Clearway Energy (CWEN) 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Document And Entity Information [Abstract]
Entity Registrant Name	NRG Yield, Inc.
Entity Central Index Key	1567683
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Current Fiscal Year End Date	-19
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	2015
Document Fiscal Period Focus	Q1
Common Class A [Member]
Class of Stock
Entity Common Stock, Shares Outstanding		34,586,250
Common Class B [Member]
Class of Stock
Entity Common Stock, Shares Outstanding		42,738,750

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating Revenues
Total operating revenues	$180	$140
Operating Costs and Expenses
Cost of operations	75	60
Depreciation and amortization	54	24	[1]
Total operating costs and expenses	132	86	[1]
Operating Income	48	54	[1]
Other Income (Expense)
Equity in earnings of unconsolidated affiliates	1	1
Other income, net	1	1
Interest expense	-70	-27
Total other expense, net	-68	-25	[1]
Income Before Income Taxes	-20	29	[1]
Income tax (benefit) expense	-4	3
Net Income	-16	26	[1]
Net Income excluding pre-acquisition net income of Acquired ROFO assets	-16	18	[1]
Net (loss) income attributable to NRG Yield, Inc.	-5	4
(Loss) Earnings Per Share Attributable to NRG Yield, Inc. Class A Common Stockholders
Weighted average number of Class A common shares outstanding	35	23
(Losses) Earnings per weighted average Class A common share — basic and diluted	($0.15)	$0.18
Dividends Per Common Share	$0.39	$0.33
Affiliated Entity [Member]
Operating Costs and Expenses
General and administrative — affiliate	3	2
Noncontrolling Interest [Member]
Other Income (Expense)
Less: Net (loss) income attributable to NRG (b)	-11	14
Acquired ROFO Assets [Domain]
Other Income (Expense)
Net Income	$0	$8
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other Comprehensive Loss, net of tax
Net Income	($16)	$26	[1]
Unrealized loss on derivatives, net of income tax benefit of $8 and $0	-17	-12
Other comprehensive loss	-17	-12	[2]
Comprehensive (Loss) Income	-33	14	[2]
Less: Pre-acquisition net income of Acquired ROFO assets	0	8
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	-15	9
Comprehensive Income (Loss), Net of Tax, Available for Common Stockholders	($18)	($3)
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Unrealized gain/loss on derivatives, income tax expense /(benefit)	$8	$0

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Current Assets
Cash and cash equivalents	$114	$406
Restricted cash	46	45
Accounts receivable — trade	63	85
Inventory	27	27
Derivative instruments	8	0
Notes receivable	7	6
Deferred income taxes	10	16
Prepayments and other current assets	18	21
Total current assets	293	606	[1]
Property, plant and equipment
In service	4,804	4,796
Under construction	17	8
Total property, plant and equipment	4,821	4,804	[1]
Less accumulated depreciation	-391	-338
Net property, plant and equipment	4,430	4,466
Other Assets
Equity investments in affiliates	188	227
Notes receivable	15	15
Intangible assets, net of accumulated amortization of $55 and $40	1,403	1,423
Derivative instruments	0	2
Deferred income taxes	143	118
Other non-current assets	123	108
Total other assets	1,872	1,893
Total Assets	6,595	6,965	[1]
Current Liabilities
Current portion of long-term debt	218	214
Accounts payable	33	20
Accounts payable — affiliate	46	46
Derivative instruments	48	48
Accrued expenses and other current liabilities	44	61
Total current liabilities	389	389	[1]
Total current liabilities
Long-term debt	4,719	4,573
Derivative instruments	97	69
Other non-current liabilities	49	49
Total non-current liabilities	4,865	4,691
Total Liabilities	5,254	5,080
Commitments and Contingencies
Stockholders' Equity
Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued	0	0
Additional Paid in Capital	1,235	1,240
Retained Earnings (Accumulated Deficit)	-2	3
Accumulated Other Comprehensive Income (Loss), Net of Tax	-23	-9
Noncontrolling interest	131	651
Total Stockholders' Equity	1,341	1,885	[1]
Total Liabilities and Stockholders’ Equity	6,595	6,965	[1]
Common Class A [Member]
Stockholders' Equity
Common Stock, Value, Issued	0	0
Common Class B [Member]
Stockholders' Equity
Common Stock, Value, Issued	$0	$0
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, except Share data, unless otherwise specified
Intangible assets, accumulated amortization	$55	$40
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	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	22,511,250
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

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash Flows from Operating Activities
Net income/(loss)	($16)	$26	[1]
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Distributions in excess of equity in earnings of unconsolidated affiliates	36	1	[1]
Depreciation and amortization	54	24	[1]
Amortization of financing costs and debt discount/premiums	3	1	[1]
Amortization of intangibles and out-of-market contracts	12	1	[1]
Changes in deferred income taxes	-4	3	[1]
Changes in derivative instruments	-2	0	[1]
Changes in other working capital	-5	-31	[1]
Net Cash Provided by Operating Activities	78	25	[1]
Cash Flows from Investing Activities
Capital expenditures	-3	-22	[1]
Acquisition of businesses, net of cash acquired	-490	0	[1]
(Increase) decrease in restricted cash	-1	34	[1]
Decrease in notes receivable	2	3	[1]
Proceeds from renewable energy grants	0	96	[1]
Investments in unconsolidated affiliates	3	3	[1]
Other	0	11	[1]
Net Cash (Used in) Provided By Investing Activities	-489	125	[1]
Cash Flows from Financing Activities
Payment of dividends and distributions to shareholders	-30	-22	[1]
Proceeds from issuance of long-term debt — external	210	374	[1]
Payment of debt issuance costs	0	-8	[1]
Net Cash Provided by Financing Activities	119	225	[1]
Net (Decrease) Increase in Cash and Cash Equivalents	-292	375	[1]
Cash and Cash Equivalents at Beginning of Period	406	59	[1]
Cash and Cash Equivalents at End of Period	114	434	[1]
NRG [Member]
Cash Flows from Financing Activities
Distributions and return of capital to NRG	0
Non-affiliate
Cash Flows from Financing Activities
Payments for long-term debt — external	-61	-96	[1]
El Segundo [Member] | NRG [Member]
Cash Flows from Financing Activities
Distributions and return of capital to NRG		($23)	[1]
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Nature_of_Business

Nature of Business	3 Months Ended
	Mar. 31, 2015
Nature of Business Disclosure [Abstract]
Nature of Business	Note 1 — Nature of Business
	NRG Yield, Inc., or the Company, is a dividend growth-oriented company formed as a Delaware corporation on December 20, 2012, to serve as the primary vehicle through which NRG owns, operates and acquires contracted renewable and conventional generation and thermal infrastructure assets.
	The Company used the net proceeds from its initial public offering of Class A common stock on July 22, 2013 to acquire 100% of the Class A units of NRG Yield LLC, including a controlling interest through its position as managing member. NRG Yield LLC, through its wholly owned subsidiary, NRG Yield Operating LLC, is a holder of a portfolio of contracted renewable and conventional generation and thermal infrastructure assets, primarily located in the Northeast, Southwest and California regions of the U.S.
	On July 29, 2014, the Company issued additional shares of Class A common stock and utilized the proceeds of the offering to acquire additional Class A units of NRG Yield LLC increasing its ownership to 44.7%. As of March 31, 2015, the Company continues to own 44.7% of NRG Yield LLC, and consolidates the results of NRG Yield LLC through its controlling interest, with NRG's 55.3% interest shown as noncontrolling interest in the financial statements. The holders of the Company's outstanding shares of Class A common stock are entitled to dividends. NRG receives its distributions from NRG Yield LLC through its ownership of NRG Yield LLC Class B units.
	The following table represents the structure of the Company as of March 31, 2015:
	As of March 31, 2015, the Company's operating assets are comprised of the following projects:
	Projects	Percentage Ownership		Net Capacity (MW)(a)	Offtake Counterparty	Expiration
	Conventional
	GenConn Middletown	49.95	%	95	Connecticut Light & Power	2041
	GenConn Devon	49.95	%	95	Connecticut Light & Power	2040
	Marsh Landing	100	%	720	Pacific Gas and Electric	2023
	El Segundo	100	%	550	Southern California Edison	2023
	Walnut Creek	100	%	485	Southern California Edison	2023
				1,945
	Utility Scale Solar
	Alpine	100	%	66	Pacific Gas and Electric	2033
	Avenal	49.95	%	23	Pacific Gas and Electric	2031
	Avra Valley	100	%	25	Tucson Electric Power	2032
	Blythe	100	%	21	Southern California Edison	2029
	Borrego	100	%	26	San Diego Gas and Electric	2038
	Roadrunner	100	%	20	El Paso Electric	2031
	CVSR	48.95	%	122	Pacific Gas and Electric	2038
	Kansas South	100	%	20	Pacific Gas and Electric	2033
	TA High Desert	100	%	20	Southern California Edison	2033
				343
	Distributed Solar
	AZ DG Solar Projects	100	%	5	Various	2025 - 2033
	PFMG DG Solar Projects	51	%	5	Various	2032
				10
	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	100	%	137	Southern California Edison	2038(c)
	Alta XI	100	%	90	Southern California Edison	2038(c)
	South Trent	100	%	101	AEP Energy Partners	2029
	Laredo Ridge	100	%	80	Nebraska Public Power District	2031
	Taloga	100	%	130	Oklahoma Gas & Electric	2031
	Pinnacle	100	%	55	Maryland Department of General Services and University System of Maryland	2031
	Buffalo Bear	100	%	19	Western Farmers Electric Co-operative	2033
				1,332
	Thermal
	Thermal equivalent MWt(b)	100	%	1,310	Various	Various
	Thermal generation	100	%	123	Various	Various
	Total net capacity (excluding equivalent MWt)			3,753
	(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 March 31, 2015.
	(b) 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 NRG Yield, Inc.'s thermal facilities and certain of its customers.
	(c) PPA begins on January 1, 2016.
	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. Three of the district energy systems are subject to rate regulation by state public utility commissions while the other district energy systems have rates determined by negotiated bilateral contracts.
	In connection with the initial public offering, the Company entered into a management services agreement with NRG for various services, including human resources, accounting, tax, legal, information systems, treasury, and risk management. Costs incurred by the Company under this agreement were $3 million and $2 million for the three months ended March 31, 2015, and 2014, respectively, which included certain direct expenses incurred by NRG on behalf of the Company.
	Stockholders' equity represents the equity associated with the Class A common stockholders, with the equity associated with the Class B common stockholders, or NRG, classified as noncontrolling interest.
	As described in Note 3, Business Acquisitions, on June 30, 2014, NRG Yield Operating LLC acquired the TA High Desert, Kansas South, and El Segundo projects from NRG for total cash consideration of $357 million plus assumed project level debt. Additionally, on January 2, 2015, NRG Yield Operating LLC acquired the Laredo Ridge, Tapestry, and Walnut Creek projects for total cash consideration of $489 million, including $9 million for working capital, plus assumed debt of $737 million. These acquisitions were accounted for as transfers of entities 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. Accordingly, the Company prepared its consolidated financial statements to reflect the transfer as if it had taken place from the beginning of the financial statements period, or from the date the entities were under common control, which was May 13, 2013, for Kansas South, March 28, 2013, for TA High Desert, and April 1, 2014, for Laredo Ridge, the Tapestry projects and Walnut Creek, which represent the dates these entities were acquired by NRG.
	The accompanying unaudited interim consolidated financial statements have been prepared in accordance with the Securities and Exchange Commission’s, or SEC’s, regulations for interim financial information. Accordingly, they do not include all of the information and notes required by U.S. 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 Company’s annual financial statements for the year ended December 31, 2014. 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 March 31, 2015, and the results of operations, comprehensive income and cash flows for the three months ended March 31, 2015, and 2014.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Use of Estimates
	The preparation of consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions. These estimates and assumptions impact the reported amount of assets and liabilities and disclosures of contingent assets and liabilities as of the date of the consolidated financial statements. They also impact the reported amount of net earnings during the reporting period. Actual results could be different from these estimates.
	Noncontrolling Interest
	The following table reflects the changes in the Company's noncontrolling interest balance:
		(In millions)
	Balance as of December 31, 2014 (as previously reported)	$	246
	Net Assets of acquired EME-NYLD-Eligible Assets as of December 31, 2014	405
	Balance as of December 31, 2014 (as currently reported)	651
	Payment to NRG for acquired EME-NYLD-Eligible Assets	(489		)
	Comprehensive loss	(15		)
	Non-cash contributions	1
	Cash distributions to NRG	(17		)
	Balance as of March 31, 2015	$	131
	On January 2, 2015, the Company acquired the Laredo Ridge, Tapestry, and Walnut Creek projects, as discussed in Note 3, Business Acquisitions. The difference between the cash paid and historical value of entities' net assets of $61 million, as well as $23 million of AOCL, were recorded as a distribution to NRG and reduced the balance of its noncontrolling interest. In addition, as the Laredo Ridge, Tapestry, and Walnut Creek projects were owned by NRG until January 2, 2015, the pre-acquisition earnings of such projects are recorded as attributable to NRG's noncontrolling interest.
	Distributions
	On February 17, 2015, NRG Yield LLC declared a distribution on its Class A and Class B units of $0.39 per unit, which was paid on March 16, 2015. The portion of the distributions paid by NRG Yield LLC to NRG was recorded as a reduction to the Company's noncontrolling interest balance.
	Recent Accounting Developments
	ASU 2015-03 — In April 2015, the FASB issued ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, or ASU No. 2015-03.  The amendments of ASU No. 2015-03 were issued to reduce complexity in the balance sheet presentation of debt issuance costs.  ASU No. 2015-03 requires that debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of debt liability, consistent with debt discounts or premiums.  The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this standard.  The guidance in ASU No. 2015-03 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years.  Early adoption is permitted for financial statements that have not been previously issued.  The adoption of this standard is not expected to have a material impact on the Company's balance sheets on a gross basis and will have no impact on net assets.
	ASU 2015-02 — In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis, or ASU No. 2015-02. The amendments of ASU No. 2015-02 were issued in an effort to minimize situations under previously existing guidance in which a reporting entity was required to consolidate another legal entity in which that reporting entity did not have: (1) the ability through contractual rights to act primarily on its own behalf; (2) ownership of the majority of the legal entity's voting rights; or (3) the exposure to a majority of the legal entity's economic benefits. ASU No. 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. All legal entities are subject to reevaluation under the revised consolidation model. The guidance in ASU No. 2015-02 is effective for periods beginning after December 15, 2015. Early adoption is permitted. The Company adopted the standard effective January 1, 2015 and the adoption of this standard did not impact the Company's results of operations, cash flows or financial position.
	ASU 2014-16 — In November 2014, the FASB issued ASU No. 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity, or ASU No. 2014-16. The amendments of ASU No. 2014-16 clarify how U.S. GAAP should be applied in determining whether the nature of a host contract is more akin to debt or equity and in evaluating whether the economic characteristics and risks of an embedded feature are "clearly and closely related" to its host contract. The guidance in ASU No. 2014-16 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. The Company adopted the standard effective January 1, 2015 and the adoption of this standard did not impact the Company's results of operations, cash flows or financial position.
	ASU 2014-09 — In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU No. 2014-09.  The amendments of ASU No. 2014-09 complete the joint effort between the FASB and the International Accounting Standards Board, or IASB, to develop a common revenue standard for U.S. GAAP and International Financial Reporting Standards, or IFRS, and to improve financial reporting.  The guidance in ASU No. 2014-09 provides that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for the goods or services provided and establishes the following steps to be applied by an entity: (1) identify the contract with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies the performance obligation.  The guidance of ASU No. 2014-09 is effective for annual reporting periods beginning after December 15, 2016, including interim periods therein. Early adoption is not permitted.  The Company is currently evaluating the impact of the standard on the Company's results of operations, cash flows and financial position.

Business_Acquisitions

Business Acquisitions	3 Months Ended
	Mar. 31, 2015
Business Acquisition, Pro Forma Information [Table Text Block]	The following unaudited supplemental pro forma information represents the results of operations as if the Company had acquired the EME-NYLD-Eligible Assets on January 1, 2014, including the impact of acquisition accounting with respect to NRG's acquisition of the projects. While the financial statements have been retrospectively adjusted, all net income or losses prior to the Company's acquisition of the projects is reflected as attributable to NRG and accordingly, no pro forma impact to earnings per Class A common share was calculated.
			For the three months ended
	(In millions)		March 31, 2014
	Operating revenues		$	166
	Net income		23
Business Acquisition, Purchase Price [Table Text Block]	The purchase price of $923 million was provisionally allocated as follows:
			Acquisition Date Fair Value at December 31, 2014			Measurement period adjustments				Revised Acquisition Date
			(In millions)
	Assets
	Cash		$	22		$	—			$	22
	Current and non-current assets		49			(2		)		47
	Property, plant and equipment		1,304			6				1,310
	Intangible assets		1,177			(6		)		1,171
	Total assets acquired		2,552			(2		)		2,550
	Liabilities
	Debt		1,591			—				1,591
	Current and non-current liabilities		38			(2		)		36
	Total liabilities assumed		1,629			(2		)		1,627
	Net assets acquired		$	923		$	—			$	923
Business Acquisition	Note 3 — Business Acquisitions
	2015 Acquisitions
	EME-NYLD-Eligible Assets from NRG — On January 2, 2015, NRG Yield Operating LLC acquired the following projects from NRG: (i) Laredo Ridge, an 80 MW wind facility located in Petersburg, Nebraska, (ii) the Tapestry projects, which include Buffalo Bear, a 19 MW wind facility in Buffalo, Oklahoma; Taloga, a 130 MW wind facility in Putnum, Oklahoma; and Pinnacle, a 55 MW wind facility in Keyser, West Virginia, and (iii)  Walnut Creek, a 485 MW natural gas facility located in City of Industry, California, for total cash consideration of $489 million, including $9 million for working capital, plus assumed project-level debt of $737 million. NRG Yield Operating LLC funded the acquisition with cash on hand and drawings under its revolving credit facility. The assets and liabilities transferred to NRG Yield Operating LLC relate to interests under common control by NRG and accordingly, 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 entities' equity of $61 million, as well as $23 million of AOCL, were recorded as a distribution to NRG and reduced the balance of its noncontrolling interest. Since the transaction constituted a transfer of 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. NRG acquired the majority of EME's assets, including Laredo Ridge, the Tapestry projects and Walnut Creek, on April 1, 2014.
	The following table presents historical information summary combining the financial information for the EME-NYLD-Eligible Assets transferred in connection with the acquisition:
		31-Dec-14
		As Previously Reported			Walnut Creek				Tapestry			Laredo Ridge		As Currently Reported
					(In millions)
	Current assets	$	539		$	46			$	14		$	7	$	606
	Property, plant and equipment	3,487			575				286			118		4,466
	Non-current assets	1,726			57				61			49		1,893
	Total assets	5,752			678				361			174		6,965
	Debt	4,050			437				192			108		4,787
	Other current and non-current liabilities	222			62				5			4		293
	Total liabilities	4,272			499				197			112		5,080
	Net Assets	$	1,480		$	179			$	164		$	62	$	1,885
	Supplemental Pro Forma Information
	As described above, the Company's acquisition of the EME-NYLD-Eligible Assets was accounted for as a transfer of entities under common control and all periods were retrospectively adjusted to reflect the entities as if they were transferred on the date the entities were under common control, which was April 1, 2014, the date NRG acquired Walnut Creek, Laredo Ridge and the Tapestry projects. The following unaudited supplemental pro forma information represents the results of operations as if the Company had acquired the EME-NYLD-Eligible Assets on January 1, 2014, including the impact of acquisition accounting with respect to NRG's acquisition of the projects. While the financial statements have been retrospectively adjusted, all net income or losses prior to the Company's acquisition of the projects is reflected as attributable to NRG and accordingly, no pro forma impact to earnings per Class A common share was calculated.
			For the three months ended
	(In millions)		March 31, 2014
	Operating revenues		$	166
	Net income		23
	Since the acquisition date, the EME-NYLD-Eligible Assets contributed $38 million in operating revenues and $11 million in net income.
	The following other acquisitions occurred in 2015 with a total purchase price of approximately $41 million, including $1 million paid for University of Bridgeport upon signing of the purchase agreement in the first quarter of 2015.
	University of Bridgeport Fuel Cell — On April 30, 2015, the Company completed the acquisition of the University of Bridgeport Fuel Cell project in Bridgeport, CT from FuelCell Energy, Inc. The project will add an additional 1.4 MW of thermal capacity with a 12 year contract, with the option for a 7-year extension.
	Spring Canyon Acquisition — On May 7, 2015, NRG Yield Operating LLC acquired a majority interest in Spring Canyon II, a 34 MW wind facility, and Spring Canyon III, a 29 MW wind facility, each located in Logan County, Colorado, from Invenergy Wind Global LLC. The purchase price was funded with cash on hand. Power generated by Spring Canyon II and Spring Canyon III is sold to Platte River Power Authority under long-term PPAs with approximately 25 years of remaining contract life.
	2014 Acquisitions
	Alta Wind Portfolio Acquisition — On August 12, 2014, the Company acquired 100% of the membership interests of Alta Wind Asset Management Holdings, LLC, Alta Wind Company, LLC, Alta Wind X Holding Company, LLC and Alta Wind XI Holding Company, LLC, which collectively own seven wind facilities that total 947 MW located in Tehachapi, California, and a portfolio of associated land leases, or the Alta Wind Portfolio. Power generated by the Alta Wind Portfolio is sold to Southern California Edison under long-term PPAs, with 21 years of remaining contract life for Alta I-V. The Alta X and XI PPAs begin in 2016 with a term of 22 years and currently sell energy and renewable energy credits on a merchant basis.
	The purchase price for the Alta Wind Portfolio was $923 million, which consisted of a base purchase price of $870 million, as well as a payment for working capital of $53 million, plus the assumption of $1.6 billion of non-recourse project-level debt. In order to fund the purchase price, the Company completed an equity offering of 12,075,000 shares of its Class A common stock at an offering price of $54.00 per share on July 29, 2014, which resulted in net proceeds of $630 million, after underwriting discounts and expenses. In addition, on August 5, 2014, NRG Yield Operating LLC issued $500 million of Senior Notes, which bear interest at a rate of 5.375% and mature in August 2024.
	The acquisition was recorded as a business combination under ASC 805, with identifiable assets acquired and liabilities assumed provisionally recorded at their estimated fair values on the acquisition date. The initial accounting for the business combination is not complete because the evaluation necessary to assess the fair values of certain net assets acquired is still in process. The provisional amounts are subject to revision until the evaluations are completed to the extent that additional information is obtained about the facts and circumstances that existed as of the acquisition date. The allocation of the purchase price may be modified up to one year from the date of the acquisition as more information is obtained about the fair value of assets acquired and liabilities assumed. The following table summarizes the provisional amounts recognized for assets acquired and liabilities assumed as of December 31, 2014, as well as adjustments made through March 31, 2015.
	The purchase price of $923 million was provisionally allocated as follows:
			Acquisition Date Fair Value at December 31, 2014			Measurement period adjustments				Revised Acquisition Date
			(In millions)
	Assets
	Cash		$	22		$	—			$	22
	Current and non-current assets		49			(2		)		47
	Property, plant and equipment		1,304			6				1,310
	Intangible assets		1,177			(6		)		1,171
	Total assets acquired		2,552			(2		)		2,550
	Liabilities
	Debt		1,591			—				1,591
	Current and non-current liabilities		38			(2		)		36
	Total liabilities assumed		1,629			(2		)		1,627
	Net assets acquired		$	923		$	—			$	923
	Fair value measurements
	The provisional fair values of the property, plant and equipment and intangible assets at the acquisition date were measured primarily based on significant inputs that are not observable in the market and thus represent a Level 3 measurement as defined in ASC 820. Significant inputs were as follows:
	•	Property, plant and equipment — The estimated fair values were determined primarily based on an income method using discounted cash flows and validated using a cost approach based on the replacement cost of the assets less economic obsolescence. The income approach was applied by determining the enterprise value for each acquired entity and subtracting the fair value of the intangible assets and working capital to determine the implied value of the tangible fixed assets. This methodology was primarily relied upon as the forecasted cash flows incorporate the specific attributes of each asset including age, useful life, equipment condition and technology. The income approach also allows for an accurate reflection of current and expected market dynamics such as supply and demand and regulatory environment as of the acquisition date.
	•	Intangible Assets - PPAs — The fair values of the PPAs acquired were determined utilizing a variation of the income approach where the incremental future cash flows resulting from the acquired PPAs compared to the cash flows based on current market prices were discounted to present value at a weighted average cost of capital reflective of a market participant. The values were corroborated with available market data. The PPA values will be amortized over the term of the PPAs, which approximate 22 years.
	•	Intangible Assets - Leasehold rights — The fair values of the leasehold rights acquired, which represent the contractual right to receive royalty payments equal to a percentage of PPA revenue from certain projects, were determined utilizing the income approach. The values were corroborated with available market data. The leasehold rights values will be amortized over a period of 21 years, which is equal to the average term of the contracts.
	Acquired ROFO Assets — On June 30, 2014, NRG Yield Operating LLC acquired from NRG: (i) El Segundo, a 550 MW fast-start, gas-fired facility located in Los Angeles County, California; (ii) TA High Desert, a 20 MW solar facility located in Los Angeles County, California; and (iii) Kansas South, a 20 MW solar facility located in Kings County, California. The Company paid total cash consideration of $357 million, which represents a base purchase price of $349 million and $8 million of working capital adjustments. In addition, the acquisition included the assumption of $612 million in project-level debt. The assets and liabilities transferred to the Company relate to interests under common control by NRG and accordingly, were recorded at historical cost in accordance with ASC 805-50. The difference between the cash proceeds and historical value of the net assets was recorded as a distribution to NRG and reduced the balance of its noncontrolling interest. Since the transaction constituted a transfer of entities 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. Accordingly, the Company prepared its consolidated financial statements to reflect the transfer as if it had taken place from the beginning of the financial statements period, or from the date the entities were under common control, which was May 13, 2013, for Kansas South, March 28, 2013, for TA High Desert, which represent the dates these entities were acquired by NRG and January 1, 2014, which represents the beginning of the financial statements period.
	The following table presents a historical information summary combining the financial information for the Acquired ROFO Assets transferred in connection with the acquisition:
		Three months ended March 31, 2014
		As Previously Reported			Kansas South				TA High Desert			El Segundo		As Currently Reported
	Operating revenues	$	110		$	1			$	1		$	28	$	140
	Operating income	38			—				—			16		54
	Net income	$	18		$	(1	)		$	(1	)	$	10	$	26
Acquired ROFO Assets [Domain]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table presents a historical information summary combining the financial information for the Acquired ROFO Assets transferred in connection with the acquisition:
		Three months ended March 31, 2014
		As Previously Reported			Kansas South				TA High Desert			El Segundo		As Currently Reported
	Operating revenues	$	110		$	1			$	1		$	28	$	140
	Operating income	38			—				—			16		54
	Net income	$	18		$	(1	)		$	(1	)	$	10	$	26

Property_Plant_and_Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure	The Company’s major classes of property, plant, and equipment were as follows:
		March 31, 2015			December 31, 2014			Depreciable Lives
		(In millions)
	Facilities and equipment	$	4,717		$	4,709		2 - 33 Years
	Land and improvements	87			87
	Construction in progress	17			8
	Total property, plant and equipment	4,821			4,804
	Accumulated depreciation	(391		)	(338		)
	Net property, plant and equipment	$	4,430		$	4,466

Investments_Accounted_for_by_t

Investments Accounted for by the Equity Method and Variable Interest Entities	3 Months Ended
	Mar. 31, 2015
Equity Method Investments and Joint Ventures [Abstract]
Investments Accounted for by the Equity Method and Variable Interest Entities	GenConn Energy LLC — The Company has a 49.95% interest in GCE Holding LLC, the owner of GenConn, which owns and operates two 190 MW peaking generation facilities in Connecticut at the Devon and Middletown sites. Each of these facilities was constructed pursuant to a 30-year cost of service type contract with the Connecticut Light & Power Company. GenConn is considered a VIE under ASC 810, however the Company is not the primary beneficiary, and accounts for its investment under the equity method.
	The project was funded through equity contributions from the owners and non-recourse, project-level debt. As of March 31, 2015, the Company's investment in GenConn was $112 million and its maximum exposure to loss is limited to its equity investment. On September 17, 2013, GenConn refinanced its existing project financing facility. The refinanced facility is comprised of a $237 million note with an interest rate of 4.73% and a maturity date of July 2041 and a 5-year, $35 million working capital facility that matures in 2018 which can be used to issue letters of credit at an interest rate of 1.875% per annum. As of March 31, 2015, $224 million was outstanding under the note and nothing was drawn on the working capital facility. The refinancing is secured by all of the GenConn assets.
	The following table presents summarized financial information for GCE Holding LLC:
		Three months ended March 31,
		2015		2014
	Income Statement Data:	(In millions)
	Operating revenues	$	22	$	26
	Operating income	9		10
	Net income	$	6	$	7
		March 31, 2015		December 31, 2014
	Balance Sheet Data:	(In millions)
	Current assets	$	30	$	33
	Non-current assets	429		438
	Current liabilities	16		20
	Non-current liabilities	$	219	$	223
	NRG RPV Holdco 1 LLC — On April 9, 2015, NRG Yield RPV Holding LLC, a subsidiary of the Company, and NRG Residential Solar Solutions LLC, a subsidiary of NRG, entered into a partnership that will invest in and hold operating portfolios of residential solar assets developed by NRG Home Solar, a subsidiary of NRG, including: (i) an existing, unlevered portfolio of over 2,200 leases across nine states representing approximately 17 MW with a weighted average remaining lease term of approximately 17 years; (ii) an in-development, tax equity financed portfolio of between 6,000 to 7,000 leases across at least ten states representing approximately 48 MW with a lease term of 20 years; and (iii) an in-development tax equity financed portfolio of 5,500 to 6,500 leases representing approximately 42 MW with a lease term of 20 years. Through the partnership, the Company will invest equity in NRG RPV Holdco and receive an allocation of 95% of the partnership's taxable income and cash distributions over the contracted life of the investments. NRG will retain a 5% residual economic interest in the portfolio and will act as managing member of the partnership. The Company has committed to invest up to an additional $150 million of cash contributions with respect to the tax equity financed portfolios into the partnership over time and expects to realize an average unlevered CAFD yield of approximately 7.5% over the contracted life of these investments. Once the Company reaches its expected return on its investment, which is expected to be achieved consistent with the expiry of the remaining lease term, allocations of taxable income and cash distributions thereafter will be 95% to NRG and 5% to the Company.
	The Company invested $26 million in NRG RPV Holdco in April 2015 related to the existing, unlevered portfolio of leases. The Company also invested $7 million of the $150 million investment in the tax equity financed portfolios. Its maximum exposure will be limited to its equity investment. NRG RPV Holdco is considered a VIE under ASC 810, however the Company is not the primary beneficiary, and will account for its investment under the equity method.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	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 March 31, 2015
		Fair Value (a)
	(In millions)	Level 2
	Derivative assets:
	Commodity contracts	$	8
	Interest rate contracts	—
	Total assets	8
	Derivative liabilities:
	Commodity contracts	3
	Interest rate contracts	142
	Total liabilities	$	145
	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of March 31, 2015.
		As of December 31, 2014
		Fair Value (a)
	(In millions)	Level 2
	Derivative assets:
	Commodity contracts	$	—
	Interest rate contracts	2
	Total assets	2
	Derivative liabilities:
	Commodity contracts	3
	Interest rate contracts	114
	Total liabilities	$	117
	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of December 31, 2014.
Fair Value of Financial Instruments	For cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accounts payable — affiliate, accrued expenses and other liabilities, the carrying amount approximates fair value because of the short-term maturity of those instruments and are classified as Level 1 within the fair value hierarchy.
	The estimated carrying amounts and fair values of the Company’s recorded financial instruments not carried at fair market value are as follows:
		As of March 31, 2015				As of December 31, 2014
		Carrying Amount		Fair Value		Carrying Amount		Fair Value
	(In millions)
	Assets:
	Notes receivable, including current portion	$	22	$	22	$	21	$	21
	Liabilities:
	Long-term debt, including current portion	$	4,937	$	5,037	$	4,787	$	4,873
	The fair value of notes receivable and long-term debt are based on expected future cash flows discounted at market interest rates, or current interest rates for similar instruments and are classified as Level 3 within the fair value hierarchy.
	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.
	Recurring Fair Value Measurements
	The Company records its derivative assets and liabilities at fair market 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 March 31, 2015
		Fair Value (a)
	(In millions)	Level 2
	Derivative assets:
	Commodity contracts	$	8
	Interest rate contracts	—
	Total assets	8
	Derivative liabilities:
	Commodity contracts	3
	Interest rate contracts	142
	Total liabilities	$	145
	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of March 31, 2015.
		As of December 31, 2014
		Fair Value (a)
	(In millions)	Level 2
	Derivative assets:
	Commodity contracts	$	—
	Interest rate contracts	2
	Total assets	2
	Derivative liabilities:
	Commodity contracts	3
	Interest rate contracts	114
	Total liabilities	$	117
	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of December 31, 2014.
	Derivative Fair Value Measurements
	A majority of 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 remainder of the assets and liabilities represent contracts for which external sources or observable market quotes are not available. These contracts are valued using various valuation techniques including but not limited to internal models that apply fundamental analysis of the market and corroboration with similar markets. As of March 31, 2015, there were no contracts valued with prices provided by models and other valuation techniques.
	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 calculated based on credit default swaps. To the extent that the net exposure is an asset, the Company uses the counterparty’s default swap rate. If the exposure is a liability, the Company uses its default swap rate. 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 March 31, 2015, the credit reserve resulted in a $3 million increase in fair value which is composed of a $2 million gain in OCI and a $1 million gain 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 as disclosed in Note 2, Summary of Significant Accounting Policies, to the Company's audited consolidated financial statements included in the Company's 2014 Form 10-K, the following item 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) a 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 March 31, 2015, credit risk exposure to these counterparties attributable to the Company's ownership interests was approximately $2.3 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, as further described in Note 11, Segment Reporting to the Company's audited consolidated financial statements included in the Company's 2014 Form 10-K. However, such regulated utility counterparties can be impacted by changes in government regulations, which the Company is unable to predict.

Accounting_for_Derivative_Inst

Accounting for Derivative Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2015
Accounting for Derivative Instruments and Hedging Activities Disclosure [Abstract]
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 Company's audited consolidated financial statements included in the Company's 2014 Form 10-K.
	Energy-Related Commodities
	As of March 31, 2015, the Company had forward contracts with an NRG subsidiary hedging the sale of power from Alta X and Alta XI extending through the end of 2015 and forward contracts for the purchase of fuel commodities relating to the forecasted usage of the Company’s district energy centers extending through 2017.  Total unrealized revenue recorded in connection with the power sale hedging transaction with the NRG subsidiary was $7 million and is recorded in derivative assets and liabilities as of March 31, 2015. At March 31, 2015, these contracts were not designated as cash flow or fair value hedges.
	Interest Rate Swaps
	As of March 31, 2015, the Company had interest rate derivative instruments on non-recourse debt extending through 2031, most of which are designated as cash flow hedges.
	Volumetric Underlying Derivative Transactions
	The following table summarizes the net notional volume buy/(sell) of the Company's open derivative transactions broken out by commodity as of March 31, 2015, and December 31, 2014.
				Total Volume
				March 31, 2015				December 31, 2014
	Commodity	Units		(In millions)
	Power	MWh		(1		)		—
	Natural Gas	MMBtu		3				2
	Interest	Dollars		$	2,779			$	2,817
	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
		March 31, 2015				December 31, 2014				March 31, 2015			December 31, 2014
		(In millions)
	Derivatives Designated as Cash Flow Hedges:
	Interest rate contracts current	$	—			$	—			$	39		$	40
	Interest rate contracts long-term	—				2				66			49
	Total Derivatives Designated as Cash Flow Hedges	—				2				105			89
	Derivatives Not Designated as Cash Flow Hedges:
	Interest rate contracts current	—				—				6			5
	Interest rate contracts long-term	—				—				31			20
	Commodity contracts current	8				—				3			3
	Total Derivatives Not Designated as Cash Flow Hedges	8				—				40			28
	Total Derivatives	$	8			$	2			$	145		$	117
	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 March 31, 2015, there was no outstanding collateral paid or received. The following table summarizes the offsetting of derivatives by counterparty master agreement level:
		Gross Amounts Not Offset in the Statement of Financial Position
	As of March 31, 2015	Gross Amounts of Recognized Assets/Liabilities				Derivative Instruments				Net Amount
	Commodity contracts:	(In millions)
	Derivative assets	$	8			$	(1	)		$	7
	Derivative liabilities	(3		)		1				(2		)
	Total commodity contracts	5				—				5
	Interest rate contracts:
	Derivative assets	—				—				—
	Derivative liabilities	(142		)		—				(142		)
	Total interest rate contracts	(142		)		—				(142		)
	Total derivative instruments	$	(137	)		$	—			$	(137	)
		Gross Amounts Not Offset in the Statement of Financial Position
	As of December 31, 2014	Gross Amounts of Recognized Assets/Liabilities				Derivative Instruments				Net Amount
	Commodity contracts:	(In millions)
	Derivative assets	$	—			$	—			$	—
	Derivative liabilities	(3		)		—				(3		)
	Total commodity contracts	(3		)		—				(3		)
	Interest rate contracts:
	Derivative assets	2				(2		)		—
	Derivative liabilities	(114		)		2				(112		)
	Total interest rate contracts	(112		)		—				(112		)
	Total derivative instruments	$	(115	)		$	—			$	(115	)
	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 March 31,
		2015				2014
		(In millions)
	Accumulated OCL beginning balance	$	(52	)		$	—
	Reclassified from accumulated OCL to income due to realization of previously deferred amounts	2				3
	Mark-to-market of cash flow hedge accounting contracts	(19		)		(15		)
	Accumulated OCL ending balance, net of income tax benefit of $14 and $1, respectively	$	(69	)		$	(12	)
	Accumulated OCL attributable to NRG	(46		)		(7		)
	Accumulated OCL attributable to NRG Yield, Inc.	$	(23	)		$	(5	)
	Losses expected to be realized from OCL during the next 12 months, net of income tax benefit of $3	$	(13	)
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 three months ended March 31, 2015, and 2014.
Impact of Derivative Instruments on the Statements of Operations
The Company has interest rate derivative instruments that are not designated as cash flow hedges as well as ineffectiveness on cash flow hedge derivatives. The effect of interest rate hedges is recorded to interest expense. For the three months ended March 31, 2015, and 2014, the impact to the consolidated statements of operations was a loss of $12 million and $3 million, respectively.
A portion of the Company’s derivative commodity contracts relate 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 statement of operations for these contracts. Commodity contracts also hedge the forecasted sale of power for Alta X and Alta XI until the start of the PPA’s on January 1, 2016. The effect of these commodity hedges is recorded to operating revenues. For the three months ended March 31, 2015, and 2014, the impact to the consolidated statements of operations was a gain of $7 million and $0 million, respectively.
See Note 6, Fair Value of Financial Instruments, for discussion regarding concentration of credit risk.

Longterm_Debt

Long-term Debt	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Long-term Debt	Note 8 — Long-term Debt
	This footnote should be read in conjunction with the complete description under Note 9, Long-term Debt, to the Company's 2014 Form 10-K. Long-term debt consisted of the following:
		March 31, 2015		December 31, 2014		Interest rate % (a)
		(In millions, except rates)
	Convertible Notes, due 2019 (b)	$	327	$	326	3.5
	Senior Notes, due 2024	500		500		5.375
	NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility, due 2019	195		—		L+2.25
	Project-level debt:
	Alta Wind I, lease financing arrangement, due 2034	261		261		7.015
	Alta Wind II, lease financing arrangement, due 2034	205		205		5.696
	Alta Wind III, lease financing arrangement, due 2034	212		212		6.067
	Alta Wind IV, lease financing arrangement, due 2034	138		138		5.938
	Alta Wind V, lease financing arrangement, due 2035	220		220		6.071
	Alta Wind X, due 2021	300		300		L+2.00
	Alta Wind XI, due 2021	191		191		L+2.00
	Alta Realty Investments, due 2031	33		34		7
	Alta Wind Asset Management, due 2031	19		20		L+2.375
	NRG West Holdings LLC, due 2023 (El Segundo Energy Center)	484		506		L+2.25 - L+2.875
	NRG Marsh Landing LLC, due 2017 and 2023	457		464		L+1.75 - L+1.875
	Walnut Creek Energy, due 2023	384		391		L+1.625
	Tapestry Wind LLC, due 2021	188		192		L+1.625
	NRG Solar Alpine LLC, due 2014 and 2022	162		163		L+1.75
	NRG Energy Center Minneapolis LLC, due 2017 and 2025	119		121		5.95 -7.25
	Laredo Ridge LLC, due 2026	107		108		L+1.875
	NRG Solar Borrego LLC, due 2025 and 2038	75		75		L+ 2.50/5.65
	South Trent Wind LLC, due 2020	65		65		L+2.75
	NRG Solar Avra Valley LLC, due 2031	63		63		L+1.75
	TA High Desert LLC, due 2020 and 2032	55		55		L+2.50/5.15
	WCEP Holdings LLC, due 2023	46		46		L+3.00
	NRG Roadrunner LLC, due 2031	42		42		L+2.01
	NRG Solar Kansas South LLC, due 2031	35		35		L+2.00
	NRG Solar Blythe LLC, due 2028	22		22		L+2.75
	PFMG and related subsidiaries financing agreement, due 2030	31		31		6
	NRG Energy Center Princeton LLC, due 2017	1		1		5.95
	Subtotal project-level debt:	3,915		3,961
	Total debt	4,937		4,787
	Less current maturities	218		214
	Total long-term debt	$	4,719	$	4,573
	(a) As of March 31, 2015, L+ equals 3 month LIBOR plus x%, except for the NRG West Holdings LLC term loan, NRG Marsh Landing term loan, Walnut Creek term loan, and the Revolving Credit Facility where L+ equals 1 month LIBOR plus x% and Kansas South where L+ equals 6 month LIBOR plus x%.
	(b) Net of discount of $18 million and $19 million as of March 31, 2015 and December 31, 2014, respectively.
	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 March 31, 2015, the Company was in compliance with all of the required covenants.
	The discussion below lists changes to or additions of long term debt for the three months ended March 31, 2015.
	NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility
	On January 2, 2015, the Company borrowed $210 million under its revolving credit facility to fund the acquisition of Walnut Creek, Laredo Ridge and the Tapestry projects. On February 2, 2015, the Company made an optional repayment of $15 million.
	Laredo Ridge
	On July 27, 2010, Laredo Ridge entered into a credit agreement with a group of lenders for a $75 million construction loan that was convertible to a term loan upon completion of the project, a $53 million cash grant loan and a $3 million working capital loan facility. The project met the conditions to convert to a term loan on March 18, 2011. The cash grant loan was repaid in July 2011 with proceeds of the cash grant. The credit agreement also included a letter of credit facility on behalf of Laredo Ridge of up to $9 million. Laredo Ridge paid a fee equal to the applicable margin on issued letters of credit.
	On December 17, 2014, Laredo Ridge amended the credit agreement to increase its term loan borrowings by an additional $41 million to reduce the working capital facility by $1 million, to increase the letter of credit facility by $1 million and to reduce the related interest rate to LIBOR plus 1.875% through December 31, 2018, LIBOR plus 2.125% from January 1, 2019 through December 31, 2023 and LIBOR plus 2.375% from January 1, 2024 through the maturity date. The fee on the working capital facility was reduced to 0.5%. In addition, the maturity date was extended to March 31, 2028. The proceeds were utilized to make a distribution of $33 million to NRG Wind LLC, an NRG subsidiary, with the remaining $8 million utilized to fund the costs of the amendment. As of March 31, 2015, $107 million was outstanding under the term loan, nothing was outstanding under the working capital facility, and $10 million of letters of credit in support of the project were issued.
	In connection with the amendment to the credit agreement, Laredo Ridge entered into a series of fixed for floating interest rate swaps that would fix the interest rate for a minimum of 75% of the outstanding notional amount. Laredo Ridge pays its counterparty the equivalent of a 2.31% fixed interest payment on a predetermined notional value, and quarterly, Laredo Ridge will receive the equivalent of a floating interest payment based on the three-month LIBOR calculated on the same notional value through December 31, 2028. All interest rate swap payments by Laredo Ridge and its counterparties are made quarterly and LIBOR is determined in advance of each interest period.
	Tapestry Wind LLC
	On December 21, 2011, Tapestry Wind LLC entered into a credit agreement with a group of lenders for a $214 million term loan and an $8 million working capital loan facility. The term loan matures in December 2021. It is secured by Tapestry Wind LLC's interest in the Buffalo Bear, Taloga, and Pinnacle projects. The term loan amortizes based upon a predetermined schedule. The working capital facility is available to fund the operating needs of Tapestry Wind LLC. The commitment fee on this facility is 0.75%. The credit agreement also includes a letter of credit facility on behalf of Tapestry Wind LLC of up to $20 million. Tapestry Wind LLC pays a fee equal to the applicable margin on issued letters of credit.
	Under the terms of the agreement, Tapestry Wind LLC entered into a series of fixed for floating interest rate swaps that would fix the interest rate for a minimum of 90% of the outstanding notional amount. Tapestry Wind LLC will pay its counterparty the equivalent of a 2.21% fixed interest payment on a predetermined notional value, and quarterly, Tapestry will receive the equivalent of a floating interest payment based on a three-month LIBOR calculated on the same notional value through December 21, 2021. All interest rate swap payments by Tapestry Wind LLC and its counterparties are made quarterly and the LIBOR is determined in advance of each interest period. Swaps became effective December 30, 2011, and amortize in proportion to the term loan. At the same time Tapestry Wind LLC entered into a series of forward starting swaps to hedge the refinancing risk. The swaps are effective December 21, 2021. Tapestry Wind LLC will pay its counterparty the equivalent of a 3.57% fixed interest payment on a predetermined notional value, and quarterly, Tapestry Wind LLC will receive the equivalent of a floating interest payment based on a three-month LIBOR calculated on the same notional value through December 21, 2029.
	On November 12, 2014, Tapestry Wind LLC amended the credit agreement to reduce the related interest rate to LIBOR plus 1.625% through December 20, 2018 and LIBOR plus 1.750% from December 21, 2018 through the maturity date. As of March 31, 2015, $188 million was outstanding under the term loan, nothing was outstanding under the working capital facility and $20 million of letters of credit in support of the project were issued.
	Walnut Creek
	On July 27, 2011, Walnut Creek entered into a credit agreement with a group of lenders for a $442 million construction loan that was convertible to a term loan upon completion of the project, and a $5 million working capital loan facility. The project met the conditions to convert to a term loan on June 21, 2013 and matures in May 2023. The term loan amortizes based upon a predetermined schedule. The working capital facility is available to fund the operating needs of Walnut Creek. The commitment fee on this facility is 0.625%. The Walnut Creek agreement also includes a letter of credit facility on behalf of Walnut Creek of up to $117 million. Walnut Creek pays a fee equal to the applicable margin on issued letters of credit.
	Under the terms of the agreement, Walnut Creek entered into a series of fixed for floating interest rate swaps that would fix the interest rate for a minimum of 90% of the outstanding notional amount. Walnut Creek will pay its counterparty the equivalent of a 3.54% fixed interest payment on a predetermined notional value, and quarterly, Walnut Creek will receive the equivalent of a floating interest payment based on a three-month LIBOR calculated on the same notional value through May 31, 2023. All interest rate swap payments by Walnut Creek and its counterparties are made quarterly and the LIBOR is determined in advance of each interest period. Swaps became effective June 28, 2013, and amortize in proportion to the term loan.
	On October 21, 2014, Walnut Creek amended the credit agreement to increase its term loan borrowings by an additional $10 million, and to reduce the related interest rate to LIBOR plus 1.625% through September 30, 2018, LIBOR plus 1.750% from October 1, 2018 through September 30, 2022, and LIBOR plus 1.875% from October 1, 2022, through the maturity date. The fee on the working capital facility was reduced to 0.5%. The proceeds were utilized to make a distribution of $6 million to WCEP Holdings LLC with the remaining $4 million utilized to fund the costs of the amendment. In addition Walnut Creek entered into an additional interest rate swap to maintain the minimum of 90% of the outstanding notional amount being swapped to a fixed interest rate. Walnut Creek pays its counterparty the equivalent of a 4.0025% fixed interest payment on a predetermined notional value, and quarterly, Walnut Creek receives the equivalent of a floating interest payment based on a three-month LIBOR calculated on the same notional value through July 31, 2020. All interest rate swap payments by Walnut Creek and its counterparties are made quarterly and the LIBOR is determined in advance of each interest period. Swaps became effective June 28, 2013 and amortize in proportion to the term loan. As of March 31, 2015, $384 million was outstanding under the term loan, nothing was outstanding under the working capital facility, and $54 million of letters of credit were issued.
	WCEP Holdings LLC
	On July 27, 2011, WCEP Holdings LLC entered into a credit agreement with a group of lenders for a $53 million construction loan that was convertible to a term loan upon completion of the Walnut Creek project. The Walnut Creek project met the conditions for the WCEP Holdings LLC loan to convert to a term loan on June 21, 2013. The term loan has an interest rate of LIBOR plus an applicable margin of 4.00%. The term loan matures in May 2023. The term loan amortizes based upon a predetermined schedule.
	Under the terms of the credit agreement, WCEP Holdings LLC entered into two fixed for floating interest rate swaps that would fix the interest rate for a minimum of 90% of the outstanding notional amount. WCEP Holdings LLC will pay its counterparty the equivalent of a 4.00% fixed interest payment on a predetermined notional value, and quarterly, WCEP Holdings LLC will receive the equivalent of a floating interest payment based on a three-month LIBOR calculated on the same notional value through May 31, 2023. All interest rate swap payments by WCEP Holdings LLC and its counterparties are made quarterly and the LIBOR is determined in advance of each interest period. Swaps became effective June 28, 2013, and amortize in proportion to the term loan.
	On October 21, 2014, WCEP Holdings LLC amended the credit agreement to reduce the related interest rate to LIBOR plus 3.00%. The proceeds of the distribution from Walnut Creek were utilized to make an optional repayment of $6 million on the term loan. In addition WCEP Holdings LLC partially terminated the interest rate agreements so that at least 90% and no more than 100% of the aggregate principal amount of the loans then outstanding shall be subject to interest rate agreements. As of March 31, 2015, $46 million was outstanding under the term loan.
	Avenal Solar Holdings LLC
	On March 18, 2015, Avenal Solar Holdings LLC, one of the Company's equity method investments, amended its credit agreement to increase its borrowings by $43 million and to reduce the related interest rate from 6 month LIBOR plus an applicable margin of 2.25% to 6 month LIBOR plus 1.75% from March 18, 2015 through March 17, 2022 and 6 month LIBOR plus 2.00% from March 18, 2022 through March 17, 2027 and 6 month LIBOR plus 2.25% from March 18, 2027 through the maturity date.  As a result of the credit agreement amendment, the Company received net proceeds of $20 million after fees from its 49.95% ownership in Avenal.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2015
Earnings (Loss) Per Share Disclosure [Abstract]
Earnings Per Share	Basic and diluted (losses) earnings per common share are computed by dividing net (loss) 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.
	The reconciliation of the Company's basic and diluted (losses) earnings per share is shown in the following table:
		Three months ended March 31,
	(In millions, except per share data)	2015			2014
	Basic and diluted (losses) earnings per share attributable to NRG Yield, Inc. Class A common stockholders
	Net (loss) income attributable to NRG Yield, Inc.	$	(5	)	$	4
	Weighted average number of Class A common shares outstanding	35			23
	(Losses) Earnings per weighted average Class A common share — basic and diluted	$	(0.15	)	$	0.18
	There were a total of seven million and four million of anti-dilutive outstanding equity instruments related to the Convertible Notes for the three months ended March 31, 2015, and March 31, 2014, respectively.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity	Recapitalization
	On February 24, 2015, the Company's board of directors approved amendments to the Company's certificate of incorporation that would adjust the Company’s capital structure by creating two new classes of capital stock, Class C common stock and Class D common stock and distribute shares of the proposed Class C and Class D common stock to holders of the Company's outstanding Class A and Class B common stock, respectively, through a stock split. The amendments were approved by the Company's stockholders at the Annual Meeting of Stockholders held on May 5, 2015, and the recapitalization is expected to become effective on or around May 14, 2015.
	The Class C common stock and Class D common stock will have the same rights and privileges and rank equally, share ratably and be identical in all respects to the shares of Class A common stock and Class B common stock, respectively, as to all matters, except that each share of Class C common stock and Class D common stock will be entitled to 1/100th of a vote on all stockholder matters. The par value per share of the Company’s Class A common stock and Class B common stock will remain unchanged at $0.01 per share after the effect of the stock split described above. Accordingly, the stock split will be accounted for as a stock dividend. Once the stock dividend is authorized, on the effective date, the Company will record a transfer between retained earnings and common stock equal to the par value of each share of Class C common stock and Class D common stock that is issued. The Company will also give retroactive effect to prior period share and per share amounts in the consolidated financial statements for the effect of the stock dividend, such that all periods are comparable.
	Dividends to Class A common stockholders
	The following table lists the dividends paid on the Company's Class A common stock during the three months ended March 31, 2015:
		First Quarter 2015
	Dividends per share	$	0.39
	Dividends on the Class A common stock and, once outstanding, the Class C common stock, are subject to available capital, market conditions, and compliance with associated laws, regulations and other contractual obligations.
	The Company also 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	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segment Reporting	Note 11 — 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.
		Three months ended March 31, 2015
	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total
	Operating revenues	$	76		$	57		$	47		$	—		$	180
	Cost of operations	21			20			34			—			75
	Depreciation and amortization	21			28			5			—			54
	General and administrative — affiliate	—			—			—			3			3
	Operating income (loss)	34			9			8			(3		)	48
	Equity in earnings of unconsolidated affiliates	3			(2		)	—			—			1
	Other income, net	1			—			—			—			1
	Interest expense	(12		)	(43		)	(2		)	(13		)	(70		)
	Income (loss) before income taxes	26			(36		)	6			(16		)	(20		)
	Income tax benefit	—			—			—			(4		)	(4		)
	Net Income (Loss)	$	26		$	(36	)	$	6		$	(12	)	$	(16	)
	Total Assets	$	2,136		$	3,781		$	451		$	227		$	6,595
		Three months ended March 31, 2014
	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total
	Operating revenues	$	56		$	19		$	65		$	—		$	140
	Cost of operations	10			4			46			—			60
	Depreciation and amortization	13			7			4			—			24
	General and administrative — affiliate	—			—			—			2			2
	Operating income (loss)	33			8			15			(2		)	54
	Equity in earnings of unconsolidated affiliates	3			(2		)	—			—			1
	Other income, net	—			1			—			—			1
	Interest expense	(11		)	(12		)	(2		)	(2		)	(27		)
	Income (loss) before income taxes	25			(5		)	13			(4		)	29
	Income tax expense	—			—			—			3			3
	Net Income (Loss)	$	25		$	(5	)	$	13		$	(7	)	$	26

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Effective Tax Rate
	The income tax provision consisted of the following:
		Three months ended March 31,
		2015			2014
		(In millions, except percentages)
	(Loss) Income before income taxes	$	(20	)	$	29
	Income tax (benefit) expense	(4		)	3
	Effective income tax rate	20		%	10.3		%
	For the three months ended March 31, 2015, the overall effective tax rate was different than the statutory rate of 35% primarily due to taxable earnings allocated to NRG resulting from its 55.3% interest in NRG Yield LLC and production tax credits generated from certain wind facilities.
	For the three months ended March 31, 2014, the overall effective tax rate was different than the statutory rate of 35% primarily due to taxable earnings allocated to NRG resulting from its 65.5% interest in NRG Yield LLC.
	The Company records NRG's 55.3% ownership as noncontrolling interest in the financial statements. 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.
	The Company's deferred tax balances reflect the difference in book and tax basis of the Company's assets primarily due to an increase in the tax basis of property, plant and equipment. The change in tax basis resulted in a non-cash addition of $27 million during the three months ended March 31, 2015, and $65 million during the year ended December 31, 2014, to the Company's additional paid-in capital.

Related_Party_Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions Disclosure	Management Services Agreement by and between NRG and the Company
	Since the Company has no employees, 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 March 31, 2015, the base management fee was approximately $7 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 future acquisitions and as a result of a change in the scope of services provided under the Management Services Agreement. During the three months ended March 31, 2015, the fee was increased by approximately $1 million per year in connection with the acquisition of the EME-NYLD-Eligible Assets. Costs incurred under this agreement were approximately $3 million and $2 million for the three months ended March 31, 2015 and 2014, respectively, which included certain direct expenses incurred by NRG on behalf of the Company in addition to the base management fee.
	Operation and Maintenance Services (O&M) Agreements by and between NRG and Thermal Entities
	On October 1, 2014, NRG entered into Plant O&M Services Agreements with certain wholly-owned subsidiaries of the Company. NRG provides necessary and appropriate services to operate and maintain the subsidiaries' plant operations, businesses and thermal facilities. NRG is to be 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. Prior to October 1, 2014, NRG provided the same services to the Thermal Business on an informal basis. Total fees incurred under the agreements were $7 million for the three months ended March 31, 2015 and 2014. There was a balance of $30 million and $22 million due to NRG in accounts payable — affiliate as of March 31, 2015 and December 31, 2014, respectively.
	Administrative Services Agreement by and between Marsh Landing and GenOn Energy Services, LLC
	Marsh Landing is a party to an administrative services agreement with GenOn Energy Services, LLC, a wholly owned subsidiary of NRG, which provides invoice processing and payment on behalf of Marsh Landing. Marsh Landing reimburses GenOn Energy Services, LLC for the amounts paid by it. The Company reimbursed costs under this agreement of approximately $2 million for the periods ended March 31, 2015 and 2014. There was a balance of $0 million and $4 million due to GenOn Energy Services, LLC in accounts payable — affiliate as of March 31, 2015 and December 31, 2014, respectively.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Noncontrolling Interest Disclosure [Text Block]	Noncontrolling Interest
	The following table reflects the changes in the Company's noncontrolling interest balance:
		(In millions)
	Balance as of December 31, 2014 (as previously reported)	$	246
	Net Assets of acquired EME-NYLD-Eligible Assets as of December 31, 2014	405
	Balance as of December 31, 2014 (as currently reported)	651
	Payment to NRG for acquired EME-NYLD-Eligible Assets	(489		)
	Comprehensive loss	(15		)
	Non-cash contributions	1
	Cash distributions to NRG	(17		)
	Balance as of March 31, 2015	$	131
Distributions [Policy Text Block]	Distributions
	On February 17, 2015, NRG Yield LLC declared a distribution on its Class A and Class B units of $0.39 per unit, which was paid on March 16, 2015. The portion of the distributions paid by NRG Yield LLC to NRG was recorded as a reduction to the Company's noncontrolling interest balance.
Use of Estimates	Use of Estimates
	The preparation of consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions. These estimates and assumptions impact the reported amount of assets and liabilities and disclosures of contingent assets and liabilities as of the date of the consolidated financial statements. They also impact the reported amount of net earnings during the reporting period. Actual results could be different from these estimates.
Recent Accounting Developments	Recent Accounting Developments
	ASU 2015-03 — In April 2015, the FASB issued ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, or ASU No. 2015-03.  The amendments of ASU No. 2015-03 were issued to reduce complexity in the balance sheet presentation of debt issuance costs.  ASU No. 2015-03 requires that debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of debt liability, consistent with debt discounts or premiums.  The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this standard.  The guidance in ASU No. 2015-03 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years.  Early adoption is permitted for financial statements that have not been previously issued.  The adoption of this standard is not expected to have a material impact on the Company's balance sheets on a gross basis and will have no impact on net assets.
	ASU 2015-02 — In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis, or ASU No. 2015-02. The amendments of ASU No. 2015-02 were issued in an effort to minimize situations under previously existing guidance in which a reporting entity was required to consolidate another legal entity in which that reporting entity did not have: (1) the ability through contractual rights to act primarily on its own behalf; (2) ownership of the majority of the legal entity's voting rights; or (3) the exposure to a majority of the legal entity's economic benefits. ASU No. 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. All legal entities are subject to reevaluation under the revised consolidation model. The guidance in ASU No. 2015-02 is effective for periods beginning after December 15, 2015. Early adoption is permitted. The Company adopted the standard effective January 1, 2015 and the adoption of this standard did not impact the Company's results of operations, cash flows or financial position.
	ASU 2014-16 — In November 2014, the FASB issued ASU No. 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity, or ASU No. 2014-16. The amendments of ASU No. 2014-16 clarify how U.S. GAAP should be applied in determining whether the nature of a host contract is more akin to debt or equity and in evaluating whether the economic characteristics and risks of an embedded feature are "clearly and closely related" to its host contract. The guidance in ASU No. 2014-16 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. The Company adopted the standard effective January 1, 2015 and the adoption of this standard did not impact the Company's results of operations, cash flows or financial position.
	ASU 2014-09 — In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU No. 2014-09.  The amendments of ASU No. 2014-09 complete the joint effort between the FASB and the International Accounting Standards Board, or IASB, to develop a common revenue standard for U.S. GAAP and International Financial Reporting Standards, or IFRS, and to improve financial reporting.  The guidance in ASU No. 2014-09 provides that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for the goods or services provided and establishes the following steps to be applied by an entity: (1) identify the contract with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies the performance obligation.  The guidance of ASU No. 2014-09 is effective for annual reporting periods beginning after December 15, 2016, including interim periods therein. Early adoption is not permitted.  The Company is currently evaluating the impact of the standard on the Company's results of operations, cash flows and financial position.

Segment_Reporting_Segment_Repo

Segment Reporting Segment Reporting (Policies)	3 Months Ended
	Mar. 31, 2015
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.

Nature_of_Business_Nature_of_B

Nature of Business Nature of Business (Tables)	3 Months Ended
	Mar. 31, 2015
Nature of Business Disclosure [Abstract]
IPO of NRG Yield	The following table represents the structure of the Company as of March 31, 2015:
The Company's operating assets are comprised of the following projects:	As of March 31, 2015, the Company's operating assets are comprised of the following projects:
	Projects	Percentage Ownership		Net Capacity (MW)(a)	Offtake Counterparty	Expiration
	Conventional
	GenConn Middletown	49.95	%	95	Connecticut Light & Power	2041
	GenConn Devon	49.95	%	95	Connecticut Light & Power	2040
	Marsh Landing	100	%	720	Pacific Gas and Electric	2023
	El Segundo	100	%	550	Southern California Edison	2023
	Walnut Creek	100	%	485	Southern California Edison	2023
				1,945
	Utility Scale Solar
	Alpine	100	%	66	Pacific Gas and Electric	2033
	Avenal	49.95	%	23	Pacific Gas and Electric	2031
	Avra Valley	100	%	25	Tucson Electric Power	2032
	Blythe	100	%	21	Southern California Edison	2029
	Borrego	100	%	26	San Diego Gas and Electric	2038
	Roadrunner	100	%	20	El Paso Electric	2031
	CVSR	48.95	%	122	Pacific Gas and Electric	2038
	Kansas South	100	%	20	Pacific Gas and Electric	2033
	TA High Desert	100	%	20	Southern California Edison	2033
				343
	Distributed Solar
	AZ DG Solar Projects	100	%	5	Various	2025 - 2033
	PFMG DG Solar Projects	51	%	5	Various	2032
				10
	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	100	%	137	Southern California Edison	2038(c)
	Alta XI	100	%	90	Southern California Edison	2038(c)
	South Trent	100	%	101	AEP Energy Partners	2029
	Laredo Ridge	100	%	80	Nebraska Public Power District	2031
	Taloga	100	%	130	Oklahoma Gas & Electric	2031
	Pinnacle	100	%	55	Maryland Department of General Services and University System of Maryland	2031
	Buffalo Bear	100	%	19	Western Farmers Electric Co-operative	2033
				1,332
	Thermal
	Thermal equivalent MWt(b)	100	%	1,310	Various	Various
	Thermal generation	100	%	123	Various	Various
	Total net capacity (excluding equivalent MWt)			3,753
	(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 March 31, 2015.
	(b) 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 NRG Yield, Inc.'s thermal facilities and certain of its customers.
	(c) PPA begins on January 1, 2016.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
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, 2014 (as previously reported)	$	246
	Net Assets of acquired EME-NYLD-Eligible Assets as of December 31, 2014	405
	Balance as of December 31, 2014 (as currently reported)	651
	Payment to NRG for acquired EME-NYLD-Eligible Assets	(489		)
	Comprehensive loss	(15		)
	Non-cash contributions	1
	Cash distributions to NRG	(17		)
	Balance as of March 31, 2015	$	131

Business_Acquisitions_Business

Business Acquisitions Business Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2015
Business Acquisition
Business Acquisition, Pro Forma Information [Table Text Block]	The following unaudited supplemental pro forma information represents the results of operations as if the Company had acquired the EME-NYLD-Eligible Assets on January 1, 2014, including the impact of acquisition accounting with respect to NRG's acquisition of the projects. While the financial statements have been retrospectively adjusted, all net income or losses prior to the Company's acquisition of the projects is reflected as attributable to NRG and accordingly, no pro forma impact to earnings per Class A common share was calculated.
			For the three months ended
	(In millions)		March 31, 2014
	Operating revenues		$	166
	Net income		23
Acquired ROFO Assets [Domain]
Business Acquisition
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table presents a historical information summary combining the financial information for the Acquired ROFO Assets transferred in connection with the acquisition:
		Three months ended March 31, 2014
		As Previously Reported			Kansas South			TA High Desert			El Segundo		As Currently Reported
	Operating revenues	$	110		$	1		$	1		$	28	$	140
	Operating income	38			—			—			16		54
	Net income	$	18		$	(1	)	$	(1	)	$	10	$	26
EME-NYLD Assets [Member]
Business Acquisition
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table presents historical information summary combining the financial information for the EME-NYLD-Eligible Assets transferred in connection with the acquisition:
		31-Dec-14
		As Previously Reported			Walnut Creek			Tapestry			Laredo Ridge		As Currently Reported
					(In millions)
	Current assets	$	539		$	46		$	14		$	7	$	606
	Property, plant and equipment	3,487			575			286			118		4,466
	Non-current assets	1,726			57			61			49		1,893
	Total assets	5,752			678			361			174		6,965
	Debt	4,050			437			192			108		4,787
	Other current and non-current liabilities	222			62			5			4		293
	Total liabilities	4,272			499			197			112		5,080
	Net Assets	$	1,480		$	179		$	164		$	62	$	1,885

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	3 Months Ended
	Mar. 31, 2015
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	The Company’s major classes of property, plant, and equipment were as follows:
		March 31, 2015			December 31, 2014			Depreciable Lives
		(In millions)
	Facilities and equipment	$	4,717		$	4,709		2 - 33 Years
	Land and improvements	87			87
	Construction in progress	17			8
	Total property, plant and equipment	4,821			4,804
	Accumulated depreciation	(391		)	(338		)
	Net property, plant and equipment	$	4,430		$	4,466

Investments_Accounted_for_by_t1

Investments Accounted for by the Equity Method and Variable Interest Entities (Tables) (GCE Holdings LLC)	3 Months Ended
	Mar. 31, 2015
GCE Holdings LLC
Schedule of Equity Method Investments
Summarized financial information of equity method investment	The following table presents summarized financial information for GCE Holding LLC:
		Three months ended March 31,
		2015		2014
	Income Statement Data:	(In millions)
	Operating revenues	$	22	$	26
	Operating income	9		10
	Net income	$	6	$	7
		March 31, 2015		December 31, 2014
	Balance Sheet Data:	(In millions)
	Current assets	$	30	$	33
	Non-current assets	429		438
	Current liabilities	16		20
	Non-current liabilities	$	219	$	223

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Estimated carrying values and fair values of the Company's recorded financial instruments	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 March 31, 2015				As of December 31, 2014
		Carrying Amount		Fair Value		Carrying Amount		Fair Value
	(In millions)
	Assets:
	Notes receivable, including current portion	$	22	$	22	$	21	$	21
	Liabilities:
	Long-term debt, including current portion	$	4,937	$	5,037	$	4,787	$	4,873
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	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 March 31, 2015
		Fair Value (a)
	(In millions)	Level 2
	Derivative assets:
	Commodity contracts	$	8
	Interest rate contracts	—
	Total assets	8
	Derivative liabilities:
	Commodity contracts	3
	Interest rate contracts	142
	Total liabilities	$	145
	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of March 31, 2015.
		As of December 31, 2014
		Fair Value (a)
	(In millions)	Level 2
	Derivative assets:
	Commodity contracts	$	—
	Interest rate contracts	2
	Total assets	2
	Derivative liabilities:
	Commodity contracts	3
	Interest rate contracts	114
	Total liabilities	$	117
	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of December 31, 2014.

Accounting_for_Derivative_Inst1

Accounting for Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2015
Accounting for 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/(sell) of the Company's open derivative transactions broken out by commodity as of March 31, 2015, and December 31, 2014.
				Total Volume
				March 31, 2015				December 31, 2014
	Commodity	Units		(In millions)
	Power	MWh		(1		)		—
	Natural Gas	MMBtu		3				2
	Interest	Dollars		$	2,779			$	2,817
Fair value within the derivative instrument valuation on the balance sheets	The following table summarizes the fair value within the derivative instrument valuation on the balance sheet:
		Fair Value
		Derivative Assets								Derivative Liabilities
		March 31, 2015				December 31, 2014				March 31, 2015			December 31, 2014
		(In millions)
	Derivatives Designated as Cash Flow Hedges:
	Interest rate contracts current	$	—			$	—			$	39		$	40
	Interest rate contracts long-term	—				2				66			49
	Total Derivatives Designated as Cash Flow Hedges	—				2				105			89
	Derivatives Not Designated as Cash Flow Hedges:
	Interest rate contracts current	—				—				6			5
	Interest rate contracts long-term	—				—				31			20
	Commodity contracts current	8				—				3			3
	Total Derivatives Not Designated as Cash Flow Hedges	8				—				40			28
	Total Derivatives	$	8			$	2			$	145		$	117
Offsetting of derivatives by counterparty master agreement level and collateral received or paid	The following table summarizes the offsetting of derivatives by counterparty master agreement level:
		Gross Amounts Not Offset in the Statement of Financial Position
	As of March 31, 2015	Gross Amounts of Recognized Assets/Liabilities				Derivative Instruments				Net Amount
	Commodity contracts:	(In millions)
	Derivative assets	$	8			$	(1	)		$	7
	Derivative liabilities	(3		)		1				(2		)
	Total commodity contracts	5				—				5
	Interest rate contracts:
	Derivative assets	—				—				—
	Derivative liabilities	(142		)		—				(142		)
	Total interest rate contracts	(142		)		—				(142		)
	Total derivative instruments	$	(137	)		$	—			$	(137	)
		Gross Amounts Not Offset in the Statement of Financial Position
	As of December 31, 2014	Gross Amounts of Recognized Assets/Liabilities				Derivative Instruments				Net Amount
	Commodity contracts:	(In millions)
	Derivative assets	$	—			$	—			$	—
	Derivative liabilities	(3		)		—				(3		)
	Total commodity contracts	(3		)		—				(3		)
	Interest rate contracts:
	Derivative assets	2				(2		)		—
	Derivative liabilities	(114		)		2				(112		)
	Total interest rate contracts	(112		)		—				(112		)
	Total derivative instruments	$	(115	)		$	—			$	(115	)
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 March 31,
		2015				2014
		(In millions)
	Accumulated OCL beginning balance	$	(52	)		$	—
	Reclassified from accumulated OCL to income due to realization of previously deferred amounts	2				3
	Mark-to-market of cash flow hedge accounting contracts	(19		)		(15		)
	Accumulated OCL ending balance, net of income tax benefit of $14 and $1, respectively	$	(69	)		$	(12	)
	Accumulated OCL attributable to NRG	(46		)		(7		)
	Accumulated OCL attributable to NRG Yield, Inc.	$	(23	)		$	(5	)
	Losses expected to be realized from OCL during the next 12 months, net of income tax benefit of $3	$	(13	)

Longterm_Debt_Tables

Long-term Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Schedule of long-term debt	Long-term debt consisted of the following:
		March 31, 2015		December 31, 2014		Interest rate % (a)
		(In millions, except rates)
	Convertible Notes, due 2019 (b)	$	327	$	326	3.5
	Senior Notes, due 2024	500		500		5.375
	NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility, due 2019	195		—		L+2.25
	Project-level debt:
	Alta Wind I, lease financing arrangement, due 2034	261		261		7.015
	Alta Wind II, lease financing arrangement, due 2034	205		205		5.696
	Alta Wind III, lease financing arrangement, due 2034	212		212		6.067
	Alta Wind IV, lease financing arrangement, due 2034	138		138		5.938
	Alta Wind V, lease financing arrangement, due 2035	220		220		6.071
	Alta Wind X, due 2021	300		300		L+2.00
	Alta Wind XI, due 2021	191		191		L+2.00
	Alta Realty Investments, due 2031	33		34		7
	Alta Wind Asset Management, due 2031	19		20		L+2.375
	NRG West Holdings LLC, due 2023 (El Segundo Energy Center)	484		506		L+2.25 - L+2.875
	NRG Marsh Landing LLC, due 2017 and 2023	457		464		L+1.75 - L+1.875
	Walnut Creek Energy, due 2023	384		391		L+1.625
	Tapestry Wind LLC, due 2021	188		192		L+1.625
	NRG Solar Alpine LLC, due 2014 and 2022	162		163		L+1.75
	NRG Energy Center Minneapolis LLC, due 2017 and 2025	119		121		5.95 -7.25
	Laredo Ridge LLC, due 2026	107		108		L+1.875
	NRG Solar Borrego LLC, due 2025 and 2038	75		75		L+ 2.50/5.65
	South Trent Wind LLC, due 2020	65		65		L+2.75
	NRG Solar Avra Valley LLC, due 2031	63		63		L+1.75
	TA High Desert LLC, due 2020 and 2032	55		55		L+2.50/5.15
	WCEP Holdings LLC, due 2023	46		46		L+3.00
	NRG Roadrunner LLC, due 2031	42		42		L+2.01
	NRG Solar Kansas South LLC, due 2031	35		35		L+2.00
	NRG Solar Blythe LLC, due 2028	22		22		L+2.75
	PFMG and related subsidiaries financing agreement, due 2030	31		31		6
	NRG Energy Center Princeton LLC, due 2017	1		1		5.95
	Subtotal project-level debt:	3,915		3,961
	Total debt	4,937		4,787
	Less current maturities	218		214
	Total long-term debt	$	4,719	$	4,573
	(a) As of March 31, 2015, L+ equals 3 month LIBOR plus x%, except for the NRG West Holdings LLC term loan, NRG Marsh Landing term loan, Walnut Creek term loan, and the Revolving Credit Facility where L+ equals 1 month LIBOR plus x% and Kansas South where L+ equals 6 month LIBOR plus x%.
	(b) Net of discount of $18 million and $19 million as of March 31, 2015 and December 31, 2014, respectively.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings (Loss) Per Share Disclosure [Abstract]
Reconciliation of NRG's basic earnings per share to diluted earnings per share	The reconciliation of the Company's basic and diluted (losses) earnings per share is shown in the following table:
		Three months ended March 31,
	(In millions, except per share data)	2015			2014
	Basic and diluted (losses) earnings per share attributable to NRG Yield, Inc. Class A common stockholders
	Net (loss) income attributable to NRG Yield, Inc.	$	(5	)	$	4
	Weighted average number of Class A common shares outstanding	35			23
	(Losses) Earnings per weighted average Class A common share — basic and diluted	$	(0.15	)	$	0.18

Stockholders_Equity_Stockholde

Stockholders' Equity Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity Attributable to Parent [Abstract]
Schedule of Dividends Paid [Table Text Block]	The following table lists the dividends paid on the Company's Class A common stock during the three months ended March 31, 2015:
		First Quarter 2015
	Dividends per share	$	0.39

Segment_Reporting_Tables

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2015																Mar. 31, 2014
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment
		Three months ended March 31, 2015																Three months ended March 31, 2014
																	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total
	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total			Operating revenues	$	56		$	19		$	65		$	—		$	140
	Operating revenues	$	76		$	57		$	47		$	—		$	180		Cost of operations	10			4			46			—			60
	Cost of operations	21			20			34			—			75			Depreciation and amortization	13			7			4			—			24
	Depreciation and amortization	21			28			5			—			54			General and administrative — affiliate	—			—			—			2			2
	General and administrative — affiliate	—			—			—			3			3			Operating income (loss)	33			8			15			(2		)	54
	Operating income (loss)	34			9			8			(3		)	48			Equity in earnings of unconsolidated affiliates	3			(2		)	—			—			1
	Equity in earnings of unconsolidated affiliates	3			(2		)	—			—			1			Other income, net	—			1			—			—			1
	Other income, net	1			—			—			—			1			Interest expense	(11		)	(12		)	(2		)	(2		)	(27		)
																	Income (loss) before income taxes	25			(5		)	13			(4		)	29
	Interest expense	(12		)	(43		)	(2		)	(13		)	(70		)
																	Income tax expense	—			—			—			3			3
	Income (loss) before income taxes	26			(36		)	6			(16		)	(20		)
																	Net Income (Loss)	$	25		$	(5	)	$	13		$	(7	)	$	26
	Income tax benefit	—			—			—			(4		)	(4		)
	Net Income (Loss)	$	26		$	(36	)	$	6		$	(12	)	$	(16	)
	Total Assets	$	2,136		$	3,781		$	451		$	227		$	6,595

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2015
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 March 31,
		2015			2014
		(In millions, except percentages)
	(Loss) Income before income taxes	$	(20	)	$	29
	Income tax (benefit) expense	(4		)	3
	Effective income tax rate	20		%	10.3		%

Nature_of_Business_Details

Nature of Business (Details) (USD $)	3 Months Ended				0 Months Ended	6 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Jul. 29, 2014	Dec. 31, 2013	Jun. 30, 2014	Jan. 02, 2015
	MW
Nature of Business
Megawatts Thermal Equivalent, Available Under right-to-use Provisions	134
Power Generation Capacity (in MWs)	3,753
Business Acquisitions, Consideration Transferred, Purchase Price	$490		$0	[1]
Conventional
Nature of Business
Power Generation Capacity (in MWs)	1,945	[2]
Utility-Scale Solar
Nature of Business
Power Generation Capacity (in MWs)	343	[2]
Distributed Solar
Nature of Business
Power Generation Capacity (in MWs)	10	[2]
Wind Farms [Member]
Nature of Business
Power Generation Capacity (in MWs)	1,332
Thermal [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	123	[2]
Steam and Chilled Water Capacity, Megawatts Thermal Equivalent	1,310	[2],[3]
NRG Yield LLC | NRG Yield, Inc.
Nature of Business
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	44.70%				44.70%
NRG Yield LLC | NRG
Nature of Business
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	55.30%				55.30%	65.50%
GenConn Middletown | Conventional
Nature of Business
Equity Method Investment, Ownership Percentage	49.95%
Power Generation Capacity (in MWs)	95	[2]
GenConn Devon [Member] | Conventional
Nature of Business
Equity Method Investment, Ownership Percentage	49.95%
Power Generation Capacity (in MWs)	95	[2]
Marsh Landing | Conventional
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	720	[2]
El Segundo [Member] | Conventional
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	550	[2]
Walnut Creek [Member] | Conventional
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	485	[2]
Alpine | Utility-Scale Solar
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	66	[2]
Avenal | Utility-Scale Solar
Nature of Business
Equity Method Investment, Ownership Percentage	49.95%
Power Generation Capacity (in MWs)	23	[2]
Avra Valley | Utility-Scale Solar
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	25	[2]
NRG Solar Blythe LLC [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	21	[2]
Borrego | Utility-Scale Solar
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	26	[2]
Roadrunner | Utility-Scale Solar
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	20	[2]
CVSR | Utility-Scale Solar
Nature of Business
Equity Method Investment, Ownership Percentage	48.95%
Power Generation Capacity (in MWs)	122	[2],[3]
RE Kansas South [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	20	[2]
TA - High Desert LLC [Member] | Utility-Scale Solar
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	20	[2]
AZ DG Solar Projects | Distributed Solar
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	5	[2]
PFMG DG Solar Projects | Distributed Solar
Nature of Business
Percentage of Ownership	51.00%
Power Generation Capacity (in MWs)	5	[2]
Alta I [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	150	[2]
Alta II [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	150	[2]
Alta III [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	150	[2]
Alta IV [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	102	[2]
Alta V [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	168	[2]
Alta X [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%	[4]
Power Generation Capacity (in MWs)	137	[4]
Alta XI [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%	[4]
Power Generation Capacity (in MWs)	90	[4]
South Trent | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	101	[2]
Laredo Ridge [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	80	[2]
Taloga [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	130	[2]
Pinnacle [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	55	[2]
Buffalo Bear [Member] | Wind Farms [Member]
Nature of Business
Percentage of Ownership	100.00%
Power Generation Capacity (in MWs)	19	[2]
Drop-down Acquisition [Member]
Nature of Business
Business Acquisitions, Consideration Transferred, Purchase Price							357
Business Combination, Consideration Transferred, Liabilities Incurred							612
Business Acquisition, Consideration Transferred, Working Capital							8
EME-NYLD Assets [Member]
Nature of Business
Business Acquisitions, Consideration Transferred, Purchase Price								489
Business Combination, Consideration Transferred, Liabilities Incurred								737
Business Acquisition, Consideration Transferred, Working Capital								9
Affiliated Entity [Member]
Nature of Business
General and administrative — affiliate	$3		$2
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of March 31, 2015.
[3]	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 NRG Yield, Inc.'s thermal facilities and certain of its customers.
[4]	(c) PPA begins on January 1, 2016.

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended			0 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014		Jan. 02, 2015	Dec. 31, 2014
Summary of Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	$131				$651
Dividends Per Common Share	$0.39	$0.33
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	-15	9
Payment of dividends and distributions to shareholders	-30	-22	[1]
EME-NYLD Assets [Member]
Summary of Significant Accounting Policies [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets					405
Business Acquisitions, Consideration Transferred, Purchase Price				-489
Business Combination, Separately Recognized Transactions, Net Gains and Losses				61
Accumulated Other Comprehensive Income (Loss), before Tax				23
Scenario, Previously Reported [Member]
Summary of Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest					246
Noncontrolling Interest [Member]
Summary of Significant Accounting Policies [Line Items]
Non-cash adjustment to non-controlling interest	1
Payment of dividends and distributions to shareholders	($17)
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Business_Acquisitions_Details

Business Acquisitions (Details) (USD $)

3 Months Ended

0 Months Ended

5 Months Ended

0 Months Ended

6 Months Ended

In Millions, except Share data, unless otherwise specified

Mar. 31, 2015

Mar. 31, 2014

Aug. 05, 2014

Jan. 30, 2015

Aug. 13, 2014

Dec. 31, 2014

Jan. 02, 2015

Jun. 30, 2014

Jul. 29, 2014

Jun. 30, 2015

Aug. 12, 2014

Jul. 30, 2014

MW

Business Acquisition

Current assets

$293

$606

[1]

Total operating revenues

180

140

Property, Plant and Equipment, Net

4,430

4,466

Business Combination, Consideration Transferred

490

0

[2]

Non-current assets

1,893

Power Generation Capacity (in MWs)

3,753

Long-term Debt

4,787

Total Assets

6,595

6,965

[1]

Other Liabilities

293

Liabilities

5,254

5,080

Net Assets

1,885

Operating Income (Loss)

48

54

[2]

Net Income (Loss), Including Portion Attributable to Noncontrolling Interest

-16

26

[2]

Other Assets

1,872

1,893

5.375% Senior Notes due in 2024 [Member]

Business Acquisition

Debt Instrument, Interest Rate, Stated Percentage

5.38%

5.375% Senior Notes due in 2024 [Member] | NRG Yield Operating LLC [Member]

Business Acquisition

Proceeds from Issuance of Senior Long-term Debt

500

Debt Instrument, Interest Rate, Stated Percentage

5.38%

TA - High Desert LLC [Member]

Business Acquisition

Total operating revenues

1

Operating Income (Loss)

0

Net Income (Loss), Including Portion Attributable to Noncontrolling Interest

-1

El Segundo [Member]

Business Acquisition

Total operating revenues

28

Operating Income (Loss)

16

Net Income (Loss), Including Portion Attributable to Noncontrolling Interest

10

RE Kansas South [Member]

Business Acquisition

Total operating revenues

1

Operating Income (Loss)

0

Net Income (Loss), Including Portion Attributable to Noncontrolling Interest

-1

UB Fuel Cell [Member]

Business Acquisition

Payments to Acquire Businesses, Gross

1

Alta Wind Portfolio [Member]

Business Acquisition

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents

22

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Cash

0

Number of Facilities

0

Payments to Acquire Businesses, Gross

923

Business Combination, Consideration Transferred

870

Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment

1,304

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles

1,177

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles

-6

Business Acquisition, Purchase Price Allocation, Intangible Assets, Other than Goodwill, Adjusted

1,171

Business Acquisition, Consideration Transferred, Working Capital

53

Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted

923

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment

6

Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment, Adjusted

1,310

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt

1,591

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Noncurrent Liabilities Longterm Debt

0

Business Acquisition, Purchase Price Allocation, Noncurrent Liabilities, Long-term Debt, Adjusted

1,591

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current and Non-Current Assets

49

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Assets

-2

Business Acquisition, Purchase Price Allocation, Other Assets, Adjusted

47

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets

2,552

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Assets

-2

Business Acquisition, Purchase Price Allocation, Assets Acquired, Adjusted

2,550

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current and Non-Current Liabilities

38

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Current and Noncurrent Liabilities

-2

Business Acquisition, Purchase Price Allocation, Current and Non-current Liabilities, Adjusted

36

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities

1,629

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities

-2

Business Acquisition, Purchase Price Allocation, Liabilities Assumed, Adjusted

1,627

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Net Assets Acquired

0

Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted

923

Alta Wind Portfolio [Member] | Supply Commitment Arrangement [Domain]

Business Acquisition

Weighted average remaining amortization period (in years)

22 years

Alta Wind Portfolio [Member] | Leasehold Rights [Member]

Business Acquisition

Weighted average remaining amortization period (in years)

21 years

Tapestry Wind [Member]

Business Acquisition

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets

14

Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment

286

Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted

164

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets

361

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities

197

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets

61

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt

192

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Current and Non-Current Liabilities

5

Laredo Ridge [Member]

Business Acquisition

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets

7

Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment

118

Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted

62

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets

174

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities

112

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets

49

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt

108

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Current and Non-Current Liabilities

4

Walnut Creek [Member]

Business Acquisition

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets

46

Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment

575

Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted

179

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets

678

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities

499

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets

57

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt

437

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Current and Non-Current Liabilities

62

EME-NYLD Assets [Member]

Business Acquisition

Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual

38

Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual

11

Business Acquisition, Pro Forma Revenue

166

Business Combination, Consideration Transferred

489

Business Acquisition, Consideration Transferred, Working Capital

9

Business Combination, Consideration Transferred, Liabilities Incurred

737

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets

405

Business Acquisitions, Consideration Transferred, Purchase Price

489

Business Acquisition, Pro Forma Net Income(Loss), Including Portion Attributable to Noncontrolling Interest

23

Business Combination, Separately Recognized Transactions, Net Gains and Losses

61

Accumulated Other Comprehensive Income (Loss), before Tax

23

Drop-down Acquisition [Member]

Business Acquisition

Business Combination, Consideration Transferred

357

Business Acquisition, Consideration Transferred, Working Capital

8

Business Combination, Consideration Transferred, Liabilities Incurred

612

Business Acquisitions, Consideration Transferred, Purchase Price

349

Alta Wind Holdings [Member]

Business Acquisition

Power Generation Capacity (in MWs)

947

Thermal [Member]

Business Acquisition

Power Generation Capacity (in MWs)

123

[3]

Thermal [Member] | UB Fuel Cell [Member]

Business Acquisition

Power Generation Capacity (in MWs)

1.4

[3]

Wind Farms [Member]

Business Acquisition

Power Generation Capacity (in MWs)

1,332

Wind Farms [Member] | Buffalo Bear [Member]

Business Acquisition

Power Generation Capacity (in MWs)

19

[3]

Wind Farms [Member] | Taloga [Member]

Business Acquisition

Power Generation Capacity (in MWs)

130

[3]

Wind Farms [Member] | Pinnacle [Member]

Business Acquisition

Power Generation Capacity (in MWs)

55

[3]

Wind Farms [Member] | Spring Canyon II [Member]

Business Acquisition

Power Generation Capacity (in MWs)

34

[3]

Wind Farms [Member] | Laredo Ridge [Member]

Business Acquisition

Power Generation Capacity (in MWs)

80

[3]

Wind Farms [Member] | Spring Canyon III [Member]

Business Acquisition

Power Generation Capacity (in MWs)

29

[3]

Utility-Scale Solar [Member]

Business Acquisition

Power Generation Capacity (in MWs)

343

[3]

Utility-Scale Solar [Member] | CVSR [Member]

Business Acquisition

Power Generation Capacity (in MWs)

122

[3],[4]

Equity Method Investment, Ownership Percentage

48.95%

Common Class A [Member] | Public Shareholders [Member]

Business Acquisition

Sale of Stock, Number of Shares Issued in Transaction

12,075,000

Share Price

$54

Proceeds from issuance of Class A common stock

630

Scenario, Previously Reported [Member]

Business Acquisition

Current assets

539

Total operating revenues

110

Property, Plant and Equipment, Net

3,487

Non-current assets

1,726

Long-term Debt

4,050

Total Assets

5,752

Other Liabilities

222

Liabilities

4,272

Net Assets

1,480

Operating Income (Loss)

38

Net Income (Loss), Including Portion Attributable to Noncontrolling Interest

18

Subsequent Event [Member] | Spring Canyon and UB Fuel Cell [Member]

Business Acquisition

Payments to Acquire Businesses, Gross

$41

[1]

Retrospectively adjusted as discussed in Note 1, Nature of Business.

[2]

(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

[3]

Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of March 31, 2015.

[4]

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 NRG Yield, Inc.'s thermal facilities and certain of its customers.

Property_Plant_and_Equipment_D

Property, Plant and Equipment (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment
Property, plant and equipment, gross	4,821	$4,804	[1]
Under construction	17	8
Less accumulated depreciation	-391	-338
Property, Plant and Equipment, Net	4,430	4,466
Support Equipment and Facilities [Member]
Property, Plant and Equipment
Property, plant and equipment, gross	4,717	4,709
Land and improvements
Property, Plant and Equipment
Property, plant and equipment, gross	87	$87
Minimum [Member] | Support Equipment and Facilities [Member]
Property, Plant and Equipment
Property, plant and equipment, useful life	2 years
Maximum [Member] | Support Equipment and Facilities [Member]
Property, Plant and Equipment
Property, plant and equipment, useful life	33 years
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Investments_Accounted_for_by_t2

Investments Accounted for by the Equity Method and Variable Interest Entities (Details) (USD $)	3 Months Ended				0 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Apr. 09, 2015	Dec. 31, 2014
	MW
Variable Interest Entity
Power Generation Capacity (in MWs)	3,753
Long-term Debt						$4,787
Operating revenues	180		140
Operating income	48		54	[1]
Net Income	-16		26	[1]
Current assets	293					606	[2]
Non-current assets						1,893
Current liabilities	389					389	[2]
Non-current liabilities	4,865					4,691
Equity investments in affiliates	188					227
GenConn Energy LLC
Variable Interest Entity
Power Generation Capacity (in MWs)	190
Power Generation Units, Number	2
GCE Holdings LLC
Variable Interest Entity
Economic interest in equity method investments (as a percent)	49.95%
Operating revenues	22		26
Operating income	9		10
Net Income	6		7
Current assets	30					33
Non-current assets	429					438
Current liabilities	16					20
Non-current liabilities	219					223
GenConn Energy LLC
Variable Interest Entity
Equity investments in affiliates	112
GenConn Energy LLC | Fixed Rate Notes
Variable Interest Entity
Long-term Debt	224
Interest rate	4.73%
Line of Credit Facility, Maximum Borrowing Capacity	237
GenConn Energy LLC | Working Capital Facility [Member]
Variable Interest Entity
Interest rate	1.88%
Line of Credit Facility, Maximum Borrowing Capacity	35
Utility-Scale Solar [Member]
Variable Interest Entity
Power Generation Capacity (in MWs)	343	[3]
Subsequent Event [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Expected Return On Investment					7.50%
Subsequent Event [Member] | NRG RPV Holdco [Member] | NRG
Variable Interest Entity
Economic Interest in Entity					5.00%
Subsequent Event [Member] | NRG RPV Holdco [Member] | NRG Yield, Inc.
Variable Interest Entity
Economic Interest in Entity					95.00%
Subsequent Event [Member] | Existing Portfolio of Leases [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Number of Solar Leases in Portfolio					2,200
Power Generation Capacity (in MWs)					17
Remaining Lease Term					17 years
Equity investments in affiliates					26
Subsequent Event [Member] | In-Development Portfolio of Leases [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Power Generation Capacity (in MWs)					48
Remaining Lease Term					20 years
Subsequent Event [Member] | In-Development Portfolio of Leases [Member] | Minimum [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Number of Solar Leases in Portfolio					6,000
Subsequent Event [Member] | In-Development Portfolio of Leases [Member] | Maximum [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Number of Solar Leases in Portfolio					7,000
Subsequent Event [Member] | In-Development Portfolio of Leases Tranche 2 [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Power Generation Capacity (in MWs)					42
Remaining Lease Term					20 years
Subsequent Event [Member] | In-Development Portfolio of Leases Tranche 2 [Member] | Minimum [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Number of Solar Leases in Portfolio					5,500
Subsequent Event [Member] | In-Development Portfolio of Leases Tranche 2 [Member] | Maximum [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Number of Solar Leases in Portfolio					6,500
Subsequent Event [Member] | Tax Equity Financed Portfolio of Leases [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Equity investments in affiliates					7
Subsequent Event [Member] | Tax Equity Financed Portfolio of Leases [Member] | Maximum [Member] | NRG RPV Holdco [Member]
Variable Interest Entity
Equity investments in affiliates					150
Scenario, Plan [Member] | Subsequent Event [Member] | NRG RPV Holdco [Member] | NRG
Variable Interest Entity
Economic Interest in Entity					95.00%
Scenario, Plan [Member] | Subsequent Event [Member] | NRG RPV Holdco [Member] | NRG Yield, Inc.
Variable Interest Entity
Economic Interest in Entity					5.00%
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[3]	Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of March 31, 2015.

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Fair Value of Financial Instruments
Derivative Liability, Fair Value Determined Using Valuation Techniques, Percentage	0.00%
Fair Value Assets, Measured on Recurring Basis, Valuation Techniques, Impact of Credit Reserve to Fair Value	$3,000,000
Derivative Assets	8,000,000		2,000,000
Long-term debt, including current portion			4,787,000,000
Derivative Asset, Fair Value Determined Using Valuation Techniques, Percentage	0.00%
Derivative Liabilities	145,000,000		117,000,000
Concentration of Credit Risk
Credit risk exposure under certain long-term agreements for the next five years	2,300,000,000
Period of credit risk exposure under certain long-term agreements (in years)	5 years
Interest rate contracts
Fair Value of Financial Instruments
Derivative Assets	0		2,000,000
Derivative Liabilities	142,000,000		114,000,000
Commodity contracts
Fair Value of Financial Instruments
Derivative Assets	8,000,000		0
Derivative Liabilities	3,000,000		3,000,000
Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments
Derivative Assets	8,000,000	[1]	2,000,000	[2]
Reported Value Measurement [Member]
Fair Value of Financial Instruments
Financing Receivable, Net	22,000,000		21,000,000
Long-term debt, including current portion	4,937,000,000		4,787,000,000
Estimate of Fair Value Measurement [Member]
Fair Value of Financial Instruments
Financing Receivable, Net	22,000,000		21,000,000
Long-term debt, including current portion	5,037,000,000		4,873,000,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments
Derivative Assets (Liabilities), at Fair Value, Net	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments
Derivative Liabilities	145,000,000		117,000,000	[2]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest rate contracts
Fair Value of Financial Instruments
Derivative Assets	0		2,000,000	[2]
Derivative Liabilities	142,000,000		114,000,000	[2]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commodity contracts
Fair Value of Financial Instruments
Derivative Assets	8,000,000		0	[2]
Derivative Liabilities	3,000,000		3,000,000	[2]
Fair Value, Measurements, Recurring [Member] | Level 1
Fair Value of Financial Instruments
Derivative Assets (Liabilities), at Fair Value, Net	0		0
Interest Expense [Member]
Fair Value of Financial Instruments
Fair Value Assets, Measured on Recurring Basis, Valuation Techniques, Impact of Credit Reserve to Fair Value	1,000,000
Gain (Loss) on Derivative Instruments [Member]
Fair Value of Financial Instruments
Fair Value Assets, Measured on Recurring Basis, Valuation Techniques, Impact of Credit Reserve to Fair Value	$2,000,000
[1]	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of March 31, 2015.
[2]	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of December 31, 2014.

Accounting_for_Derivative_Inst2

Accounting for Derivative Instruments and Hedging Activities (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Derivative
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	$0	$0
Unrealized Gain (Loss) on Derivatives, Mark To Market, Economic Hedging Activities	7
Fair Value of Derivative Instruments
Derivative Liabilities	-145		-117
Derivative Assets	8		2
Derivative instruments	8		0
Fair Value of Gross Derivative Assets/(Liabilities), Net	-137		-115
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0		0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	-137		-115
Accumulated Other Comprehensive Income (Loss), Net of Tax
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months, Tax	3
Accumulated OCL beginning balance	-52	0
Mark-to-market of cash flow hedge accounting contracts	-19	-15
Accumulated OCL ending balance, net of income tax benefit of $14 and $1, respectively	-69	-12
Accumulated OCL ending balance, net of income tax benefit of $14 and $1, respectively	14	1
Loss expected to be realized from OCI during the next 12 months, net of tax	-13
Summary of Derivative Instruments Impact on Results of Operations
Derivative, Collateral, Right to Reclaim Cash	0		0
Derivative, Collateral, Obligation to Return Cash	0		0
Derivative Asset, Fair Value Determined Using Valuation Techniques, Percentage	0.00%
Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss), Net of Tax
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	2	3
Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-105		-89
Derivative Assets	0		2
Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-40		-28
Derivative Assets	8		0
Interest rate contracts current | Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-39		-40
Derivative Assets	0		0
Interest rate contracts current | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-6		-5
Derivative Assets	0		0
Interest rate contracts long-term | Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-66		-49
Derivative Assets	0		2
Interest rate contracts long-term | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-31		-20
Derivative Assets	0		0
Commodity contracts current | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-3		-3
Derivative Assets	8		0
Commodity contracts
Derivative
Derivative Liability	-2		-3
Fair Value of Derivative Instruments
Derivative Liabilities	-3		-3
Derivative Assets	8		0
Derivative instruments	7		0
Fair Value of Gross Derivative Assets/(Liabilities), Net	5		-3
Derivative Liability, Fair Value, Gross Asset	1		0
Derivative Asset, Fair Value, Gross Liability	-1		0
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0		0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	5		-3
Interest rate contracts
Derivative
Derivative Liability	-142		-112
Fair Value of Derivative Instruments
Derivative Liabilities	-142		-114
Derivative Assets	0		2
Derivative instruments	0		0
Fair Value of Gross Derivative Assets/(Liabilities), Net	-142		-112
Derivative Liability, Fair Value, Gross Asset	0		2
Derivative Asset, Fair Value, Gross Liability	0		-2
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0		0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	-142		-112
MWh. [Member] | Power [Member]
Derivative
Derivative, Notional Amount	-1		0
MMbtu | Natural Gas [Member]
Derivative
Derivative, Notional Amount	3		2
Dollars | Interest
Derivative
Derivative, Notional Amount	2,779		2,817
Successor
Accumulated Other Comprehensive Income (Loss), Net of Tax
Accumulated OCL ending balance, net of income tax benefit of $14 and $1, respectively	-23	-5
Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax
Accumulated OCL ending balance, net of income tax benefit of $14 and $1, respectively	-46	-7
Interest Expense [Member] | Interest rate contracts
Summary of Derivative Instruments Impact on Results of Operations
Unrealized gain/(loss) on derivatives	12	3
Operating Revenues [Member] | Commodity contracts
Summary of Derivative Instruments Impact on Results of Operations
Unrealized gain/(loss) on derivatives	$7	$0

Longterm_Debt_Details

Long-term Debt (Details) (USD $)

0 Months Ended

3 Months Ended

0 Months Ended

Dec. 17, 2014

Oct. 21, 2014

Mar. 31, 2015

Jul. 27, 2011

Dec. 21, 2011

Feb. 05, 2015

Aug. 05, 2014

Nov. 12, 2014

Mar. 18, 2015

Dec. 31, 2014

Jul. 27, 2010

Jan. 02, 2015

Long-term Debt Disclosure

Long-term Debt

$4,787,000,000

Long-term debt, current maturities

218,000,000

214,000,000

Long-term debt, excluding current maturities

4,719,000,000

4,573,000,000

Non-affiliate

Long-term Debt Disclosure

Long-term Debt

4,937,000,000

4,787,000,000

NRG Yield LLC [Member]

Long-term Debt Disclosure

Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Paid

33,000,000

WCEP Holdings LLC [Member]

Long-term Debt Disclosure

Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Paid

6,000,000

3.5% Convertible Notes due 2019 [Member]

Long-term Debt Disclosure

Long-term Debt

327,000,000

326,000,000

Debt Instrument, Convertible, Carrying Amount of Equity Component

18,000,000

19,000,000

Alta Wind I, lease financing arrangement, due 2034 [Member] | Non-affiliate

Long-term Debt Disclosure

Interest rate

7.01%

Alta Realty Investments, due 2031 [Member] | Non-affiliate

Long-term Debt Disclosure

Interest rate

7.00%

NRG Marsh Landing LLC, due 2017 and 2023 | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

457,000,000

464,000,000

NRG Marsh Landing LLC, due 2023

Long-term Debt Disclosure

Variable rate basis

1 month LIBOR

Basis spread on variable rate

1.88%

Walnut Creek Energy, LLC, due in 2023 [Member]

Long-term Debt Disclosure

Variable rate basis

1 month LIBOR

Basis spread on variable rate

1.63%

Walnut Creek Energy, LLC, due in 2023 [Member] | Interest Rate Swap [Member]

Long-term Debt Disclosure

Percentage of Debt Hedged by Interest Rate Derivatives

90.00%

Derivative, Fixed Interest Rate

4.00%

3.54%

Walnut Creek Energy, LLC, due in 2023 [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

384,000,000

391,000,000

Walnut Creek Energy, LLC, due in 2023 [Member] | Term Loan Facility

Long-term Debt Disclosure

Debt Issuance Cost

4,000,000

Long-term Debt

442,000,000

Proceeds from Issuance of Debt

10,000,000

Walnut Creek Energy, LLC, due in 2023 [Member] | Working Capital Facility [Member]

Long-term Debt Disclosure

Line of Credit Facility, Commitment Fee Percentage

0.50%

0.63%

Line of Credit Facility, Maximum Borrowing Capacity

5,000,000

Line of Credit Facility, Fair Value of Amount Outstanding

0

Walnut Creek Energy, LLC, due in 2023 [Member] | Letter of Credit [Member]

Long-term Debt Disclosure

Letters of Credit Outstanding, Amount

54,000,000

Line of Credit Facility, Maximum Borrowing Capacity

117,000,000

Marsh Landing Tranche A due December 2017 [Member]

Long-term Debt Disclosure

Variable rate basis

1 month LIBOR

Basis spread on variable rate

1.75%

NRG Solar Alpine, due 2022

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Tapestry Wind LLC due in 2021 [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

1.63%

Tapestry Wind LLC due in 2021 [Member] | Interest Rate Swap [Member]

Long-term Debt Disclosure

Percentage of Debt Hedged by Interest Rate Derivatives

90.00%

Derivative, Fixed Interest Rate

2.21%

Derivative, Forward Interest Rate

3.57%

Tapestry Wind LLC due in 2021 [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

188,000,000

192,000,000

Tapestry Wind LLC due in 2021 [Member] | Term Loan Facility

Long-term Debt Disclosure

Long-term Debt

214,000,000

Tapestry Wind LLC due in 2021 [Member] | Working Capital Facility [Member]

Long-term Debt Disclosure

Line of Credit Facility, Commitment Fee Percentage

0.75%

Line of Credit Facility, Maximum Borrowing Capacity

8,000,000

Line of Credit Facility, Fair Value of Amount Outstanding

0

Tapestry Wind LLC due in 2021 [Member] | Letter of Credit [Member]

Long-term Debt Disclosure

Letters of Credit Outstanding, Amount

20,000,000

Line of Credit Facility, Maximum Borrowing Capacity

20,000,000

Alpine Financing Agreement [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

162,000,000

163,000,000

Laredo Ridge Wind, LLC, due in 2026 [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

1.88%

Laredo Ridge Wind, LLC, due in 2026 [Member] | Interest Rate Swap [Member]

Long-term Debt Disclosure

Percentage of Debt Hedged by Interest Rate Derivatives

75.00%

Laredo Ridge Wind, LLC, due in 2026 [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

107,000,000

108,000,000

Laredo Ridge Wind, LLC, due in 2026 [Member] | Cash Grant Loan

Long-term Debt Disclosure

Long-term Debt

53,000,000

Laredo Ridge Wind, LLC, due in 2026 [Member] | Term Loan Facility

Long-term Debt Disclosure

Debt Issuance Cost

8,000,000

Long-term Debt

75,000,000

Proceeds from Issuance of Debt

41,000,000

Laredo Ridge Wind, LLC, due in 2026 [Member] | Working Capital Facility [Member]

Long-term Debt Disclosure

Line of Credit Facility, Commitment Fee Percentage

0.50%

Line of Credit Facility, Maximum Borrowing Capacity

3,000,000

Credit Facility, Maximum Borrowing Capacity, Amendment

1,000,000

Line of Credit Facility, Fair Value of Amount Outstanding

0

Laredo Ridge Wind, LLC, due in 2026 [Member] | Letter of Credit [Member]

Long-term Debt Disclosure

Letters of Credit Outstanding, Amount

10,000,000

Line of Credit Facility, Maximum Borrowing Capacity

9,000,000

Credit Facility, Maximum Borrowing Capacity, Amendment

-1,000,000

Borrego Financing [Member] | Interest Rate Swap [Member]

Long-term Debt Disclosure

Derivative, Fixed Interest Rate

2.31%

Borrego Financing [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

75,000,000

75,000,000

NRG Energy Center Minneapolis LLC, senior secured notes, due 2013, 2017, and 2025 | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

119,000,000

121,000,000

NRG Energy Center Minneapolis LLC, senior secured notes, due 2017

Long-term Debt Disclosure

Interest rate

5.95%

NRG Energy Center Minneapolis LLC, senior secured notes, due 2025

Long-term Debt Disclosure

Interest rate

7.25%

NRG Borrego I LLC, due 2024

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

2.50%

NRG Borrego I LLC, due 2038

Long-term Debt Disclosure

Basis spread on variable rate

5.65%

South Trent Wind LLC, due 2020

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

2.75%

South Trent Wind LLC, due 2020 | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

65,000,000

65,000,000

NRG Solar Avra Valley LLC, due 2031

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

1.75%

NRG Solar Avra Valley LLC, due 2031 | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

63,000,000

63,000,000

High Desert Facility [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

55,000,000

55,000,000

WCEP Holdings, LLC, due in 2023 [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

3.00%

WCEP Holdings, LLC, due in 2023 [Member] | Interest Rate Swap [Member]

Long-term Debt Disclosure

Percentage of Debt Hedged by Interest Rate Derivatives

90.00%

Derivative, Fixed Interest Rate

4.00%

WCEP Holdings, LLC, due in 2023 [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

46,000,000

46,000,000

WCEP Holdings, LLC, due in 2023 [Member] | Term Loan Facility

Long-term Debt Disclosure

Long-term Debt

53,000,000

Variable rate basis

LIBOR

LIBOR

Basis spread on variable rate

3.00%

4.00%

Repayments of Debt

6,000,000

NRG Roadrunner LLC, due 2031

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

2.01%

NRG Roadrunner LLC, due 2031 | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

42,000,000

42,000,000

Kansas South Facility, due 2031 [Member]

Long-term Debt Disclosure

Variable rate basis

6-Month LIBOR

Basis spread on variable rate

2.00%

Kansas South Facility, due 2031 [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

35,000,000

35,000,000

NRG Solar Blythe LLC, due 2028

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

2.75%

NRG Solar Blythe LLC, due 2028 | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

22,000,000

22,000,000

PFMG and related subsidiaries, due 2030 | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

31,000,000

31,000,000

Interest rate

6.00%

NRG Energy Center Princeton LLC, due 2017 | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

1,000,000

1,000,000

Interest rate

5.95%

NRG Yield Revolving Credit Facility

Long-term Debt Disclosure

Repayments of Debt

15,000,000

Line of Credit Facility, Fair Value of Amount Outstanding

210,000,000

Convertible Debt [Member]

Long-term Debt Disclosure

Interest rate

3.50%

5.375% Senior Notes due in 2024 [Member]

Long-term Debt Disclosure

Interest rate

5.38%

Senior Notes

500,000,000

500,000,000

5.375% Senior Notes due in 2024 [Member] | NRG Yield Operating LLC [Member]

Long-term Debt Disclosure

Interest rate

5.38%

Proceeds from Issuance of Senior Long-term Debt

500,000,000

Revolving Credit Facility [Member]

Long-term Debt Disclosure

Long-term Debt

195,000,000

0

Variable rate basis

1 month LIBOR

Basis spread on variable rate

2.25%

Alta Wind Asset Management, due 2031 [Member]

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.38%

West Holdings Credit Agreement [Member]

Long-term Debt Disclosure

Variable rate basis

1 month LIBOR

West Holdings Credit Agreement [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

484,000,000

506,000,000

Alta Wind X, due 2020 [Member]

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.00%

Alta Wind XI, due 2020 [Member]

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.00%

Alta Wind II, lease financing arrangement, due 2034 [Member] | Non-affiliate

Long-term Debt Disclosure

Interest rate

5.70%

Alta Wind III, lease financing arrangement, due 2034 [Member] | Non-affiliate

Long-term Debt Disclosure

Interest rate

6.07%

Alta Wind IV, lease financing arrangement, due 2034 [Member] | Non-affiliate

Long-term Debt Disclosure

Interest rate

5.94%

Alta Wind V, lease financing arrangement, due 2035 [Member] | Non-affiliate

Long-term Debt Disclosure

Interest rate

6.07%

Project [Domain] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

3,915,000,000

3,961,000,000

High Desert Facility, due 2033 [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

2.50%

TA - High Desert, due 2023 [Member]

Long-term Debt Disclosure

Interest rate

5.15%

December 30, 2034 [Member] | Alta Wind I, lease financing arrangement, due 2034 [Member] | Lease Financing Arrangement [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

261,000,000

261,000,000

December 30, 2034 [Member] | Alta Wind II, lease financing arrangement, due 2034 [Member] | Lease Financing Arrangement [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

205,000,000

205,000,000

December 30, 2034 [Member] | Alta Wind III, lease financing arrangement, due 2034 [Member] | Lease Financing Arrangement [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

212,000,000

212,000,000

December 30, 2034 [Member] | Alta Wind IV, lease financing arrangement, due 2034 [Member] | Lease Financing Arrangement [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

138,000,000

138,000,000

January 31, 2031 [Member] | Alta Realty Investments, due 2031 [Member] | Notes Payable, Other Payables [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

33,000,000

34,000,000

May 15, 2031 [Member] | Alta Wind Asset Management, due 2031 [Member] | Term Loan Facility | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

19,000,000

20,000,000

March 31, 2020 [Member] | Alta Wind X, due 2020 [Member] | Term Loan Facility | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

300,000,000

300,000,000

March 31, 2020 [Member] | Alta Wind XI, due 2020 [Member] | Term Loan Facility | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

191,000,000

191,000,000

June 30, 2035 [Member] | Alta Wind V, lease financing arrangement, due 2035 [Member] | Lease Financing Arrangement [Member] | Non-affiliate

Long-term Debt Disclosure

Long-term Debt

220,000,000

220,000,000

Minimum [Member] | Alpine [Member]

Long-term Debt Disclosure

Basis spread on variable rate

1.75%

Minimum [Member] | WCEP Holdings, LLC, due in 2023 [Member] | Interest Rate Swap [Member]

Long-term Debt Disclosure

Percentage of Debt Hedged by Interest Rate Derivatives

90.00%

Minimum [Member] | West Holdings Credit Agreement [Member]

Long-term Debt Disclosure

Basis spread on variable rate

2.25%

Maximum [Member] | Alpine [Member]

Long-term Debt Disclosure

Basis spread on variable rate

2.50%

Maximum [Member] | WCEP Holdings, LLC, due in 2023 [Member] | Interest Rate Swap [Member]

Long-term Debt Disclosure

Percentage of Debt Hedged by Interest Rate Derivatives

100.00%

Maximum [Member] | West Holdings Credit Agreement [Member]

Long-term Debt Disclosure

Basis spread on variable rate

2.88%

December 17, 2014 to December 31, 2018 [Member] | Laredo Ridge Wind, LLC, due in 2026 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

LIBOR

Basis spread on variable rate

1.88%

January 1, 2019 to December 31, 2023 [Member] | Laredo Ridge Wind, LLC, due in 2026 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

LIBOR

Basis spread on variable rate

2.13%

January 1, 2024 to March 31, 2028 [Member] | Laredo Ridge Wind, LLC, due in 2026 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

LIBOR

Basis spread on variable rate

2.38%

November 12, 2014 to December 20, 2018 [Member] | Tapestry Wind LLC due in 2021 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

LIBOR

Basis spread on variable rate

1.63%

December 21, 2018 to December 31, 2021 [Member] | Tapestry Wind LLC due in 2021 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

LIBOR

Basis spread on variable rate

1.75%

October 21, 2014 to September 30, 2018 [Member] | Walnut Creek Energy, LLC, due in 2023 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

LIBOR

Basis spread on variable rate

1.63%

October 1, 2018 to September 30, 2022 [Member] | Walnut Creek Energy, LLC, due in 2023 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

LIBOR

Basis spread on variable rate

1.75%

October 1, 2022 to May 31, 2023 [Member] | Walnut Creek Energy, LLC, due in 2023 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

LIBOR

Basis spread on variable rate

1.88%

Avenal | Term Loan Facility

Long-term Debt Disclosure

Debt Instrument, Face Amount

43,000,000

Proceeds from Debt, Net of Issuance Costs

$20,000,000

Avenal | September 22, 2010 to March 18, 2015 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

6 month LIBOR

Basis spread on variable rate

2.25%

Avenal | March 18, 2015 to March 17, 2022 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

6 month LIBOR

Basis spread on variable rate

1.75%

Avenal | March 18, 2022 to March 17, 2027 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

6 month LIBOR

Basis spread on variable rate

2.00%

Avenal | March 18, 2027 through Maturity [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

6 month LIBOR

Basis spread on variable rate

2.25%

Utility-Scale Solar [Member] | Avenal

Long-term Debt Disclosure

Equity Method Investment, Ownership Percentage

49.95%

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings (Loss) Per Share Disclosure [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	7	4
Numerator:
Net (loss) income attributable to NRG Yield, Inc.	($5)	$4
Denominator:
Weighted average number of Class A common shares outstanding	35	23
Basic and diluted loss per share:
(Losses) Earnings per weighted average Class A common share — basic and diluted	($0.15)	$0.18

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Jul. 22, 2013	Feb. 24, 2015
Statement of Stockholders' Equity
Dividends Per Common Share	$0.39	$0.33
Preferred Stock, Shares Authorized	10,000,000		10,000,000	10,000,000
Preferred Stock, Par or Stated Value Per Share				$0.01
Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued	$0		$0
Common Class C [Member]
Statement of Stockholders' Equity
Common Stock, Voting Rights	1/100th
Common Class B [Member]
Statement of Stockholders' Equity
Common Stock, Par or Stated Value Per Share					$10,000
Common Class D [Member]
Statement of Stockholders' Equity
Common Stock, Voting Rights	1/100th
Common Class A [Member]
Statement of Stockholders' Equity
Common Stock, Par or Stated Value Per Share	$0.01		$0.01		$0.01

Segment_Reporting_Details

Segment Reporting (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014		Dec. 31, 2014
Segment Reporting
Total operating revenues	$180	$140
Cost of operations	75	60
Depreciation and amortization	54	24	[1]
Operating income	48	54	[1]
Equity in earnings of unconsolidated affiliates	1	1
Other Nonoperating Income (Expense)	1	1
Interest Expense	-70	-27
Income Before Income Taxes	-20	29	[1]
Income tax (benefit) expense	-4	3
Net Income	-16	26	[1]
Total Assets	6,595			6,965	[2]
Conventional Generation
Segment Reporting
Total operating revenues	76	56
Cost of operations	21	10
Depreciation and amortization	21	13
Operating income	34	33
Equity in earnings of unconsolidated affiliates	3	3
Other Nonoperating Income (Expense)	1	0
Interest Expense	-12	-11
Income Before Income Taxes	26	25
Income tax (benefit) expense	0	0
Net Income	26	25
Total Assets	2,136
Renewables
Segment Reporting
Total operating revenues	57	19
Cost of operations	20	4
Depreciation and amortization	28	7
Operating income	9	8
Equity in earnings of unconsolidated affiliates	-2	-2
Other Nonoperating Income (Expense)	0	1
Interest Expense	-43	-12
Income Before Income Taxes	-36	-5
Income tax (benefit) expense	0	0
Net Income	-36	-5
Total Assets	3,781
Thermal [Member]
Segment Reporting
Total operating revenues	47	65
Cost of operations	34	46
Depreciation and amortization	5	4
Operating income	8	15
Equity in earnings of unconsolidated affiliates	0	0
Other Nonoperating Income (Expense)	0	0
Interest Expense	-2	-2
Income Before Income Taxes	6	13
Income tax (benefit) expense	0	0
Net Income	6	13
Total Assets	451
Corporate
Segment Reporting
Total operating revenues	0	0
Cost of operations	0	0
Depreciation and amortization	0	0
Operating income	-3	-2
Equity in earnings of unconsolidated affiliates	0	0
Other Nonoperating Income (Expense)	0	0
Interest Expense	-13	-2
Income Before Income Taxes	-16	-4
Income tax (benefit) expense	-4	3
Net Income	-12	-7
Total Assets	227
Affiliated Entity [Member]
Segment Reporting
General and administrative — affiliate	3	2
Affiliated Entity [Member] | Conventional Generation
Segment Reporting
General and administrative — affiliate	0	0
Affiliated Entity [Member] | Renewables
Segment Reporting
General and administrative — affiliate	0	0
Affiliated Entity [Member] | Thermal [Member]
Segment Reporting
General and administrative — affiliate	0	0
Affiliated Entity [Member] | Corporate
Segment Reporting
General and administrative — affiliate	$3	$2
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Income_Taxes_Provision_Details

Income Taxes (Provision) (Details) (USD $)	3 Months Ended			12 Months Ended	0 Months Ended	6 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014		Dec. 31, 2014	Jul. 29, 2014	Dec. 31, 2013
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income tax (benefit) expense	($4)	$3
Effective tax rate (as a percent)	20.00%	10.30%
U.S. federal statutory rate (as a percent)	35.00%
Reconciliation of the U.S. federal statutory rate to the Company's effective rate from continuing operations
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	-20	29	[1]
Adjustment to additional paid-in capital for tax basis differences	$27			$65
NRG | NRG Yield LLC
Reconciliation of the U.S. federal statutory rate to the Company's effective rate from continuing operations
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	55.30%				55.30%	65.50%
NRG Yield, Inc. | NRG Yield LLC
Reconciliation of the U.S. federal statutory rate to the Company's effective rate from continuing operations
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	44.70%				44.70%
[1]	(a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Management Services Agreement with NRG
Related Party Transaction
Management Services Fee, Increase	$1
Scenario, Plan [Member] | Management Services Agreement with NRG
Related Party Transaction
Management Services Fee, Annual	7
Affiliated Entity [Member]
Related Party Transaction
General and administrative — affiliate	3	2
CVSR [Member] | Utility-Scale Solar [Member]
Related Party Transaction
Equity Method Investment, Ownership Percentage	48.95%
Thermal [Member] | NRG [Member]
Related Party Transaction
Due to Related Parties	30		22
Related Party Transaction, Expenses from Transactions with Related Party	7	7
Marsh Landing [Member] | GenOn Energy Services LLC [Member]
Related Party Transaction
Due to Related Parties			0	4
Related Party Costs, Capitalized Amount	2
Related Party Transaction, Expenses from Transactions with Related Party		$2