley interest rate swaps, while positively correlated, no longer contain matching terms for cash flow hedge accounting. As a result, the Company voluntarily de-designated the Marsh Landing, Walnut Creek and Avra Valley cash flow hedges as of April 28, 2017, and will prospectively mark these derivatives to market through the income statement. Impact of Derivative Instruments on the Statements of Income The Company has interest rate derivative instruments that are not designated as cash flow hedges. The effect of interest rate hedges is recorded to interest expense. For the three months ended June 30, 2017 and 2016 , the impact to the consolidated statements of income was a loss of $11 million and $2 million , respectively. For the six months ended June 30, 2017 and 2016 , the impact to the consolidated statements of income was a loss of $9 million in each period. A portion of the Company’s derivative commodity contracts relates to its Thermal Business for the purchase of fuel commodities based on the forecasted usage of the thermal district energy centers. Realized gains and losses on these contracts are reflected in the fuel costs that are permitted to be billed to customers through the related customer contracts or tariffs and, accordingly, no gains or losses are reflected in the consolidated statements of income for these contracts. See Note 5 , Fair Value of Financial Instruments , for a discussion regarding concentration of credit risk.

Long-term Debt

Long-term Debt	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Long-term Debt	Long-term Debt This footnote should be read in conjunction with the complete description under Note 10 , Long-term Debt , to the consolidated financial statements for the year ended December 31, 2016 included in the Company's May 9, 2017 Form 8-K. Long-term debt consisted of the following: June 30, 2017 December 31, 2016 June 30, 2017, interest rate % (a) Letters of Credit Outstanding at June 30, 2017 (In millions, except rates) 2019 Convertible Notes $ 345 $ 345 3.500 2020 Convertible Notes 288 288 3.250 2024 Senior Notes 500 500 5.375 2026 Senior Notes 350 350 5.000 Project-level debt: Agua Caliente Borrower 2, due 2038 41 — 5.430 17 Alpine, due 2022 142 145 L+1.750 37 Alta Wind I, lease financing arrangement, due 2034 234 242 7.015 16 Alta Wind II, lease financing arrangement, due 2034 186 191 5.696 23 Alta Wind III, lease financing arrangement, due 2034 193 198 6.067 23 Alta Wind IV, lease financing arrangement, due 2034 125 128 5.938 16 Alta Wind V, lease financing arrangement, due 2035 201 206 6.071 26 Alta Realty Investments, due 2031 31 31 7.000 — Alta Wind Asset Management, due 2031 18 18 L+2.500 — Avra Valley, due 2031 55 57 L+1.750 3 Blythe, due 2028 19 19 L+1.625 2 Borrego, due 2025 and 2038 68 69 L+ 2.750/5.650 5 CVSR, due 2037 757 771 2.339 - 3.775 — CVSR Holdco Notes, due 2037 193 199 4.680 13 El Segundo Energy Center, due 2023 414 443 L+1.625 - L+2.250 82 Energy Center Minneapolis, due 2017 and 2025 85 96 5.950 -7.250 — Energy Center Minneapolis Series D Notes, due 2031 125 125 3.550 — Kansas South, due 2031 29 30 L+2.000 4 Laredo Ridge, due 2028 97 100 L+1.875 10 Marsh Landing, due 2017 and 2023 358 370 L+1.750 - L+1.875 49 Apple I LLC projects and related subsidiaries financing agreement, due 2030 27 27 6.000 — Roadrunner, due 2031 36 37 L+1.625 5 South Trent Wind, due 2020 55 57 L+1.625 10 TA High Desert, due 2020 and 2032 48 49 L+2.500/5.150 — Tapestry, due 2021 166 172 L+1.625 20 Utah Solar Portfolio, due 2022 284 287 L+2.625 11 Viento, due 2023 169 178 L+2.750 27 Walnut Creek, due 2023 299 310 L+1.625 60 WCEP Holdings, due 2023 45 46 L+3.000 — Subtotal project-level debt: 4,500 4,601 Total debt 5,983 6,084 Less current maturities (298 ) (291 ) Less net debt issuance costs (66 ) (70 ) Less discounts (b) (22 ) (27 ) Total long-term debt $ 5,597 $ 5,696 (a) As of June 30, 2017 , L+ equals 3 month LIBOR plus x%, except for the Utah Solar Portfolio and NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility, where L+ equals 1 month LIBOR plus x% and Kansas South, where L+ equals 6 month LIBOR plus x%. (b) Discounts relate to the 2019 Convertible Notes and 2020 Convertible Notes. The financing arrangements listed above contain certain covenants, including financial covenants that the Company is required to be in compliance with during the term of the respective arrangement. As of June 30, 2017 , the Company was in compliance with all of the required covenants. The discussion below describes material changes to or additions of long-term debt for the six months ended June 30, 2017 . NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility As of June 30, 2017 , there were no outstanding borrowings under the revolving credit facility and the Company had $68 million of letters of credit outstanding. Thermal Financing On March 16, 2017, NRG Energy Center Minneapolis LLC, a subsidiary of NRG Thermal LLC, amended the shelf facility of its existing Thermal financing arrangement to allow for the issuance of an additional $10 million of Series F notes at a 4.60% interest rate, or Series F Notes, increasing the total principal amount of notes available for issuance under the shelf facility to $80 million . The Series F Notes will be secured by substantially all of the assets of NRG Energy Center Minneapolis LLC. NRG Thermal LLC has guaranteed the indebtedness and its guarantee is secured by a pledge of the equity interests in all of NRG Thermal LLC’s subsidiaries. Financing related to the 2017 March Drop Down Assets Agua Caliente Borrower 2, due 2038 On February 17, 2017, Agua Caliente Borrower 1 LLC, an indirect subsidiary of NRG, and Agua Caliente Borrower 2 LLC, issued $130 million of senior secured notes under the Agua Caliente Borrower 1 LLC and Agua Caliente Borrower 2 LLC financing agreement, or Agua Caliente Holdco Financing Agreement, that bear interest at 5.43% and mature on December 31, 2038. As described in Note 3 , Business Acquisitions , on March 27, 2017, the Company acquired Agua Caliente Borrower 2 LLC from NRG and assumed NRG's portion of senior secured notes under the Agua Caliente Holdco Financing Agreement. Agua Caliente Borrower 2 LLC holds $41 million of the Agua Caliente Holdco debt as of June 30, 2017 . The debt is joint and several with respect to Agua Caliente Borrower 1 LLC and Agua Caliente Borrower 2 LLC and is secured by the equity interests of each borrower in the Agua Caliente solar facility. Utah Solar Portfolio, due 2022 As part of the March 2017 Drop Down Assets acquisition, the Company assumed non-recourse debt of $287 million relating to the Utah Solar Portfolio at an interest rate of LIBOR plus 2.625% . The debt matures on December 16, 2022. The $287 million consisted of $222 million outstanding at the time of NRG's acquisition of the Utah Solar Portfolio on November 2, 2016, and additional borrowings of $65 million , net of debt issuance costs, incurred during 2016. The Company holds $284 million of the Utah Solar Portfolio debt as of June 30, 2017 .

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per common share is computed by dividing net income by the weighted average number of common shares outstanding. Shares issued during the year are weighted for the portion of the year that they were outstanding. Diluted earnings per share is computed in a manner consistent with that of basic earnings per share while giving effect to all potentially dilutive common shares that were outstanding during the period. The reconciliation of the Company's basic and diluted earnings per share is shown in the following tables: Three months ended June 30, 2017 2016 (In millions, except per share data) (a) Common Class A Common Class C Common Class A Common Class C Basic earnings per share attributable to NRG Yield, Inc. common stockholders Net income attributable to NRG Yield, Inc. $ 10 $ 18 $ 11 $ 21 Weighted average number of common shares outstanding — basic 35 63 35 63 Earnings per weighted average common share — basic $ 0.29 $ 0.29 $ 0.33 $ 0.33 Diluted earnings per share attributable to NRG Yield, Inc. common stockholders Net income attributable to NRG Yield, Inc. $ 13 $ 21 $ 14 $ 23 Weighted average number of common shares outstanding — diluted 49 74 49 73 Earnings per weighted average common share — diluted $ 0.26 $ 0.28 $ 0.29 $ 0.31 Six months ended June 30, 2017 2016 (In millions, except per share data) (a) Common Class A Common Class C Common Class A Common Class C Basic and diluted earnings per share attributable to NRG Yield, Inc. common stockholders Net income attributable to NRG Yield, Inc. $ 9 $ 16 $ 13 $ 24 Weighted average number of common shares outstanding — basic and diluted 35 63 35 63 Earnings per weighted average common share — basic and diluted $ 0.26 $ 0.26 $ 0.38 $ 0.38 (a) Basic and diluted earnings per share might not recalculate due to presenting values in millions rather than whole dollars. The following table summarizes the Company's outstanding equity instruments that are anti-dilutive and were not included in the computation of the Company's diluted earnings per share: Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions of shares) 2019 Convertible Notes - Common Class A — — 15 15 2020 Convertible Notes - Common Class C — — 10 10

Changes in Capital Structure

Changes in Capital Structure	6 Months Ended
	Jun. 30, 2017
Changes in Capital Structure [Abstract]
Partners' Capital Notes Disclosure [Text Block]	Changes in Capital Structure NRG Yield, Inc. is party to an equity distribution agreement with Barclays Capital Inc., Credit Suisse Securities (USA) LLC, J.P. Morgan Securities LLC and RBC Capital Markets, LLC, as sales agents. Pursuant to the terms of the equity distribution agreement, NRG Yield, Inc. may offer and sell shares of its Class C common stock par value $0.01 per share, from time to time through the sales agents up to an aggregate sales price of $150,000,000 through an at-the-market equity offering program, or the ATM Program. NRG Yield, Inc. may also sell shares of its Class C common stock to any of the sales agents, as principals for its own account, at a price agreed upon at the time of sale. During the three months ended June 30, 2017 , NRG Yield, Inc. issued 510,112 shares of Class C common stock under the ATM Program for gross proceeds of $9 million . During the six months ended June 30, 2017 , NRG Yield, Inc. issued 934,139 shares of Class C common stock under the ATM Program for gross proceeds of $16 million and incurred commission fees of approximately $163 thousand . As a result of the Company's sale of shares of Class C common stock, the public shareholders of Class C common stock increased their economic and voting interests to 53.5% , and 44.9% , respectively, as of June 30, 2017. Dividends to Class A and Class C common stockholders The following table lists the dividends paid on the Company's Class A common stock and Class C common stock during the six months ended June 30, 2017 : Second Quarter 2017 First Quarter 2017 Dividends per Class A share $ 0.27 $ 0.26 Dividends per Class C share $ 0.27 $ 0.26 Dividends on the Class A common stock and Class C common stock are subject to available capital, market conditions, and compliance with associated laws, regulations and other contractual obligations. The Company expects that, based on current circumstances, comparable cash dividends will continue to be paid in the foreseeable future. On July 25, 2017 , the Company declared quarterly dividends on its Class A common stock and Class C common stock of $0.28 per share payable on September 15, 2017 , to stockholders of record as of September 1, 2017 . The Company also has authorized 10,000,000 shares of preferred stock, par value $0.01 per share. None of the shares of preferred stock have been issued.

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company’s segment structure reflects how management currently operates and allocates resources. The Company's businesses are primarily segregated based on conventional power generation, renewable businesses which consist of solar and wind, and the thermal and chilled water business. The Corporate segment reflects the Company's corporate costs. The Company'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, and CAFD, as well as economic gross margin and net income (loss). Three months ended June 30, 2017 (In millions) Conventional Generation Renewables Thermal Corporate Total Operating revenues $ 83 $ 161 $ 40 $ — $ 284 Cost of operations 15 35 27 — 77 Depreciation and amortization 26 47 5 — 78 General and administrative — — — 6 6 Acquisition-related transaction and integration costs — — — 1 1 Operating income (loss) 42 79 8 (7 ) 122 Equity in earnings of unconsolidated affiliates 3 13 — — 16 Other income, net — — — 1 1 Interest expense (14 ) (49 ) (2 ) (21 ) (86 ) Income (loss) before income taxes 31 43 6 (27 ) 53 Income tax expense — — — 8 8 Net Income (Loss) $ 31 $ 43 $ 6 $ (35 ) $ 45 Total Assets $ 1,948 $ 5,855 $ 417 $ 293 $ 8,513 Three months ended June 30, 2016 (In millions) Conventional Generation Renewables Thermal Corporate Total Operating revenues $ 85 $ 159 $ 39 $ — $ 283 Cost of operations 16 34 27 — 77 Depreciation and amortization 20 50 5 — 75 General and administrative — — — 3 3 Operating income (loss) 49 75 7 (3 ) 128 Equity in earnings of unconsolidated affiliates 4 10 — — 14 Other income, net — 2 — — 2 Interest expense (12 ) (36 ) (1 ) (19 ) (68 ) Income (loss) before income taxes 41 51 6 (22 ) 76 Income tax expense — — — 12 12 Net Income (Loss) $ 41 $ 51 $ 6 $ (34 ) $ 64 Six months ended June 30, 2017 (In millions) Conventional Generation Renewables Thermal Corporate Total Operating revenues $ 158 $ 260 $ 84 $ — $ 502 Cost of operations 37 67 57 — 161 Depreciation and amortization 50 93 10 — 153 General and administrative — — — 10 10 Acquisition-related transaction and integration costs — — — 2 2 Operating income (loss) 71 100 17 (12 ) 176 Equity in earnings of unconsolidated affiliates 6 29 — — 35 Other income, net — 1 — 1 2 Interest expense (26 ) (89 ) (5 ) (42 ) (162 ) Income (loss) before income taxes 51 41 12 (53 ) 51 Income tax expense — — — 7 7 Net Income (Loss) $ 51 $ 41 $ 12 $ (60 ) $ 44 Total Assets $ 1,948 $ 5,855 $ 417 $ 293 $ 8,513 Six months ended June 30, 2016 (In millions) Conventional Generation Renewables Thermal Corporate Total Operating revenues $ 164 $ 270 $ 83 $ — $ 517 Cost of operations 39 67 56 — 162 Depreciation and amortization 40 99 10 — 149 General and administrative — — — 6 6 Operating income (loss) 85 104 17 (6 ) 200 Equity in earnings of unconsolidated affiliates 7 11 — — 18 Other income, net — 2 — — 2 Interest expense (23 ) (78 ) (3 ) (38 ) (142 ) Income (loss) before income taxes 69 39 14 (44 ) 78 Income tax expense — — — 12 12 Net Income (Loss) $ 69 $ 39 $ 14 $ (56 ) $ 66

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Tax Rate The income tax provision consisted of the following: Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions, except percentages) Income before income taxes $ 53 $ 76 $ 51 $ 78 Income tax expense 8 12 7 12 Effective income tax rate 15.1 % 15.8 % 13.7 % 15.4 % For the three and six months ended June 30, 2017 and 2016 , the overall effective tax rate was different than the statutory rate of 35% primarily due to taxable earnings allocated to NRG resulting from its interest in NRG Yield LLC and production and investment tax credits generated from certain wind and solar assets, respectively. For tax purposes, NRG Yield LLC is treated as a partnership; therefore, the Company and NRG each record their respective share of taxable income or loss.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions Disclosure	Related Party Transactions In addition to the transactions and relationships described elsewhere in these notes to the consolidated financial statements, NRG and certain subsidiaries of NRG provide services to the Company and its project entities. Amounts due to NRG subsidiaries are recorded as accounts payable - affiliate and amounts due to the Company from NRG or its subsidiaries are recorded as accounts receivable - affiliate in the Company's balance sheet. Power Purchase Agreements (PPAs) between the Company and NRG Power Marketing Elbow Creek and Dover are parties to PPAs with NRG Power Marketing and generate revenue under the PPAs, which are recorded to operating revenue in the Company's consolidated statements of operations. For the three months and six months ended June 30, 2017 , Elbow Creek and Dover, collectively, generated revenue of $3 million and $7 million , respectively. For the three months and six months ended June 30, 2016 , Elbow Creek and Dover, collectively, generated revenue of $3 million and $6 million , respectively. Energy Marketing Services Agreement by and between Thermal entities and NRG Power Marketing NRG Energy Center Dover LLC, NRG Energy Center Minneapolis, NRG Energy Center Phoenix LLC, and NRG Energy Center Paxton LLC, or Thermal entities, are parties to Energy Marketing Services Agreements with NRG Power Marketing, a wholly-owned subsidiary of NRG. Under the agreements, NRG Power Marketing procures fuel and fuel transportation for the operation of Thermal entities. For the three months and six months ended June 30, 2017 , Thermal entities purchased $2 million and $6 million , respectively, of natural gas from NRG Power Marketing. For the three months and six months ended June 30, 2016 , Thermal entities purchased $1 million and $5 million , respectively, of natural gas from NRG Power Marketing. Operation and Maintenance (O&M) Services Agreements by and between Company's subsidiaries and NRG Certain of the Company's subsidiaries are party to O&M Services Agreements with NRG, pursuant to which NRG subsidiaries provide necessary and appropriate services to operate and maintain the subsidiaries' plant operations, businesses and thermal facilities. NRG is reimbursed for the provided services, as well as for all reasonable and related expenses and expenditures, and payments to third parties for services and materials rendered to or on behalf of the parties to the agreements. NRG is not entitled to any management fee or mark-up under the agreements. The following table summarizes material O&M costs recorded in the cost of operations line in the Company's consolidated statements of operations: Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Thermal entities $ 7 $ 8 $ 15 $ 15 Conventional entities 2 2 4 4 Total $ 9 $ 10 $ 19 $ 19 There were balances of $20 million and $22 million due from the entities above to NRG in accounts payable — affiliate as of June 30, 2017 and December 31, 2016 , respectively. As of June 30, 2017 , $9 million was recorded in long term liabilities of the consolidated balance sheet. O&M Services Agreements by and between GenConn and NRG GenConn incurs fees under two O&M agreements with wholly-owned subsidiaries of NRG. For the three months and six months ended June 30, 2017 and June 30, 2016, the aggregate fees incurred under the agreements were $2 million and $3 million for each period in each year, respectively. Administrative Services Agreement by and between Marsh Landing and NRG West Coast LLC On December 19, 2016, Marsh Landing entered into an administrative services agreement with NRG West Coast LLC, a wholly owned subsidiary of NRG. The administrative services agreement was previously between Marsh Landing and GenOn Energy Services, LLC, a wholly-owned subsidiary of NRG and was subsequently assigned to and assumed by NRG West Coast LLC. The Company reimbursed costs under this agreement of $3 million and $6 million for the three and six months ended June 30, 2017 , respectively. The Company reimbursed costs under the agreement of $3 million and $5 million for the three and six months ended June 30, 2016 , respectively. Administrative Services Agreements by and between the Company and NRG Renew Operation & Maintenance LLC Various wholly-owned subsidiaries of the Company in the Renewables segment are party to administrative services agreements with NRG Renew Operation and Maintenance LLC, or RENOM, a wholly-owned subsidiary of NRG, which provides O&M services on behalf of these entities. The Company incurred total expenses for these services in the amount of $7 million and $10 million for the three and six months ended June 30, 2017 , respectively. The Company incurred total expenses for these services of $3 million and $5 million for the three and six months ended June 30, 2016 , respectively. There was a balance of $3 million and $5 million due to RENOM as of June 30, 2017 and December 31, 2016 , respectively. Management Services Agreement by and between the Company and NRG NRG provides the Company with various operation, management, and administrative services, which include human resources, accounting, tax, legal, information systems, treasury, and risk management, as set forth in the Management Services Agreement. As of June 30, 2017 , the base management fee was approximately $8 million per year, subject to an inflation-based adjustment annually at an inflation factor based on the year-over-year U.S. consumer price index. The fee is also subject to adjustments following the consummation of acquisitions and as a result of a change in the scope of services provided under the Management Services Agreement. Costs incurred under this agreement were $4 million and $6 million for the three and six months ended June 30, 2017 , respectively. Costs incurred under this agreement for the three and six months ended June 30, 2016 were $3 million and $5 million , respectively. The costs incurred under the Management Service Agreement included certain direct expenses incurred by NRG on behalf of the Company in addition to the base management fee.

Contingencies (Notes)

Contingencies (Notes)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Contingencies Disclosure [Text Block]	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. The Company 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. In addition, legal costs are expensed as incurred. Management assesses such matters based on current information and makes a judgment concerning its potential outcome, considering the nature of the claim, the amount and nature of damages sought, and the probability of success. The Company is unable to predict the outcome of the legal proceedings below 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, the Company 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 the Company's consolidated financial position, results of operations, or cash flows. Braun v. NRG Yield, Inc. — On April 19, 2016, plaintiffs filed a putative class action lawsuit against NRG Yield, Inc., the current and former members of its board of directors individually, and other parties in California Superior Court in Kern County, CA. Plaintiffs allege various violations of the Securities Act due to the defendants’ alleged failure to disclose material facts related to low wind production prior to NRG Yield, Inc.'s June 22, 2015 Class C common stock offering. Plaintiffs seek compensatory damages, rescission, attorney’s fees and costs. The defendants filed demurrers and a motion challenging jurisdiction on October 18, 2016. On June 16, 2017, the court approved the parties' stipulation which provides the plaintiffs' opposition is due on September 15, 2017 and defendants' reply is due on November 15, 2017. Ahmed v. NRG Energy, Inc. and the NRG Yield Board of Directors — On September 15, 2016, plaintiffs filed a putative class action lawsuit against NRG Energy, Inc., the directors of NRG Yield, Inc., and other parties in the Delaware Chancery Court. The complaint alleges that the defendants breached their respective fiduciary duties with regard to the recapitalization of NRG Yield, Inc. common stock in 2015. The plaintiffs generally seek economic damages, attorney’s fees and injunctive relief. The defendants filed a motion to dismiss the lawsuit on December 21, 2016. Plaintiffs filed their objection to the motion to dismiss on February 15, 2017. The defendants' reply was filed on March 24, 2017. The court heard oral argument on the defendants' motion to dismiss on June 20, 2017. GenOn Noteholders' Lawsuit — On December 13, 2016, certain indenture trustees for an ad hoc group of holders, or the Noteholders, of the GenOn Energy, Inc., or GenOn, 7.875% Senior Notes due 2017, 9.500% Notes due 2018, and 9.875% Notes due 2020, and the GenOn Americas Generation, LLC 8.50% Senior Notes due 2021 and 9.125% Senior Notes due 2031, along with certain of the Noteholders, filed a complaint in the Superior Court of the State of Delaware against NRG and GenOn alleging certain claims related to the Services Agreement between NRG and GenOn. On April 30, 2017, the Noteholders filed an amended complaint that asserts additional claims of fraudulent transfer, insider preference and breach of fiduciary duties. In addition to NRG and GenOn, the amended complaint names NRG Yield LLC and certain current and former officers and directors of GenOn as defendants. The plaintiffs, among other things, generally seek return of all monies paid under the Services Agreement and any other damages that the court deems appropriate. On April 28, 2017, the bondholders filed an amended complaint adding the GenOn directors and officers as defendants and asserting claims that they breached certain fiduciary duties. Plaintiffs specifically allege that the transfer of Marsh Landing to NRG Yield LLC constituted a fraudulent transfer. On June 12, 2017, certain GenOn entities, NRG and certain holders of the GenOn and GenOn Americas Generation, LLC senior notes entered into a restructuring support and lock-up agreement. Pursuant to the terms of the restructuring support and lock-up agreement, this matter should ultimately be resolved if GenOn's plan of reorganization is approved by the United States Bankruptcy Court for the Southern District of Texas, Houston Division.

Summary of Significant Accoun21

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions. These estimates and assumptions impact the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities as of the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could be different from these estimates.
Noncontrolling Interest Disclosure [Text Block]	Noncontrolling Interests Stockholders' equity represents the equity associated with the Class A and Class C common stockholders, the equity associated with the Class B and Class D common stockholder, NRG, and the third-party interests under certain tax equity arrangements are classified as noncontrolling interests. The following table reflects the changes in the Company's noncontrolling interest balance: (In millions) Balance as of December 31, 2016 689 Capital contributions from tax equity investors, net of distributions 13 Payment for March 2017 Drop Down Assets (131 ) Pre-acquisition net income of Drop Down Assets 12 Comprehensive income 7 Distributions to NRG for Drop Down Assets, net of contributions (47 ) NRG Yield LLC distributions to NRG (45 ) Balance as of June 30, 2017 $ 498 Distributions and Contributions to and from NRG for Drop Down Assets Distributions and contributions to and from NRG for Drop Down Assets relate primarily to NRG's interests in the March 2017 Drop Down Assets prior to the acquisition by the Company, as well as NRG's 25% interest in the November 2015 Drop Down Assets. This amount includes cash and non-cash distributions and includes a distribution to NRG from Agua Caliente Borrower 2 LLC following the issuance of the Agua Caliente Holdco financing, as described in Note 7 , Long-term Debt . NRG Yield LLC Distributions to NRG The following table lists the distributions paid to NRG on NRG Yield LLC's Class B and D units during the six months ended June 30, 2017 : Second Quarter 2017 First Quarter 2017 Distributions per Class B Unit $ 0.27 $ 0.26 Distributions per Class D Unit $ 0.27 $ 0.26 On July 25, 2017 , NRG Yield LLC declared a distribution on its Class A, Class B, Class C and Class D units of $0.28 per unit payable on September 15, 2017 to unit holders of record as of September 1, 2017 .
Distributions [Policy Text Block]	Distributions to NRG The following table lists the distributions paid to NRG on NRG Yield LLC's Class B and D units during the six months ended June 30, 2017 : Second Quarter 2017 First Quarter 2017 Distributions per Class B Unit $ 0.27 $ 0.26 Distributions per Class D Unit $ 0.27 $ 0.26 On July 25, 2017 , NRG Yield LLC declared a distribution on its Class A, Class B, Class C and Class D units of $0.28 per unit payable on September 15, 2017 to unit holders of record as of September 1, 2017 .
Recent Accounting Developments	Recent Accounting Developments ASU 2016-18 — In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230) , Restricted Cash, or ASU No. 2016-18. The amendments of ASU No. 2016-18 require an entity to include amounts generally described as restricted cash and restricted cash equivalents with cash and cash equivalents when reconciling the beginning of period and end of period total amounts on the statement of cash flows. The amendments of ASU No. 2016-18 are effective for annual reporting periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted and the adoption of ASU No. 2016-18 will be applied retrospectively. The Company early adopted ASU No. 2016-18 during the second quarter of 2017. Net cash flows used in investing activities for the six months ended June 30, 2016 increased by $7 million. The sum of Company's cash and cash equivalents and restricted cash reported within the consolidated balance sheet as of December 31, 2016 equals the beginning balances of cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows for the six months ended June 30, 2017. The sum of Company's cash and cash equivalents and restricted cash reported within the consolidated balance sheet as of June 30, 2017 equals to the ending balances of cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows for the six months ended June 30, 2017. ASU 2016-02 — In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or Topic 842, with the objective to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and to improve financial reporting by expanding the related disclosures. The guidance in Topic 842 provides that a lessee that may have previously accounted for a lease as an operating lease under current GAAP should recognize the assets and liabilities that arise from a lease on the balance sheet. In addition, Topic 842 expands the required quantitative and qualitative disclosures with regards to lease arrangements. The Company expects to adopt the standard effective January 1, 2019 utilizing the required modified retrospective approach for the earliest period presented. The Company expects to elect certain of the practical expedients permitted, including the expedient that permits the Company to retain its existing lease assessment and classification. The Company is currently working through an adoption plan and evaluating the anticipated impact on the Company's results of operations, cash flows and financial position. While the Company is currently evaluating the impact the new guidance will have on its financial position and results of operations, the Company expects to recognize lease liabilities and right of use assets. The extent of the increase to assets and liabilities associated with these amounts remains to be determined pending the Company’s review of its existing lease contracts and service contracts which may contain embedded leases. While this review is still in process, the Company believes the adoption of Topic 842 may be material to its financial statements. 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, which was further amended through various updates issued by the FASB thereafter. The amendments of ASU No. 2014-09 completed the joint effort between the FASB and the IASB, to develop a common revenue standard for GAAP and IFRS, and to improve financial reporting. The guidance under Topic 606 provides that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for the goods or services provided and establishes a five step model to be applied by an entity in evaluating its contracts with customers. The Company expects to adopt the standard effective January 1, 2018 and apply the guidance retrospectively to contracts at the date of adoption. The Company will recognize the cumulative effect of applying Topic 606 at the date of initial application, as prescribed under the modified retrospective transition method. The Company also expects to elect the practical expedient available under Topic 606 for measuring progress toward complete satisfaction of a performance obligation and for disclosure requirements of remaining performance obligations. The practical expedient allows an entity to recognize revenue in the amount to which the entity has the right to invoice such that the entity has a right to the consideration in an amount that corresponds directly with the value to the customer for performance completed to date by the entity. The majority of the Company's revenues are obtained through PPAs, which are currently accounted for as operating leases. In connection with the implementation of Topic 842, as described above, the Company expects to elect certain of the practical expedients permitted, including the expedient that permits the Company to retain its existing lease assessment and classification. As leases are excluded from the scope of Topic 606, the Company expects the standard to have an immaterial impact on the Company's results of operations, cash flows and financial position; however, the Company continues to assess the impact in connection with its plan of adoption.

Segment Reporting Segment Repor

Segment Reporting Segment Reporting (Policies)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment Reporting, Policy [Policy Text Block]	The Company’s segment structure reflects how management currently operates and allocates resources. The Company's businesses are primarily segregated based on conventional power generation, renewable businesses which consist of solar and wind, and the thermal and chilled water business. The Corporate segment reflects the Company's corporate costs. The Company'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, and CAFD, as well as economic gross margin and net income (loss).

Nature of Business Nature of Bu

Nature of Business Nature of Business (Tables)	6 Months Ended
	Jun. 30, 2017
Nature of Business Disclosure [Abstract]
IPO of NRG Yield	The following table represents the structure of the Company as of June 30, 2017 :
Schedule of Ownership	As of June 30, 2017 , the Company's operating assets are comprised of the following projects: Projects Percentage Ownership Net Capacity (MW) (a) Offtake Counterparty Expiration Conventional El Segundo 100 % 550 Southern California Edison 2023 GenConn Devon 50 % 95 Connecticut Light & Power 2040 GenConn Middletown 50 % 95 Connecticut Light & Power 2041 Marsh Landing 100 % 720 Pacific Gas and Electric 2023 Walnut Creek 100 % 485 Southern California Edison 2023 1,945 Utility Scale Solar Agua Caliente 16 % 46 Pacific Gas and Electric 2039 Alpine 100 % 66 Pacific Gas and Electric 2033 Avenal 50 % 23 Pacific Gas and Electric 2031 Avra Valley 100 % 26 Tucson Electric Power 2032 Blythe 100 % 21 Southern California Edison 2029 Borrego 100 % 26 San Diego Gas and Electric 2038 CVSR 100 % 250 Pacific Gas and Electric 2038 Desert Sunlight 250 25 % 63 Southern California Edison 2035 Desert Sunlight 300 25 % 75 Pacific Gas and Electric 2040 Kansas South 100 % 20 Pacific Gas and Electric 2033 Roadrunner 100 % 20 El Paso Electric 2031 TA High Desert 100 % 20 Southern California Edison 2033 Utah Solar Portfolio (e) 50 % 265 PacifiCorp 2036 921 Distributed Solar Apple I LLC Projects 100 % 9 Various 2032 AZ DG Solar Projects 100 % 5 Various 2025 - 2033 14 Wind Alta I 100 % 150 Southern California Edison 2035 Alta II 100 % 150 Southern California Edison 2035 Alta III 100 % 150 Southern California Edison 2035 Alta IV 100 % 102 Southern California Edison 2035 Alta V 100 % 168 Southern California Edison 2035 Alta X (b) 100 % 137 Southern California Edison 2038 Alta XI (b) 100 % 90 Southern California Edison 2038 Buffalo Bear 100 % 19 Western Farmers Electric Co-operative 2033 Crosswinds (b) (f) 74.3 % 16 Corn Belt Power Cooperative 2027 Elbow Creek (b) (f) 75 % 92 NRG Power Marketing LLC 2022 Elkhorn Ridge (b) (f) 50.3 % 41 Nebraska Public Power District 2029 Forward (b) (f) 75 % 22 Constellation NewEnergy, Inc. 2017 Goat Wind (b) (f) 74.9 % 113 Dow Pipeline Company 2025 Hardin (b) (f) 74.3 % 11 Interstate Power and Light Company 2027 Laredo Ridge 100 % 80 Nebraska Public Power District 2031 Lookout (b) (f) 75 % 29 Southern Maryland Electric Cooperative 2030 Projects Percentage Ownership Net Capacity (MW) (a) Offtake Counterparty Expiration Odin (b) (f) 74.9 % 15 Missouri River Energy Services 2028 Pinnacle 100 % 55 Maryland Department of General Services and University System of Maryland 2031 San Juan Mesa (b) (f) 56.3 % 68 Southwestern Public Service Company 2025 Sleeping Bear (b) (f) 75 % 71 Public Service Company of Oklahoma 2032 South Trent 100 % 101 AEP Energy Partners 2029 Spanish Fork (b) (f) 75 % 14 PacifiCorp 2028 Spring Canyon II (b) 90.1 % 29 Platte River Power Authority 2039 Spring Canyon III (b) 90.1 % 25 Platte River Power Authority 2039 Taloga 100 % 130 Oklahoma Gas & Electric 2031 Wildorado (b) (f) 74.9 % 121 Southwestern Public Service Company 2027 1,999 Thermal NRG Dover Energy Center LLC 100 % 103 NRG Power Marketing LLC 2018 Thermal generation 100 % 20 Various Various 123 Total net generation capacity (c) 5,002 Thermal equivalent MWt (d) 100 % 1,319 Various Various (a) Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of June 30, 2017 . (b) Projects are part of tax equity arrangements. (c) The Company's total generation capacity is net of 6 MWs for noncontrolling interest for Spring Canyon II and III. The Company's generation capacity including this noncontrolling interest was 5,008 MWs. (d) For thermal energy, net capacity represents MWt for steam or chilled water and excludes 134 MWt available under the right-to-use provisions contained in agreements between two of the Company's thermal facilities and certain of its customers. (e) Represents interests in Four Brothers Solar, LLC, Granite Mountain Holdings, LLC, and Iron Springs Holdings, LLC, all acquired as part of the March 2017 Drop Down Assets (ownership percentage is based upon cash to be distributed). (f) Projects are part of NRG Wind TE Holdco portfolio.

Summary of Significant Accoun24

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Schedule of Accumulated Depreciation and Amortization [Table Text Block]	The following table presents the accumulated depreciation included in the property, plant and equipment, net, and accumulated amortization included in intangible assets, net, respectively, as of June 30, 2017 and December 31, 2016: June 30, 2017 December 31, 2016 (In millions) Property, Plant and Equipment Accumulated Depreciation $ 1,102 $ 951 Intangible Assets Accumulated Amortization 198 163
Schedule of Change in Noncontrolling Interest [Table Text Block]	The following table reflects the changes in the Company's noncontrolling interest balance: (In millions) Balance as of December 31, 2016 689 Capital contributions from tax equity investors, net of distributions 13 Payment for March 2017 Drop Down Assets (131 ) Pre-acquisition net income of Drop Down Assets 12 Comprehensive income 7 Distributions to NRG for Drop Down Assets, net of contributions (47 ) NRG Yield LLC distributions to NRG (45 ) Balance as of June 30, 2017 $ 498
Distributions Made to Limited Liability Company (LLC) Member, by Distribution [Table Text Block]	The following table lists the distributions paid to NRG on NRG Yield LLC's Class B and D units during the six months ended June 30, 2017 : Second Quarter 2017 First Quarter 2017 Distributions per Class B Unit $ 0.27 $ 0.26 Distributions per Class D Unit $ 0.27 $ 0.26

Business Acquisitions Busines25

Business Acquisitions Business Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2017
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Information [Table Text Block]	The following tables present a summary of the Company's historical information combining the financial information for the March 2017 Drop Down Assets transferred in connection with the acquisition: Three months ended June 30, 2016 Six months ended June 30, 2016 As Previously Reported (a) March 2017 Drop Down Assets As Currently Reported As Previously Reported (a) March 2017 Drop Down Assets As Currently Reported (In millions) Total operating revenues $ 283 $ — $ 283 $ 517 $ — $ 517 Operating income 128 — 128 200 — 200 Net income 63 1 64 64 2 66 (a) As previously reported in the Form 8-K filed with the SEC on September 6, 2016 in connection with the CVSR Drop Down completed on September 1, 2016.
March 2017 Drop Down Assets [Member]
Business Acquisition [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following is a summary of assets and liabilities transferred in connection with the acquisition of the March 2017 Drop Down Assets as of March 27, 2017: (In millions) Assets: Cash $ 6 Equity investment in projects 456 Total assets acquired 462 Liabilities: Debt (Current and non-current) (a) 320 Other current and non-current liabilities 3 Total liabilities assumed 323 Net assets acquired $ 139 (a) Net of $8 million of debt issuance costs.

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	6 Months Ended
	Jun. 30, 2017
Schedule of Equity Method Investments [Line Items]
Equity Method Investments [Table Text Block]	The following tables present summarized financial information for the Company's significant equity method investments: Three months ended June 30, Six months ended June 30, (In millions) 2017 2016 2017 2016 Income Statement Data: Utah Solar Portfolio Operating revenues $ 24 $ — $ 37 $ — Operating income 10 — 8 — Net income 10 — 8 — June 30, 2017 December 31, 2016 Balance Sheet Data: (In millions) Utah Solar Portfolio Current assets $ 29 $ 20 Non-current assets 1,101 1,105 Current liabilities 9 14 Non-current liabilities 26 38
Entities that are not consolidated [Member]
Schedule of Equity Method Investments [Line Items]
Schedule of Variable Interest Entities [Table Text Block]	The Company's maximum exposure to loss as of June 30, 2017 is limited to its equity investment in the unconsolidated entities, as further summarized in the table below: (In millions) Maximum exposure to loss Four Brothers Solar, LLC $ 226 Granite Mountain Holdings, LLC 82 Iron Springs Holdings, LLC 57 GenConn Energy LLC 104 NRG DGPV Holdco 1 LLC 73 NRG RPV Holdco 1 LLC 67 NRG DGPV Holdco 2 LLC 44
Consolidated Entities [Member]
Schedule of Equity Method Investments [Line Items]
Schedule of Variable Interest Entities [Table Text Block]	Summarized financial information for the Company's consolidated VIEs consisted of the following as of June 30, 2017 : (In millions) NRG Wind TE Holdco Alta Wind TE Holdco Spring Canyon Other current and non-current assets $ 184 $ 22 $ 3 Property, plant and equipment 428 449 98 Intangible assets 2 268 — Total assets 614 739 101 Current and non-current liabilities 203 8 6 Total liabilities 203 8 6 Noncontrolling interest 125 102 64 Net assets less noncontrolling interests $ 286 $ 629 $ 31

Fair Value of Financial Instr27

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Estimated carrying values and fair values	The estimated carrying amounts and fair values of the Company’s recorded financial instruments not carried at fair market value are as follows: As of June 30, 2017 As of December 31, 2016 Carrying Amount Fair Value Carrying Amount Fair Value (In millions) Assets: Notes receivable, including current portion $ 21 $ 21 $ 30 $ 30 Liabilities: Long-term debt, including current portion $ 5,961 $ 6,017 $ 6,057 $ 6,056
Fair Value, Option, Quantitative Disclosures [Table Text Block]	The fair value of the Company's publicly-traded long-term debt is based on quoted market prices and is classified as Level 2 within the fair value hierarchy. The fair value of debt securities, non-publicly traded long-term debt and certain notes receivable of the Company are based on expected future cash flows discounted at market interest rates, or current interest rates for similar instruments with equivalent credit quality and are classified as Level 3 within the fair value hierarchy. The following table presents the level within the fair value hierarchy for long-term debt, including current portion as of June 30, 2017 and December 31, 2016 : As of June 30, 2017 As of December 31, 2016 Level 2 Level 3 Level 2 Level 3 (In millions) Long-term debt, including current portion $ 1,516 $ 4,501 $ 1,455 $ 4,601
Schedule of Fair Value, Assets and Liabilities [Table Text Block]	The Company records its derivative assets and liabilities at fair value on its consolidated balance sheet. The following table presents assets and liabilities measured and recorded at fair value on the Company's consolidated balance sheets on a recurring basis and their level within the fair value hierarchy: As of June 30, 2017 As of December 31, 2016 Fair Value (a) Fair Value (a) Fair Value (a) (In millions) Level 2 Level 1 Level 2 Derivative assets: Commodity contracts $ 1 $ 1 $ 1 Interest rate contracts — — 1 Total assets 1 1 2 Derivative liabilities: Commodity contracts 2 — 1 Interest rate contracts 78 — 75 Total liabilities $ 80 $ — $ 76 (a) There were no derivative assets or liabilities classified as Level 1 as of June 30, 2017 . There were no derivative assets or liabilities classified as Level 3 as of June 30, 2017 and December 31, 2016 .

Accounting for Derivative Ins28

Accounting for Derivative Instruments and Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net notional volume buy/(sell) of NRG Yield's open derivative transactions broken out by commodity	The following table summarizes the net notional volume buy of the Company's open derivative transactions broken out by commodity: Total Volume June 30, 2017 December 31, 2016 Commodity Units (In millions) Natural Gas MMBtu 2 3 Interest Dollars $ 2,045 $ 2,070
Fair value within the derivative instrument valuation on the balance sheets	he following table summarizes the fair value within the derivative instrument valuation on the balance sheet: Fair Value Derivative Assets Derivative Liabilities June 30, 2017 December 31, 2016 June 30, 2017 December 31, 2016 (In millions) Derivatives Designated as Cash Flow Hedges: Interest rate contracts current $ — $ — $ 8 $ 26 Interest rate contracts long-term — 1 16 39 Total Derivatives Designated as Cash Flow Hedges — 1 24 65 Derivatives Not Designated as Cash Flow Hedges: Interest rate contracts current — — 17 5 Interest rate contracts long-term — — 37 5 Commodity contracts current 1 2 1 1 Commodity contracts long-term — — 1 — Total Derivatives Not Designated as Cash Flow Hedges 1 2 56 11 Total Derivatives $ 1 $ 3 $ 80 $ 76
Offsetting of derivatives by counterparty master agreement level and collateral received or paid	As of June 30, 2017 Gross Amounts of Recognized Assets/Liabilities Derivative Instruments Net Amount Commodity contracts: (In millions) Derivative assets $ 1 $ (1 ) $ — Derivative liabilities (2 ) 1 (1 ) Total commodity contracts (1 ) — (1 ) Interest rate contracts: Derivative liabilities (78 ) — (78 ) Total interest rate contracts (78 ) — (78 ) Total derivative instruments $ (79 ) $ — $ (79 ) As of December 31, 2016 Gross Amounts of Recognized Assets/Liabilities Derivative Instruments Net Amount Commodity contracts: (In millions) Derivative assets $ 2 $ — $ 2 Derivative liabilities (1 ) — (1 ) Total commodity contracts 1 — 1 Interest rate contracts: Derivative assets 1 (1 ) — Derivative liabilities (75 ) 1 (74 ) Total interest rate contracts (74 ) — (74 ) Total derivative instruments $ (73 ) $ — $ (73 )
Effects of NRG Yield's accumulated OCI balance attributable to interest rate swaps designated as cash flow hedge derivatives, net of tax	The following table summarizes the effects on the Company’s accumulated OCL balance attributable to interest rate swaps designated as cash flow hedge derivatives, net of tax: Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions) Accumulated OCL beginning balance $ (64 ) $ (124 ) $ (70 ) $ (83 ) Reclassified from accumulated OCL to income due to realization of previously deferred amounts 2 3 6 6 Mark-to-market of cash flow hedge accounting contracts (8 ) (19 ) (6 ) (63 ) Accumulated OCL ending balance, net of income tax benefit of $16 and $28, respectively (70 ) (140 ) (70 ) (140 ) Accumulated OCL attributable to noncontrolling interests (42 ) (93 ) (42 ) (93 ) Accumulated OCL attributable to NRG Yield, Inc. $ (28 ) $ (47 ) $ (28 ) $ (47 ) Losses expected to be realized from OCL during the next 12 months, net of income tax benefit of $4 $ 14 $ 14

Long-term Debt (Tables)

Long-term Debt (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Schedule of long-term debt	Long-term debt consisted of the following: June 30, 2017 December 31, 2016 June 30, 2017, interest rate % (a) Letters of Credit Outstanding at June 30, 2017 (In millions, except rates) 2019 Convertible Notes $ 345 $ 345 3.500 2020 Convertible Notes 288 288 3.250 2024 Senior Notes 500 500 5.375 2026 Senior Notes 350 350 5.000 Project-level debt: Agua Caliente Borrower 2, due 2038 41 — 5.430 17 Alpine, due 2022 142 145 L+1.750 37 Alta Wind I, lease financing arrangement, due 2034 234 242 7.015 16 Alta Wind II, lease financing arrangement, due 2034 186 191 5.696 23 Alta Wind III, lease financing arrangement, due 2034 193 198 6.067 23 Alta Wind IV, lease financing arrangement, due 2034 125 128 5.938 16 Alta Wind V, lease financing arrangement, due 2035 201 206 6.071 26 Alta Realty Investments, due 2031 31 31 7.000 — Alta Wind Asset Management, due 2031 18 18 L+2.500 — Avra Valley, due 2031 55 57 L+1.750 3 Blythe, due 2028 19 19 L+1.625 2 Borrego, due 2025 and 2038 68 69 L+ 2.750/5.650 5 CVSR, due 2037 757 771 2.339 - 3.775 — CVSR Holdco Notes, due 2037 193 199 4.680 13 El Segundo Energy Center, due 2023 414 443 L+1.625 - L+2.250 82 Energy Center Minneapolis, due 2017 and 2025 85 96 5.950 -7.250 — Energy Center Minneapolis Series D Notes, due 2031 125 125 3.550 — Kansas South, due 2031 29 30 L+2.000 4 Laredo Ridge, due 2028 97 100 L+1.875 10 Marsh Landing, due 2017 and 2023 358 370 L+1.750 - L+1.875 49 Apple I LLC projects and related subsidiaries financing agreement, due 2030 27 27 6.000 — Roadrunner, due 2031 36 37 L+1.625 5 South Trent Wind, due 2020 55 57 L+1.625 10 TA High Desert, due 2020 and 2032 48 49 L+2.500/5.150 — Tapestry, due 2021 166 172 L+1.625 20 Utah Solar Portfolio, due 2022 284 287 L+2.625 11 Viento, due 2023 169 178 L+2.750 27 Walnut Creek, due 2023 299 310 L+1.625 60 WCEP Holdings, due 2023 45 46 L+3.000 — Subtotal project-level debt: 4,500 4,601 Total debt 5,983 6,084 Less current maturities (298 ) (291 ) Less net debt issuance costs (66 ) (70 ) Less discounts (b) (22 ) (27 ) Total long-term debt $ 5,597 $ 5,696 (a) As of June 30, 2017 , L+ equals 3 month LIBOR plus x%, except for the Utah Solar Portfolio and NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility, where L+ equals 1 month LIBOR plus x% and Kansas South, where L+ equals 6 month LIBOR plus x%. (b) Discounts relate to the 2019 Convertible Notes and 2020 Convertible Notes.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The reconciliation of the Company's basic and diluted earnings per share is shown in the following tables: Three months ended June 30, 2017 2016 (In millions, except per share data) (a) Common Class A Common Class C Common Class A Common Class C Basic earnings per share attributable to NRG Yield, Inc. common stockholders Net income attributable to NRG Yield, Inc. $ 10 $ 18 $ 11 $ 21 Weighted average number of common shares outstanding — basic 35 63 35 63 Earnings per weighted average common share — basic $ 0.29 $ 0.29 $ 0.33 $ 0.33 Diluted earnings per share attributable to NRG Yield, Inc. common stockholders Net income attributable to NRG Yield, Inc. $ 13 $ 21 $ 14 $ 23 Weighted average number of common shares outstanding — diluted 49 74 49 73 Earnings per weighted average common share — diluted $ 0.26 $ 0.28 $ 0.29 $ 0.31 Six months ended June 30, 2017 2016 (In millions, except per share data) (a) Common Class A Common Class C Common Class A Common Class C Basic and diluted earnings per share attributable to NRG Yield, Inc. common stockholders Net income attributable to NRG Yield, Inc. $ 9 $ 16 $ 13 $ 24 Weighted average number of common shares outstanding — basic and diluted 35 63 35 63 Earnings per weighted average common share — basic and diluted $ 0.26 $ 0.26 $ 0.38 $ 0.38

Changes in Capital Structure St

Changes in Capital Structure Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2017
Dividends Payable [Line Items]
Dividends Declared [Table Text Block]	The following table lists the dividends paid on the Company's Class A common stock and Class C common stock during the six months ended June 30, 2017 : Second Quarter 2017 First Quarter 2017 Dividends per Class A share $ 0.27 $ 0.26 Dividends per Class C share $ 0.27 $ 0.26

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Three months ended June 30, 2017 (In millions) Conventional Generation Renewables Thermal Corporate Total Operating revenues $ 83 $ 161 $ 40 $ — $ 284 Cost of operations 15 35 27 — 77 Depreciation and amortization 26 47 5 — 78 General and administrative — — — 6 6 Acquisition-related transaction and integration costs — — — 1 1 Operating income (loss) 42 79 8 (7 ) 122 Equity in earnings of unconsolidated affiliates 3 13 — — 16 Other income, net — — — 1 1 Interest expense (14 ) (49 ) (2 ) (21 ) (86 ) Income (loss) before income taxes 31 43 6 (27 ) 53 Income tax expense — — — 8 8 Net Income (Loss) $ 31 $ 43 $ 6 $ (35 ) $ 45 Total Assets $ 1,948 $ 5,855 $ 417 $ 293 $ 8,513 Three months ended June 30, 2016 (In millions) Conventional Generation Renewables Thermal Corporate Total Operating revenues $ 85 $ 159 $ 39 $ — $ 283 Cost of operations 16 34 27 — 77 Depreciation and amortization 20 50 5 — 75 General and administrative — — — 3 3 Operating income (loss) 49 75 7 (3 ) 128 Equity in earnings of unconsolidated affiliates 4 10 — — 14 Other income, net — 2 — — 2 Interest expense (12 ) (36 ) (1 ) (19 ) (68 ) Income (loss) before income taxes 41 51 6 (22 ) 76 Income tax expense — — — 12 12 Net Income (Loss) $ 41 $ 51 $ 6 $ (34 ) $ 64 Six months ended June 30, 2017 (In millions) Conventional Generation Renewables Thermal Corporate Total Operating revenues $ 158 $ 260 $ 84 $ — $ 502 Cost of operations 37 67 57 — 161 Depreciation and amortization 50 93 10 — 153 General and administrative — — — 10 10 Acquisition-related transaction and integration costs — — — 2 2 Operating income (loss) 71 100 17 (12 ) 176 Equity in earnings of unconsolidated affiliates 6 29 — — 35 Other income, net — 1 — 1 2 Interest expense (26 ) (89 ) (5 ) (42 ) (162 ) Income (loss) before income taxes 51 41 12 (53 ) 51 Income tax expense — — — 7 7 Net Income (Loss) $ 51 $ 41 $ 12 $ (60 ) $ 44 Total Assets $ 1,948 $ 5,855 $ 417 $ 293 $ 8,513 Six months ended June 30, 2016 (In millions) Conventional Generation Renewables Thermal Corporate Total Operating revenues $ 164 $ 270 $ 83 $ — $ 517 Cost of operations 39 67 56 — 162 Depreciation and amortization 40 99 10 — 149 General and administrative — — — 6 6 Operating income (loss) 85 104 17 (6 ) 200 Equity in earnings of unconsolidated affiliates 7 11 — — 18 Other income, net — 2 — — 2 Interest expense (23 ) (78 ) (3 ) (38 ) (142 ) Income (loss) before income taxes 69 39 14 (44 ) 78 Income tax expense — — — 12 12 Net Income (Loss) $ 69 $ 39 $ 14 $ (56 ) $ 66

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Reconciliation of the U.S. federal statutory rate to the Company's effective rate	The income tax provision consisted of the following: Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 (In millions, except percentages) Income before income taxes $ 53 $ 76 $ 51 $ 78 Income tax expense 8 12 7 12 Effective income tax rate 15.1 % 15.8 % 13.7 % 15.4 %

Related Party Transactions Rela

Related Party Transactions Related Party Transactions (Tables)	6 Months Ended
	Jun. 30, 2017
Related Party Transaction
Schedule of Related Party Transactions [Table Text Block]
Operations and Maintenance services [Member]
Related Party Transaction
Schedule of Related Party Transactions [Table Text Block]	The following table summarizes material O&M costs recorded in the cost of operations line in the Company's consolidated statements of operations: Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Thermal entities $ 7 $ 8 $ 15 $ 15 Conventional entities 2 2 4 4 Total $ 9 $ 10 $ 19 $ 19

Nature of Business (Details)

Nature of Business (Details) $ in Millions		Mar. 27, 2017USD ($)MW	Sep. 02, 2016USD ($)	Jun. 30, 2017MW	Sep. 01, 2016USD ($)
Nature of Business
Weighted Average Remaining PPA Term				16 years
Megawatts Thermal Equivalent, Available Under right-to-use Provisions				134
Power Generation Capacity, Megawatts, including portion attributable to noncontrolling interest	[1]			5,008
Power Generation Capacity, Megawatts	[1],[2]			5,002
Conventional Generation, Utility-Scale Solar, Distributed Solar, and Wind [Member]
Nature of Business
Power Generation Capacity, Megawatts	[1]			4,879
Conventional Generation [Member]
Nature of Business
Power Generation Capacity, Megawatts	[1]			1,945
Utility-Scale Solar
Nature of Business
Power Generation Capacity, Megawatts	[1]			921
Distributed Solar [Member]
Nature of Business
Power Generation Capacity, Megawatts	[1]			14
Wind Farms [Member]
Nature of Business
Power Generation Capacity, Megawatts	[1]			1,999
Thermal [Member]
Nature of Business
Percentage of Ownership	[2]			100.00%
Power Generation Capacity, Megawatts	[1]			123
Power Generation Capacity, Megawatts and Megawatt Thermal Equivalent	[1]			123
Steam and Chilled Water Capacity, Megawatts Thermal Equivalent	[1],[2],[3]			1,319
NRG Energy Center Dover [Member]
Nature of Business
Percentage of Ownership				100.00%
NRG Yield, Inc. [Member]
Nature of Business
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Voting Interest				44.90%
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest				53.50%
NRG Yield LLC
Nature of Business
Sale of Stock, Percentage of Ownership after Transaction				100.00%
NRG Yield LLC | NRG [Member]
Nature of Business
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Voting Interest				55.10%
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest				46.50%
GenConn Middletown | Conventional Generation [Member]
Nature of Business
Equity Method Investment, Ownership Percentage				50.00%
Power Generation Capacity, Megawatts	[1]			95
GenConn Devon [Member] | Conventional Generation [Member]
Nature of Business
Equity Method Investment, Ownership Percentage				50.00%
Power Generation Capacity, Megawatts	[1]			95
Marsh Landing | Conventional Generation [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			720
El Segundo [Member] | Conventional Generation [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			550
Walnut Creek [Member] | Conventional Generation [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			485
Agua Caliente [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership				16.00%
Power Generation Capacity, Megawatts	[1]			46
Alpine [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			66
Avenal [Member] | Utility-Scale Solar
Nature of Business
Equity Method Investment, Ownership Percentage				50.00%
Power Generation Capacity, Megawatts	[1]			23
Avra Valley | Utility-Scale Solar
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			26
NRG Solar Blythe LLC [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			21
Borrego [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			26
CVSR [Member] | Utility-Scale Solar
Nature of Business
Equity Method Investment, Ownership Percentage				100.00%
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			250
Desert Sunlight [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership				25.00%
Kansas South [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			20
Roadrunner | Utility-Scale Solar
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			20
TA - High Desert LLC [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			20
Utah Portfolio [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership	[4]			50.00%
Power Generation Capacity, Megawatts	[1],[4]			265
AZ DG Solar Projects [Member] | Distributed Solar [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			5
PFMG DG Solar Projects [Member] | Distributed Solar [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			9
Alta I [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			150
Alta II [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			150
Alta III [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			150
Alta IV [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			102
Alta V [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			168
Alta X [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5]			100.00%
Power Generation Capacity, Megawatts	[1],[5]			137
Alta XI [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5]			100.00%
Power Generation Capacity, Megawatts	[1],[5]			90
South Trent | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			101
Spanish Fork [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			75.00%
Power Generation Capacity, Megawatts	[1],[5],[6]			14
Spring Canyon II [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5]			90.10%
Power Generation Capacity, Megawatts	[1],[5]			29
Laredo Ridge [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			80
Lookout [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			75.00%
Power Generation Capacity, Megawatts	[1],[5],[6]			29
Odin Wind Farm [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			74.90%
Power Generation Capacity, Megawatts	[1],[5],[6]			15
Taloga [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			130
Wildorado [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			74.90%
Power Generation Capacity, Megawatts	[1],[5],[6]			121
Pinnacle [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			55
San Juan Mesa Wind Project, LLC [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			56.30%
Power Generation Capacity, Megawatts	[1],[5],[6]			68
Sleeping Bear [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			75.00%
Power Generation Capacity, Megawatts	[1],[5],[6]			71
Buffalo Bear [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership				100.00%
Power Generation Capacity, Megawatts	[1]			19
Crosswinds [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			74.30%
Power Generation Capacity, Megawatts	[1],[5],[6]			16
Elbow Creek [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			75.00%
Power Generation Capacity, Megawatts	[1],[5],[6]			92
Elkhorn Ridge Wind, LLC [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			50.30%
Power Generation Capacity, Megawatts	[1],[5],[6]			41
Forward [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			75.00%
Power Generation Capacity, Megawatts	[1],[5],[6]			22
Goat Wind [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			74.90%
Power Generation Capacity, Megawatts	[1],[5],[6]			113
Hardin [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5],[6]			74.30%
Power Generation Capacity, Megawatts	[1],[5],[6]			11
Spring Canyon [Member] | Wind Farms [Member]
Nature of Business
Power Generation Capacity, Megawatts attributed to noncontrolling interest	[1],[5]			6
Spring Canyon III [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	[5]			90.10%
Power Generation Capacity, Megawatts	[1],[5]			25
Thermal [Member] | Thermal [Member]
Nature of Business
Power Generation Capacity, Megawatts	[1]			20
NRG Energy Center Dover [Member] | Thermal [Member]
Nature of Business
Power Generation Capacity, Megawatts	[1]			103
CVSR [Member]
Nature of Business
Payments to Acquire Businesses, Gross | $			$ 78.5
Business Combination, Long-term Debt | $					$ 496
Southern California Edison [Member] | Desert Sunlight [Member] | Utility-Scale Solar
Nature of Business
Power Generation Capacity, Megawatts	[1]			63
Pacific Gas and Electric [Member] | Desert Sunlight [Member] | Utility-Scale Solar
Nature of Business
Power Generation Capacity, Megawatts	[1]			75
Common Class D [Member] | NRG Yield LLC
Nature of Business
Sale of Stock, Percentage of Ownership after Transaction				100.00%
Agua Caliente [Member]
Nature of Business
Equity Method Investment, Ownership Percentage		16.00%
March 2017 Drop Down Assets [Member]
Nature of Business
Business Acquisitions, Purchase Price | $		$ 130
Business Acquisition, Consideration Transferred, Working Capital | $		1
Business Combination, Long-term Debt | $		$ 328
Agua Caliente Borrower 2 [Member]
Nature of Business
Power Generation Capacity, Megawatts		46
Pro-Rate Share of Debt Held by Unconsolidated Affiliates | $		$ 135
Agua Caliente Borrower 2 [Member] | NRG [Member]
Nature of Business
Percentage of Ownership		51.00%
[1]	a) Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of June 30, 2017.
[2]	(c) The Company's total generation capacity is net of 6 MWs for noncontrolling interest for Spring Canyon II and III. The Company's generation capacity including this noncontrolling interest was 5,008 MWs.
[3]	(d) For thermal energy, net capacity represents MWt for steam or chilled water and excludes 134 MWt available under the right-to-use provisions contained in agreements between two of the Company's thermal facilities and certain of its customers.
[4]	(e) Represents interests in Four Brothers Solar, LLC, Granite Mountain Holdings, LLC, and Iron Springs Holdings, LLC, all acquired as part of the March 2017 Drop Down Assets (ownership percentage is based upon cash to be distributed).
[5]	(b) Projects are part of tax equity arrangements
[6]	(f) Projects are part of NRG Wind TE Holdco portfolio.

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	[1]	Jun. 30, 2017	Jun. 30, 2016		Dec. 31, 2016
Summary of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 181				$ 181			$ 322
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,102				1,102			951
Finite-Lived Intangible Assets, Accumulated Amortization	198				198			163
Stockholders' Equity Attributable to Noncontrolling Interest	(498)				(498)			(689)
Pre-acquisition net income of Drop Down Assets	0		$ 6		12	$ 6	[1],[2]
Comprehensive income	14		$ 13		7	(14)	[1]
NRG Yield LLC distributions to NRG					(45)
Payments of Capital Distribution					$ (42)	$ (15)	[3]
Dividends Payable, Date Declared					Jul. 25, 2017
Common Stock, Dividends, Per Share, Declared					$ 0.28
Dividends Payable, Date to be Paid					Sep. 15, 2017
Dividends Payable, Date of Record					Sep. 1, 2017
Restricted cash	$ 114				$ 114			$ 165
March 2017 Drop Down Assets [Member]
Summary of Significant Accounting Policies [Line Items]
Payments to Acquire Businesses, Gross					(131)
Financial Institutions [Member]
Summary of Significant Accounting Policies [Line Items]
Capital contributions from tax equity investors, net of distributions					13
Common Class B [Member]
Summary of Significant Accounting Policies [Line Items]
Distribution Made to Limited Liability Company (LLC) Member, Distributions Paid, Per Unit	$ 0.27	$ 0.26
Common Class D [Member]
Summary of Significant Accounting Policies [Line Items]
Distribution Made to Limited Liability Company (LLC) Member, Distributions Paid, Per Unit	$ 0.27	$ 0.26
Drop Down Assets [Member]
Summary of Significant Accounting Policies [Line Items]
Payments of Capital Distribution					$ (47)
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[3]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Business Acquisitions Busines37

Business Acquisitions Business Acquisitions - August 2017 Drop Down (Details) $ in Millions		Aug. 02, 2017USD ($)	Aug. 01, 2017	Jun. 30, 2017MW
Business Acquisition [Line Items]
Power Generation Capacity, Megawatts | MW	[1],[2]			5,002
Subsequent Event [Member] | August 2017 Drop Down Assets [Member]
Business Acquisition [Line Items]
Percentage of NRG's Ownership			25.00%
Business Combination, Consideration Transferred | $		$ 41.5
[1]	(c) The Company's total generation capacity is net of 6 MWs for noncontrolling interest for Spring Canyon II and III. The Company's generation capacity including this noncontrolling interest was 5,008 MWs.
[2]	a) Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of June 30, 2017.

Business Acquisitions Busines38

Business Acquisitions Business Acquisitions - March 2017 Drop Down (Details) $ in Millions		Mar. 27, 2017USD ($)MW	Jun. 30, 2017USD ($)MW	Jun. 30, 2016USD ($)		Jun. 30, 2017USD ($)MW	Jun. 30, 2016USD ($)		Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Total operating revenues			$ 284	$ 283	[1]	$ 502	$ 517	[1]
Power Generation Capacity, Megawatts | MW	[2],[3]		5,002			5,002
Equity investments in affiliates			$ 1,161			$ 1,161			$ 1,152
Debt Issuance Costs, Net			66			66			$ 70
Operating Income (Loss)			122	128	[1]	176	200	[1]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			45	64	[1],[4]	44	66	[1],[4]
Agua Caliente [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage		16.00%
Agua Caliente Borrower 2 [Member]
Business Acquisition [Line Items]
Percentage of NRG's Ownership		31.00%
Power Generation Capacity, Megawatts | MW		46
Power Purchase Agreement Period		25 years
Remaining Power Purchase Agreement term		22 years
Non-Recourse Debt		$ 41
Utah Portfolio [Member]
Business Acquisition [Line Items]
Total operating revenues			$ 24	0		$ 37	0
Remaining Power Purchase Agreement term		20 years
Percentage of Cash Available for Distributions			50.00%			50.00%
Non-Recourse Debt		$ 287
Operating Income (Loss)			$ 10	0		$ 8	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			$ 10	0		$ 8	0
March 2017 Drop Down Assets [Member]
Business Acquisition [Line Items]
Total operating revenues				0			0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents		6
Business Combination, Consideration Transferred		130
Business Acquisition, Consideration Transferred, Working Capital		1
Business Combination, Separately Recognized Transactions, Net Gains and Losses		8
Equity investments in affiliates		456
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		462
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt	[5]	320
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other		3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		323
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		139
Debt Issuance Costs, Net		$ 8
Operating Income (Loss)				0			0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest				1			2
NRG [Member] | Agua Caliente Borrower 2 [Member]
Business Acquisition [Line Items]
Percentage of Ownership		51.00%
NRG [Member] | Utah Portfolio [Member]
Business Acquisition [Line Items]
Percentage of Cash Available for Distributions		50.00%
Scenario, Previously Reported [Member]
Business Acquisition [Line Items]
Total operating revenues	[6]			283			517
Operating Income (Loss)	[6]			128			200
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	[6]			$ 63			$ 64
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(c) The Company's total generation capacity is net of 6 MWs for noncontrolling interest for Spring Canyon II and III. The Company's generation capacity including this noncontrolling interest was 5,008 MWs.
[3]	a) Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of June 30, 2017.
[4]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[5]	Net of $8 million of debt issuance costs.
[6]	As previously reported in the Form 8-K filed with the SEC on September 6, 2016 in connection with the CVSR Drop Down completed on September 1, 2016.

Business Acquisitions Busines39

Business Acquisitions Business Acquisitions - CVSR (Details) - USD ($) $ in Millions	Sep. 02, 2016	Jun. 30, 2017	Dec. 31, 2016	Sep. 01, 2016	Jun. 30, 2016
Business Acquisition [Line Items]
Assets, Current		$ 491	$ 656
Property, Plant and Equipment, Net		5,322	5,460
Total Assets		8,513	8,836
Liabilities		6,177	6,297
Accumulated other comprehensive loss		(28)	(28)		$ (47)
Debt Issuance Costs, Net		66	70
Long-term Debt		5,983	6,084
CVSR [Member]
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired				51.05%
Payments to Acquire Businesses, Gross	$ 78.5
Business Combination, Long-term Debt				$ 496
CVSR [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred	6
Business Combination, Separately Recognized Transactions, Net Gains and Losses	$ 112
CVSR Financing Agreement [Member]
Business Acquisition [Line Items]
Long-term Debt		757	771
CVSR Financing Agreement [Member] | CVSR [Member]
Business Acquisition [Line Items]
Long-term Debt				771
CVSR Holdco due 2037 [Member]
Business Acquisition [Line Items]
Long-term Debt		$ 193	$ 199
CVSR Holdco due 2037 [Member] | CVSR [Member]
Business Acquisition [Line Items]
Long-term Debt				$ 200
Utility-Scale Solar [Member] | CVSR [Member]
Business Acquisition [Line Items]
Percentage of Ownership		100.00%

Variable Interest Entities Vari

Variable Interest Entities Variable Interest Entities - Consolidated Entities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Other Assets	$ 2,700	$ 2,720
Property, Plant and Equipment, Net	5,322	5,460
Total Assets	8,513	8,836
Liabilities	6,177	$ 6,297
November 2015 Drop Down Assets [Member]
Schedule of Equity Method Investments [Line Items]
Other Assets	184
Property, Plant and Equipment, Net	428
Intangible Assets	2
Total Assets	614
Liabilities	203
Noncontrolling Interest in Variable Interest Entity	125
Net Assets	286
Alta X and XI TE Holdco [Member]
Schedule of Equity Method Investments [Line Items]
Other Assets	22
Property, Plant and Equipment, Net	449
Intangible Assets	268
Total Assets	739
Liabilities	8
Noncontrolling Interest in Variable Interest Entity	102
Net Assets	629
Spring Canyon [Member]
Schedule of Equity Method Investments [Line Items]
Other Assets	3
Property, Plant and Equipment, Net	98
Intangible Assets	0
Total Assets	101
Liabilities	6
Noncontrolling Interest in Variable Interest Entity	64
Net Assets	$ 31

Variable Interest Entities Va41

Variable Interest Entities Variable Interest Entities - Unconsolidated Entities (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016		Mar. 27, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Operating revenues	$ 284	$ 283	[1]	$ 502	$ 517	[1]
Equity investments in affiliates	1,161			1,161				$ 1,152
Operating Income (Loss)	122	128	[1]	176	200	[1]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	45	64	[1],[2]	44	66	[1],[2]
Assets, Current	491			491				656
Liabilities, Current	438			438				472
Liabilities, Noncurrent	5,739			5,739				5,825
Agua Caliente [Member]
Schedule of Equity Method Investments [Line Items]
Debt Instrument, Basis Spread on Libor Rate							0.40%
Utah Portfolio [Member]
Schedule of Equity Method Investments [Line Items]
Operating revenues	24	0		37	0
Operating Income (Loss)	10	0		8	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	10	$ 0		8	$ 0
Assets, Current	29			29				20
Assets, Noncurrent	1,101			1,101				1,105
Liabilities, Current	9			9				14
Liabilities, Noncurrent	26			26				$ 38
NRG DGPV Holdco [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments in affiliates	26			26
Four Brothers Solar [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments in affiliates	226			226
Granite Mountain Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments in affiliates	82			82
Iron Springs Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments in affiliates	57			57
NRG DGPV Holdco 1 [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments in affiliates	73			73
NRG DGPV Holdco 2 [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments in affiliates	44			44
NRG RPV Holdco [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments in affiliates	67			67
Gen Conn Energy LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments in affiliates	104			104
NRG DGPV Holdco 2 [Member] | NRG [Member]
Schedule of Equity Method Investments [Line Items]
Due to Affiliate	$ 9			$ 9
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Variable Interest Entities Va42

Variable Interest Entities Variable Interest Entities - Utah Solar Portfolio (Details) - Utah Portfolio [Member]	Jun. 30, 2017
Variable Interest Entity [Line Items]
Percentage of Cash Available for Distributions	50.00%
Capital Unit, Class A [Member]
Variable Interest Entity [Line Items]
Percentage of Ownership	100.00%
Financial Institutions [Member] | Capital Unit, Class B [Member]
Variable Interest Entity [Line Items]
Taxable Income Allocation, Pre-Flip	99.00%
Taxable Income Allocation, Post-Flip	50.00%

Variable Interest Entities Va43

Variable Interest Entities Variable Interest Entities - Debt Held by Unconsolidated Affiliates (Details) - USD ($) $ in Millions	Jun. 30, 2017	Mar. 27, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Long-term Debt	$ 5,983		$ 6,084
Agua Caliente [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		16.00%
Long-term Debt	$ 843
Agua Caliente Borrower 2 [Member]
Schedule of Equity Method Investments [Line Items]
Pro-Rate Share of Debt Held by Unconsolidated Affiliates		$ 135

Fair Value of Financial Instr44

Fair Value of Financial Instruments Fair Value of Financial Instruments - Balance Sheet Grouping (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financing Receivable, Net	$ 21	$ 30
Long-term Debt and Capital Lease Obligations, Including Current Maturities	6,017	6,056
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financing Receivable, Net	21	30
Long-term Debt and Capital Lease Obligations, Including Current Maturities	5,961	6,057
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt and Capital Lease Obligations, Including Current Maturities	1,516	1,455
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt and Capital Lease Obligations, Including Current Maturities	$ 4,501	$ 4,601

Fair Value of Financial Instr45

Fair Value of Financial Instruments Fair Value of Financial Instruments - Recurring Fair Value (Details) - USD ($)		Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 1,000,000	$ 3,000,000
Derivative Liability, Fair Value, Gross Liability		80,000,000	76,000,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]		1,000,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	1,000,000	2,000,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Gross Liability	[1]		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Fair Value, Gross Liability	[1]	80,000,000	76,000,000
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 Assets (Liabilities), at Fair Value, Net		0	0
Commodity Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset		1,000,000	2,000,000
Derivative Liability, Fair Value, Gross Liability		2,000,000	1,000,000
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]		1,000,000
Derivative Liability, Fair Value, Gross Liability	[1]		0
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	1,000,000	1,000,000
Derivative Liability, Fair Value, Gross Liability	[1]	2,000,000	1,000,000
Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset			1,000,000
Derivative Liability, Fair Value, Gross Liability		78,000,000	75,000,000
Interest Rate Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]		0
Derivative Liability, Fair Value, Gross Liability	[1]		0
Interest Rate Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	0	1,000,000
Derivative Liability, Fair Value, Gross Liability	[1]	$ 78,000,000	$ 75,000,000
[1]	(a) There were no derivative assets or liabilities classified as Level 1 as of June 30, 2017. There were no derivative assets or liabilities classified as Level 3 as of June 30, 2017 and December 31, 2016.

Fair Value of Financial Instr46

Fair Value of Financial Instruments Fair Value of Financial Instruments - Credit Risk and Derivative FV Measurements (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017USD ($)
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value Assets, Valuation Techniques, Impact of Credit Reserve to Fair Value	$ 1
Estimated Counterparty Credit Risk Exposure to Certain Counterparties, Period	5 years
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	$ 3,000

Accounting for Derivative Ins47

Accounting for Derivative Instruments and Hedging Activities Accounting for Derivative Instruments and Hedging Activities - FV of Derivatives (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	$ 0		$ 0		$ 0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	(79)		(79)		(73)
Derivative Asset, Fair Value, Gross Asset	1		1		3
Derivative Liability, Fair Value, Gross Liability	80		80		76
Derivative, Collateral, Right to Reclaim Cash	0		0		0
Derivative, Collateral, Obligation to Return Cash	0		0		0
Fair Value of Gross Derivative Assets/(Liabilities), Net	(79)		(79)		(73)
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0		1
Derivative Liability, Fair Value, Gross Liability	24		24		65
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1		1		2
Derivative Liability, Fair Value, Gross Liability	56		56		11
Interest Rate Contract Current [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0		0
Derivative Liability, Fair Value, Gross Liability	8		8		26
Interest Rate Contract Current [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0		0
Derivative Liability, Fair Value, Gross Liability	17		17		5
Interest Rate Contract Non Current [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0		1
Derivative Liability, Fair Value, Gross Liability	16		16		39
Interest Rate Contract Non Current [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0		0
Derivative Liability, Fair Value, Gross Liability	37		37		5
Commodity Contract Current [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1		1		2
Derivative Liability, Fair Value, Gross Liability	1		1		1
Commodity Contract Non Current [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset					0
Derivative Liability, Fair Value, Gross Liability	1		1		0
Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0		0		0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	(1)		(1)		1
Derivative Asset, Fair Value, Gross Asset	1		1		2
Derivative Liability, Fair Value, Gross Liability	2		2		1
Derivative Asset, Fair Value, Gross Liability	1		1		0
Derivative Asset	0		0		2
Derivative Liability, Fair Value, Gross Asset	1		1		0
Derivative Liability	1		1		1
Fair Value of Gross Derivative Assets/(Liabilities), Net	(1)		(1)		1
Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0		0		0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	(78)		(78)		(74)
Derivative Asset, Fair Value, Gross Asset					1
Derivative Liability, Fair Value, Gross Liability	78		78		75
Derivative Asset, Fair Value, Gross Liability					1
Derivative Asset					0
Derivative Liability, Fair Value, Gross Asset	0		0		1
Derivative Liability	78		78		74
Fair Value of Gross Derivative Assets/(Liabilities), Net	(78)		(78)		(74)
Interest [Member] | United States of America, Dollars
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,045		2,045		2,070
Natural Gas [Member] | MMbtu [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2		2		$ 3
Interest Expense [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Unrealized Gain (Loss) on Derivatives	$ 11	$ 2	$ 9	$ 9

Accounting for Derivative Ins48

Accounting for Derivative Instruments and Hedging Activities Accounting for Derivative Instruments and Hedging Activities - AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Accumulated Other Comprehensive Loss, Net of Tax	$ (70)	$ (140)	$ (70)	$ (140)	$ (64)	$ (70)	$ (124)	$ (83)
Accumulated Other Comprehensive Loss, Cumulative Change in Loss from Cash Flow Hedges, Tax Amount	(15)	(25)	(15)	(25)
Reclassified from accumulated OCL to income due to realization of previously deferred amounts	2	3	6	6
Mark-to-market of cash flow hedge accounting contracts	(8)	(19)	(6)	(63)
Losses expected to be realized from OCL during the next 12 months, net of income tax benefit of $4			14
Losses expected to be realized from OCL during the next 12 months, Tax Amount	(3)		(3)
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net			0	0
Noncontrolling Interest [Member]
Derivative [Line Items]
Accumulated Other Comprehensive Loss, Net of Tax	(42)	(93)	(42)	(93)
Successor [Member]
Derivative [Line Items]
Accumulated Other Comprehensive Loss, Net of Tax	$ (28)	$ (47)	$ (28)	$ (47)

Accounting for Derivative Ins49

Accounting for Derivative Instruments and Hedging Activities Accounting for Derivative Instruments and Hedging Activities - Impact to Statement of Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest Rate Contract [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	$ (11)	$ (2)	$ (9)	$ (9)

Long-term Debt Long-term Debt -

Long-term Debt Long-term Debt - Debt Table (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2017	Mar. 27, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term Debt		$ 5,983		$ 6,084
Current portion of long-term debt		(298)		(291)
Debt Issuance Costs, Net		(66)		(70)
Long-term Debt, Excluding Current Maturities		5,597		5,696
Debt Instrument, Unamortized Discount	[1]	(22)		(27)
3.5% Convertible Notes due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 345		345
Debt Instrument, Interest Rate, Stated Percentage	[2]	3.50%
3.25% Convertible Notes due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 288		288
Debt Instrument, Interest Rate, Stated Percentage	[2]	3.25%
5.375% Senior Notes due in 2024 [Member]
Debt Instrument [Line Items]
Senior Notes		$ 500		500
Debt Instrument, Interest Rate, Stated Percentage	[2]	5.375%
5.00% Senior Notes due in 2026 [Member]
Debt Instrument [Line Items]
Senior Notes		$ 350		350
Debt Instrument, Interest Rate, Stated Percentage	[2]	5.00%
NRG Yield Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	[2]	1 month LIBOR
Debt Instrument, Basis Spread on Variable Rate	[1]	2.75%
Agua Caliente Borrower 2 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 41		0
Debt Instrument, Interest Rate, Stated Percentage	[2]	5.43%
Alta Wind I, lease financing arrangement, due 2034 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 234		242
Debt Instrument, Interest Rate, Stated Percentage	[2]	7.015%
Alta Wind II, lease financing arrangement, due 2034 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 186		191
Debt Instrument, Interest Rate, Stated Percentage	[2]	5.696%
Alta Wind III, lease financing arrangement, due 2034 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 193		198
Debt Instrument, Interest Rate, Stated Percentage	[2]	6.067%
Alta Wind IV, lease financing arrangement, due 2034 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 125		128
Debt Instrument, Interest Rate, Stated Percentage	[2]	5.938%
Alta Wind V, lease financing arrangement, due 2035 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 201		206
Debt Instrument, Interest Rate, Stated Percentage	[2]	6.071%
Alta Realty Investments, due 2031 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 31		31
Debt Instrument, Interest Rate, Stated Percentage	[2]	7.00%
Alta Wind Asset Management, due 2031 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 18		18
Debt Instrument, Description of Variable Rate Basis	[2]	3 month LIBOR
Debt Instrument, Basis Spread on Variable Rate		2.375%
West Holdings Credit Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 414		443
Debt Instrument, Description of Variable Rate Basis	[2]	3 month LIBOR
West Holdings Credit Agreement due 2023 Tranche A [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.625%
Marsh Landing Term Loan Facility [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 358		370
Walnut Creek Energy, LLC, due in 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 299		310
Debt Instrument, Description of Variable Rate Basis	[2]	3 month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.625%
Tapestry Wind LLC due in 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 166		172
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.625%
Utah Solar Portfolio, due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 284	$ 287	287
Debt Instrument, Description of Variable Rate Basis		1-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		2.625%
Viento Funding II, Inc., due in 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 169		178
Debt Instrument, Description of Variable Rate Basis	[2]	1-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		2.75%
NRG Energy Center Minneapolis LLC Senior Secured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 85		96
NRG Energy Center Minneapolis Series D Notes [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 125		125
Debt Instrument, Interest Rate, Stated Percentage	[2]	3.55%
Laredo Ridge Wind, LLC, due in 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 97		100
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.875%
South Trent Financing Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 55		57
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.625%
Avra Valley Financing Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 55		57
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.75%
High Desert Facility [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 48		49
WCEP Holdings, LLC, due in 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 45		46
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		3.00%
Roadrunner Financing Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 36		37
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.625%
Kansas South Facility, due 2031 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 29		30
Debt Instrument, Description of Variable Rate Basis	[2]	6-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		2.00%
NRG Solar Blythe LLC Credit Agreement Due 2028 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 19		19
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.625%
PFMG Financing Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 27		27
Debt Instrument, Interest Rate, Stated Percentage	[2]	6.00%
Project [Domain]
Debt Instrument [Line Items]
Long-term Debt		$ 4,500		4,601
West Holdings Credit Agreement due 2023 Tranche B [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.25%
Marsh Landing Tranche A due December 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	[2]	3 month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.75%
Marsh Landing Tranche B due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	[2]	3 month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.875%
Alpine Financing Agreement, due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 142		145
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		1.75%
NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.95%
NRG Energy Center Minneapolis LLC Senior Secured Notes, due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.25%
Borrego Financing Agreement, due 2024 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 68		69
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		2.50%
CVSR Financing Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 757		771
CVSR Holdco due 2037 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 193		$ 199
Debt Instrument, Interest Rate, Stated Percentage	[2]	4.68%
Borrego Financing Agreement, due 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.65%
High Desert Facility, due 2033 [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	[2]	3-Month LIBOR
Debt Instrument, Basis Spread on Variable Rate		2.50%
TA - High Desert, due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.15%
Minimum [Member] | CVSR Financing Agreement [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		2.339%
Maximum [Member] | CVSR Financing Agreement [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.775%
Letter of Credit [Member] | NRG Yield Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		$ 68
Letter of Credit [Member] | Agua Caliente Borrower 2 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		17
Letter of Credit [Member] | Alta Wind I, lease financing arrangement, due 2034 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		16
Letter of Credit [Member] | Alta Wind II, lease financing arrangement, due 2034 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		23
Letter of Credit [Member] | Alta Wind III, lease financing arrangement, due 2034 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		23
Letter of Credit [Member] | Alta Wind IV, lease financing arrangement, due 2034 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		16
Letter of Credit [Member] | Alta Wind V, lease financing arrangement, due 2035 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		26
Letter of Credit [Member] | Alta Realty Investments, due 2031 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		0
Letter of Credit [Member] | Alta Wind Asset Management, due 2031 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		0
Letter of Credit [Member] | West Holdings Credit Agreement [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		82
Letter of Credit [Member] | Marsh Landing Term Loan Facility [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		49
Letter of Credit [Member] | Walnut Creek Energy, LLC, due in 2023 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		60
Letter of Credit [Member] | Tapestry Wind LLC due in 2021 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		20
Letter of Credit [Member] | Utah Solar Portfolio, due 2022 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		11
Letter of Credit [Member] | Viento Funding II, Inc., due in 2023 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		27
Letter of Credit [Member] | NRG Energy Center Minneapolis LLC Senior Secured Notes [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		0
Letter of Credit [Member] | NRG Energy Center Minneapolis Series D Notes [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		0
Letter of Credit [Member] | Laredo Ridge Wind, LLC, due in 2026 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		10
Letter of Credit [Member] | South Trent Financing Agreement [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		10
Letter of Credit [Member] | Avra Valley Financing Agreement [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		3
Letter of Credit [Member] | High Desert Facility [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		0
Letter of Credit [Member] | WCEP Holdings LLC [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		0
Letter of Credit [Member] | Roadrunner Financing Agreement [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		5
Letter of Credit [Member] | Kansas South Facility, due 2031 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		4
Letter of Credit [Member] | NRG Solar Blythe LLC Credit Agreement Due 2028 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		2
Letter of Credit [Member] | PFMG Financing Agreement [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		0
Letter of Credit [Member] | Alpine Financing Agreement, due 2022 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		37
Letter of Credit [Member] | Borrego Financing Agreement, due 2024 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		5
Letter of Credit [Member] | CVSR Financing Agreement [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		0
Letter of Credit [Member] | CVSR Holdco due 2037 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		$ 13
[1]	(b) Discounts relate to the 2019 Convertible Notes and 2020 Convertible Notes.
[2]	(a) As of June 30, 2017, L+ equals 3 month LIBOR plus x%, except for the Utah Solar Portfolio and NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility, where L+ equals 1 month LIBOR plus x% and Kansas South, where L+ equals 6 month LIBOR plus x%

Long-term Debt Long-term Debt51

Long-term Debt Long-term Debt - Debt Disclosures (Details) - USD ($) $ in Millions		2 Months Ended	6 Months Ended
		Dec. 31, 2016	Jun. 30, 2017	Mar. 27, 2017	Mar. 16, 2017	Feb. 17, 2017	Nov. 02, 2016
Debt Instrument [Line Items]
Long-term Debt		$ 6,084	$ 5,983
NRG Yield Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	[1]		2.75%
Line of Credit Facility, Fair Value of Amount Outstanding			$ 0
NRG Energy Center Minneapolis Series D Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[2]		3.55%
Long-term Debt		125	$ 125
NRG Energy Center Minneapolis Series F Notes [Member]
Debt Instrument [Line Items]
Credit Facility, Maximum Borrowing Capacity, Amendment					$ 10
Debt Instrument, Interest Rate, Stated Percentage			4.60%
Line of Credit Facility, Maximum Borrowing Capacity			$ 80
Agua Caliente Borrower 1, due 2038 [Member]
Debt Instrument [Line Items]
Long-term Debt						$ 130
Agua Caliente Borrower 2 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[2]		5.43%
Long-term Debt		0	$ 41
Utah Solar Portfolio, due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate			2.625%
Proceeds from Issuance of Debt		65
Business Combination, Long-term Debt							$ 222
Long-term Debt		$ 287	$ 284	$ 287
Letter of Credit [Member] | NRG Yield Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount			68
Letter of Credit [Member] | NRG Energy Center Minneapolis Series D Notes [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount			0
Letter of Credit [Member] | Agua Caliente Borrower 2 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount			17
Letter of Credit [Member] | Utah Solar Portfolio, due 2022 [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount			$ 11
[1]	(b) Discounts relate to the 2019 Convertible Notes and 2020 Convertible Notes.
[2]	(a) As of June 30, 2017, L+ equals 3 month LIBOR plus x%, except for the Utah Solar Portfolio and NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility, where L+ equals 1 month LIBOR plus x% and Kansas South, where L+ equals 6 month LIBOR plus x%

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic		$ 28	$ 32	[1]	$ 25	$ 37	[1]
Common Class A [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic	[2]	$ 10	$ 11
Weighted Average Number of Shares Outstanding, Basic	[2]	35	35
Earnings Per Share, Basic	[2]	$ 0.29	$ 0.33
Net Income (Loss) Available to Common Stockholders, Diluted	[2]	$ 13	$ 14
Weighted Average Number of Shares Outstanding, Diluted	[2]	49	49
Earnings Per Share, Diluted	[2]	$ 0.26	$ 0.29
Net Income (Loss) Available to Common Stockholders, Basic and Diluted	[2]				$ 9,000,000	$ 13,000,000
Weighted Average Number of Shares Outstanding, Basic and Diluted	[2]				35	35
Earnings Per Share, Basic and Diluted	[2]				$ 0.26	$ 0.38
Common Class C [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic	[2]	$ 18	$ 21
Weighted Average Number of Shares Outstanding, Basic	[2]	63	63
Earnings Per Share, Basic	[2]	$ 0.29	$ 0.33		(0.03)	0.38
Net Income (Loss) Available to Common Stockholders, Diluted	[2]	$ 21	$ 23
Weighted Average Number of Shares Outstanding, Diluted	[2]	74	73
Earnings Per Share, Diluted	[2]	$ 0.28	$ 0.31
Net Income (Loss) Available to Common Stockholders, Basic and Diluted	[2]				$ 16,000,000	$ 24,000,000
Weighted Average Number of Shares Outstanding, Basic and Diluted	[2]				63	63
Earnings Per Share, Basic and Diluted	[2]				$ 0.26	$ 0.38
3.5% Convertible Notes due 2019 [Member] | Common Class A [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount					15	15
3.25% Convertible Notes due 2020 [Member] | Common Class A [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		0	0
3.25% Convertible Notes due 2020 [Member] | Common Class C [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		0	0		10	10
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) Basic and diluted earnings per share might not recalculate due to presenting values in millions rather than whole dollars.

Changes in Capital Structure Ch

Changes in Capital Structure Changes in Capital Structure - Stock Issuance (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	[1]
Class of Stock [Line Items]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
ATM Program, Maximum Dollar Value of Shares to Be Issued	$ 150,000,000	$ 150,000,000
Common Stock, Shares, Issued	510,112	934,139
Proceeds from the issuance of common stock	$ 9,000,000	$ 16,000,000	$ 0
Commissions, Policy [Policy Text Block]		$ 163,000
NRG Yield, Inc. [Member]
Class of Stock [Line Items]
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest		53.50%
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Voting Interest		44.90%
NRG Yield, Inc. [Member]
Class of Stock [Line Items]
Proceeds from the issuance of common stock		$ 16,000,000
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Changes in Capital Structure 54

Changes in Capital Structure Changes in Capital Structure - Dividends (Details) - $ / shares	3 Months Ended				6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	[1]	Jun. 30, 2017	Jun. 30, 2016	[1]	Dec. 31, 2016
Class of Stock [Line Items]
Dividends Payable, Date Declared					Jul. 25, 2017
Dividends Per Common Share, Cash Paid	$ 0.27
Common Stock, Dividends, Per Share, Declared					$ 0.28
Dividends Payable, Date to be Paid					Sep. 15, 2017
Dividends Payable, Date of Record					Sep. 1, 2017
Preferred Stock, Shares Authorized	10,000,000				10,000,000			10,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01				$ 0.01
Common Class A [Member]
Class of Stock [Line Items]
Dividends Per Common Share, Cash Paid	0.27	$ 0.26	$ 0.23		0.53	$ 0.455
Common Class C [Member]
Class of Stock [Line Items]
Dividends Per Common Share, Cash Paid	$ 0.27	$ 0.26	$ 0.23		$ 0.53	$ 0.455
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016		Dec. 31, 2016
Segment Reporting
Operating revenues	$ 284	$ 283	[1]	$ 502	$ 517	[1]
Cost of operations	77	77		161	162
Depreciation and amortization	78	75	[1]	153	149	[1]
General and administrative	6	3	[1]	10	6	[1]
Acquisition-related transaction and integration costs	1	0	[1]	2	0	[1]
Operating Income	122	128	[1]	176	200	[1]
Equity in earnings of unconsolidated affiliates	16	14	[1]	35	18	[1]
Other income, net	1	2	[1]	2	2	[1]
Interest expense	(86)	(68)	[1]	(162)	(142)	[1]
Total Assets	8,513			8,513			$ 8,836
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	53	76	[1]	51	78	[1]
Income tax expense	8	12	[1]	7	12	[1]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	45	64	[1],[2]	44	66	[1],[2]
Conventional Generation
Segment Reporting
Operating revenues	83	85		158	164
Cost of operations	15	16		37	39
Depreciation and amortization	26	20		50	40
General and administrative	0	0		0	0
Acquisition-related transaction and integration costs	0			0
Operating Income	42	49		71	85
Equity in earnings of unconsolidated affiliates	3	4		6	7
Other income, net	0	0		0	0
Interest expense	(14)	(12)		(26)	(23)
Total Assets	1,948			1,948
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	31	41		51	69
Income tax expense	0	0		0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	31	41		51	69
Renewables
Segment Reporting
Operating revenues	161	159		260	270
Cost of operations	35	34		67	67
Depreciation and amortization	47	50		93	99
General and administrative	0	0		0	0
Acquisition-related transaction and integration costs	0			0
Operating Income	79	75		100	104
Equity in earnings of unconsolidated affiliates	13	10		29	11
Other income, net	0	2		1	2
Interest expense	(49)	(36)		(89)	(78)
Total Assets	5,855			5,855
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	43	51		41	39
Income tax expense	0	0		0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	43	51		41	39
Thermal [Member]
Segment Reporting
Operating revenues	40	39		84	83
Cost of operations	27	27		57	56
Depreciation and amortization	5	5		10	10
General and administrative	0	0		0	0
Acquisition-related transaction and integration costs	0			0
Operating Income	8	7		17	17
Equity in earnings of unconsolidated affiliates	0	0		0	0
Other income, net	0	0		0	0
Interest expense	(2)	(1)		(5)	(3)
Total Assets	417			417
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	6	6		12	14
Income tax expense	0	0		0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	6	6		12	14
Corporate
Segment Reporting
Operating revenues	0	0		0	0
Cost of operations	0	0		0	0
Depreciation and amortization	0	0		0	0
General and administrative	6	3		10	6
Acquisition-related transaction and integration costs	1			2
Operating Income	(7)	(3)		(12)	(6)
Equity in earnings of unconsolidated affiliates	0	0		0	0
Other income, net	1	0		1	0
Interest expense	(21)	(19)		(42)	(38)
Total Assets	293			293
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(27)	(22)		(53)	(44)
Income tax expense	8	12		7	12
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (35)	$ (34)		$ (60)	$ (56)
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Income Taxes (Provision) (Detai

Income Taxes (Provision) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income before income taxes	$ 53	$ 76	[1]	$ 51	$ 78	[1]
Income tax expense	$ 8	$ 12	[1]	$ 7	$ 12	[1]
Effective income tax rate	15.10%	15.80%		13.70%	15.40%
U.S. federal statutory rate (as a percent)				35.00%
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016		Jun. 30, 2017	Jun. 30, 2016		Dec. 31, 2016
Related Party Transaction
General and administrative	$ 6	$ 3	[1]	$ 10	$ 6	[1]
Due to Affiliate, Current	31			31			$ 40
GenOn Energy Services LLC [Member]
Related Party Transaction
Due to Affiliate							6
NRG [Member]
Related Party Transaction
Revenue from Related Parties	3	3		7	6
NRG RENOM [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	7	3		10	5
Due to Affiliate	3			3			5
NRG Yield [Member] | NRG [Member]
Related Party Transaction
General and administrative	4	3		6	5
NRG Yield [Member] | NRG [Member] | Scenario, Plan [Member]
Related Party Transaction
Management Services Fee, Annual				8
Thermal [Member] | NRG [Member]
Related Party Transaction
Due to Affiliate	20			20			$ 22
Accounts payable — affiliate	9			9
NRG Energy Center Minneapolis LLC [Member] | NRG [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	2	1		6	5
Marsh Landing [Member] | GenOn Energy Services LLC [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	3	3		6	5
NRG DGPV Holdco 2 [Member] | NRG [Member]
Related Party Transaction
Due to Affiliate	9			9
Operations and Maintenance services [Member] | NRG [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	9	10		19	19
Operations and Maintenance services [Member] | Thermal [Member] | NRG [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	7	8		15	15
Operations and Maintenance services [Member] | GCE Holding LLC [Member] | NRG [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	2			3
Operations and Maintenance services [Member] | Walnut Creek [Member] | NRG [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	$ 2	$ 2		$ 4	$ 4
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.