Clearway Energy (CWEN) 8-K 22 May 15 2014 FY Other Events Financial data

Document_and_Entity_Informatio

Document and Entity Information	12 Months Ended
	Dec. 31, 2014
Class of Stock
Entity Registrant Name	NRG Yield, Inc.
Entity Central Index Key	1567683
Document Type	8-K
Document Period End Date	31-Dec-14
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	2014
Document Fiscal Period Focus	FY

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	12 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Operating Revenues
Total operating revenues	$689,000,000		$379,000,000	[1]	$175,000,000	[1]
Operating Costs and Expenses
Cost of operations	239,000,000		144,000,000	[1]	114,000,000	[1]
Depreciation and amortization	166,000,000		61,000,000	[1]	25,000,000	[1]
Acquisition-related transaction and integration costs	4,000,000		0	[1]	0	[1]
Total operating costs and expenses	417,000,000		212,000,000	[1]	146,000,000	[1]
Operating Income	272,000,000		167,000,000	[1]	29,000,000	[1]
Other Income (Expense)
Equity in earnings of unconsolidated affiliates	27,000,000		22,000,000	[1]	19,000,000	[1]
Other income, net	3,000,000		3,000,000	[1]	2,000,000	[1]
Interest expense	-186,000,000		-52,000,000	[1]	-28,000,000	[1]
Total other expense	-156,000,000		-27,000,000	[1]	-7,000,000	[1]
Income Before Income Taxes	116,000,000	[2]	140,000,000	[1],[3]	22,000,000	[1],[3]
Income tax expense	4,000,000	[2]	8,000,000	[1],[3]	10,000,000	[1],[3]
Net Income	112,000,000		132,000,000	[1]	12,000,000	[1]
Net Income excluding pre-acquisition net income of Acquired ROFO assets	64,000,000		109,000,000	[1]
Less: Net income attributable to NRG (b)	64,000,000
Net income attributable to NRG Yield, Inc.	16,000,000		13,000,000
Affiliated Entity [Member]
Operating Costs and Expenses
General and administrative — affiliate	8,000,000		7,000,000	[1]	7,000,000	[1]
Predecessor
Other Income (Expense)
Net Income	0		54,000,000	[1]
Noncontrolling Interest
Other Income (Expense)
Less: Net income attributable to NRG (b)	48,000,000	[4]	42,000,000	[1],[4]
Drop-down Acquisition [Member]
Other Income (Expense)
Net Income	48,000,000		23,000,000	[1]
Less: Net income attributable to NRG (b)	48,000,000
Common Class A [Member]
Other Income (Expense)
Net income attributable to NRG Yield, Inc.	8,000,000		6,500,000
Earnings Per Share Attributable to NRG Yield, Inc. Class A and Class C Common Stockholders:
Weighted average number of common shares outstanding	28		23
Earnings per weighted average common share — basic and diluted	$0.30		$0.29
Dividends Per Class A Common Share	$1.42		$0.23
Common Class C [Member]
Other Income (Expense)
Net income attributable to NRG Yield, Inc.	$8,000,000		$6,500,000
Earnings Per Share Attributable to NRG Yield, Inc. Class A and Class C Common Stockholders:
Weighted average number of common shares outstanding	28		23
Earnings per weighted average common share — basic and diluted	$0.30		$0.29
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) - Represents 34.5% ownership for the period July 22, 2013 through December 31, 2013
[3]	(b) - Represents pro forma tax provision for NRG Yield LLC
[4]	The calculation of income attributable to NRG excludes pre-acquisition net income of the Drop Down Assets.

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (USD $)	6 Months Ended		7 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Jul. 22, 2013		Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Other Comprehensive (Loss) Income, net of tax
Net Income			$54		$112	$132	[1]	$12	[1]
Unrealized (loss) gain on derivatives, net of income tax benefit (expense) of $5, $(16), and $7					-52	48	[1]	-20	[1]
Other comprehensive (loss) income					-52	48	[1]	-20	[1]
Comprehensive Income (Loss)					60	180	[1]	-8	[1]
Comprehensive income attributable to noncontrolling interest	69	[1]			5
Comprehensive Income (Loss), Net of Tax, Available for Common Stockholders	15				7
Predecessor
Other Comprehensive (Loss) Income, net of tax
Net Income					0	54	[1]
Comprehensive Income (Loss)			73	[1]	0
Drop-down Acquisition [Member]
Other Comprehensive (Loss) Income, net of tax
Net Income					$48	$23	[1]
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Unrealized gain/loss on derivatives, income tax expense /(benefit)	$5	($16)	$7

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current Assets
Cash and cash equivalents	$406	$59	[1]
Restricted cash	45	67	[1]
Accounts receivable — trade	85	51	[1]
Accounts receivable — affiliate	0	5	[1]
Inventory	27	15	[1]
Derivative instruments	0	1	[1]
Notes receivable	6	6	[1]
Renewable energy grant receivable	0	147	[1]
Deferred income taxes	16	0	[1]
Prepayments and other current assets	21	27	[1]
Total current assets	606	378	[1]
Property, plant and equipment
In service	4,796	2,459	[1]
Under construction	8	6
Total property, plant and equipment	4,804	2,465	[1]
Less accumulated depreciation	-338	-174
Net property, plant and equipment	4,466	2,291	[1]
Other Assets
Equity investments in affiliates	227	227	[1]
Notes receivable	15	21	[1]
Intangible assets, net of accumulated amortization of $36 and $7	1,423	103	[1]
Derivative instruments	2	20	[1]
Deferred income taxes	118	146	[1]
Other non-current assets	108	50	[1]
Total other assets	1,893	569	[1]
Total Assets	6,965	3,238	[1]
Current Liabilities
Current portion of long-term debt	214	214	[1]
Accounts payable	20	42	[1]
Accounts payable — affiliate	46	52	[1]
Derivative instruments	48	31	[1]
Accrued expenses and other current liabilities	61	30	[1]
Total current liabilities	389	369	[1]
Total current liabilities
Long-term debt	4,573	1,569	[1]
Derivative instruments	69	16	[1]
Other non-current liabilities	49	32	[1]
Total non-current liabilities	4,691	1,617	[1]
Total Liabilities	5,080	1,986	[1]
Commitments and Contingencies	0	0	[1]
Stockholders' Equity
Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued	0	0	[1]
Additional Paid in Capital	1,240	621	[1]
Retained Earnings (Accumulated Deficit)	3	8	[1]
Accumulated Other Comprehensive Income (Loss), Net of Tax	-9	0	[1]
Noncontrolling interest	651	623	[1]
Total Stockholders' Equity	1,885	1,252	[1]
Total Liabilities and Stockholders’ Equity	6,965	3,238	[1]
Common Stock [Member]
Stockholders' Equity
Common Stock, Value, Issued	0	0	[1]
Common Class C [Member]
Stockholders' Equity
Total Stockholders' Equity	0	0
Common Class B [Member]
Stockholders' Equity
Total Stockholders' Equity	0	0
Common Class D [Member]
Stockholders' Equity
Total Stockholders' Equity	$0	$0
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Intangible assets, accumulated amortization	$36	$7
Common Stock, Par or Stated Value Per Share		$0.01
Preferred Stock, Par or Stated Value Per Share	$0.01	$0.01
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
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	34,586,250	22,511,250
Common Class C [Member]
Common Stock, Par or Stated Value Per Share	$0.01
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common Stock, Shares, Issued	34,586,250	22,511,250
Common Class B [Member]
Common Stock, Par or Stated Value Per Share	$10,000
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	42,738,750	42,738,750
Common Class D [Member]
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common Stock, Shares, Issued	42,738,750	42,738,750

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements Of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Interest Paid, Net	($174,000,000)		($63,000,000)		($17,000,000)
Cash Flows from Operating Activities
Net income/(loss)	112,000,000		132,000,000	[1]	12,000,000	[1]
Adjustments to reconcile net income to net cash provided by operating activities:
Distributions and equity in earnings of unconsolidated affiliates	-3,000,000		-6,000,000		2,000,000
Depreciation and amortization	166,000,000		61,000,000	[1]	25,000,000	[1]
Amortization of financing costs and debt discount/premiums	10,000,000		4,000,000		0
Amortization of intangibles and out-of-market contracts	27,000,000		1,000,000		0
Changes in deferred income taxes	4,000,000		8,000,000		10,000,000
Changes in derivative instruments	-8,000,000		-21,000,000		2,000,000
Changes in other working capital	-15,000,000		-59,000,000		5,000,000
Net Cash Provided by Operating Activities	293,000,000		120,000,000		56,000,000
Cash Flows from Investing Activities
Capital expenditures	-33,000,000		-353,000,000		-564,000,000
Acquisition of businesses, net of cash acquired	-901,000,000		-120,000,000		0
Decrease (increase) in restricted cash	50,000,000		-43,000,000		-12,000,000
Decrease (increase) in notes receivable, including affiliates	8,000,000		10,000,000		-17,000,000
Proceeds from renewable energy grants	137,000,000		25,000,000		28,000,000
Investments in unconsolidated affiliates	7,000,000		-34,000,000		-27,000,000
Other	11,000,000		0		-2,000,000
Net Cash Used in Investing Activities	-1,057,000,000		-515,000,000		-594,000,000
Cash Flows from Financing Activities
Distributions and return of capital to NRG	-84,000,000				-72,000,000
Proceeds from issuance of Class A common stock			468,000,000		0
Payment of dividends and distributions	-101,000,000		-15,000,000		0
Proceeds from issuance of long-term debt — external	975,000,000		594,000,000		308,000,000
Payment of debt issuance costs	-36,000,000		-5,000,000		-12,000,000
Net Cash Provided by Financing Activities	1,111,000,000		432,000,000		536,000,000
Net Increase (Decrease) in Cash and Cash Equivalents	347,000,000		37,000,000		-2,000,000
Cash and Cash Equivalents at Beginning of Period	59,000,000	[1]	22,000,000		24,000,000
Cash and Cash Equivalents at End of Period	406,000,000		59,000,000	[1]	22,000,000
Additions to fixed assets for accrued capital expenditures	0		1,000,000		121,000,000
Decrease to fixed assets for accrued grants	0		-207,000,000		-1,000,000
Decrease to fixed assets for deferred tax asset	0		-12,000,000		0
Non-cash addition to additional paid-in capital for change in tax basis of property, plant and equipment for assets acquired from NRG	-14,000,000
Proceeds from Contributions from Affiliates	16,000,000
Affiliated Entity [Member]
Cash Flows from Financing Activities
Capital contributions from NRG	2,000,000		171,000,000		355,000,000
Distributions and return of capital to NRG			-707,000,000		-72,000,000
Payments for long-term debt — affiliate	0		-2,000,000		-6,000,000
Non-affiliated Entity [Member]
Cash Flows from Financing Activities
Payments for long-term debt — external	-273,000,000		-72,000,000		-37,000,000
Non-cash [Member]
Cash Flows from Financing Activities
Distributions and return of capital to NRG	0		-76,000,000		0
Non-cash addition to additional paid-in capital for change in tax basis of property, plant and equipment for assets acquired from NRG	-14,000,000				0
Proceeds from Contributions from Affiliates	16,000,000		80,000,000		166,000,000
ROFO Assets [Member]
Cash Flows from Investing Activities
Acquisition of businesses, net of cash acquired	$336,000,000		$0		$0
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders Equity (USD $)	0 Months Ended		3 Months Ended				6 Months Ended		7 Months Ended		12 Months Ended
	Jul. 22, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2013		Jul. 22, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Apr. 01, 2014	Dec. 31, 2011
Statement of Stockholders' Equity
Total Stockholders' Equity	$986,000,000		$1,885,000,000		$1,252,000,000	[1]	$1,252,000,000	[1]	$986,000,000		$1,885,000,000		$1,252,000,000	[1]	$1,002,000,000			$561,000,000
Assets Transferred, Carrying Value																	460,000,000
Retained Earnings (Accumulated Deficit)			3,000,000		8,000,000	[1]	8,000,000	[1]			3,000,000		8,000,000	[1]
Allocation of Predecessor's equity							0
Less: Net income attributable to NRG (b)							78,000,000				64,000,000
Net income attributable to NRG Yield, Inc.			0		4,000,000						16,000,000		13,000,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			-5,000,000	[2]	-37,000,000				-54,000,000		-112,000,000		-132,000,000	[1]	-12,000,000	[1]
Unrealized gain/(loss) on derivatives							6,000,000		38,000,000		-52,000,000				-20,000,000
Net Assets Acquired, ROFO Assets											-357,000,000
Partners' Capital Account, Contributions															355,000,000
Proceeds from Contributions from Affiliates							-14,000,000				-16,000,000
Partners' Capital Account, Return of Capital							-395,000,000
Payments of Capital Distribution									-312,000,000		-84,000,000				-72,000,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders							-43,000,000
Common Stock, Value, Issued							468,000,000				630,000,000
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt											23,000,000
Non-cash addition to additional paid-in capital for change in tax basis of property, plant and equipment for assets acquired from NRG							153,000,000				-14,000,000
Payments of Ordinary Dividends, Common Stock							-15,000,000
Proceeds from issuance of Class A common stock	468,000,000												468,000,000		0
Preferred Stock [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity	0		0		0		0		0		0		0		0			0
Additional Paid-in Capital
Statement of Stockholders' Equity
Total Stockholders' Equity	0		1,240,000,000		621,000,000		621,000,000		0		1,240,000,000		621,000,000		0			0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest															-12,000,000	[3]
Unrealized gain/(loss) on derivatives									38,000,000	[3]					-20,000,000	[3]
Common Stock, Value, Issued							468,000,000
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt											23,000,000
Non-cash addition to additional paid-in capital for change in tax basis of property, plant and equipment for assets acquired from NRG											-14,000,000
Payments of Ordinary Dividends, Common Stock											-20,000,000
Proceeds from issuance of Class A common stock											630,000,000
Other Additional Capital [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity	986,000,000	[3]	0		0		0		986,000,000	[3]	0		0		1,002,000,000	[3]		561,000,000	[3]
Allocation of Predecessor's equity							-591,000,000	[3]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest									-54,000,000	[3]
Partners' Capital Account, Return of Capital							-395,000,000	[3]
Payments of Capital Distribution									-312,000,000	[3]
Retained Earnings
Statement of Stockholders' Equity
Total Stockholders' Equity	0				8,000,000		8,000,000		0				8,000,000		0			0
Net income attributable to NRG Yield, Inc.											16,000,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest							-13,000,000
Accumulated Other Comprehensive Income (Loss)
Statement of Stockholders' Equity
Total Stockholders' Equity	0		-9,000,000		0		0		0		-9,000,000		0		0			0
Allocation of Predecessor's equity							3,000,000
Unrealized gain/(loss) on derivatives							-3,000,000				-9,000,000				0
Noncontrolling Interest
Statement of Stockholders' Equity
Total Stockholders' Equity	0		651,000,000		623,000,000		623,000,000		0		651,000,000		623,000,000		0
Allocation of Predecessor's equity							588,000,000
Less: Net income attributable to NRG (b)							65,000,000				48,000,000	[4]	42,000,000	[1],[4]
Unrealized gain/(loss) on derivatives											-43,000,000		9,000,000
Net Assets Acquired, ROFO Assets											-357,000,000
Proceeds from Contributions from Affiliates											-16,000,000
Payments of Capital Distribution											-84,000,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders							-43,000,000
Non-cash addition to additional paid-in capital for change in tax basis of property, plant and equipment for assets acquired from NRG											0
Common Class D [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity	0		0		0		0		0		0		0		0			0
Common Class C [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity	0		0		0		0		0		0		0		0			0
Net income attributable to NRG Yield, Inc.											8,000,000		6,500,000
Common Class B [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity	0		0		0		0		0		0		0		0			0
Payments of Ordinary Dividends, Common Stock											-101,000,000
Common Class B [Member] | Noncontrolling Interest
Statement of Stockholders' Equity
Payments of Ordinary Dividends, Common Stock							-10,000,000				-60,000,000
Common Class A [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity	0		0		0		0		0		0		0		0			0
Net income attributable to NRG Yield, Inc.											8,000,000		6,500,000
Common Class A [Member] | Retained Earnings
Statement of Stockholders' Equity
Payments of Ordinary Dividends, Common Stock							-5,000,000				-21,000,000
Scenario, Previously Reported [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity																		387,000,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			10,000,000		-24,000,000								-109,000,000
Scenario, Previously Reported [Member] | Other Additional Capital [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity																		387,000,000	[3]
Cash [Member] | Additional Paid-in Capital
Statement of Stockholders' Equity
Proceeds from Contributions from Affiliates															-355,000,000	[3]
Non-cash [Member]
Statement of Stockholders' Equity
Proceeds from Contributions from Affiliates									-66,000,000		-16,000,000		-80,000,000		-166,000,000
Payments of Capital Distribution									-33,000,000		0		-76,000,000		0
Non-cash addition to additional paid-in capital for change in tax basis of property, plant and equipment for assets acquired from NRG							153,000,000				-14,000,000				0
Non-cash [Member] | Additional Paid-in Capital
Statement of Stockholders' Equity
Proceeds from Contributions from Affiliates															-166,000,000	[3]
Payments of Capital Distribution															-72,000,000	[3]
Non-cash [Member] | Other Additional Capital [Member]
Statement of Stockholders' Equity
Proceeds from Contributions from Affiliates									-66,000,000	[3]
Payments of Capital Distribution									-33,000,000	[3]
Non-cash [Member] | Noncontrolling Interest
Statement of Stockholders' Equity
Proceeds from Contributions from Affiliates							-14,000,000
Acquired ROFO Assets [Domain]
Statement of Stockholders' Equity
Total Stockholders' Equity																		174,000,000
Proceeds from Contributions from Affiliates									-171,000,000
Acquired ROFO Assets [Domain] | Other Additional Capital [Member]
Statement of Stockholders' Equity
Total Stockholders' Equity																		174,000,000	[3]
Proceeds from Contributions from Affiliates									-171,000,000	[3]
EME-NYLD Assets [Member] | Noncontrolling Interest
Statement of Stockholders' Equity
Assets Transferred, Carrying Value																	460,000,000
Drop-down Acquisition [Member]
Statement of Stockholders' Equity
Less: Net income attributable to NRG (b)											48,000,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest											($48,000,000)		($23,000,000)	[1]
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	The Company's unaudited quarterly financial data was recast for the effect of the EME-NYLD-Eligible Assets, from the date the entities were under common control or April 1, 2014.
[3]	(a) Retrospectively adjusted starting on January 1, 2012, as discussed in Note 1, Nature of Business.
[4]	The calculation of income attributable to NRG excludes pre-acquisition net income of the Drop Down Assets.

Schedule_1_Yield_Incs_FS_2014_

Schedule 1 - Yield, Inc,'s FS 2014, 2013 NRG Yield PL (USD $)	6 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014		Dec. 31, 2013
Interest Expense		($186,000,000)		($52,000,000)	[1]
Income Before Income Taxes		116,000,000	[2]	140,000,000	[1],[3]
Net Income		112,000,000		132,000,000	[1]
Income tax expense		4,000,000	[2]	8,000,000	[1],[3]
Less: Net income attributable to NRG (b)	78,000,000	64,000,000
Net income attributable to NRG Yield, Inc.		16,000,000		13,000,000
Common Class A [Member]
Net income attributable to NRG Yield, Inc.		8,000,000		6,500,000
Drop-down Acquisition [Member]
Net Income		48,000,000		23,000,000	[1]
Less: Net income attributable to NRG (b)		48,000,000
NRG Yield, Inc.
Equity in Earnings of Consolidated Subsidiaries		121,000,000		86,000,000
Interest Expense		-5,000,000		0
Income Before Income Taxes		116,000,000		86,000,000
Net Income		112,000,000		78,000,000
Income tax expense		4,000,000		8,000,000
Less: Net income attributable to NRG (b)	42,000,000	48,000,000
Net income attributable to NRG Yield, Inc.	$13,000,000	$16,000,000
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	(a) - Represents 34.5% ownership for the period July 22, 2013 through December 31, 2013
[3]	(b) - Represents pro forma tax provision for NRG Yield LLC

Schedule_1_Yield_Incs_FS_2014_1

Schedule 1 - Yield, Inc,'s FS 2014, 2013 NRG Yield BS (USD $)	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
In Millions, except Share data, unless otherwise specified
Deferred income taxes	$16	$0	[1]
Cash and cash equivalents	406	59	[1]	22
Deferred Tax Assets, Gross	118	146	[1]
Total Assets	6,965	3,238	[1]
Long-term Debt	4,806	1,783
Total Liabilities	5,080	1,986	[1]
Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued	0	0	[1]
Additional Paid in Capital	1,240	621	[1]
Retained Earnings (Accumulated Deficit)	3	8	[1]
Accumulated Other Comprehensive Income (Loss), Net of Tax	-9	0	[1]
Noncontrolling interest	651	623	[1]
Total Stockholders' Equity	1,885	1,252	[1]	1,002
Total Liabilities and Stockholders’ Equity	6,965	3,238	[1]
Common Stock, Par or Stated Value Per Share		$0.01
Preferred Stock, Par or Stated Value Per Share	$0.01	$0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	0	0
Common Class A [Member]
Total Stockholders' Equity	0	0		0
Common Stock, Par or Stated Value Per Share	$0.01
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	34,586,250	22,511,250
Common Stock [Member]
Common Stock, Value, Issued	0	0	[1]
Common Class B [Member]
Total Stockholders' Equity	0	0		0
Common Stock, Par or Stated Value Per Share	$10,000
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	42,738,750	42,738,750
NRG Yield, Inc.
Deferred income taxes	16	0
Investments in subsidiaries	1,735	1,106
Deferred Finance Costs, Noncurrent, Net	5	0
Notes Receivable, Related Parties	337	0
Deferred Tax Assets, Gross	118	146
Total Assets	2,211	1,252
Deferred income taxes	0	0
Long-term Debt	326	0
Total Liabilities	326	0
Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued	0	0
Additional Paid in Capital	1,240	621
Retained Earnings (Accumulated Deficit)	3	8
Accumulated Other Comprehensive Income (Loss), Net of Tax	-9	0
Noncontrolling interest	651	623
Total Stockholders' Equity	1,885	1,252
Total Liabilities and Stockholders’ Equity	2,211	1,252
Preferred Stock, Par or Stated Value Per Share	$0.01			$0
Preferred Stock, Shares Authorized	10,000,000			0
Preferred Stock, Shares Issued	0			0
NRG Yield, Inc. | Common Class A [Member]
Common Stock, Par or Stated Value Per Share	$0.01			$0
Common Stock, Shares Authorized	500,000,000			0
Common Stock, Shares, Issued	22,511,250			0
NRG Yield, Inc. | Common Stock [Member]
Common Stock, Value, Issued	0	0
NRG Yield, Inc. | Common Class B [Member]
Common Stock, Shares Authorized	500,000,000			0
Common Stock, Shares, Issued	42,738,750			0
NRG Yield [Member]
Cash and cash equivalents	$0	$0
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Schedule_1_Yield_Incs_FS_2014_2

Schedule 1 - Yield, Inc,'s FS 2014, 2013 NRG Yield CF (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Operating Income (Loss)	$272,000,000	$167,000,000	[1]
Income (Loss) from Equity Method Investments	-27,000,000	-22,000,000	[1]
Net Cash Provided by (Used in) Operating Activities	293,000,000	120,000,000
Payments of Capital Distribution	-84,000,000
Proceeds from Issuance of Long-term Debt	975,000,000	594,000,000
Net Cash Used in Investing Activities	-1,057,000,000	-515,000,000
Proceeds from issuance of Class A common stock		468,000,000
Proceeds from Contributions from Affiliates	16,000,000
Net Cash Provided by Financing Activities	1,111,000,000	432,000,000
Cash and Cash Equivalents, Period Increase (Decrease)	347,000,000	37,000,000
Cash and cash equivalents	406,000,000	59,000,000	[1]
NRG Yield [Member]
Net Cash Provided by (Used in) Operating Activities	-1,000,000	5,000,000
Payments of Capital Distribution	-630,000,000	-468,000,000
Proceeds from Issuance of Long-term Debt	345,000,000	0
Increase (Decrease) in Notes Receivable, Related Parties	-337,000,000	0
Net Cash Used in Investing Activities	-967,000,000	-468,000,000
Proceeds from issuance of Class A common stock	630,000,000	468,000,000
Payments of Financing Costs	-7,000,000	0
Proceeds from Contributions from Affiliates	41,000,000	0
Payments of Ordinary Dividends, Common Stock	-41,000,000	-5,000,000
Net Cash Provided by Financing Activities	968,000,000	463,000,000
Cash and Cash Equivalents, Period Increase (Decrease)	0	0
Cash and cash equivalents	0	0
Affiliated Entity [Member]
Payments of Capital Distribution		($707,000,000)
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Nature_of_Business

Nature of Business	12 Months Ended
	Dec. 31, 2014
Nature of Business Disclosure [Abstract]
Nature of Business	Nature of Business
	NRG Yield, Inc., or the Company, is a dividend growth-oriented company formed on December 20, 2012.The Company used the net proceeds from its initial public offering of Class A common stock on July 22, 2013 to acquire 100%, or 22,511,250, of the Class A units of NRG Yield LLC. In connection with the acquisition of the Class A units, the Company also became the sole managing member of NRG Yield LLC, thereby acquiring a controlling interest. 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.
	Prior to the secondary offering, the Company and NRG owned 34.5% and 65.5% of NRG Yield LLC, respectively. On July 29, 2014, the Company issued 12,075,000 shares of Class A common stock in a secondary offering for net proceeds, after underwriting discount and expenses, of $630 million. The Company utilized the proceeds of the offering to acquire 12,075,000 additional Class A units of NRG Yield LLC and, as a result, subsequent to the secondary offering and as of December 31, 2014, the Company owns 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 issued and outstanding shares of Class A common stock are entitled to 100% of the Company's economic interests and are entitled to dividends. NRG receives distributions from Yield LLC through its ownership of Class B common units.
	On May 5, 2015, the Company's stockholders approved amendments to the Company's certificate of incorporation that resulted in the creation of two new classes of capital stock, Class C common stock and Class D common stock. The recapitalization became effective on May 14, 2015, with the split of each outstanding share of Class A common stock into one share of Class A common stock and one share of Class C common stock, and the split of each outstanding share of Class B common stock into one share of Class B common stock and one share of Class D common stock.
	The Class C common stock and Class D common stock have the same rights and privileges and rank equally, share ratably and are 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 is 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 remains unchanged at $0.01 per share after the effect of the stock split described above. Accordingly, the stock split is accounted for as a stock dividend. The Company recorded 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 also gave retrospective effect to prior period share and per share amounts in the audited historical consolidated financial statements for the effect of the stock dividend, such that all periods are comparable. As such, the Company's historical financial statements previously filed with the SEC have been recast in this Current Report on Form 8-K to include the retrospective effect of the stock split on all the periods reported.
	As described in Note 3, Business Acquisitions, on June 30, 2014, NRG Yield Operating LLC acquired the TA High Desert, RE Kansas South, and El Segundo projects, or the Acquired ROFO Assets, from NRG for total cash consideration of $357 million plus assumed project level debt. Additionally, as described in Note 3, Business Acquisitions, on January 2, 2015, NRG Yield Operating LLC acquired Pinnacle, Buffalo Bear and Taloga, or the Tapestry projects, as well as Laredo Ridge and Walnut Creek, or collectively, the EME-NYLD-Eligible Assets, for total cash consideration of $489 million, plus assumed project-level debt. The acquisitions of the Acquired ROFO Assets and the EME-NYLD-Eligible Assets, or collectively the Drop Down Assets, from NRG were accounted for as transfers of entities 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 were recorded as a distribution to NRG and reduced the balance of its noncontrolling interest. 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 transfers as if they had taken place from the beginning of the financial statements period, or from the date the entities were under common control, which was January 1, 2013 for El Segundo, May 13, 2013, for RE Kansas South, March 28, 2013, for TA High Desert and April 1, 2014, for Laredo Ridge, Walnut Creek and Tapestry. For RE Kansas South, TA High Desert, Laredo Ridge, Walnut Creek and Tapestry, the dates represent the dates these entities were acquired by NRG. Member's equity represents NRG's equity in the subsidiaries, and accordingly, in connection with the acquisition by the Company, the balances were reclassified into noncontrolling interest. The Company's historical financial statements in all reports filed with the SEC subsequent to June 30, 2014, were previously recast to include the results attributable to the Acquired ROFO Assets. The Company's historical financial statements for and as of the year ended December 31, 2014 previously filed with the SEC have been recast in this Current Report on Form 8-K to include the results attributable to the EME-NYLD-Eligible Assets from the date these entities were under common control, or April 1, 2014.
	The following table represents the structure of the Company as of December 31, 2014, with the retrospective application of the stock split that took place on May 14, 2015:
	For all periods prior to the initial public offering, the accompanying combined financial statements represent the combination of the assets that NRG Yield LLC acquired and were prepared using NRG's historical basis in the assets and liabilities. For the purposes of the combined financial statements, the term "NRG Yield" represents the accounting predecessor, or the combination of the acquired businesses. For all periods subsequent to the initial public offering, the accompanying audited consolidated financial statements represent the consolidated results of the Company, which consolidates NRG Yield LLC through its controlling interest.
	As of December 31, 2014, 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
	RE 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	%	124	Various	Various
	Total net capacity (excluding equivalent MWt)			3,754
	(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 December 31, 2014.
	(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.
	The historical combined financial statements include allocations of certain NRG corporate expenses. Management believes the assumptions and methodology underlying the allocation of general corporate overhead expenses are reasonable. The allocated costs include legal, accounting, tax, treasury, information technology, insurance, employee benefit costs, and other corporate costs. However, such expenses may not be indicative of the actual level of expense that would have been incurred if the Company had operated as an independent, publicly-traded company during the periods prior to the offering or of the costs expected to be incurred in the future. Allocations of NRG corporate expenses were $4 million for the period beginning on January 1, 2013 and ending on July 22, 2013 and $7 million for the year ended December 31, 2012. 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 for the period beginning July 23, 2013 and ending December 31, 2013 and $8 million for the year ended December 31, 2014, which included certain direct expenses incurred by NRG on behalf of the Company.
	For all periods prior to the initial public offering, member's equity represents the combined equity of the Company's subsidiaries, including adjustments necessary to present the Company's financial statements as if the Company were in existence as of the beginning of the periods presented. Member's equity represents NRG's equity in the subsidiaries, and accordingly, in connection with the initial public offering, the historical equity balance as of that date was reclassified into noncontrolling interest. Subsequent to the initial public offering, 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.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Basis of Presentation and Principles of Consolidation
	The Company's consolidated and combined financial statements have been prepared in accordance with U.S. GAAP. The Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or ASC, is the source of authoritative U.S. GAAP to be applied by nongovernmental entities. In addition, the rules and interpretative releases of the SEC under authority of federal securities laws are also sources of authoritative U.S. GAAP for SEC registrants.
	The consolidated and combined financial statements include the Company's accounts and operations and those of its subsidiaries in which it has a controlling interest. All significant intercompany transactions and balances have been eliminated in consolidation. The usual condition for a controlling financial interest is ownership of a majority of the voting interests of an entity. However, a controlling financial interest may also exist through arrangements that do not involve controlling voting interests. As such, the Company applies the guidance of ASC 810, Consolidations, or ASC 810, to determine when an entity that is insufficiently capitalized or not controlled through its voting interests, referred to as a variable interest entity, or VIE, should be consolidated.
	Cash and Cash Equivalents
	Cash and cash equivalents include highly liquid investments with an original maturity of three months or less at the time of purchase.
	Restricted Cash
	Restricted cash consists primarily of funds held to satisfy the requirements of certain debt agreements and funds held within the Company's projects that are restricted in their use. These funds are used to pay for capital expenditures, current operating expenses and current debt service payments as well as to fund required equity contributions, per the restrictions of the debt agreements.
	Trade Receivables and Allowance for Doubtful Accounts
	Trade receivables are reported on the balance sheet at the invoiced amount adjusted for any write-offs and the allowance for doubtful accounts. The allowance for doubtful accounts is reviewed periodically based on amounts past due and significance. The allowance for doubtful accounts was immaterial as of December 31, 2014, and 2013.
	Inventory
	Inventory consists principally of spare parts and fuel oil and is valued at the lower of weighted average cost or market, unless evidence indicates that the weighted average cost will be recovered with a normal profit in the ordinary course of business. The Company removes fuel inventories as they are used in the production of steam, chilled water or electricity. Spare parts inventory are removed when they are used for repairs, maintenance or capital projects.
	Property, Plant and Equipment
	Property, plant and equipment are stated at cost or, in the case of business acquisitions, fair value; however impairment adjustments are recorded whenever events or changes in circumstances indicate that their carrying values may not be recoverable. See Note 3, Business Acquisitions, for more information on acquired property, plant and equipment. Significant additions or improvements extending asset lives are capitalized as incurred, while repairs and maintenance that do not improve or extend the life of the respective asset are charged to expense as incurred. Depreciation is computed using the straight-line method over the estimated useful lives. Certain assets and their related accumulated depreciation amounts are adjusted for asset retirements and disposals with the resulting gain or loss included in cost of operations in the consolidated statements of operations.
	Additionally, the Company reduces the book value of the property, plant and equipment of its eligible renewable energy projects for any cash grants that are submitted to the U.S. Treasury Department when the receivable is recorded for the net realizable amount. The related deferred tax asset is also recorded with a corresponding reduction to the book value of the property, plant and equipment. For further discussion of these matters see Note 4, Property, Plant and Equipment.
	Asset Impairments
	Long-lived assets that are held and used are reviewed for impairment whenever events or changes in circumstances indicate carrying values may not be recoverable. Such reviews are performed in accordance with ASC 360. An impairment loss is recognized if the total future estimated undiscounted cash flows expected from an asset are less than its carrying value. An impairment charge is measured by the difference between an asset's carrying amount and fair value with the difference recorded in operating costs and expenses in the statements of operations. Fair values are determined by a variety of valuation methods, including appraisals, sales prices of similar assets and present value techniques.
	Investments accounted for by the equity method are reviewed for impairment in accordance with ASC 323, Investments-Equity Method and Joint Ventures, or ASC 323, which requires that a loss in value of an investment that is other than a temporary decline should be recognized. The Company identifies and measures losses in the value of equity method investments based upon a comparison of fair value to carrying value.
	Capitalized Interest
	Interest incurred on funds borrowed to finance capital projects is capitalized, until the project under construction is ready for its intended use. The amount of interest capitalized for the years ended December 31, 2014, 2013 and 2012 was less than $1 million, $18 million and $31 million, respectively.
	When a project is available for operations, capitalized interest is reclassified to property, plant and equipment and amortized on a straight-line basis over the estimated useful life of the project's related assets.
	Debt Issuance Costs
	Debt issuance costs are capitalized and amortized as interest expense on a basis which approximates the effective interest method over the term of the related debt.
	Intangible Assets
	Intangible assets represent contractual rights held by NRG Yield, Inc. The Company recognizes specifically identifiable intangible assets including customer contracts, customer relationship, power purchase agreements and development rights when specific rights and contracts are acquired. These intangible assets are amortized primarily on a straight-line basis.
	Notes Receivable
	Notes receivable consist of receivables related to the financing of required network upgrades and a variable-rate note secured by the equity interest in a joint venture. The notes issued with respect to network upgrades will be repaid within a 5 year period following the date each facility reaches commercial operations.
	Income Taxes
	The Company accounts for income taxes using the liability method in accordance with ASC 740, Income Taxes, or ASC 740, which requires that it use the asset and liability method of accounting for deferred income taxes and provide deferred income taxes for all significant temporary differences.
	The Company has two categories of income tax expense or benefit — current and deferred, as follows:
	•	Current income tax expense or benefit consists solely of current taxes payable less applicable tax credits, and
	•	Deferred income tax expense or benefit is the change in the net deferred income tax asset or liability, excluding amounts charged or credited to accumulated other comprehensive income.
	The Company reports some of its revenues and expenses differently for financial statement purposes than for income tax return purposes, resulting in temporary and permanent differences between the Company's financial statements and income tax returns. The tax effects of such temporary differences are recorded as either deferred income tax assets or deferred income tax liabilities in the Company's consolidated balance sheets. The Company measures its deferred income tax assets and deferred income tax liabilities using income tax rates that are currently in effect. The Company believes it is more likely than not that the results of future operations will generate sufficient taxable income which includes the future reversal of existing taxable temporary differences to realize deferred tax assets, net of valuation allowances. A valuation allowance is recorded to reduce the net deferred tax assets to an amount that is more-likely-than-not to be realized.
	The Company accounts for uncertain tax positions in accordance with ASC 740, which applies to all tax positions related to income taxes. Under ASC 740, tax benefits are recognized when it is more-likely-than-not that a tax position will be sustained upon examination by the authorities. The benefit recognized from a position that has surpassed the more-likely-than-not threshold is the largest amount of benefit that is more than 50% likely to be realized upon settlement. The Company recognizes interest and penalties accrued related to uncertain tax benefits as a component of income tax expense.
	In accordance with ASC 805 and as discussed further in Note 13, Income Taxes, changes to existing net deferred tax assets or valuation allowances or changes to uncertain tax benefits, are recorded to income tax expense.
	Revenue Recognition
	Thermal Revenues
	Steam and chilled water revenue is recognized based on customer usage as determined by meter readings taken at month-end. Some locations read customer meters throughout the month, and recognize estimated revenue for the period between meter read date and month-end. The Thermal Business subsidiaries collect and remit state and local taxes associated with sales to their customers, as required by governmental authorities. Related revenues are presented on a net basis in the income statement.
	Power Purchase Agreements, or PPAs
	The majority of the Company’s revenues are obtained through PPAs or other contractual agreements. In order to determine lease classification as operating, the Company evaluates the terms of the PPA to determine if the lease includes any of the following provisions which would indicate capital lease treatment:
	•	Transfers the ownership of the generating facility,
	•	Bargain purchase option at the end of the term of the lease,
	•	Lease term is greater than 75% of the economic life of the generating facility, or
	•	Present value of minimum lease payments exceed 90% of the fair value of the generating facility at inception of the lease
	In considering the above it was determined that all of Company’s PPAs are operating leases. ASC 840 requires the minimum lease payments received to be amortized over the term of the lease and contingent rentals are recorded when the achievement of the contingency becomes probable. Judgment is required by management in determining the economic life of each generating facility, in evaluating whether certain lease provisions constitute minimum payments or represent contingent rent and other factors in determining whether a contract contains a lease and whether the lease is an operating lease or capital lease.
	Certain of these leases have no minimum lease payments and all of the rental income under these leases is recorded as contingent rent on an actual basis when the electricity is delivered. The contingent rental income recognized in the years ended December 31, 2014, 2013 and 2012 was $194 million, $105 million and $33 million, respectively.
	Derivative Financial Instruments
	The Company accounts for derivative financial instruments under ASC 815, Derivatives and Hedging, or ASC 815, which requires the Company to record all derivatives on the balance sheet at fair value unless they qualify for a NPNS exception. Changes in the fair value of non-hedge derivatives are immediately recognized in earnings. Changes in the fair value of derivatives accounted for as hedges, if elected for hedge accounting, are either:
	•	Recognized in earnings as an offset to the changes in the fair value of the related hedged assets, liabilities and firm commitments; or
	•	Deferred and recorded as a component of accumulated OCI until the hedged transactions occur and are recognized in earnings.
	The Company's primary derivative instruments are fuels purchase contracts used to control customer reimbursable fuel cost and interest rate instruments used to mitigate variability in earnings due to fluctuations in interest rates. On an ongoing basis, the Company assesses the effectiveness of all derivatives that are designated as hedges for accounting purposes in order to determine that each derivative continues to be highly effective in offsetting changes in fair values or cash flows of hedged items. Internal analyses that measure the statistical correlation between the derivative and the associated hedged item determine the effectiveness of such a contract designated as a hedge. If it is determined that the derivative instrument is not highly effective as a hedge, hedge accounting will be discontinued prospectively. In this case, the gain or loss previously deferred in accumulated OCI would be frozen until the underlying hedged item is delivered unless the transaction being hedged is no longer probable of occurring in which case the amount in OCI would be immediately reclassified into earnings. If the derivative instrument is terminated, the effective portion of this derivative deferred in accumulated OCI will be frozen until the underlying hedged item is delivered.
	Revenues and expenses on contracts that qualify for the NPNS exception are recognized when the underlying physical transaction is delivered. While these contracts are considered derivative financial instruments under ASC 815, they are not recorded at fair value, but on an accrual basis of accounting. If it is determined that a transaction designated as NPNS no longer meets the scope exception, the fair value of the related contract is recorded on the balance sheet and immediately recognized through earnings.
	Concentrations of Credit Risk
	Financial instruments which potentially subject the Company to concentrations of credit risk consist primarily of accounts receivable, notes receivable and derivative instruments. Accounts receivable, notes receivable, and derivative instruments are concentrated within entities engaged in the energy and financial industry. These industry concentrations may impact the overall exposure to credit risk, either positively or negatively, in that the customers may be similarly affected by changes in economic, industry or other conditions. In addition, many of the Company's projects have only one customer. However, the Company believes that the credit risk posed by industry concentration is offset by the diversification and creditworthiness of its customer base. See Note 6, Fair Value of Financial Instruments, for a further discussion of derivative concentrations and Note 12, Segment Reporting for concentration of counterparties.
	Fair Value of Financial Instruments
	The carrying amount of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, intercompany accounts payable and receivable, and accrued expenses and other liabilities approximate fair value because of the short-term maturity of these instruments. See Note 6, Fair Value of Financial Instruments, for a further discussion of fair value of financial instruments.
	Asset Retirement Obligations
	Asset retirement obligations, or AROs, are accounted for in accordance with ASC 410-20, Asset Retirement Obligations, or ASC 410-20. Retirement obligations associated with long-lived assets included within the scope of ASC 410-20 are those for which a legal obligation exists under enacted laws, statutes, and written or oral contracts, including obligations arising under the doctrine of promissory estoppel, and for which the timing and/or method of settlement may be conditional on a future event. ASC 410-20 requires an entity to recognize the fair value of a liability for an ARO in the period in which it is incurred and a reasonable estimate of fair value can be made.
	Upon initial recognition of a liability for an ARO, the asset retirement cost is capitalized by increasing the carrying amount of the related long-lived asset by the same amount. Over time, the liability is accreted to its future value, while the capitalized cost is depreciated over the useful life of the related asset. The Company's asset retirement obligations were $27 million and $9 million for the years ended December 31, 2014, and 2013, respectively. The Company records AROs as part of other non-current liabilities on its balance sheet.
	Guarantees
	The Company enters into various contracts that include indemnification and guarantee provisions as a routine part of its business activities. Examples of these contracts include EPC agreements, operation and maintenance agreements, service agreements, commercial sales arrangements and other types of contractual agreements with vendors and other third parties, as well as affiliates. These contracts generally indemnify the counterparty for tax, environmental liability, litigation and other matters, as well as breaches of representations, warranties and covenants set forth in these agreements. Because many of the guarantees and indemnities the Company issues to third parties and affiliates do not limit the amount or duration of its obligations to perform under them, there exists a risk that the Company may have obligations in excess of the amounts agreed upon in the contracts mentioned above. For those guarantees and indemnities that do not limit the liability exposure, it may not be able to estimate what the liability would be, until a claim is made for payment or performance, due to the contingent nature of these contracts.
	Investments Accounted for by the Equity Method
	The Company has investments in three energy projects accounted for by the equity method, one of which is a VIE, where the Company is not a primary beneficiary. The equity method of accounting is applied to these investments in affiliates because the ownership structure prevents the Company from exercising a controlling influence over the operating and financial policies of the projects. Under this method, equity in pre-tax income or losses of the investments is reflected as equity in earnings of unconsolidated affiliates.
	Sale Leaseback Arrangements
The Company is party to sale-leaseback arrangements that provide for the sale of certain assets to a third party and simultaneous leaseback to the Company. In accordance with ASC 840-40, Sale-Leaseback Transactions, if the seller-lessee retains, through the leaseback, substantially all of the benefits and risks incident to the ownership of the property sold, the sale-leaseback transaction is accounted for as a financing arrangement. An example of this type of continuing involvement would include an option to repurchase the assets or the buyer-lessor having the option to sell the assets back to the Company. This provision is included in most of the Company’s sale-leaseback arrangements. As such, the Company accounts for these arrangements as financings.
Under the financing method, the Company does not recognize as income any of the sale proceeds received from the lessor that contractually constitutes payment to acquire the assets subject to these arrangements. Instead, the sale proceeds received are accounted for as financing obligations and leaseback payments made by the Company are allocated between interest expense and a reduction to the financing obligation. Interest on the financing obligation is calculated using the Company’s incremental borrowing rate at the inception of the arrangement on the outstanding financing obligation. Judgment is required to determine the appropriate borrowing rate for the arrangement and in determining any gain or loss on the transaction that would be recorded either at the end of or over the lease term.
Business Combinations
The Company accounts for its business combinations in accordance with ASC 805, Business Combinations, or ASC 805. ASC 805 requires an acquirer to recognize and measure in its financial statements the identifiable assets acquired, the liabilities assumed, and any noncontrolling interest in the acquiree at fair value at the acquisition date. It also recognizes and measures the goodwill acquired or a gain from a bargain purchase in the business combination and determines what information to disclose to enable users of an entity's financial statements to evaluate the nature and financial effects of the business combination. In addition, transaction costs are expensed as incurred.
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 amounts of assets and liabilities as of the date of the financial statements. They also impact the reported amount of net earnings during the reporting period. Actual results could be different from these estimates.
In recording transactions and balances resulting from business operations, the Company uses estimates based on the best information available. Estimates are used for such items as plant depreciable lives, tax provisions, uncollectible accounts, environmental liabilities, acquisition accounting and legal costs incurred in connection with recorded loss contingencies, among others. As better information becomes available or actual amounts are determinable, the recorded estimates are revised. Consequently, operating results can be affected by revisions to prior accounting estimates.
Reclassifications
Certain prior-year amounts have been reclassified for comparative purposes.
Recent Accounting Developments
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 is currently evaluating the impact of the standard on the Company's results of operations, cash flows and financial position.
ASU 2014-09 - In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU No. 2014-09. The amendments of ASU No. 2014-09 complete the joint effort between the FASB and the 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 considerations 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.
ASU 2013-11 - In July 2013, the FASB issued ASU No. 2013-11, Income Taxes (Topic 740) Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists, or ASU No. 2013-11.  The amendments of ASU 2013-11, require an entity to present an unrecognized tax benefit, or a portion of an unrecognized tax benefit, as a reduction of a deferred tax asset for an NOL, a similar tax loss or tax credit carryforwards rather than a liability when the uncertain tax position would reduce the NOL or other carryforward under the tax law of the applicable jurisdiction and the entity intends to use the deferred tax asset for that purpose.  The guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The Company adopted this standard effective January 1, 2014. The adoption of this standard did not impact the Company's results of operations or cash flows as the Company has no uncertain tax benefits as of December 31, 2014.

Business_Acquisitions

Business Acquisitions	12 Months Ended
	Dec. 31, 2014
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 Alta Wind Portfolio on January 1, 2013:
			For the year ended December 31,
	(In millions, except per share amounts)		2014			2013
	Operating Revenues		$	821		$	531
	Net Income		94			87
	Net Income Attributable to NRG Yield, Inc.		7			8
	Earnings per Weighted Average Class A and Class C Common Share - Basic and Diluted		$	0.1		$	0.12
Business Acquisition, Purchase Price [Table Text Block]	The purchase price of $923 million was provisionally allocated as follows:
			Acquisition Date			Measurement period adjustments				Revised Acquisition Date
			(In millions)
	Assets
	Cash		$	22		$	—			$	22
	Current and non-current assets		49			—				49
	Property, plant and equipment		1,057			247				1,304
	Intangible assets		1,420			(243		)		1,177
	Total assets acquired		2,548			4				2,552
	Liabilities
	Debt		1,591			—				1,591
	Current and non-current liabilities		34			4				38
	Total liabilities assumed		1,625			4				1,629
	Net assets acquired		$	923		$	—			$	923
Business Acquisition	Business Acquisitions
	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 and 22 years, beginning in 2016, for Alta X and XI.
	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 purchase price of $923 million was provisionally allocated as follows:
			Acquisition Date			Measurement period adjustments				Revised Acquisition Date
			(In millions)
	Assets
	Cash		$	22		$	—			$	22
	Current and non-current assets		49			—				49
	Property, plant and equipment		1,057			247				1,304
	Intangible assets		1,420			(243		)		1,177
	Total assets acquired		2,548			4				2,552
	Liabilities
	Debt		1,591			—				1,591
	Current and non-current liabilities		34			4				38
	Total liabilities assumed		1,625			4				1,629
	Net assets acquired		$	923		$	—			$	923
	The Company incurred and expensed acquisition-related transaction costs related to the acquisition of the Alta Wind Portfolio of $2 million for the year ended December 31, 2014.
	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.
	Supplemental Pro Forma Information
	Since the acquisition date, the Alta Wind Portfolio contributed $49 million in operating revenues and $39 million in net losses. The following unaudited supplemental pro forma information represents the results of operations as if the Company had acquired the Alta Wind Portfolio on January 1, 2013:
			For the year ended December 31,
	(In millions, except per share amounts)		2014			2013
	Operating Revenues		$	821		$	531
	Net Income		94			87
	Net Income Attributable to NRG Yield, Inc.		7			8
	Earnings per Weighted Average Class A and Class C Common Share - Basic and Diluted		$	0.1		$	0.12
	The supplemental unaudited pro forma information has been adjusted to include the pro forma impact of depreciation of property, plant and equipment and amortization of PPAs, based on the preliminary purchase price allocations. The pro forma data has also been adjusted to reflect the additional interest expense in connection with the issuance of Senior Notes, adjustment to the non-controlling interest due to the change in NRG's ownership interest to 55.3% from 65.5% effective July 29, 2014, as well as the related tax impact. There were no transactions during the periods between NRG and the Alta Wind Portfolio. The pro forma results are presented for illustrative purposes only and do not reflect the realization of potential cost savings or any related integration costs.
	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) RE 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.
	The following is a summary of assets and liabilities transferred in connection with the acquisition as of June 30, 2014:
		RE Kansas South			TA High Desert				El Segundo
		(In millions)
	Current assets	$	1		$	3			$	43
	Property, plant and equipment	50			67				625
	Non-current assets	2			13				76
	Total assets	53			83				744
	Debt	35			57				520
	Other current and non-current liabilities	2			—				30
	Total liabilities	37			57				550
	Net assets acquired	$	16		$	26			$	194
	The following table presents historical information summary combining the financial information for the Acquired ROFO Assets transferred in connection with the acquisition:
		December 31, 2013
		As Previously Reported			RE Kansas South				TA High Desert			El Segundo		As Currently Reported
					(In millions)
	Current assets	$	267		$	25			$	28		$	58	$	378
	Property, plant and equipment	1,541			51				63			636		2,291
	Non-current assets	505			3				10			51		569
	Total assets	2,313			79				101			745		3,238
	Debt	1,133			58				80			512		1,783
	Other current and non-current liabilities	169			5				3			26		203
	Total liabilities	$	1,302		$	63			$	83		$	538	$	1,986
		Year ended December 31, 2013
		As Previously Reported			RE Kansas South				TA High Desert			El Segundo		As Currently Reported
	Operating revenues	$	313		$	2			$	8		$	56	$	379
	Operating income	128			1				4			34		167
	Net income	$	109		$	(1	)		$	1		$	23	$	132
	2013 Acquisitions
	Energy Systems — On December 31, 2013, NRG Energy Center Omaha Holdings, LLC, an indirect wholly owned subsidiary of NRG Yield LLC, acquired Energy Systems Company, or Energy Systems, for approximately $120 million. The acquisition was financed from cash on hand. Energy Systems is an operator of steam and chilled water thermal facilities that provides heating and cooling services to nonresidential customers in Omaha, Nebraska. 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 purchase price was primarily allocated to property, plant and equipment of $60 million, customer relationships of $59 million, and $1 million of working capital. The accounting for Energy Systems was completed as of September 30, 2014, at which point the provisional fair values became final with no material changes.
	2012 Acquisitions
Marsh Landing — On December 14, 2012, through its acquisition of GenOn Energy, Inc., or GenOn, NRG acquired 100% of the Marsh Landing project, a 720 MW natural gas-fueled peaking facility being constructed near Antioch, California. Immediately prior to the initial public offering, NRG transferred ownership of Marsh Landing to NRG Yield LLC. Power generated from Marsh Landing is sold to Pacific Gas & Electric, or PG&E, under a 10 year PPA. In connection with the acquisition, the Company assumed obligations under a credit agreement for up to $650 million in construction and permanent financing for the Marsh Landing generating facility. The Marsh Landing generating facility reached commercial operations on May 1, 2013.
The fair value of the net assets acquired was $138 million. The accounting for the acquisition was completed on December 13, 2013. The Company recorded a measurement period adjustment increasing the provisional fair value of the acquired property, plant and equipment by $73 million, from $537 million to $610 million. The primary driver for the revised fair value was the refinement of the methodology used to value the assets.
2015 Acquisition of EME-NYLD-Eligible Assets from NRG
On January 2, 2015, NRG Yield Operating LLC acquired the following projects from NRG: (i) Laredo Ridge, a 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 plus assumed project level debt of $737 million, including $9 million for working capital. The Company funded the acquisition with cash on hand and drawings under the Company's revolving credit facility. 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, 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 net assets under common control, the guidance requires retrospective combination of the entities for all periods presented as if the combination has been in effect since the inception of common control. The Company funded the acquisition with cash on hand and borrowings under the Company's revolving credit facility.
The following is a summary of assets and liabilities transferred in connection with the acquisition on January 2, 2015:
	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 acquired	$	1,480		$	179			$	164		$	62	$	1,885
Supplemental Pro Forma Information
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, 2013:
		For the year ended December 31,
(In millions, except per share amounts)		2014			2013
Operating Revenues		$	715		$	513
Net Income		97			145
Net Income Attributable to NRG Yield, Inc.		21			16
Earnings per Weighted Average Class A and Class C Common Share - Basic and Diluted		$	0.38		$	0.35
Acquired ROFO Assets [Domain]
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 Acquired ROFO Assets transferred in connection with the acquisition:
		December 31, 2013
		As Previously Reported			RE Kansas South				TA High Desert			El Segundo		As Currently Reported
					(In millions)
	Current assets	$	267		$	25			$	28		$	58	$	378
	Property, plant and equipment	1,541			51				63			636		2,291
	Non-current assets	505			3				10			51		569
	Total assets	2,313			79				101			745		3,238
	Debt	1,133			58				80			512		1,783
	Other current and non-current liabilities	169			5				3			26		203
	Total liabilities	$	1,302		$	63			$	83		$	538	$	1,986
		Year ended December 31, 2013
		As Previously Reported			RE Kansas South				TA High Desert			El Segundo		As Currently Reported
	Operating revenues	$	313		$	2			$	8		$	56	$	379
	Operating income	128			1				4			34		167
	Net income	$	109		$	(1	)		$	1		$	23	$	132
	The following is a summary of assets and liabilities transferred in connection with the acquisition as of June 30, 2014:
		RE Kansas South			TA High Desert				El Segundo
		(In millions)
	Current assets	$	1		$	3			$	43
	Property, plant and equipment	50			67				625
	Non-current assets	2			13				76
	Total assets	53			83				744
	Debt	35			57				520
	Other current and non-current liabilities	2			—				30
	Total liabilities	37			57				550
	Net assets acquired	$	16		$	26			$	194

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure	Property, Plant and Equipment
	The Company’s major classes of property, plant, and equipment were as follows:
		December 31, 2014			December 31, 2013			Depreciable Lives
		(In millions)
	Facilities and equipment	$	4,709		$	2,373		2 - 40 Years
	Land and improvements	87			86
	Construction in progress	8			6
	Total property, plant and equipment	4,804			2,465
	Accumulated depreciation	(338		)	(174		)
	Net property, plant and equipment	$	4,466		$	2,291
	Renewable Energy Grants
	The Borrego solar project achieved commercial operations on February 12, 2013 and transferred the construction in progress to property, plant and equipment. On May 16, 2013, the Borrego solar project, as a qualified renewable energy project, applied for a cash grant in lieu of investment tax credit from the U.S. Treasury Department in the amount of $39 million. A receivable for the cash grant was recorded when the application was filed, which resulted in a reduction to the book basis of the property, plant and equipment. In addition, the receivable was reduced to $36 million as a result of the federal government’s sequestration, which was put into effect on March 1, 2013. The related deferred tax asset of $10 million was recorded with a corresponding reduction of the book value of Borrego’s property, plant and equipment. In March 2014, the Company received payment of $30 million for the cash grant related to Borrego. The Company recorded a reserve for the shortage pending further discussions with the US treasury Department.
	The TA High Desert solar project achieved commercial operations on March 25, 2013 and transferred the construction in progress to property, plant and equipment. On May 22, 2013, the TA High Desert solar project, as a qualified renewable energy project, applied for a cash grant in lieu of investment tax credit from the U.S. Treasury Department in the amount of $25 million. A receivable for the cash grant was recorded when the application was filed, which resulted in a reduction to the book basis of the property, plant and equipment. In addition, the receivable was reduced to $20 million as a result of the federal government’s sequestration, which was put into effect on March 1, 2013. The related deferred tax asset of $6 million was recorded with a corresponding reduction of the book value of TA High Desert's property, plant and equipment. In April 2014, TA High Desert received a payment of $20 million for the cash grant and reduced the book value of its property, plant and equipment by the amount by which the grant was reduced.
	The RE Kansas South solar project achieved commercial operations on June 7, 2013, and transferred the construction in progress to property, plant and equipment. On June 27, 2013, the RE Kansas South solar project, as a qualified renewable energy project, applied for a cash grant in lieu of investment tax credit from the U.S. Treasury Department in the amount of $23 million. A receivable for the cash grant was recorded when the application was filed, which resulted in a reduction to the book basis of the property, plant and equipment. In addition, the receivable was reduced to $21 million as a result of the federal government’s sequestration, which was put into effect on March 1, 2013. The related deferred tax asset of $6 million was recorded with a corresponding reduction of the book value of RE Kansas South's property, plant and equipment. In April 2014, RE Kansas South received a payment of $21 million for the cash grant.

Investments_Accounted_for_by_t

Investments Accounted for by the Equity Method and Variable Interest Entities	12 Months Ended
	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Investments Accounted for by the Equity Method and Variable Interest Entities	Investments Accounted for by the Equity Method and Variable Interest Entities
	Equity Method Investments
	Avenal—The Company owns a 49.95% equity interest in Avenal, which consists of three solar PV projects in Kings County, California, approximately 45 MWs, all of which became commercially operational during the third quarter of 2011. NRG retained a 0.05% interest and Eurus Energy owns the remaining 50% of Avenal. Power generated by the projects is sold under a 20-year PPA. On September 22, 2010, Avenal entered into a $35 million promissory note facility with the Company. Amounts drawn under the promissory note facility accrue interest at 4.5% per annum. As of December 31, 2013, the amount outstanding under the facility was $2 million. The facility was repaid in January 2014. Also, on September 22, 2010, Avenal entered into a $209 million financing arrangement with a syndicate of banks, or the Avenal Facility. As of December 31, 2014, and 2013, Avenal had outstanding $107 million and $112 million, respectively, under the Avenal Facility. As of December 31, 2014, the Company had an $11 million equity investment in Avenal.
	CVSR—The Company owns 48.95% of CVSR, located in San Luis Obispo, California, totaling 250 MW, while NRG continues to own the remaining 51.05% of CVSR. Power generated by the project is sold under a 25-year PPA. As of December 31, 2014, the Company had a $102 million equity investment in CVSR.
	In 2011, High Plains Ranch II, LLC, the direct owner of CVSR, entered into the CVSR Financing Agreement with the FFB to borrow up to $1.2 billion to fund the costs of constructing the solar facility. The CVSR Financing Agreement matures in 2037 and the loans provided by the FFB are guaranteed by the U.S. DOE. Amounts borrowed under the CVSR Financing Agreement accrue interest at a fixed rate based on U.S. Treasury rates plus a spread of 0.375% and are secured by the assets of CVSR. As of December 31, 2014, and 2013, $815 million and $1,104 million, respectively, were outstanding under the loan. In 2012 and 2013, CVSR submitted applications to the U.S. Treasury Department for cash grants as each phase of the project began commercial operations. In January 2014, the U.S. Treasury Department awarded cash grants on the CVSR project of $307 million ($285 million net of sequestration), which is approximately 75% of the cash grant amount for which the Company had applied. The cash grant proceeds were used to pay the outstanding balance of the bridge loan due in February 2014 and the remaining amount was used to pay a portion of the outstanding balance on the bridge loan due in August 2014. The remaining balance of the bridge loan due in August 2014 was paid by SunPower. CVSR is evaluating the basis for the U.S. Treasury Department’s award and all of its options for recovering the amount by which the U.S. Treasury Department reduced the CVSR cash grant award.
	The following table presents summarized financial information for CVSR:
		Year Ended December 31,
		2014		2013		2012
	Income Statement Data:	(In millions)
	Operating revenues	$	82	$	47	$	2
	Operating income	40		22		1
	Net income	17		4		1
				As of December 31,
				2014		2013
				(In millions)
	Balance Sheet Data:
	Current assets			$	173	$	455
	Non-current assets			868		932
	Current liabilities			33		412
	Non-current liabilities			799		769
	Variable Interest Entities, or VIEs
	GenConn Energy LLC — The Company has a 49.95% interest in GCE Holding LLC, the owner of GenConn Energy LLC, or 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. All four units at the GenConn Devon facility reached commercial operation in June 2010 and were released to the ISO-NE by July 2010. In June 2011, all four units at the GenConn Middletown facility reached commercial operation and were released to the ISO-NE. 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 December 31, 2014, the Company's investment in GenConn was $114 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 December 31, 2014 $228 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:
		Year ended December 31,
		2014		2013		2012
	Income Statement Data:	(In millions)
	Operating revenues	$	82	$	80	$	78
	Operating income	40		44		45
	Net income	28		31		29
		December 31, 2014		December 31, 2013
	Balance Sheet Data:	(In millions)
	Current assets	$	33	$	32
	Non-current assets	438		454
	Current liabilities	20		18
	Non-current liabilities	223		232
	The following table presents undistributed equity earnings for the Company's three equity method investments:
		As of December 31,
		2014		2013
		(In millions)
	Undistributed earnings from equity investments	$	22	$	19

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2014										Dec. 31, 2013
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 December 31, 2013
		As of December 31, 2014										Fair Value (a)
		Fair Value (a)									(In millions)	Level 2		Level 3		Total
	(In millions)	Level 2									Derivative assets:
	Derivative assets:										Commodity contracts	$	1	$	—	$	1
	Commodity contracts	$	—
											Interest rate contracts	20		—		20
	Interest rate contracts	2
											Total assets	21		—		21
	Total assets	$	2
											Derivative liabilities:
	Derivative liabilities:										Commodity contracts	1		1		2
	Commodity contracts	$	3
											Interest rate contracts	45		—		45
	Interest rate contracts	114
											Total liabilities	$	46	$	1	$	47
	Total liabilities	$	117
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	For cash and cash equivalents, restricted cash, accounts receivable, accounts payable, intercompany accounts payable and receivable, 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 December 31, 2014					As of December 31, 2013
		Carrying Amount			Fair Value		Carrying Amount		Fair Value
		(In millions)
	Assets:
	Notes receivable, including current portion — affiliate	$	—		$	—	$	2	$	2
	Notes receivable, including current portion	21			21		27		27
	Liabilities:
	Long-term debt, including current portion	4,787			4,873		1,783		1,785
	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 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.
		As of December 31, 2013
		Fair Value (a)
	(In millions)	Level 2			Level 3		Total
	Derivative assets:
	Commodity contracts	$	1		$	—	$	1
	Interest rate contracts	20			—		20
	Total assets	21			—		21
	Derivative liabilities:
	Commodity contracts	1			1		2
	Interest rate contracts	45			—		45
	Total liabilities	$	46		$	1	$	47
	(a) There were no assets or liabilities classified as Level 1 as of December 31, 2013.
	There were no transfers during the years ended December 31, 2014 and 2013, between Levels 1 and 2. The following table reconciles, for the year ended December 31, 2014, the beginning and ending balances for derivative instruments that are recognized at fair value in the consolidated financial statements, at least annually, using significant unobservable inputs:
		Fair Value Measurement Using Significant Unobservable Inputs (Level 3)
	(In millions)	Year ended December 31, 2014
		Derivatives
	Beginning balance	$	(1	)
	Total gains and losses (realized/unrealized) included in earnings	1
	Ending balance as of December 31, 2014	$	—
	There have been no transfers in and/or out of Level 3 during the year ended 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 December 31, 2014, 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 December 31, 2014, the credit reserve resulted in a $1 million increase in fair value which is a gain in OCI. 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, 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 December 31, 2014, credit risk exposure to these counterparties attributable to the Company's ownership interests was approximately $2.2 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 12, Segment Reporting. 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	12 Months Ended
	Dec. 31, 2014
Accounting for Derivative Instruments and Hedging Activities Disclosure [Abstract]
Accounting for Derivative Instruments and Hedging Activities	Accounting for Derivative Instruments and Hedging Activities
	ASC 815 requires the Company to recognize all derivative instruments on the balance sheet as either assets or liabilities and to measure them at fair value each reporting period unless they qualify for a NPNS exception. The Company may elect to designate certain derivatives as cash flow hedges, if certain conditions are met, and defer the effective portion of the change in fair value of the derivatives to accumulated OCI, until the hedged transactions occur and are recognized in earnings. The ineffective portion of a cash flow hedge is immediately recognized in earnings. For derivatives that are not designated as cash flow hedges or do not qualify for hedge accounting treatment, the changes in the fair value will be immediately recognized in earnings. Certain derivative instruments may qualify for the NPNS exception and are therefore exempt from fair value accounting treatment. ASC 815 applies to the Company's energy related commodity contracts and interest rate swaps.
	Energy-Related Commodities
	To manage the commodity price risk associated with its competitive supply activities and the price risk associated with wholesale power sales, the Company may enter into derivative hedging instruments, namely, forward contracts that commit the Company to sell energy commodities or purchase fuels in the future. The objectives for entering into derivatives contracts designated as hedges include fixing the price for a portion of anticipated future electricity sales and fixing the price of a portion of anticipated fuel purchases for the operation of its subsidiaries. At December 31, 2014, the Company had forward and financial contracts for the purchase/sale of electricity and related products economically hedging the Company's district energy centers' forecasted output or load obligations through 2015. The Company also had forward contracts for the purchase of fuel commodities relating to the forecasted usage of the district energy centers through 2017. At December 31, 2014, these contracts were not designated as cash flow or fair value hedges.
	Also, as of December 31, 2014, the Company had other energy-related contracts that did not meet the definition of a derivative instrument or qualified for the NPNS exception and were therefore exempt from fair value accounting treatment as follows:
	•	Power tolling contracts through 2038, and
	•	Natural gas transportation contracts through 2028.
	Interest Rate Swaps
	The Company is exposed to changes in interest rates through the issuance of variable and fixed rate debt. In order to manage interest rate risk, it enters into interest rate swap agreements.
	As of December 31, 2014, the Company had interest rate derivative instruments on non-recourse debt extending through 2031, some 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 December 31, 2014, and 2013.
				Total Volume
				December 31, 2014				December 31, 2013
	Commodity	Units		(In millions)
	Natural Gas	MMBtu		2				2
	Interest	Dollars		$	2,817			$	1,234
	The increase in the interest rate position was primarily the result of the interest rate swaps acquired with the Alta Wind Portfolio.
	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
		December 31, 2014				December 31, 2013				December 31, 2014			December 31, 2013
		(In millions)
	Derivatives Designated as Cash Flow Hedges:
	Interest rate contracts current	$	—			$	—			$	40		$	26
	Interest rate contracts long-term	2				14				49			16
	Total Derivatives Designated as Cash Flow Hedges	2				14				89			42
	Derivatives Not Designated as Cash Flow Hedges:
	Interest rate contracts current	—				—				5			3
	Interest rate contracts long-term	—				6				20			—
	Commodity contracts current	—				1				3			2
	Total Derivatives Not Designated as Cash Flow Hedges	—				7				28			5
	Total Derivatives	$	2			$	21			$	117		$	47
	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 December 31, 2014, 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 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	)
		Gross Amounts Not Offset in the Statement of Financial Position
	As of December 31, 2013	Gross Amounts of Recognized Assets/Liabilities				Derivative Instruments				Net Amount
	Commodity contracts:	(In millions)
	Derivative assets	$	1			$	—			$	1
	Derivative liabilities	(2		)		—				(2		)
	Total commodity contracts	(1		)		—				(1		)
	Interest rate contracts:
	Derivative assets	20				(12		)		8
	Derivative liabilities	(45		)		12				(33		)
	Total interest rate contracts	(25		)		—				(25		)
	Total derivative instruments	$	(26	)		$	—			$	(26	)
	Accumulated Other Comprehensive Loss
	The following table summarizes the effects on the Company’s accumulated other comprehensive loss, or OCL, balance attributable to interest rate swaps designated as cash flow hedge derivatives, net of tax:
		Year ended December 31,
		2014				2013				2012
		(In millions)
	Accumulated OCL beginning balance	$	—			$	(48	)		$	(28	)
	Reclassified from accumulated OCL to income due to realization of previously deferred amounts	13				13				5
Mark-to-market of cash flow hedge accounting contracts	(65		)		35				(25		)
Accumulated OCL ending balance, net of income tax benefit of $6, $1 and $17, respectively	$	(52	)		$	—			$	(48	)
Accumulated OCL attributable to NRG	(43		)		—
Accumulated OCL attributable to NRG Yield, Inc.	$	(9	)		$	—
Losses expected to be realized from OCL during the next 12 months, net of income tax of $3	$	(27	)
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 years ended December 31, 2014 and 2013, the impact to the consolidated statements of operations was a loss of $22 million and a gain of $13 million, respectively.
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.
See Note 6, Fair Value of Financial Instruments, for discussion regarding concentration of credit risk.

Intangible_Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets
	Intangible Assets — The Company's intangible assets as of December 31, 2014, and 2013 primarily reflect intangible assets established from its business acquisitions and are comprised of the following:
	•	Emission Allowances — These intangibles primarily consist of SO2 and NOx emission allowances established with the El Segundo and Walnut Creek acquisitions. These emission allowances are held-for-use and are amortized to cost of operations, with NOx allowances amortized on a straight-line basis and SO2 allowances amortized based on units of production.
	•	Development rights — Arising primarily from the acquisition of solar businesses in 2010 and 2011, these intangibles are amortized to depreciation and amortization expense on a straight-line basis over the estimated life of the related project portfolio.
	•	Customer contracts — Established with the acquisition of Northwind Phoenix, these intangibles represent the fair value at the acquisition date of contracts that primarily provide chilled water, steam and electricity to its customers. These contracts are amortized to revenues based on expected volumes.
	•	Customer relationships — Established with the acquisition of Northwind Phoenix and Energy Systems, these intangibles represent the fair value at the acquisition date of the businesses' customer base. The customer relationships are amortized to depreciation and amortization expense based on the expected discounted future net cash flows by year.
	•	PPAs — Established predominantly with the acquisitions of the Alta Wind Portfolio, Walnut Creek, Tapestry and Laredo Ridge, these represent the fair value of the PPAs acquired. These will be amortized, generally on a straight-line basis, over the term of the PPA.
	•	Leasehold Rights — Established with the acquisition of the Alta Wind Portfolio, this represents the fair value of contractual rights to receive royalty payments equal to a percentage of PPA revenue from certain projects. These will be amortized on a straight-line basis.
	•	Other — Consists of the acquisition date fair value of the contractual rights to a ground lease for South Trent and to utilize certain interconnection facilities for Blythe.
	The following tables summarize the components of intangible assets subject to amortization:
	Year ended December 31, 2014	Emission Allowances			Development			Customer Contracts			Customer			PPAs			Leasehold Rights			Other		Total
					Rights						Relationships
					(In millions)
	1-Jan-14	$	8		$	4		$	15		$	66		$	14		$	—		$	3	$	110
	Acquisition of Alta Wind Portfolio	—			—			—			—			1,091			86			—		1,177
	Transfer of EME-NYLD-Eligible Assets	7			—			—			—			160			—			—		167
	Other	1			—			—			—			4			—			—		5
	31-Dec-14	16			4			15			66			1,269			86			3		1,459
	Less accumulated amortization	—			(1		)	(5		)	(2		)	(26		)	(2		)	—		(36		)
	Net carrying amount	$	16		$	3		$	10		$	64		$	1,243		$	84		$	3	$	1,423
	Year ended December 31, 2013	Emission			Development Rights			Customer Contracts			Customer Relationships			PPAs			Leasehold Rights			Other		Total
		Allowances
		(In millions)
	1-Jan-13	$	8		$	4		$	15		$	7		$	4		$	—		$	3	$	41
	Business acquisition/transfer	—			—			—			59			10			—			—		69
	31-Dec-13	8			4			15			66			14			—			3		110
	Less accumulated amortization	—			(1		)	(4		)	(1		)	(1		)	—			—		(7		)
	Net carrying amount	$	8		$	3		$	11		$	65		$	13		$	—		$	3	$	103
	The Company recorded amortization of $29 million, $4 million and $1 million during the years ended December 31, 2014, 2013 and 2012. Of these amounts, $28 million for the year ended December 31, 2014 was recorded as contra-revenue reflecting the amortization of the fair value of the acquired intangible assets. The following table presents estimated amortization of the Company's intangible assets for each of the next five years:
	Year Ended December 31,		Total
			(In millions)
	2015		$	58
	2016		71
	2017		71
	2018		71
	2019		72
	The weighted average amortization period related to the intangibles acquired in the year ended December 31, 2014 was 22 years for power purchase agreements and 21 years for leasehold rights.
	Out-of-market contracts — The out-of-market contract liability represents the out-of-market value of the PPA for the Blythe solar project and the out-of-market value of the land lease for Alta Wind XI Holding Company, LLC, as of their respective acquisition dates. The Blythe solar project's liability of $5 million is recorded to other non-current liabilities and is amortized to revenue on a units-of-production basis over the twenty-year term of the agreement. The Alta Wind XI Holding Company, LLC's liability of $5 million is recorded to other non-current liabilities and is amortized to cost of operations on a straight-line basis over the term of the land lease. At December 31, 2014, accumulated amortization of out-of-market contracts was $2 million and amortization expense was less than $1 million for the year ended December 31, 2014.

Longterm_Debt

Long-term Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Long-term Debt	Long-term Debt
	The Company's borrowings, including short term and long term portions consisted of the following:
		December 31, 2014				December 31, 2013			Interest rate % (a)
		(In millions, except rates)
	Convertible Notes, due 2019 (b)	$	326			—			3.5
	Senior Notes, due 2024	500				—			5.375
	Project-level debt:
	Alta Wind I, lease financing arrangement, due 2034	261				—			7.015
	Alta Wind II, lease financing arrangement, due 2034	205				—			5.696
	Alta Wind III, lease financing arrangement, due 2034	212				—			6.067
	Alta Wind IV, lease financing arrangement, due 2034	138				—			5.938
	Alta Wind V, lease financing arrangement, due 2035	220				—			6.071
	Alta Wind X, due 2021	300				—			L+2.00
	Alta Wind XI, due 2021	191				—			L+2.00
	Alta Realty Investments, due 2031	34				—			7
	Alta Wind Asset Management, due 2031	20				—			L+2.375
	NRG West Holdings LLC, due 2023	506				512			L+2.25 - L+2.875; L+2.25 - L+2.75
	NRG Marsh Landing LLC, due 2017 and 2023	464				473			L+ 1.75 - L+1.875; L+2.75 - L+3.00
	Walnut Creek Energy LLC, due 2023	391				—			L+1.625
	Tapestry Wind LLC, due 2021	192				—			L+1.625
	NRG Solar Alpine LLC, due 2014 and 2022	163				221			L+1.75 - L+2.50; L+2.25 - L+2.50
	NRG Energy Center Minneapolis LLC, due 2017 and 2025	121				127			5.95 -7.31
	Laredo Ridge LLC, due 2026	108				—			L+1.875
	NRG Solar Borrego LLC, due 2024 and 2038	75				78			L+ 2.50/5.65
	South Trent Wind LLC, due 2020	65				69			L+2.75;L+2.625
	NRG Solar Avra Valley LLC, due 2031	63				63			L+1.75; L+2.25
	TA High Desert LLC, due 2023 and 2033	55				80			L+2.50/5.15
	WCEP Holdings LLC, due 2023	46				—			L+3.00
	NRG Roadrunner LLC, due 2031	42				44			L+2.01
	NRG Solar Kansas South LLC, due 2031	35				58			L+2.00;L+2.625
	NRG Solar Blythe LLC, due 2028	22				24			L+2.75
	PFMG and related subsidiaries financing agreement, due 2030	31				32			6
	NRG Energy Center Princeton LLC, due 2017	1				2			5.95
	Subtotal project-level debt:	3,961				1,783
	Total debt	4,787				1,783
	Less current maturities	214				214
	Total long-term debt	$	4,573			$	1,569
	(a) As of December 31, 2014, L+ equals 3 month LIBOR plus x%, except for RE Kansas South where L+ equals 6 month LIBOR plus x%.
	(b) Net of discount of $19 million as of December 31, 2014.
	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 arrangement. As of December 31, 2014, 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 year ended December 31, 2014.
	NRG Yield, Inc. Convertible Notes
	During the first quarter of 2014, the Company closed on its offering of $345 million of Convertible Notes. The Convertible Notes bear interest of 3.50% and mature in February 2019.  Interest on the Convertible Notes is payable semi-annually in arrears on February 1 and August 1 of each year, commencing on August 1, 2014. The Convertible Notes are convertible, under certain circumstances, into the Company’s Class A common stock, cash or a combination thereof at an initial conversion price of $46.55 per Class A common share, which is equivalent to an initial conversion rate of approximately 21.4822 shares of Class A common stock per $1,000 principal amount of Convertible Notes. The Convertible Notes mature on February 1, 2019, unless earlier repurchased or converted in accordance with their terms. Prior to the close of business on the business day immediately preceding August 1, 2018, the Convertible Notes will be convertible only upon the occurrence of certain events and during certain periods, and thereafter, at any time until the close of business on the second scheduled trading day immediately preceding the maturity date. The Convertible Notes are guaranteed by NRG Yield Operating LLC and NRG Yield LLC.
	The Convertible Notes are accounted for in accordance with ASC 470-20, Debt with Conversion and Other Options. Under ASC 470-20, issuers of convertible debt instruments that may be settled in cash upon conversion, including partial cash settlement, are required to separately account for the liability (debt) and equity (conversion option) components. The application of ACS 470-20 resulted in the recognition of $23 million as the value for the equity component with the offset to debt discount. The debt discount is amortized to interest expense using the effective interest method through February 2019.
	As of December 31, 2014, the Convertible Notes were trading at approximately 114% of their face value, resulting in a total market value of $395 million compared to a carrying value of $326 million. The actual conversion value of the Convertible Notes is based on the product of the conversion rate and the market price of the Company's common stock, as defined in the Convertible Debt indenture. As of December 31, 2014, the Company's common stock closed at $47.14 per share, resulting in a pro forma conversion value for the Convertible Notes of approximately $349 million.
	During the years ended December 31, 2014, the Company recorded the following expense in relation to the Convertible Notes at the effective rate of 5.00%:
	(In millions)
	Interest expense at 3.5% coupon rate		11
	Debt discount amortization		4
	Debt issuance costs amortization		1
			$	16
	NRG Yield Operating LLC Senior Notes
	On August 5, 2014, NRG Yield Operating LLC issued $500 million of senior unsecured notes, or the Senior Notes. The Senior Notes bear interest at 5.375% and mature in August 2024. Interest on the notes is payable semi-annually on February 15 and August 15 of each year, and commenced on February 15, 2015. The Senior Notes are senior unsecured obligations of NRG Yield Operating LLC and are guaranteed by NRG Yield LLC, and by certain of NRG Yield Operating LLC’s wholly owned current and future subsidiaries.
	NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility
	In connection with the Company's initial public offering of Class A common stock in July 2013, as further described in Note 1, Nature of Business, NRG Yield LLC and NRG Yield Operating LLC entered into a senior secured revolving credit facility, or the Yield Credit Facility, which provided a revolving line of credit of $60 million. On April 25, 2014, NRG Yield LLC and NRG Yield Operating LLC amended the revolving credit facility to increase the available line of credit to $450 million and extend its maturity to April 2019. The Company's revolving credit facility can be used for cash or for the issuance of letters of credit. There was no cash drawn and $38 million of letters of credit issued in support of the obligations of the Alta Wind Portfolio under the revolving credit facility as of December 31, 2014.
	On January 2, 2015, the Company borrowed $210 million under the Yield 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 of principal and interest.
	Project - level Debt
	NRG West Holdings Credit Agreement
	On August 23, 2011, NRG West Holdings LLC, or West Holdings, entered into a credit agreement with a group of lenders in respect to the El Segundo project, or the West Holdings Credit Agreement. The West Holdings Credit Agreement is comprised of a $540 million two tranche construction loan facility with additional facilities for the issuance of letters of credit or working capital loans and is secured by the assets of West Holdings.
	The two tranche construction loan facility consists of the $480 million Tranche A Construction Facility, or the Tranche A Facility, and the $60 million Tranche B Construction Facility, or the Tranche B Facility. The Tranche A and Tranche B Facilities, which mature in August 2023, convert to a term loan and have an interest rate of 3-month LIBOR, plus an applicable margin which (i) increases by 0.125% periodically from conversion through year eight for the Tranche A Facility, and (ii) increases by (a) 0.125% upon term conversion and on the third and sixth anniversary of the term conversion and (b) by 0.250% on the eighth anniversary of the term conversion for the Tranche B Facility. The Tranche A and Tranche B Facilities amortize based upon a predetermined schedule over the term of the loan with the balance payable at maturity. The construction loan converted to a term loan on January 28, 2014.
	The West Holdings Credit Agreement also provides for the issuance of letters of credit and working capital loans to support the El Segundo project's collateral needs. This includes letter of credit facilities on behalf of West Holdings of up to $90 million in support of the PPA, up to $48 million in support of the collateral agent, and a working capital facility which permits loans or the issuance of letters of credit of up to $10 million.
	As of December 31, 2014, under the West Holdings Credit Agreement, West Holdings had $447 million outstanding under the Tranche A Facility, $59 million under the Tranche B Facility, issued a $33 million letter of credit in support of the PPA, a $48 million letter in support of debt service and a $1 million letter of credit under the working capital facility.
	Alpine Financing
	On March 16, 2012, NRG Solar Alpine LLC, or Alpine, entered into a credit agreement with a group of lenders for a $166 million construction loan that was convertible to a term loan upon completion of the project and a $68 million cash grant loan. On January 15, 2013, the credit agreement was amended reducing the cash grant loan to $63 million. On March 26, 2013, Alpine met the conditions under the credit agreement to convert the construction loan to a term loan. Immediately prior to the conversion, the Company drew an additional $164 million under the construction loan and $62 million under the cash grant loan. The term loan amortizes on a predetermined schedule with final maturity in November 2022.
In January 2014, Alpine repaid the $62 million of outstanding cash grant loan, including accrued interest and breakage fees, with the proceeds that it had received from the U.S. Treasury Department. On June 24, 2014, Alpine amended the credit agreement to increase its term loan borrowings by an additional $13 million and to reduce the related interest rate to 3 month LIBOR plus 1.75% through June 30, 2019 and 3 month LIBOR plus 2.00% through November 2022. The proceeds were utilized to make a distribution of $11 million to NRG Yield Operating LLC with the remaining $2 million utilized to fund the costs of the amendment.
Borrego Financing
On March 28, 2013, NRG Solar Borrego I LLC, or Borrego, entered into a credit agreement with a group of lenders, or the Borrego Financing Agreement, for $45 million of 5.65% fixed rate notes and a $36 million term loan. The term loan has an interest rate of 3 month LIBOR plus an applicable margin of 2.50%, which escalates 0.25% on the fourth and eighth anniversary of the closing date. The fixed rate notes mature in February 2038 and the term loan matures in December 2024. Both amortize based upon predetermined schedules. The Borrego Financing Agreement also includes a letter of credit facility on behalf of Borrego of up to $5 million. Borrego pays an availability fee of 100% of the applicable margin on issued letters of credit. As of December 31, 2014, $45 million was outstanding under the fixed rate notes, $30 million was outstanding under the term loans, and $5 million of letters of credit in support of the project were issued.
Under the terms of the Borrego Financing Agreement on March 28, 2013, Borrego was required to enter into two fixed for floating interest rate swaps that would fix the interest rate for a minimum of 75% of the outstanding notional amount. Borrego will pay its counterparty the equivalent of a 1.125% fixed interest payment on a predetermined notional value, and quarterly, Borrego will receive the equivalent of a floating interest payment based on a 3 month LIBOR calculated on the same notional value through June 30, 2020. All interest rate swap payments by Borrego and its counterparties are made quarterly and the LIBOR rate is determined in advance of each interest period. The original notional amount of the swaps, which became effective April 3, 2013, was $15 million and will amortize in proportion to the term loan.
Marsh Landing Credit Agreement Term Conversion
In May 2013, Marsh Landing met the conditions under the credit agreement to convert the construction loan for the facility to a term loan which will amortize on a predetermined basis. Prior to term conversion, Marsh Landing drew the remaining funds available under the facility in order to pay costs due for construction. Marsh Landing issued a $24 million letter of credit under the facility in support of its debt service requirements. As of December 31, 2014, $108 million was outstanding under the Tranche A loan, $356 million was outstanding under the Tranche B loans, and $22 million of letters of credit in support of the project were issued.
On July 17, 2014, Marsh Landing amended its credit agreement to increase its borrowings by $34 million and to reduce the related interest rate for the Tranche A borrowings from 3 month LIBOR plus an applicable margin of 2.75% to 3 month LIBOR plus 1.75% through December 2017; and for the Tranche B to reduce the related interest rate from 3 month LIBOR plus 3.00% to 3 month LIBOR plus 1.875% through December 2017 and to 3 month LIBOR plus 2.125% through December 2020 and to 3 month LIBOR plus 2.375% thereafter. The proceeds from the borrowings were utilized to make a distribution of $29 million to NRG Yield Operating LLC and to fund the costs of the amendment.
TA High Desert Facility
The TA High Desert Facility is comprised of $53 million of fixed rate notes due 2033 at an interest rate of 5.15%, $7 million of floating rate notes due 2023, $22 million of bridge notes due the earlier of ten days after receipt of the cash grant or May 2014, and a revolving facility of $12 million. The floating rate notes have an interest rate of 3 month LIBOR plus 2.5% with LIBOR floor of 1.5%, while the bridge notes have an interest rate of 1 month LIBOR plus 2.50%. As described in Note 4, Property, Plant and Equipment, in April 2014, TA High Desert received payment of $20 million for its cash grant and utilized the proceeds, along with an additional $2 million of cash contributed by NRG to repay the cash grant bridge loan. The revolving facility can be used for cash or for the issuance of up to $9 million in letters of credit. As of December 31, 2014, $55 million of notes were outstanding and $8 million of letters of credit were outstanding under the revolving facility.  The notes amortize on predetermined schedules and are secured by all of the assets of TA High Desert.
Kansas South Facility
The Kansas South Facility includes a $38 million term loan due 2031 and a $21 million cash grant bridge loan due ten days after receipt of the cash grant. The term loan has an interest rate of 6 month LIBOR plus an applicable margin of 2.625% and increases by 0.25% every 4 years. The cash grant bridge loan had an interest rate of 1 month LIBOR plus an applicable margin of 2.00%. The term loan amortizes on a predetermined schedule and is secured by all of the assets of RE Kansas South. As described in Note 4, Property, Plant and Equipment, in April 2014, the Company received payment of $21 million for the cash grant related to RE Kansas South and utilized the proceeds to repay the cash grant bridge loan. On September 26, 2014, RE Kansas South amended its credit agreement to change the interest rate to 6 month LIBOR plus 2.00% through September 30, 2019 and to 6 month LIBOR plus 2.250% thereafter. As of December 31, 2014, $35 million was outstanding under the term loan and $4 million of letters of credit were issued under the Kansas South Facility.
Avra Valley Credit Agreement
On July 9, 2014, Avra Valley amended its credit agreement to increase its borrowings by $3 million and to reduce the related interest rate from 3 month LIBOR plus an applicable margin of 2.25% to 3 month LIBOR plus 1.75%. The proceeds were primarily utilized to make a distribution to NRG Yield Operating LLC.
Alta Wind Financing Arrangements
As described in Note 3, Business Acquisitions, the Company acquired the Alta Wind Portfolio on August 12, 2014. In connection with the acquisition, the Company assumed the following debt arrangements:
Term Loan and Note Facilities
In June 2013, Alta Wind X entered into a credit agreement with several lenders for $337 million, which provided loans for the construction of the plant, letters of credit commitments to support certain obligations and a debt reserve loan commitment. The agreement contains a $300 million construction loan which converted to a term loan on March 31, 2014 and matures in March 2021. The term loan has an interest rate of 3 month LIBOR plus an applicable margin. The applicable margin was initially set at 2.00% for LIBOR-based loan increasing to 2.25% on the fourth anniversary of term loan conversion. The Company pays a commitment fee on the unused portion of all instruments of 0.75% quarterly in arrears on the last business day of March, June, September and December. The credit agreement also provides for a $20 million letter of credit facility to support obligations of the project, which expires on the term loan maturity date and a $17 million debt service loan commitments in the event the project is unable to meet its debt service obligations. As of December 31, 2014, $5 million of letters of credit were issued and no borrowings were made under the debt service loan commitments. In addition, a $3 million letter of credit to support a liquidity reserve requirement was issued under the Yield Credit Facility.
In June 2013, Alta Wind XI entered into a credit agreement with several lenders for $212 million, which provided loans for the construction of the plant, letters of credit commitments to support certain obligations and a debt reserve loan commitment. The agreement contains a $191 million construction loan which converted to a term loan on March 31, 2014 and matures in March 2021. The term loan has an interest rate of 3 month LIBOR plus an applicable margin. The applicable margin was initially set at 2.00% for LIBOR-based loan increasing to 2.25% on the fourth anniversary of term loan conversion. The Company pays a commitment fee on the unused portion of all instruments of 0.75% quarterly in arrears on the last business day of March, June, September and December. The credit agreement also provides for a $10 million letter of credit facility to support obligations under the PPA, which expires on the term loan maturity date and an $11 million in debt service loan commitments in the event the project is unable to meet its debt service obligations. As of December 31, 2014, no letters of credit were issued and no borrowings were made under the debt service loan commitments. In addition, a $3 million letter of credit to support a liquidity reserve requirement was issued under the Yield Credit Facility.
On May 22, 2013, AWAM entered into a credit agreement with a lender and borrowed a $20 million term loan. The proceeds from the issuance of the term loan were utilized to pay transactions costs and fund certain restricted cash accounts. AWAM has a $20 million term loan as of December 31, 2014, which has an interest rate of 3 month LIBOR plus an applicable margin of 2.375% and increases every four years to a maximum applicable margin of 2.88%. Principal and interest are payable quarterly on February 15, May 15, August 15 with a final maturity on May 15, 2031. The loan is secured by substantially all of the assets of AWAM. The term loan also has a debt service requirement, which is satisfied with a $1 million letter of credit issued under the Yield Credit Facility.
On January 31, 2011, Alta Realty entered into a $30 million note purchase agreement with a group of institutional investors with interest and principal payable quarterly on January 31, April 30, July 31, and October 31. The note has an interest rate of 7% and matures on January 31, 2031. The note purchase agreement also has a debt service requirement, which is satisfied with a $2 million letter of credit issued under the Yield Credit Facility. As of December 31, 2014, $34 million was outstanding under the note purchase agreement.
Lease financing arrangements
Alta Wind Holdings (Alta Wind II - V) and Alta I (operating entities) have finance lease obligations issued under lease transactions whereby the respective operating entities sold and leased back undivided interests in specific assets of the project. The sale and related lease transactions are accounted for as financing arrangements as the operating entities have continued involvement with the property. The terms and conditions of each facility lease are substantially similar. Each operating entity makes rental payments as stipulated in the facility lease agreements on a semiannual basis every June 30 and December 30 through the final maturity dates. In addition, the operating entities have a credit agreement with a group of lenders that provides for the issuance of letters of credit to support certain operating and debt service obligations. Certain O&M and rent reserve requirements are satisfied by letters of credit issued under the NRG Yield Operating agreement. As of December 31, 2014, $1,036 million was outstanding under the finance lease obligations, and $114 million of letters of credit issued under the credit agreement and $29 million issued under the Yield Credit Facility.
Laredo Ridge Credit Agreement
Prior to the acquisition of Laredo Ridge by NRG, Laredo Ridge LLC entered into a credit agreement with a group of lenders for a $75 million construction loan that was converted to a term loan upon completion of the project, a $53 million cash grant loan, which was repaid prior to the acquisition, and a $3 million working capital loan facility, all of which are secured by the assets of Laredo Ridge LLC. The credit agreement also included a letter of credit facility on behalf of Laredo Ridge LLC of up to $9 million, with a fee equal to the applicable margin on issued letters of credit. On December 17, 2014, Laredo Ridge LLC 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, with the remaining $8 million utilized to fund the costs of the amendment. As of December 31, 2014, $108 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.
Tapestry Wind Credit Agreement
Prior to the acquisition of the Tapestry projects by NRG, 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 and 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 with a commitment fee of 0.75%. The credit agreement also includes a letter of credit facility on behalf of Tapestry Wind LLC of up to $20 million, with a fee equal to the applicable margin on issued letters of credit.
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 December 31, 2014, $192 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 Credit Agreement
Prior to the acquisition of Walnut Creek by NRG, Walnut Creek Energy LLC entered into a credit agreement, or the Walnut Creek Agreement, with a group of lenders for a $442 million construction loan that was converted to a term loan upon completion of the project, and a $5 million working capital loan facility, which are secured by the assets of Walnut Creek Energy LLC. The term loan amortizes based upon a predetermined schedule and matures in May 2023. The working capital facility is available to fund the operating needs of Walnut Creek Energy LLC, with a commitment fee of 0.625%. The Walnut Creek Agreement also includes a letter of credit facility of up to $117 million, with a fee equal to the applicable margin on issued letters of credit. As of December 31, 2014, $391 million was outstanding under the term loan, nothing was outstanding under the working capital facility, and $41 million of letters of credit were issued.
On October 21, 2014, the Walnut Creek Agreement was amended 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 Energy LLC pays its counterparty the equivalent of a 4.0025% fixed interest payment on a predetermined notional value, and quarterly, Walnut Creek Energy LLC 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 are made quarterly and the LIBOR is determined in advance of each interest period.
WCEP Holdings LLC
Prior to the acquisition of Walnut Creek by NRG, WCEP Holdings LLC, the holding company of Walnut Creek Energy LLC, entered into a credit agreement with a group of lenders for a $53 million construction loan that was converted to a term loan upon completion of the Walnut Creek project. The term loan has an interest rate of LIBOR plus an applicable margin of 4.00%, amortizes based upon a predetermined schedule, matures in May 2023 and is secured by WCEP Holdings LLC's interest in the Walnut Creek project. As of December 31, 2014, $46 million was outstanding under 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 Energy LLC were utilized to make an optional repayment of $6 million on the term loan. In addition, WCEP Holdings LLC partially terminated its interest rate swap agreements so that at least 90% and no more than 100% of the aggregate principal amount of the loans then outstanding would be subject to interest rate agreements.
Interest Rate Swaps — Project Financings
Many of the Company's project subsidiaries entered into interest rate swaps, intended to hedge the risks associated with interest rates on non-recourse project level debt. These swaps amortize in proportion to their respective loans and are floating for fixed where the project subsidiary pays its counterparty the equivalent of a fixed interest payment on a predetermined notional value and will receive quarterly the equivalent of a floating interest payment based on the same notional value. All interest rate swap payments by the project subsidiary and its counterparty are made quarterly and the LIBOR is determined in advance of each interest period. In connection with the acquisition of the Alta Wind Portfolio, as described in Note 3, Business Acquisitions, the Company acquired thirty-one additional interest rate swaps.
The following table summarizes the swaps, some of which are forward starting as indicated, related to the Company's project level debt as of December 31, 2014.
		% of Principal		Fixed Interest Rate		Floating Interest Rate	Notional Amount at December 31, 2014		Effective Date	Maturity Date
							(In millions)
NRG Marsh Landing LLC		75%		3.24%		3-Month LIBOR	$	431	June 28, 2013	June 30, 2023
NRG West Holdings LLC		75%		2.42%		3-Month LIBOR	384		November 30, 2011	August 31, 2023
South Trent Wind LLC		75%		3.26%		3-Month LIBOR	48		June 15, 2010	June 14, 2020
South Trent Wind LLC		75%		4.95%		3-Month LIBOR	21		June 30, 2020	June 14, 2028
NRG Solar Roadrunner LLC		75%		4.31%		3-Month LIBOR	31		September 30, 2011	December 31, 2029
NRG Solar Blythe LLC		75%		3.56%		3-Month LIBOR	17		June 25, 2010	June 25, 2028
NRG Solar Avra Valley LLC		85%		2.33%		3-Month LIBOR	54		November 30, 2012	November 30, 2030
NRG Solar Alpine LLC		85%		2.74%		3-Month LIBOR	129		various	December 31, 2029
NRG Solar Alpine LLC		85%		2.42%		3-Month LIBOR	10		June 24, 2014	June 30, 2025
Kansas South LLC		75%		2.37%		3-Month LIBOR	26		June 28, 2013	December 31, 2030
NRG Solar Borrego LLC		75%		1.13%		3-Month LIBOR	11		April 3, 2013	June 30, 2020
Alta X		100%		various		3-Month LIBOR	174		December 31, 2013	December 31, 2015
Alta X		100%		various		3-Month LIBOR	126		December 31, 2013	December 31, 2025
Alta X		100%		various		3-Month LIBOR	162		December 31, 2015	December 31, 2020
Alta X		100%		various		3-Month LIBOR	103		December 31, 2020	December 31, 2025
Alta XI		100%		various		3-Month LIBOR	138		December 31, 2013	December 31, 2015
Alta XI		100%		various		3-Month LIBOR	54		December 31, 2013	December 31, 2025
Alta XI		100%		various		3-Month LIBOR	103		December 31, 2015	December 31, 2020
Alta XI		100%		various		3-Month LIBOR	65		December 31, 2020	December 31, 2025
AWAM		100%		2.47%		3-Month LIBOR	20		May 22, 2013	May 15, 2031
Laredo Ridge		90%		2.31%		3-Month LIBOR	86		31-Mar-11	31-Mar-26
Tapestry		90%		2.21%		3-Month LIBOR	172		30-Dec-11	21-Dec-21
Tapestry		50%		3.57%		3-Month LIBOR	60		21-Dec-21	21-Dec-29
Walnut Creek Energy		90%		various		3-Month LIBOR	345		28-Jun-13	31-May-23
WCEP Holdings		90%		4.00%		3-Month LIBOR	47		28-Jun-13	31-May-23
Total							$	2,817
Annual Maturities
Annual payments based on the maturities of the Company's debt, for the years ending after December 31, 2014, are as follows:
	(In millions)
2015	$	214
2016	246
2017	259
2018	264
2019	625
Thereafter	3,198
Total	$	4,806
Long-Term Debt
For a discussion of NRG Yield Inc.’s financing arrangements, see Note 9, Debt and Capital Leases, to the Company's consolidated financial statements.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2014
Earnings (Loss) Per Share Disclosure [Abstract]
Earnings Per Share	Earnings Per Share
	Basic and diluted earnings per common share are computed by dividing net income by the weighted average number of common shares outstanding. Shares issued during the year are weighted for the portion of the year that they were outstanding.
	The reconciliation of the Company's basic and diluted earnings per share is shown in the following table, after giving effect to the stock split as described in Note 1, Nature of Business:
		Class A Common Stock				Class C Common Stock
		Year ended December 31, 2014		Period from July 23, 2013 to December 31, 2013		Year ended December 31, 2014		Period from July 23, 2013 to December 31, 2013
	(In millions, except per share data)
	Basic and diluted earnings per share attributable to NRG Yield, Inc. common stockholders
	Net income attributable to NRG Yield, Inc.	$	8	$	7	$	8	$	7
	Weighted average number of common shares outstanding	28		23		28		23
	Earnings per weighted average common share — basic and diluted	$	0.3	$	0.29	$	0.3	$	0.29
	There were a total of six million anti-dilutive outstanding equity instruments related to the Convertible Notes for the year ended December 31, 2014 with respect to the calculation of diluted earnings per share for the Company's Class A common stock and a total of six million anti-dilutive outstanding equity instruments related to the Convertible Notes for the year ended December 31, 2014 with respect to the calculation of diluted earnings per share for the Company's Class C common stock.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity	Stockholders' Equity
	On July 22, 2013, in connection with its initial public offering, the Company authorized 500,000,000 shares of Class A common stock, par value $0.01 per share, of which 22,511,250 were issued to the public in connection with the initial public offering and became outstanding. In return for the issuance of these shares, the Company received $468 million, net of underwriting discounts and commissions of $27 million. In addition, in connection with the initial public offering, the Company authorized 500,000,000 shares of Class B common stock, par value $0.01 per share, of which 42,738,750 were issued to NRG concurrently with the initial public offering and became outstanding. The Company utilized $395 million of the proceeds from the issuance of the Class A common stock to acquire a controlling interest in NRG Yield LLC from NRG. Each share of both of the Class A common stock and Class B common stock entitles the holder to one vote on all matters. Class A common stockholders hold 100% of the economic interest and a 34.5% voting interest in the Company. Class B common stockholders held a 65.5% voting interest in NRG, Yield, Inc. prior to the secondary offering
	On July 29, 2014, the Company issued 12,075,000 shares of Class A common stock for net proceeds, after underwriting discount and expenses, of $630 million. The Company utilized the proceeds of the offering to acquire 12,075,000 additional Class A units of NRG Yield LLC and, as a result, as of December 31, 2014, the Company owns 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.
	Recapitalization
	On May 5, 2015, the Company's stockholders approved amendments to the Company's certificate of incorporation that resulted in the creation of two new classes of capital stock, Class C common stock and Class D common stock. The recapitalization became effective on May 14, 2015, with the split of each outstanding share of Class A common stock into one share of Class A common stock and one share of Class C common stock, and the split of each outstanding share of Class B common stock into one share of Class B common stock and one share of Class D common stock.
	The Class C common stock and Class D common stock have the same rights and privileges and rank equally, share ratably and are 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 is 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 remains unchanged at $0.01 per share after the effect of the stock split described above. Accordingly, the stock split is accounted for as a stock dividend. The Company recorded 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 also gave retrospective effect to prior period share and per share amounts in the audited historical consolidated financial statements for the effect of the stock dividend, such that all periods are comparable.
	Dividends to Class A and Class C common stockholders
	The following table lists the dividends paid on the Company's Class A common stock during the year ended December 31, 2014:
		Fourth Quarter 2014		Third Quarter 2014		Second Quarter 2014		First Quarter 2014
	Dividends per share	$	0.375	$	0.365	$	0.35	$	0.33
	On February 17, 2015, the Company declared a quarterly dividend on its Class A common stock of $0.39 per share payable on March 16, 2015, to stockholders of record as of March 2, 2015.
	On May 20, 2015, the Company declared a quarterly dividend on its Class A common stock and Class C common stock of $0.20 per share payable on June 15, 2015, to holders of Class A common stock and Class C common stock of record as of June 1, 2015.
	Dividends on the Class A common stock and Class C common stock are subject to available capital, market conditions, and compliance with associated laws, regulations and other contractual obligations.
	The Company 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.
	Distributions to NRG
	The following table lists the distributions paid to NRG during the year ended December 31, 2014:
		Fourth Quarter 2014		Third Quarter 2014		Second Quarter 2014		First Quarter 2014
	Distributions per unit	$	0.375	$	0.365	$	0.35	$	0.33
	The portion of the distributions paid by NRG Yield LLC to NRG was recorded as a reduction to the Company's noncontrolling interest balance. The portion of the distributions paid by NRG Yield LLC to the Company was utilized to fund the dividends to the Class A common stockholders described above.
	On February 17, 2015, the Company declared a quarterly distribution on its Class B units of $0.39 per unit payable on March 16, 2015.
	On June 30, 2014, the Company acquired the TA High Desert, RE Kansas South, and El Segundo projects, as discussed in Note 3, Business Acquisitions. The difference between the cash paid and historical value of the entities' equity of $113 million was recorded as a distribution to NRG and reduced the balance of its noncontrolling interest. In addition, as the TA High Desert, RE Kansas South and El Segundo projects were owned by NRG until June 30, 2014, the pre-acquisition earnings of such projects are recorded as attributable to NRG's noncontrolling interest. Prior to the date of acquisition, El Segundo made a distribution to NRG of $23 million. Additionally, NRG Repowering Holding LLC (a wholly owned subsidiary of NRG) paid a contribution of $2 million to TA High Desert.
	On January 2, 2015, the Company acquired Laredo Ridge, Walnut Creek, and Tapestry projects, as discussed in Note 3, Business Acquisitions. The difference between the cash paid and historical value of the entities' equity of $61 million, as well as $23 million of AOCL, was recorded as a distribution to NRG and reduced the balance of its noncontrolling interest. In addition, as Laredo Ridge, Walnut Creek and Tapestry 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. Prior to the date of acquisition, Laredo Ridge, Walnut Creek and Tapestry projects made distributions to NRG, net of contributions, of $41 million.

Segment_Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2014																Dec. 31, 2013																Dec. 31, 2011
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment
		Year ended December 31, 2014																Year ended December 31, 2013																Year ended December 31, 2012
																	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total			(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total
	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total			Operating revenues	$	138		$	89		$	152		$	—		$	379		Operating revenues	$	—		$	33		$	142		$	—		$	175
	Operating revenues	$	317		$	177		$	195		$	—		$	689		Cost of operations	23			11			110			—			144			Cost of operations	2			9			103			—			114
	Cost of operations	55			45			139			—			239			Depreciation and amortization	20			26			15			—			61			Depreciation and amortization	—			10			15			—			25
	Depreciation and amortization	82			66			18			—			166			General and administrative — affiliate	—			—			—			7			7			General and administrative — affiliate	—			—			—			7			7
	General and administrative — affiliate	—			—			—			8			8			Operating income (loss)	95			52			27			(7		)	167			Operating income (loss)	(2		)	14			24			(7		)	29
	Acquisition-related transaction and integration costs	—			—			—			4			4			Equity in earnings of unconsolidated affiliates	16			6			—			—			22			Equity in earnings of unconsolidated affiliates	15			4			—			—			19
	Operating income (loss)	180			66			38			(12		)	272			Other income, net	1			2			—			—			3			Other income, net	1			1			—			—			2
	Equity in earnings of unconsolidated affiliates	14			13			—			—			27			Interest expense	(25		)	(20		)	(7		)	—			(52		)	Interest expense	—			(20		)	(8		)	—			(28		)
	Other income, net	—			2			—			1			3			Income (loss) before income taxes	87			40			20			(7		)	140			Income (loss) before income taxes	14			(1		)	16			(7		)	22
	Interest expense	(53		)	(96		)	(7		)	(30		)	(186		)	Income tax expense	—			—			—			8			8			Income tax expense	—			—			—			10			10
	Income (loss) before income taxes	141			(15		)	31			(41		)	116			Net Income (Loss)	$	87		$	40		$	20		$	(15	)	$	132		Net Income (Loss)	$	14		$	(1	)	$	16		$	(17	)	$	12
	Income tax expense	—			—			—			4			4			Balance Sheet
																	Equity investments in affiliates	$	118		$	109		$	—		$	—		$	227
	Net Income (Loss)	$	141		$	(15	)	$	31		$	(45	)	$	112
																	Capital expenditures (a)	168			30			15			—			213
	Balance Sheet
																	Total Assets	$	1,584		$	1,046		$	436		$	172		$	3,238
	Equity investment in affiliates	$	114		$	113		$	—		$	—		$	227
	Capital expenditures(a)	6			(1		)	7			—			12
	Total Assets	$	2,194		$	3,856		$	437		$	478		$	6,965
Segment Reporting	Segment Reporting
	The Company’s segment structure reflects how management currently makes financial decisions and allocates resources. Its businesses are primarily segregated based on conventional power generation, renewable businesses which consist of solar and wind, and the thermal and chilled water business. The Corporate segment reflects the Company's corporate costs.
	The Company generated more than 10% of its revenues from the following customers for the years ended December 31, 2014, and 2013. For the year ended December 31, 2012, there were no customers from whom the Company derived more than 10% of consolidated revenue.
		2014			2013
	Customer	Conventional (%)		Renewables (%)	Conventional (%)		Renewables (%)
	Southern California Edison	28%		9%	15%		4%
	Pacific Gas and Electric	18%		4%	22%		7%
		Year ended December 31, 2014
	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total
	Operating revenues	$	317		$	177		$	195		$	—		$	689
	Cost of operations	55			45			139			—			239
	Depreciation and amortization	82			66			18			—			166
	General and administrative — affiliate	—			—			—			8			8
	Acquisition-related transaction and integration costs	—			—			—			4			4
	Operating income (loss)	180			66			38			(12		)	272
	Equity in earnings of unconsolidated affiliates	14			13			—			—			27
	Other income, net	—			2			—			1			3
	Interest expense	(53		)	(96		)	(7		)	(30		)	(186		)
	Income (loss) before income taxes	141			(15		)	31			(41		)	116
	Income tax expense	—			—			—			4			4
	Net Income (Loss)	$	141		$	(15	)	$	31		$	(45	)	$	112
	Balance Sheet
	Equity investment in affiliates	$	114		$	113		$	—		$	—		$	227
	Capital expenditures(a)	6			(1		)	7			—			12
	Total Assets	$	2,194		$	3,856		$	437		$	478		$	6,965
	(a) Includes accruals. Capital expenditures for Renewables include a sales tax refund received by Alpine in the first quarter of 2014.
		Year ended December 31, 2013
	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total
	Operating revenues	$	138		$	89		$	152		$	—		$	379
	Cost of operations	23			11			110			—			144
	Depreciation and amortization	20			26			15			—			61
	General and administrative — affiliate	—			—			—			7			7
	Operating income (loss)	95			52			27			(7		)	167
	Equity in earnings of unconsolidated affiliates	16			6			—			—			22
	Other income, net	1			2			—			—			3
	Interest expense	(25		)	(20		)	(7		)	—			(52		)
	Income (loss) before income taxes	87			40			20			(7		)	140
	Income tax expense	—			—			—			8			8
	Net Income (Loss)	$	87		$	40		$	20		$	(15	)	$	132
	Balance Sheet
	Equity investments in affiliates	$	118		$	109		$	—		$	—		$	227
	Capital expenditures (a)	168			30			15			—			213
	Total Assets	$	1,584		$	1,046		$	436		$	172		$	3,238
	(a) Includes accruals.
		Year ended December 31, 2012
	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total
	Operating revenues	$	—		$	33		$	142		$	—		$	175
	Cost of operations	2			9			103			—			114
	Depreciation and amortization	—			10			15			—			25
	General and administrative — affiliate	—			—			—			7			7
	Operating income (loss)	(2		)	14			24			(7		)	29
	Equity in earnings of unconsolidated affiliates	15			4			—			—			19
	Other income, net	1			1			—			—			2
	Interest expense	—			(20		)	(8		)	—			(28		)
	Income (loss) before income taxes	14			(1		)	16			(7		)	22
	Income tax expense	—			—			—			10			10
	Net Income (Loss)	$	14		$	(1	)	$	16		$	(17	)	$	12

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	Effective Tax Rate
	The income tax provision from continuing operations consisted of the following amounts:
		Year Ended December 31,
		2014			2013			2012
		(In millions, except percentages)
	Current
	U.S. Federal	$	—		$	—		$	7
	Total — current	—			—			7
	Deferred
	U.S. Federal	2			14			1
	State	2			(6		)	2
	Total — deferred	4			8			3
	Total income tax expense	$	4		$	8		$	10
	Effective tax rate	3.4		%	5.7		%	45.7		%
	A reconciliation of the U.S. federal statutory rate of 35% to the Company's effective rate is as follows:
		Year Ended December 31,
		2014			2013 (a)			2012 (b)
		(In millions, except percentages)
	Income Before Income Taxes	116			140			22
	Tax at 35%	41			49			8
	State taxes, net of federal benefit	1			(6		)	2
	Impact of non-taxable equity earnings	(33		)	(35		)	—
	Production tax credits	(6		)	—			—
	Change in state effective tax rate	1			—			—
	Income tax expense	$	4		$	8		$	10
	Effective income tax rate	3.4		%	5.7		%	45.7		%
	(a) - Represents 34.5% ownership for the period July 22, 2013 through December 31, 2013
	(b) - Represents pro forma tax provision for NRG Yield LLC
	For the year ended December 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 55.3% interest in NRG Yield LLC and production tax credits generated from certain Alta Wind Portfolio facilities.
	For the year ended December 31, 2013, 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.
	On July 22, 2013, the Company acquired a controlling interest in NRG Yield LLC and its subsidiary NRG Yield Operating LLC. On July 29, 2014, the Company issued additional shares of Class A common stock, and as a result, it currently owns 44.7% of NRG Yield LLC and consolidates the results due to its controlling interest. 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 temporary differences, which gave rise to the Company's deferred tax assets, consisted of the following:
		As of December 31,
		2014			2013
		(In millions)
	Deferred tax assets:
	Investment in projects	$	47		$	81
	Production tax credits carryforwards	6			—
	U.S. Federal net operating loss carryforwards	74			61
	State net operating loss carryforwards	7			4
	Total deferred tax assets	134			146
	Net deferred tax asset	$	134		$	146
	The following table summarizes the Company's net deferred tax position:
		As of December 31,
		2014			2013
		(In millions)
	Net deferred tax asset — current	$	16		$	—
	Net deferred tax asset — noncurrent	118			146
	Net deferred tax asset	$	134		$	146
	Tax Receivable and Payable
	As of December 31, 2014, the Company had a domestic tax receivable of $6 million which related to federal cash grants for Borrego project. This amount is fully reserved pending further discussions with the US Treasury Department.
	Deferred Tax Assets and Valuation Allowance
	Net deferred tax balance — As of December 31, 2014, and 2013, NRG recorded a net deferred tax asset of $134 million and $146 million, respectively. The Company believes it is more likely than not that the results of future operations will generate sufficient taxable income which includes the future reversal of existing taxable temporary differences to realize deferred tax assets. In arriving at this conclusion to utilize projections of future profit before tax in its estimate of future taxable income, the Company considered the profit before tax generated in recent years.
	NOL carryforwards — At December 31, 2014, the Company had domestic NOLs consisting of carryforwards for federal income tax purposes of $74 million and cumulative state NOLs of $7 million tax-effected.
	Uncertain Tax Positions
	The Company had no identified uncertain tax positions that require evaluation as of December 31, 2014.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions Disclosure	Related Party Transactions
	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 December 31, 2014, the base management fee was approximately $6 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 year ended December 31, 2014, the fee was increased by approximately $2 million per year in connection with the acquisition of the Acquired ROFO Assets and Alta Wind Portfolio. Costs incurred under this agreement were approximately $8 million for the year ended December 31, 2014 and $3 million for the period beginning July 23, 2013 and ending December 31, 2013. These costs included certain direct expenses incurred by NRG on behalf of the Company in addition to the base management fee, $5 million of which was unpaid as of December 31, 2014 and bears no interest. The balance was classified as a liability under accounts payable — affiliate in the Company's consolidated balance sheets as of December 31, 2014, and repaid in February 2015.
	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 same services to Thermal entities on an informal basis. For the years ended December 31, 2014 and 2013, total fees incurred under the agreements were $27 million and $24 million, respectively. There was a balance of $22 million due to NRG in accounts payable — affiliate as of December 31, 2014.
	O&M Services Agreements by and between NRG and GenConn
	GenConn incurs fees under two O&M agreements with wholly-owned subsidiaries of NRG. The fees incurred under the agreements were $6 million, $5 million and $5 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Power Sales and Services Agreement by and between NRG and NRG Energy Center Dover LLC
	NRG Energy Center Dover LLC, or NRG Dover, a subsidiary of the Company is party to a Power Sales and Services Agreement with NRG Power Marketing LLC, or NRG Power Marketing, a wholly-owned subsidiary of NRG. The agreement is automatically renewed on a month-to-month basis unless terminated by either party upon at least 30 day written notice. Under the agreement, NRG Power Marketing has the exclusive right to (i) manage, market and sell power, (ii) procure fuel and fuel transportation for operation of the Dover generating facility, to include for purposes other than generating power, (iii) procure transmission services required for the sale of power, and (iv) procure and market emissions credits for operation of the Dover generating facility.
	In addition, NRG Power Marketing has the exclusive right and obligation to direct the output from the generating facility, in accordance with and to meet the terms of any power sales contracts executed against the power generation of the Dover facility. Under the agreement, NRG Power Marketing pays NRG Dover gross receipts generated through sales, less costs incurred by NRG Power Marketing related to providing such services as transmission and delivery costs, as well as fuel costs. During 2011, the existing coal purchase contract expired and NRG Power Marketing entered into a new contract, which expired in December 2012, to purchase coal for the Dover Facility. For the year ended December 31, 2012, NRG Dover purchased approximately $2 million under this agreement. In July 2013, the originally coal-fueled plant was converted to a natural gas facility. For the years ended December 31, 2014, and 2013, NRG Dover purchased approximately $10 million and $5 million, respectively, of natural gas from NRG Power Marketing.
	O&M Services Agreements by and between El Segundo and NRG El Segundo Operations
	El Segundo incurs fees under an O&M agreement with NRG El Segundo Operations, Inc., a wholly-owned subsidiary of NRG. Under the O&M agreement, NRG El Segundo Operations, Inc. manages, operates and maintains the El Segundo facility for an initial term of ten years following the commercial operations date. For the years ended December 31, 2014, 2013, and 2012, the costs incurred under the agreement were approximately $4 million, $5 million, and $1 million, respectively. For the years ended December 31, 2013 and 2012, $2 million and $1 million of the costs incurred were capitalized and recorded to property, plant and equipment in the Company's consolidated balance sheets.
	Ground Lease and Easement Agreement by and between El Segundo and El Segundo Power, LLC
	El Segundo incurred lease expense under a ground lease and easement agreement with El Segundo Power, LLC, a wholly-owned subsidiary of NRG, for a parcel of real property in the city of El Segundo, California. The nonexclusive easements are for the support infrastructure for the project. The initial term of the agreement was over the construction of the project through the twentieth anniversary of the commercial operations date. For the years ended December 31, 2014, 2013, and 2012, the Company incurred costs of approximately $1 million for each year. The costs are included in cost of operations in the Company's consolidated statements of operations.
	Construction Management Services Agreement by and between El Segundo and NRG Construction Services LLC
	El Segundo incurred fees under a construction management services agreement with NRG Construction Services LLC, a wholly-owned subsidiary of NRG, to act as construction manager of the project to manage the design, engineering, procurement and construction, commissioning, testing initial start-up and closeout of construction activities for the facility. For the years ended December 31, 2013 and 2012, total costs incurred were $4 million and $4 million, respectively. The costs were capitalized and recorded to property, plant and equipment in the Company's consolidated balance sheets. El Segundo achieved commercial operations in August 2013.
	Energy Marketing Services Agreement with NRG Power Marketing LLC
	El Segundo was a party to an energy marketing services agreement with NRG Power Marketing LLC, a wholly-owned subsidiary of NRG, to procure fuel and market capacity, energy and ancillary output of the facility prior to the start of the PPA with Southern California Edison. The agreement began in April 2013 and ended at the commercial operations date in August 2013. For the years ended December 31, 2014 and 2013, the Company recorded approximately $1 million and $12 million, respectively, in costs related to this agreement of which $9 million was recorded to property, plant and equipment in 2013, with remaining amount recorded to cost of operations in the Company's statement of operations.
	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 with processing and paying invoices services 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 $13 million, $36 million, and $2 million for the years ended December 31, 2014, 2013 and 2012, respectively. For the years ended December 31, 2014, 2013 and 2012, $2 million, $29 million and $2 million, respectively, were capitalized. There was a balance of $4 million and $2 million due to GenOn Energy Services, LLC in accounts payable - affiliate as of December 31, 2014 and 2013, respectively.
	Accounts Payable to NRG Renew LLC
	During the third quarter of 2013, NRG Renew LLC (formerly known as NRG Solar LLC), a wholly-owned subsidiary of NRG, made 100% of the required capital contributions to CVSR, including the Company's 48.95% portion, of which $14 million was outstanding as of December 31, 2013. This balance was repaid to NRG Renew LLC during the quarter ended March 31, 2014.
	Accounts Payable to NRG Repowering Holdings LLC
	During 2013, NRG Repowering Holdings, LLC, a wholly-owned subsidiary of NRG, made payments to BA Leasing BSC, LLC, or BA Leasing, of $18 million, which were expected to be repaid with the proceeds of the cash grant received by BA leasing with respect to the PFMG DG Solar Projects, in connection with a sale-leaseback arrangement between the PFMG DG Solar Projects and BA Leasing. As of December 31, 2013, PFMG DG Solar Projects had a corresponding receivable for the reimbursement of the cash grant from BA Leasing and related payable to NRG Repowering Holdings, LLC. In the first quarter of 2014, the PFMG DG Solar Projects received $11 million from BA Leasing and reduced the remaining receivable with an offset to the deferred liability recorded in connection with the sale - leaseback arrangement. The PFMG DG Solar Projects utilized the $11 million to repay NRG Repowering Holdings LLC.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Operating Lease Commitments
	The Company leases certain facilities and equipment under operating leases, some of which include escalation clauses, expiring on various dates through 2048. The effects of these scheduled rent increases, leasehold incentives, and rent concessions are recognized on a straight-line basis over the lease term unless another systematic and rational allocation basis is more representative of the time pattern in which the leased property is physically employed. Lease expense under operating leases was $5 million for the year ended December 31, 2014, and $2 million for each of the years ended 2013 and 2012.
	Future minimum lease commitments under operating leases for the years ending after December 31, 2014, are as follows:
	Period	(In millions)
	2015	$	12
	2016	11
	2017	7
	2018	7
	2019	7
	Thereafter	133
	Total	$	177
	Gas and Transportation Commitments
	The Company has entered into contractual arrangements to procure power, fuel and associated transportation services. For the years ended December 31, 2014, 2013 and 2012, the Company purchased $55 million, $40 million, and $30 million, respectively, under such arrangements.
	As of December 31, 2014, the Company's commitments under such outstanding agreements are estimated as follows:
	Period	(In millions)
	2015	$	15
	2016	4
	2017	3
	2018	3
	2019	2
	Thereafter	26
	Total	$	53
	Contingencies
	In the normal course of business, the Company is subject to various claims and litigation. Management expects that these various litigation items will not have a material adverse effect on the Company's results of operations or financial position.
	Commitments, Contingencies and Guarantees
	See Note 13, Income Taxes and Note 15, Commitments and Contingencies to the Company's consolidated financial statements for a detailed discussion of NRG Yield, Inc.’s commitments and contingencies.
	Note 4 — Dividends
	Cash distributions paid to NRG Yield, Inc. by its subsidiary, NRG Yield LLC, were $41 million and $5 million for the years ended December 31, 2014 and 2013, respectively.

Unaudited_Quarterly_Financial_

Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Financial Data	Unaudited Quarterly Data
	Refer to Note 2, Summary of Significant Accounting Policies and Note 3, Business Acquisitions for a description of the effect of unusual or infrequently occurring events during the quarterly periods. Summarized unaudited quarterly financial data is as follows:
		Quarter Ended
		December 31, (a)			September 30, (a)		June 30, (a)		March 31, (c)
		2014
	(As recast)	(In millions, except per share data)
	Operating Revenues	$	192		$	184	$	173	$	140
	(As previously reported in 2014 Form 10-K)
	Operating Revenues	148			161		134		140
	(Change )	44			23		39		—
	(As recast)
	Operating Income	70			84		64		54
	(As previously reported in 2014 Form 10-K)
	Operating Income	46			70		51		54
	Change	24			14		13		—
	(As recast)
	Net Income	5			40		41		26
	(As previously reported in 2014 Form 10-K)
	Net (Loss) Income	$	(10	)	$	31	$	34	$	26
	(Change)	15			9		7		—
	Net Income Attributable to NRG Yield, Inc.	$	—		$	6	$	6	$	4
	Weighted average number of Class A common shares outstanding - basic and diluted (b)	35			31		23		23
	Earnings per Weighted Average Class A Common Share - Basic and Diluted (b)	$	0.01		$	0.1	$	0.13	$	0.09
	Weighted average number of Class C common shares outstanding - basic and diluted (b)	35			31		23		23
	Earnings per Weighted Average Class C Common Share - Basic and Diluted (b)	$	0.01		$	0.1	$	0.13	$	0.09
	(a) The Company's unaudited quarterly financial data was recast for the effect of the EME-NYLD-Eligible Assets, from the date the entities were under common control or April 1, 2014.
	(b) Adjusted to give effect to the stock split, as described in Note 1, Nature of Business.
	(c) The Acquired ROFO Assets were purchased on June 30, 2014, and accordingly the Company had previously reported operating revenues of $110 million, operating income of $38 million and net income of $18 million for the three months ended March 31, 2014.
		Quarter Ended
		December 31, (c)			September 30, (a) (c)		June 30, (c)		March 31, (c)
		2013
	(As recast)	(In millions, except per share data)
	Operating Revenues	$	118		$	126	$	82	$	53
	(As previously reported in 2013 Form 10-K)
	Operating Revenues	86			95		79		53
	(Change )	32			31		3		—
	(As recast)
	Operating Income	54			63		38		12
	(As previously reported in 2013 Form 10-K)
	Operating Income	33			45		38		12
	(Change )	21			18		—		—
	(As recast)
	Net Income	37			49		35		11
	(As previously reported in 2013 Form 10-K)
	Net Income	$	24		40		$	34	$	11
	(Change )	13			9		1		—
	Net Income Attributable to NRG Yield, Inc.	$	4		$	9	n/a		n/a
	Weighted average number of Class A common shares outstanding - basic and diluted	23			23		n/a		n/a
	Weighted average number of Class C common shares outstanding - basic and diluted	23			23		n/a		n/a
	Earnings per Weighted Average Class A Common Share - Basic and Diluted (b)	$	0.09		$	0.2	n/a		n/a
	Earnings per Weighted Average Class C Common Share - Basic and Diluted (b)	$	0.09		$	0.2	n/a		n/a
	(a) Earnings per weighted average class A and Class C common share are calculated for the period of July 22, 2013 to September 30, 2013.
	(b) Adjusted to give effect to the stock split, as described in Note 1, Nature of Business.
	(c) The Company's unaudited quarterly financial data was recast for the effect of the Acquired ROFO Assets.

Background_and_Basis_of_Presen

Background and Basis of Presentation - Yield, Inc (Parent) (Notes)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	Background and Basis of Presentation
	Background
	NRG Yield, Inc., or the Company, is a dividend growth-oriented company formed on December 20, 2012. The Company used the net proceeds from its initial public offering of Class A common stock on July 22, 2013 to acquire 100%, or 22,511,250, of the Class A units of NRG Yield LLC. In connection with the acquisition of the Class A units, the Company also became the sole managing member of NRG Yield LLC, thereby acquiring a controlling interest. 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.
	Prior to the secondary offering, the Company and NRG owned 34.5% and 65.5% of NRG Yield LLC, respectively. On July 29, 2014, the Company issued 12,075,000 shares of Class A common stock in a secondary offering for net proceeds, after underwriting discount and expenses, of $630 million. The Company utilized the proceeds of the offering to acquire 12,075,000 additional Class A units of NRG Yield LLC and, as a result, subsequent to the secondary offering and as of December 31, 2014, the Company owns 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 issued and outstanding shares of Class A common stock an entitled to 100% of the Company's economic interests and are entitled to dividends. NRG receives distributions from Yield LLC through its ownership of Class B common units.
	On May 5, 2015, the Company's stockholders approved amendments to the Company's certificate of incorporation that resulted in the creation of two new classes of capital stock, Class C common stock and Class D common stock. The recapitalization became effective on May 14, 2015, with the split of each outstanding share of Class A common stock into one share of Class A common stock and one share of Class C common stock, and the split of each outstanding share of Class B common stock into one share of Class B common stock and one share of Class D common stock.
	The Class C common stock and Class D common stock have the same rights and privileges and rank equally, share ratably and are 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 is 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 remains unchanged at $0.01 per share after the effect of the stock split described above. Accordingly, the stock split is accounted for as a stock dividend. The Company recorded 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 also gave retrospective effect to prior period share and per share amounts in the audited historical consolidated financial statements for the effect of the stock dividend, such that all periods are comparable. As such, the Company's historical financial statements previously filed with the SEC have been recast in this Current Report on Form 8-K to include the retrospective effect of the stock split on all the periods reported.
	Basis of Presentation
	The condensed parent-only company financial statements have been prepared in accordance with Rule 12-04 of
	Regulation S-X, as the restricted net assets of NRG Yield, Inc.’s subsidiaries exceed 25% of the consolidated net assets of
	NRG Yield, Inc. The parent's 100% investment in its subsidiaries has been recorded using the equity basis of accounting in the accompanying condensed parent-only financial statements. These statements should be read in conjunction with the consolidated statements and notes thereto of NRG Yield, Inc.

Long_Term_Debt_Yield_Parent_No

Long Term Debt (Yield - Parent) (Notes)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Long-term Debt	Long-term Debt
	The Company's borrowings, including short term and long term portions consisted of the following:
		December 31, 2014				December 31, 2013			Interest rate % (a)
		(In millions, except rates)
	Convertible Notes, due 2019 (b)	$	326			—			3.5
	Senior Notes, due 2024	500				—			5.375
	Project-level debt:
	Alta Wind I, lease financing arrangement, due 2034	261				—			7.015
	Alta Wind II, lease financing arrangement, due 2034	205				—			5.696
	Alta Wind III, lease financing arrangement, due 2034	212				—			6.067
	Alta Wind IV, lease financing arrangement, due 2034	138				—			5.938
	Alta Wind V, lease financing arrangement, due 2035	220				—			6.071
	Alta Wind X, due 2021	300				—			L+2.00
	Alta Wind XI, due 2021	191				—			L+2.00
	Alta Realty Investments, due 2031	34				—			7
	Alta Wind Asset Management, due 2031	20				—			L+2.375
	NRG West Holdings LLC, due 2023	506				512			L+2.25 - L+2.875; L+2.25 - L+2.75
	NRG Marsh Landing LLC, due 2017 and 2023	464				473			L+ 1.75 - L+1.875; L+2.75 - L+3.00
	Walnut Creek Energy LLC, due 2023	391				—			L+1.625
	Tapestry Wind LLC, due 2021	192				—			L+1.625
	NRG Solar Alpine LLC, due 2014 and 2022	163				221			L+1.75 - L+2.50; L+2.25 - L+2.50
	NRG Energy Center Minneapolis LLC, due 2017 and 2025	121				127			5.95 -7.31
	Laredo Ridge LLC, due 2026	108				—			L+1.875
	NRG Solar Borrego LLC, due 2024 and 2038	75				78			L+ 2.50/5.65
	South Trent Wind LLC, due 2020	65				69			L+2.75;L+2.625
	NRG Solar Avra Valley LLC, due 2031	63				63			L+1.75; L+2.25
	TA High Desert LLC, due 2023 and 2033	55				80			L+2.50/5.15
	WCEP Holdings LLC, due 2023	46				—			L+3.00
	NRG Roadrunner LLC, due 2031	42				44			L+2.01
	NRG Solar Kansas South LLC, due 2031	35				58			L+2.00;L+2.625
	NRG Solar Blythe LLC, due 2028	22				24			L+2.75
	PFMG and related subsidiaries financing agreement, due 2030	31				32			6
	NRG Energy Center Princeton LLC, due 2017	1				2			5.95
	Subtotal project-level debt:	3,961				1,783
	Total debt	4,787				1,783
	Less current maturities	214				214
	Total long-term debt	$	4,573			$	1,569
	(a) As of December 31, 2014, L+ equals 3 month LIBOR plus x%, except for RE Kansas South where L+ equals 6 month LIBOR plus x%.
	(b) Net of discount of $19 million as of December 31, 2014.
	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 arrangement. As of December 31, 2014, 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 year ended December 31, 2014.
	NRG Yield, Inc. Convertible Notes
	During the first quarter of 2014, the Company closed on its offering of $345 million of Convertible Notes. The Convertible Notes bear interest of 3.50% and mature in February 2019.  Interest on the Convertible Notes is payable semi-annually in arrears on February 1 and August 1 of each year, commencing on August 1, 2014. The Convertible Notes are convertible, under certain circumstances, into the Company’s Class A common stock, cash or a combination thereof at an initial conversion price of $46.55 per Class A common share, which is equivalent to an initial conversion rate of approximately 21.4822 shares of Class A common stock per $1,000 principal amount of Convertible Notes. The Convertible Notes mature on February 1, 2019, unless earlier repurchased or converted in accordance with their terms. Prior to the close of business on the business day immediately preceding August 1, 2018, the Convertible Notes will be convertible only upon the occurrence of certain events and during certain periods, and thereafter, at any time until the close of business on the second scheduled trading day immediately preceding the maturity date. The Convertible Notes are guaranteed by NRG Yield Operating LLC and NRG Yield LLC.
	The Convertible Notes are accounted for in accordance with ASC 470-20, Debt with Conversion and Other Options. Under ASC 470-20, issuers of convertible debt instruments that may be settled in cash upon conversion, including partial cash settlement, are required to separately account for the liability (debt) and equity (conversion option) components. The application of ACS 470-20 resulted in the recognition of $23 million as the value for the equity component with the offset to debt discount. The debt discount is amortized to interest expense using the effective interest method through February 2019.
	As of December 31, 2014, the Convertible Notes were trading at approximately 114% of their face value, resulting in a total market value of $395 million compared to a carrying value of $326 million. The actual conversion value of the Convertible Notes is based on the product of the conversion rate and the market price of the Company's common stock, as defined in the Convertible Debt indenture. As of December 31, 2014, the Company's common stock closed at $47.14 per share, resulting in a pro forma conversion value for the Convertible Notes of approximately $349 million.
	During the years ended December 31, 2014, the Company recorded the following expense in relation to the Convertible Notes at the effective rate of 5.00%:
	(In millions)
	Interest expense at 3.5% coupon rate		11
	Debt discount amortization		4
	Debt issuance costs amortization		1
			$	16
	NRG Yield Operating LLC Senior Notes
	On August 5, 2014, NRG Yield Operating LLC issued $500 million of senior unsecured notes, or the Senior Notes. The Senior Notes bear interest at 5.375% and mature in August 2024. Interest on the notes is payable semi-annually on February 15 and August 15 of each year, and commenced on February 15, 2015. The Senior Notes are senior unsecured obligations of NRG Yield Operating LLC and are guaranteed by NRG Yield LLC, and by certain of NRG Yield Operating LLC’s wholly owned current and future subsidiaries.
	NRG Yield LLC and NRG Yield Operating LLC Revolving Credit Facility
	In connection with the Company's initial public offering of Class A common stock in July 2013, as further described in Note 1, Nature of Business, NRG Yield LLC and NRG Yield Operating LLC entered into a senior secured revolving credit facility, or the Yield Credit Facility, which provided a revolving line of credit of $60 million. On April 25, 2014, NRG Yield LLC and NRG Yield Operating LLC amended the revolving credit facility to increase the available line of credit to $450 million and extend its maturity to April 2019. The Company's revolving credit facility can be used for cash or for the issuance of letters of credit. There was no cash drawn and $38 million of letters of credit issued in support of the obligations of the Alta Wind Portfolio under the revolving credit facility as of December 31, 2014.
	On January 2, 2015, the Company borrowed $210 million under the Yield 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 of principal and interest.
	Project - level Debt
	NRG West Holdings Credit Agreement
	On August 23, 2011, NRG West Holdings LLC, or West Holdings, entered into a credit agreement with a group of lenders in respect to the El Segundo project, or the West Holdings Credit Agreement. The West Holdings Credit Agreement is comprised of a $540 million two tranche construction loan facility with additional facilities for the issuance of letters of credit or working capital loans and is secured by the assets of West Holdings.
	The two tranche construction loan facility consists of the $480 million Tranche A Construction Facility, or the Tranche A Facility, and the $60 million Tranche B Construction Facility, or the Tranche B Facility. The Tranche A and Tranche B Facilities, which mature in August 2023, convert to a term loan and have an interest rate of 3-month LIBOR, plus an applicable margin which (i) increases by 0.125% periodically from conversion through year eight for the Tranche A Facility, and (ii) increases by (a) 0.125% upon term conversion and on the third and sixth anniversary of the term conversion and (b) by 0.250% on the eighth anniversary of the term conversion for the Tranche B Facility. The Tranche A and Tranche B Facilities amortize based upon a predetermined schedule over the term of the loan with the balance payable at maturity. The construction loan converted to a term loan on January 28, 2014.
	The West Holdings Credit Agreement also provides for the issuance of letters of credit and working capital loans to support the El Segundo project's collateral needs. This includes letter of credit facilities on behalf of West Holdings of up to $90 million in support of the PPA, up to $48 million in support of the collateral agent, and a working capital facility which permits loans or the issuance of letters of credit of up to $10 million.
	As of December 31, 2014, under the West Holdings Credit Agreement, West Holdings had $447 million outstanding under the Tranche A Facility, $59 million under the Tranche B Facility, issued a $33 million letter of credit in support of the PPA, a $48 million letter in support of debt service and a $1 million letter of credit under the working capital facility.
	Alpine Financing
	On March 16, 2012, NRG Solar Alpine LLC, or Alpine, entered into a credit agreement with a group of lenders for a $166 million construction loan that was convertible to a term loan upon completion of the project and a $68 million cash grant loan. On January 15, 2013, the credit agreement was amended reducing the cash grant loan to $63 million. On March 26, 2013, Alpine met the conditions under the credit agreement to convert the construction loan to a term loan. Immediately prior to the conversion, the Company drew an additional $164 million under the construction loan and $62 million under the cash grant loan. The term loan amortizes on a predetermined schedule with final maturity in November 2022.
In January 2014, Alpine repaid the $62 million of outstanding cash grant loan, including accrued interest and breakage fees, with the proceeds that it had received from the U.S. Treasury Department. On June 24, 2014, Alpine amended the credit agreement to increase its term loan borrowings by an additional $13 million and to reduce the related interest rate to 3 month LIBOR plus 1.75% through June 30, 2019 and 3 month LIBOR plus 2.00% through November 2022. The proceeds were utilized to make a distribution of $11 million to NRG Yield Operating LLC with the remaining $2 million utilized to fund the costs of the amendment.
Borrego Financing
On March 28, 2013, NRG Solar Borrego I LLC, or Borrego, entered into a credit agreement with a group of lenders, or the Borrego Financing Agreement, for $45 million of 5.65% fixed rate notes and a $36 million term loan. The term loan has an interest rate of 3 month LIBOR plus an applicable margin of 2.50%, which escalates 0.25% on the fourth and eighth anniversary of the closing date. The fixed rate notes mature in February 2038 and the term loan matures in December 2024. Both amortize based upon predetermined schedules. The Borrego Financing Agreement also includes a letter of credit facility on behalf of Borrego of up to $5 million. Borrego pays an availability fee of 100% of the applicable margin on issued letters of credit. As of December 31, 2014, $45 million was outstanding under the fixed rate notes, $30 million was outstanding under the term loans, and $5 million of letters of credit in support of the project were issued.
Under the terms of the Borrego Financing Agreement on March 28, 2013, Borrego was required to enter into two fixed for floating interest rate swaps that would fix the interest rate for a minimum of 75% of the outstanding notional amount. Borrego will pay its counterparty the equivalent of a 1.125% fixed interest payment on a predetermined notional value, and quarterly, Borrego will receive the equivalent of a floating interest payment based on a 3 month LIBOR calculated on the same notional value through June 30, 2020. All interest rate swap payments by Borrego and its counterparties are made quarterly and the LIBOR rate is determined in advance of each interest period. The original notional amount of the swaps, which became effective April 3, 2013, was $15 million and will amortize in proportion to the term loan.
Marsh Landing Credit Agreement Term Conversion
In May 2013, Marsh Landing met the conditions under the credit agreement to convert the construction loan for the facility to a term loan which will amortize on a predetermined basis. Prior to term conversion, Marsh Landing drew the remaining funds available under the facility in order to pay costs due for construction. Marsh Landing issued a $24 million letter of credit under the facility in support of its debt service requirements. As of December 31, 2014, $108 million was outstanding under the Tranche A loan, $356 million was outstanding under the Tranche B loans, and $22 million of letters of credit in support of the project were issued.
On July 17, 2014, Marsh Landing amended its credit agreement to increase its borrowings by $34 million and to reduce the related interest rate for the Tranche A borrowings from 3 month LIBOR plus an applicable margin of 2.75% to 3 month LIBOR plus 1.75% through December 2017; and for the Tranche B to reduce the related interest rate from 3 month LIBOR plus 3.00% to 3 month LIBOR plus 1.875% through December 2017 and to 3 month LIBOR plus 2.125% through December 2020 and to 3 month LIBOR plus 2.375% thereafter. The proceeds from the borrowings were utilized to make a distribution of $29 million to NRG Yield Operating LLC and to fund the costs of the amendment.
TA High Desert Facility
The TA High Desert Facility is comprised of $53 million of fixed rate notes due 2033 at an interest rate of 5.15%, $7 million of floating rate notes due 2023, $22 million of bridge notes due the earlier of ten days after receipt of the cash grant or May 2014, and a revolving facility of $12 million. The floating rate notes have an interest rate of 3 month LIBOR plus 2.5% with LIBOR floor of 1.5%, while the bridge notes have an interest rate of 1 month LIBOR plus 2.50%. As described in Note 4, Property, Plant and Equipment, in April 2014, TA High Desert received payment of $20 million for its cash grant and utilized the proceeds, along with an additional $2 million of cash contributed by NRG to repay the cash grant bridge loan. The revolving facility can be used for cash or for the issuance of up to $9 million in letters of credit. As of December 31, 2014, $55 million of notes were outstanding and $8 million of letters of credit were outstanding under the revolving facility.  The notes amortize on predetermined schedules and are secured by all of the assets of TA High Desert.
Kansas South Facility
The Kansas South Facility includes a $38 million term loan due 2031 and a $21 million cash grant bridge loan due ten days after receipt of the cash grant. The term loan has an interest rate of 6 month LIBOR plus an applicable margin of 2.625% and increases by 0.25% every 4 years. The cash grant bridge loan had an interest rate of 1 month LIBOR plus an applicable margin of 2.00%. The term loan amortizes on a predetermined schedule and is secured by all of the assets of RE Kansas South. As described in Note 4, Property, Plant and Equipment, in April 2014, the Company received payment of $21 million for the cash grant related to RE Kansas South and utilized the proceeds to repay the cash grant bridge loan. On September 26, 2014, RE Kansas South amended its credit agreement to change the interest rate to 6 month LIBOR plus 2.00% through September 30, 2019 and to 6 month LIBOR plus 2.250% thereafter. As of December 31, 2014, $35 million was outstanding under the term loan and $4 million of letters of credit were issued under the Kansas South Facility.
Avra Valley Credit Agreement
On July 9, 2014, Avra Valley amended its credit agreement to increase its borrowings by $3 million and to reduce the related interest rate from 3 month LIBOR plus an applicable margin of 2.25% to 3 month LIBOR plus 1.75%. The proceeds were primarily utilized to make a distribution to NRG Yield Operating LLC.
Alta Wind Financing Arrangements
As described in Note 3, Business Acquisitions, the Company acquired the Alta Wind Portfolio on August 12, 2014. In connection with the acquisition, the Company assumed the following debt arrangements:
Term Loan and Note Facilities
In June 2013, Alta Wind X entered into a credit agreement with several lenders for $337 million, which provided loans for the construction of the plant, letters of credit commitments to support certain obligations and a debt reserve loan commitment. The agreement contains a $300 million construction loan which converted to a term loan on March 31, 2014 and matures in March 2021. The term loan has an interest rate of 3 month LIBOR plus an applicable margin. The applicable margin was initially set at 2.00% for LIBOR-based loan increasing to 2.25% on the fourth anniversary of term loan conversion. The Company pays a commitment fee on the unused portion of all instruments of 0.75% quarterly in arrears on the last business day of March, June, September and December. The credit agreement also provides for a $20 million letter of credit facility to support obligations of the project, which expires on the term loan maturity date and a $17 million debt service loan commitments in the event the project is unable to meet its debt service obligations. As of December 31, 2014, $5 million of letters of credit were issued and no borrowings were made under the debt service loan commitments. In addition, a $3 million letter of credit to support a liquidity reserve requirement was issued under the Yield Credit Facility.
In June 2013, Alta Wind XI entered into a credit agreement with several lenders for $212 million, which provided loans for the construction of the plant, letters of credit commitments to support certain obligations and a debt reserve loan commitment. The agreement contains a $191 million construction loan which converted to a term loan on March 31, 2014 and matures in March 2021. The term loan has an interest rate of 3 month LIBOR plus an applicable margin. The applicable margin was initially set at 2.00% for LIBOR-based loan increasing to 2.25% on the fourth anniversary of term loan conversion. The Company pays a commitment fee on the unused portion of all instruments of 0.75% quarterly in arrears on the last business day of March, June, September and December. The credit agreement also provides for a $10 million letter of credit facility to support obligations under the PPA, which expires on the term loan maturity date and an $11 million in debt service loan commitments in the event the project is unable to meet its debt service obligations. As of December 31, 2014, no letters of credit were issued and no borrowings were made under the debt service loan commitments. In addition, a $3 million letter of credit to support a liquidity reserve requirement was issued under the Yield Credit Facility.
On May 22, 2013, AWAM entered into a credit agreement with a lender and borrowed a $20 million term loan. The proceeds from the issuance of the term loan were utilized to pay transactions costs and fund certain restricted cash accounts. AWAM has a $20 million term loan as of December 31, 2014, which has an interest rate of 3 month LIBOR plus an applicable margin of 2.375% and increases every four years to a maximum applicable margin of 2.88%. Principal and interest are payable quarterly on February 15, May 15, August 15 with a final maturity on May 15, 2031. The loan is secured by substantially all of the assets of AWAM. The term loan also has a debt service requirement, which is satisfied with a $1 million letter of credit issued under the Yield Credit Facility.
On January 31, 2011, Alta Realty entered into a $30 million note purchase agreement with a group of institutional investors with interest and principal payable quarterly on January 31, April 30, July 31, and October 31. The note has an interest rate of 7% and matures on January 31, 2031. The note purchase agreement also has a debt service requirement, which is satisfied with a $2 million letter of credit issued under the Yield Credit Facility. As of December 31, 2014, $34 million was outstanding under the note purchase agreement.
Lease financing arrangements
Alta Wind Holdings (Alta Wind II - V) and Alta I (operating entities) have finance lease obligations issued under lease transactions whereby the respective operating entities sold and leased back undivided interests in specific assets of the project. The sale and related lease transactions are accounted for as financing arrangements as the operating entities have continued involvement with the property. The terms and conditions of each facility lease are substantially similar. Each operating entity makes rental payments as stipulated in the facility lease agreements on a semiannual basis every June 30 and December 30 through the final maturity dates. In addition, the operating entities have a credit agreement with a group of lenders that provides for the issuance of letters of credit to support certain operating and debt service obligations. Certain O&M and rent reserve requirements are satisfied by letters of credit issued under the NRG Yield Operating agreement. As of December 31, 2014, $1,036 million was outstanding under the finance lease obligations, and $114 million of letters of credit issued under the credit agreement and $29 million issued under the Yield Credit Facility.
Laredo Ridge Credit Agreement
Prior to the acquisition of Laredo Ridge by NRG, Laredo Ridge LLC entered into a credit agreement with a group of lenders for a $75 million construction loan that was converted to a term loan upon completion of the project, a $53 million cash grant loan, which was repaid prior to the acquisition, and a $3 million working capital loan facility, all of which are secured by the assets of Laredo Ridge LLC. The credit agreement also included a letter of credit facility on behalf of Laredo Ridge LLC of up to $9 million, with a fee equal to the applicable margin on issued letters of credit. On December 17, 2014, Laredo Ridge LLC 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, with the remaining $8 million utilized to fund the costs of the amendment. As of December 31, 2014, $108 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.
Tapestry Wind Credit Agreement
Prior to the acquisition of the Tapestry projects by NRG, 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 and 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 with a commitment fee of 0.75%. The credit agreement also includes a letter of credit facility on behalf of Tapestry Wind LLC of up to $20 million, with a fee equal to the applicable margin on issued letters of credit.
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 December 31, 2014, $192 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 Credit Agreement
Prior to the acquisition of Walnut Creek by NRG, Walnut Creek Energy LLC entered into a credit agreement, or the Walnut Creek Agreement, with a group of lenders for a $442 million construction loan that was converted to a term loan upon completion of the project, and a $5 million working capital loan facility, which are secured by the assets of Walnut Creek Energy LLC. The term loan amortizes based upon a predetermined schedule and matures in May 2023. The working capital facility is available to fund the operating needs of Walnut Creek Energy LLC, with a commitment fee of 0.625%. The Walnut Creek Agreement also includes a letter of credit facility of up to $117 million, with a fee equal to the applicable margin on issued letters of credit. As of December 31, 2014, $391 million was outstanding under the term loan, nothing was outstanding under the working capital facility, and $41 million of letters of credit were issued.
On October 21, 2014, the Walnut Creek Agreement was amended 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 Energy LLC pays its counterparty the equivalent of a 4.0025% fixed interest payment on a predetermined notional value, and quarterly, Walnut Creek Energy LLC 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 are made quarterly and the LIBOR is determined in advance of each interest period.
WCEP Holdings LLC
Prior to the acquisition of Walnut Creek by NRG, WCEP Holdings LLC, the holding company of Walnut Creek Energy LLC, entered into a credit agreement with a group of lenders for a $53 million construction loan that was converted to a term loan upon completion of the Walnut Creek project. The term loan has an interest rate of LIBOR plus an applicable margin of 4.00%, amortizes based upon a predetermined schedule, matures in May 2023 and is secured by WCEP Holdings LLC's interest in the Walnut Creek project. As of December 31, 2014, $46 million was outstanding under 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 Energy LLC were utilized to make an optional repayment of $6 million on the term loan. In addition, WCEP Holdings LLC partially terminated its interest rate swap agreements so that at least 90% and no more than 100% of the aggregate principal amount of the loans then outstanding would be subject to interest rate agreements.
Interest Rate Swaps — Project Financings
Many of the Company's project subsidiaries entered into interest rate swaps, intended to hedge the risks associated with interest rates on non-recourse project level debt. These swaps amortize in proportion to their respective loans and are floating for fixed where the project subsidiary pays its counterparty the equivalent of a fixed interest payment on a predetermined notional value and will receive quarterly the equivalent of a floating interest payment based on the same notional value. All interest rate swap payments by the project subsidiary and its counterparty are made quarterly and the LIBOR is determined in advance of each interest period. In connection with the acquisition of the Alta Wind Portfolio, as described in Note 3, Business Acquisitions, the Company acquired thirty-one additional interest rate swaps.
The following table summarizes the swaps, some of which are forward starting as indicated, related to the Company's project level debt as of December 31, 2014.
		% of Principal		Fixed Interest Rate		Floating Interest Rate	Notional Amount at December 31, 2014		Effective Date	Maturity Date
							(In millions)
NRG Marsh Landing LLC		75%		3.24%		3-Month LIBOR	$	431	June 28, 2013	June 30, 2023
NRG West Holdings LLC		75%		2.42%		3-Month LIBOR	384		November 30, 2011	August 31, 2023
South Trent Wind LLC		75%		3.26%		3-Month LIBOR	48		June 15, 2010	June 14, 2020
South Trent Wind LLC		75%		4.95%		3-Month LIBOR	21		June 30, 2020	June 14, 2028
NRG Solar Roadrunner LLC		75%		4.31%		3-Month LIBOR	31		September 30, 2011	December 31, 2029
NRG Solar Blythe LLC		75%		3.56%		3-Month LIBOR	17		June 25, 2010	June 25, 2028
NRG Solar Avra Valley LLC		85%		2.33%		3-Month LIBOR	54		November 30, 2012	November 30, 2030
NRG Solar Alpine LLC		85%		2.74%		3-Month LIBOR	129		various	December 31, 2029
NRG Solar Alpine LLC		85%		2.42%		3-Month LIBOR	10		June 24, 2014	June 30, 2025
Kansas South LLC		75%		2.37%		3-Month LIBOR	26		June 28, 2013	December 31, 2030
NRG Solar Borrego LLC		75%		1.13%		3-Month LIBOR	11		April 3, 2013	June 30, 2020
Alta X		100%		various		3-Month LIBOR	174		December 31, 2013	December 31, 2015
Alta X		100%		various		3-Month LIBOR	126		December 31, 2013	December 31, 2025
Alta X		100%		various		3-Month LIBOR	162		December 31, 2015	December 31, 2020
Alta X		100%		various		3-Month LIBOR	103		December 31, 2020	December 31, 2025
Alta XI		100%		various		3-Month LIBOR	138		December 31, 2013	December 31, 2015
Alta XI		100%		various		3-Month LIBOR	54		December 31, 2013	December 31, 2025
Alta XI		100%		various		3-Month LIBOR	103		December 31, 2015	December 31, 2020
Alta XI		100%		various		3-Month LIBOR	65		December 31, 2020	December 31, 2025
AWAM		100%		2.47%		3-Month LIBOR	20		May 22, 2013	May 15, 2031
Laredo Ridge		90%		2.31%		3-Month LIBOR	86		31-Mar-11	31-Mar-26
Tapestry		90%		2.21%		3-Month LIBOR	172		30-Dec-11	21-Dec-21
Tapestry		50%		3.57%		3-Month LIBOR	60		21-Dec-21	21-Dec-29
Walnut Creek Energy		90%		various		3-Month LIBOR	345		28-Jun-13	31-May-23
WCEP Holdings		90%		4.00%		3-Month LIBOR	47		28-Jun-13	31-May-23
Total							$	2,817
Annual Maturities
Annual payments based on the maturities of the Company's debt, for the years ending after December 31, 2014, are as follows:
	(In millions)
2015	$	214
2016	246
2017	259
2018	264
2019	625
Thereafter	3,198
Total	$	4,806
Long-Term Debt
For a discussion of NRG Yield Inc.’s financing arrangements, see Note 9, Debt and Capital Leases, to the Company's consolidated financial statements.

Commitments_and_Contingencies_

Commitments and Contingencies Yield (Parent) (Notes)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Operating Lease Commitments
	The Company leases certain facilities and equipment under operating leases, some of which include escalation clauses, expiring on various dates through 2048. The effects of these scheduled rent increases, leasehold incentives, and rent concessions are recognized on a straight-line basis over the lease term unless another systematic and rational allocation basis is more representative of the time pattern in which the leased property is physically employed. Lease expense under operating leases was $5 million for the year ended December 31, 2014, and $2 million for each of the years ended 2013 and 2012.
	Future minimum lease commitments under operating leases for the years ending after December 31, 2014, are as follows:
	Period	(In millions)
	2015	$	12
	2016	11
	2017	7
	2018	7
	2019	7
	Thereafter	133
	Total	$	177
	Gas and Transportation Commitments
	The Company has entered into contractual arrangements to procure power, fuel and associated transportation services. For the years ended December 31, 2014, 2013 and 2012, the Company purchased $55 million, $40 million, and $30 million, respectively, under such arrangements.
	As of December 31, 2014, the Company's commitments under such outstanding agreements are estimated as follows:
	Period	(In millions)
	2015	$	15
	2016	4
	2017	3
	2018	3
	2019	2
	Thereafter	26
	Total	$	53
	Contingencies
	In the normal course of business, the Company is subject to various claims and litigation. Management expects that these various litigation items will not have a material adverse effect on the Company's results of operations or financial position.
	Commitments, Contingencies and Guarantees
	See Note 13, Income Taxes and Note 15, Commitments and Contingencies to the Company's consolidated financial statements for a detailed discussion of NRG Yield, Inc.’s commitments and contingencies.
	Note 4 — Dividends
	Cash distributions paid to NRG Yield, Inc. by its subsidiary, NRG Yield LLC, were $41 million and $5 million for the years ended December 31, 2014 and 2013, respectively.

Environmental_Matters_Notes

Environmental Matters (Notes)	12 Months Ended
	Dec. 31, 2014
Environmental Remediation Obligations [Abstract]
Environmental Loss Contingency Disclosure [Text Block]	Environmental Matters
	In 2013, NRG Energy Center San Francisco LLC, a wholly owned indirect subsidiary of the Company, received a notice of violation from the San Francisco Department of Public Health alleging improper monitoring of three underground storage tanks. The tanks have not leaked. The Company settled the matter in July 2014 for $123,000.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	The Company's consolidated and combined financial statements have been prepared in accordance with U.S. GAAP. The Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or ASC, is the source of authoritative U.S. GAAP to be applied by nongovernmental entities. In addition, the rules and interpretative releases of the SEC under authority of federal securities laws are also sources of authoritative U.S. GAAP for SEC registrants.
Principles of Consolidation	The consolidated and combined financial statements include the Company's accounts and operations and those of its subsidiaries in which it has a controlling interest. All significant intercompany transactions and balances have been eliminated in consolidation. The usual condition for a controlling financial interest is ownership of a majority of the voting interests of an entity. However, a controlling financial interest may also exist through arrangements that do not involve controlling voting interests. As such, the Company applies the guidance of ASC 810, Consolidations, or ASC 810, to determine when an entity that is insufficiently capitalized or not controlled through its voting interests, referred to as a variable interest entity, or VIE, should be consolidated.
Cash and Cash Equivalents	Cash and Cash Equivalents
	Cash and cash equivalents include highly liquid investments with an original maturity of three months or less at the time of purchase.
Restricted Cash	Restricted Cash
	Restricted cash consists primarily of funds held to satisfy the requirements of certain debt agreements and funds held within the Company's projects that are restricted in their use. These funds are used to pay for capital expenditures, current operating expenses and current debt service payments as well as to fund required equity contributions, per the restrictions of the debt agreements.
Trade Receivables and Allowance for Doubtful Accounts	Notes Receivable
	Notes receivable consist of receivables related to the financing of required network upgrades and a variable-rate note secured by the equity interest in a joint venture. The notes issued with respect to network upgrades will be repaid within a 5 year period following the date each facility reaches commercial operations.
	Trade Receivables and Allowance for Doubtful Accounts
	Trade receivables are reported on the balance sheet at the invoiced amount adjusted for any write-offs and the allowance for doubtful accounts. The allowance for doubtful accounts is reviewed periodically based on amounts past due and significance. The allowance for doubtful accounts was immaterial as of December 31, 2014, and 2013.
Inventory	Inventory
	Inventory consists principally of spare parts and fuel oil and is valued at the lower of weighted average cost or market, unless evidence indicates that the weighted average cost will be recovered with a normal profit in the ordinary course of business. The Company removes fuel inventories as they are used in the production of steam, chilled water or electricity. Spare parts inventory are removed when they are used for repairs, maintenance or capital projects.
Property, Plant and Equipment	Property, Plant and Equipment
	Property, plant and equipment are stated at cost or, in the case of business acquisitions, fair value; however impairment adjustments are recorded whenever events or changes in circumstances indicate that their carrying values may not be recoverable. See Note 3, Business Acquisitions, for more information on acquired property, plant and equipment. Significant additions or improvements extending asset lives are capitalized as incurred, while repairs and maintenance that do not improve or extend the life of the respective asset are charged to expense as incurred. Depreciation is computed using the straight-line method over the estimated useful lives. Certain assets and their related accumulated depreciation amounts are adjusted for asset retirements and disposals with the resulting gain or loss included in cost of operations in the consolidated statements of operations.
	Additionally, the Company reduces the book value of the property, plant and equipment of its eligible renewable energy projects for any cash grants that are submitted to the U.S. Treasury Department when the receivable is recorded for the net realizable amount. The related deferred tax asset is also recorded with a corresponding reduction to the book value of the property, plant and equipment. For further discussion of these matters see Note 4, Property, Plant and Equipment.
Asset Impairments	Asset Impairments
	Long-lived assets that are held and used are reviewed for impairment whenever events or changes in circumstances indicate carrying values may not be recoverable. Such reviews are performed in accordance with ASC 360. An impairment loss is recognized if the total future estimated undiscounted cash flows expected from an asset are less than its carrying value. An impairment charge is measured by the difference between an asset's carrying amount and fair value with the difference recorded in operating costs and expenses in the statements of operations. Fair values are determined by a variety of valuation methods, including appraisals, sales prices of similar assets and present value techniques.
	Investments accounted for by the equity method are reviewed for impairment in accordance with ASC 323, Investments-Equity Method and Joint Ventures, or ASC 323, which requires that a loss in value of an investment that is other than a temporary decline should be recognized. The Company identifies and measures losses in the value of equity method investments based upon a comparison of fair value to carrying value.
Capitalized Interest	Capitalized Interest
	Interest incurred on funds borrowed to finance capital projects is capitalized, until the project under construction is ready for its intended use. The amount of interest capitalized for the years ended December 31, 2014, 2013 and 2012 was less than $1 million, $18 million and $31 million, respectively.
	When a project is available for operations, capitalized interest is reclassified to property, plant and equipment and amortized on a straight-line basis over the estimated useful life of the project's related assets.
Debt Issuance Costs	Debt Issuance Costs
	Debt issuance costs are capitalized and amortized as interest expense on a basis which approximates the effective interest method over the term of the related debt.
Intangible Assets	Intangible Assets
	Intangible assets represent contractual rights held by NRG Yield, Inc. The Company recognizes specifically identifiable intangible assets including customer contracts, customer relationship, power purchase agreements and development rights when specific rights and contracts are acquired. These intangible assets are amortized primarily on a straight-line basis.
Income Taxes	Income Taxes
	The Company accounts for income taxes using the liability method in accordance with ASC 740, Income Taxes, or ASC 740, which requires that it use the asset and liability method of accounting for deferred income taxes and provide deferred income taxes for all significant temporary differences.
	The Company has two categories of income tax expense or benefit — current and deferred, as follows:
	•	Current income tax expense or benefit consists solely of current taxes payable less applicable tax credits, and
	•	Deferred income tax expense or benefit is the change in the net deferred income tax asset or liability, excluding amounts charged or credited to accumulated other comprehensive income.
	The Company reports some of its revenues and expenses differently for financial statement purposes than for income tax return purposes, resulting in temporary and permanent differences between the Company's financial statements and income tax returns. The tax effects of such temporary differences are recorded as either deferred income tax assets or deferred income tax liabilities in the Company's consolidated balance sheets. The Company measures its deferred income tax assets and deferred income tax liabilities using income tax rates that are currently in effect. The Company believes it is more likely than not that the results of future operations will generate sufficient taxable income which includes the future reversal of existing taxable temporary differences to realize deferred tax assets, net of valuation allowances. A valuation allowance is recorded to reduce the net deferred tax assets to an amount that is more-likely-than-not to be realized.
	The Company accounts for uncertain tax positions in accordance with ASC 740, which applies to all tax positions related to income taxes. Under ASC 740, tax benefits are recognized when it is more-likely-than-not that a tax position will be sustained upon examination by the authorities. The benefit recognized from a position that has surpassed the more-likely-than-not threshold is the largest amount of benefit that is more than 50% likely to be realized upon settlement. The Company recognizes interest and penalties accrued related to uncertain tax benefits as a component of income tax expense.
	In accordance with ASC 805 and as discussed further in Note 13, Income Taxes, changes to existing net deferred tax assets or valuation allowances or changes to uncertain tax benefits, are recorded to income tax expense.
Revenue Recognition	Revenue Recognition
	Thermal Revenues
	Steam and chilled water revenue is recognized based on customer usage as determined by meter readings taken at month-end. Some locations read customer meters throughout the month, and recognize estimated revenue for the period between meter read date and month-end. The Thermal Business subsidiaries collect and remit state and local taxes associated with sales to their customers, as required by governmental authorities. Related revenues are presented on a net basis in the income statement.
	Power Purchase Agreements, or PPAs
	The majority of the Company’s revenues are obtained through PPAs or other contractual agreements. In order to determine lease classification as operating, the Company evaluates the terms of the PPA to determine if the lease includes any of the following provisions which would indicate capital lease treatment:
	•	Transfers the ownership of the generating facility,
	•	Bargain purchase option at the end of the term of the lease,
	•	Lease term is greater than 75% of the economic life of the generating facility, or
	•	Present value of minimum lease payments exceed 90% of the fair value of the generating facility at inception of the lease
	In considering the above it was determined that all of Company’s PPAs are operating leases. ASC 840 requires the minimum lease payments received to be amortized over the term of the lease and contingent rentals are recorded when the achievement of the contingency becomes probable. Judgment is required by management in determining the economic life of each generating facility, in evaluating whether certain lease provisions constitute minimum payments or represent contingent rent and other factors in determining whether a contract contains a lease and whether the lease is an operating lease or capital lease.
	Certain of these leases have no minimum lease payments and all of the rental income under these leases is recorded as contingent rent on an actual basis when the electricity is delivered. The contingent rental income recognized in the years ended December 31, 2014, 2013 and 2012 was $194 million, $105 million and $33 million, respectively.
Derivative Financial Instruments	Derivative Financial Instruments
	The Company accounts for derivative financial instruments under ASC 815, Derivatives and Hedging, or ASC 815, which requires the Company to record all derivatives on the balance sheet at fair value unless they qualify for a NPNS exception. Changes in the fair value of non-hedge derivatives are immediately recognized in earnings. Changes in the fair value of derivatives accounted for as hedges, if elected for hedge accounting, are either:
	•	Recognized in earnings as an offset to the changes in the fair value of the related hedged assets, liabilities and firm commitments; or
	•	Deferred and recorded as a component of accumulated OCI until the hedged transactions occur and are recognized in earnings.
	The Company's primary derivative instruments are fuels purchase contracts used to control customer reimbursable fuel cost and interest rate instruments used to mitigate variability in earnings due to fluctuations in interest rates. On an ongoing basis, the Company assesses the effectiveness of all derivatives that are designated as hedges for accounting purposes in order to determine that each derivative continues to be highly effective in offsetting changes in fair values or cash flows of hedged items. Internal analyses that measure the statistical correlation between the derivative and the associated hedged item determine the effectiveness of such a contract designated as a hedge. If it is determined that the derivative instrument is not highly effective as a hedge, hedge accounting will be discontinued prospectively. In this case, the gain or loss previously deferred in accumulated OCI would be frozen until the underlying hedged item is delivered unless the transaction being hedged is no longer probable of occurring in which case the amount in OCI would be immediately reclassified into earnings. If the derivative instrument is terminated, the effective portion of this derivative deferred in accumulated OCI will be frozen until the underlying hedged item is delivered.
	Revenues and expenses on contracts that qualify for the NPNS exception are recognized when the underlying physical transaction is delivered. While these contracts are considered derivative financial instruments under ASC 815, they are not recorded at fair value, but on an accrual basis of accounting. If it is determined that a transaction designated as NPNS no longer meets the scope exception, the fair value of the related contract is recorded on the balance sheet and immediately recognized through earnings.
Concentrations of Credit Risk	Concentrations of Credit Risk
	Financial instruments which potentially subject the Company to concentrations of credit risk consist primarily of accounts receivable, notes receivable and derivative instruments. Accounts receivable, notes receivable, and derivative instruments are concentrated within entities engaged in the energy and financial industry. These industry concentrations may impact the overall exposure to credit risk, either positively or negatively, in that the customers may be similarly affected by changes in economic, industry or other conditions. In addition, many of the Company's projects have only one customer. However, the Company believes that the credit risk posed by industry concentration is offset by the diversification and creditworthiness of its customer base. See Note 6, Fair Value of Financial Instruments, for a further discussion of derivative concentrations and Note 12, Segment Reporting for concentration of counterparties.
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	The carrying amount of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, intercompany accounts payable and receivable, and accrued expenses and other liabilities approximate fair value because of the short-term maturity of these instruments. See Note 6, Fair Value of Financial Instruments, for a further discussion of fair value of financial instruments.
Asset Retirement Obligations	Asset Retirement Obligations
	Asset retirement obligations, or AROs, are accounted for in accordance with ASC 410-20, Asset Retirement Obligations, or ASC 410-20. Retirement obligations associated with long-lived assets included within the scope of ASC 410-20 are those for which a legal obligation exists under enacted laws, statutes, and written or oral contracts, including obligations arising under the doctrine of promissory estoppel, and for which the timing and/or method of settlement may be conditional on a future event. ASC 410-20 requires an entity to recognize the fair value of a liability for an ARO in the period in which it is incurred and a reasonable estimate of fair value can be made.
	Upon initial recognition of a liability for an ARO, the asset retirement cost is capitalized by increasing the carrying amount of the related long-lived asset by the same amount. Over time, the liability is accreted to its future value, while the capitalized cost is depreciated over the useful life of the related asset. The Company's asset retirement obligations were $27 million and $9 million for the years ended December 31, 2014, and 2013, respectively. The Company records AROs as part of other non-current liabilities on its balance sheet.
Guarantees	Guarantees
	The Company enters into various contracts that include indemnification and guarantee provisions as a routine part of its business activities. Examples of these contracts include EPC agreements, operation and maintenance agreements, service agreements, commercial sales arrangements and other types of contractual agreements with vendors and other third parties, as well as affiliates. These contracts generally indemnify the counterparty for tax, environmental liability, litigation and other matters, as well as breaches of representations, warranties and covenants set forth in these agreements. Because many of the guarantees and indemnities the Company issues to third parties and affiliates do not limit the amount or duration of its obligations to perform under them, there exists a risk that the Company may have obligations in excess of the amounts agreed upon in the contracts mentioned above. For those guarantees and indemnities that do not limit the liability exposure, it may not be able to estimate what the liability would be, until a claim is made for payment or performance, due to the contingent nature of these contracts.
Investments Accounted for by the Equity Method	Investments Accounted for by the Equity Method
	The Company has investments in three energy projects accounted for by the equity method, one of which is a VIE, where the Company is not a primary beneficiary. The equity method of accounting is applied to these investments in affiliates because the ownership structure prevents the Company from exercising a controlling influence over the operating and financial policies of the projects. Under this method, equity in pre-tax income or losses of the investments is reflected as equity in earnings of unconsolidated affiliates.
Lease, Policy [Policy Text Block]	Sale Leaseback Arrangements
	The Company is party to sale-leaseback arrangements that provide for the sale of certain assets to a third party and simultaneous leaseback to the Company. In accordance with ASC 840-40, Sale-Leaseback Transactions, if the seller-lessee retains, through the leaseback, substantially all of the benefits and risks incident to the ownership of the property sold, the sale-leaseback transaction is accounted for as a financing arrangement. An example of this type of continuing involvement would include an option to repurchase the assets or the buyer-lessor having the option to sell the assets back to the Company. This provision is included in most of the Company’s sale-leaseback arrangements. As such, the Company accounts for these arrangements as financings.
	Under the financing method, the Company does not recognize as income any of the sale proceeds received from the lessor that contractually constitutes payment to acquire the assets subject to these arrangements. Instead, the sale proceeds received are accounted for as financing obligations and leaseback payments made by the Company are allocated between interest expense and a reduction to the financing obligation. Interest on the financing obligation is calculated using the Company’s incremental borrowing rate at the inception of the arrangement on the outstanding financing obligation. Judgment is required to determine the appropriate borrowing rate for the arrangement and in determining any gain or loss on the transaction that would be recorded either at the end of or over the lease term.
Business Combinations	Business Combinations
	The Company accounts for its business combinations in accordance with ASC 805, Business Combinations, or ASC 805. ASC 805 requires an acquirer to recognize and measure in its financial statements the identifiable assets acquired, the liabilities assumed, and any noncontrolling interest in the acquiree at fair value at the acquisition date. It also recognizes and measures the goodwill acquired or a gain from a bargain purchase in the business combination and determines what information to disclose to enable users of an entity's financial statements to evaluate the nature and financial effects of the business combination. In addition, transaction costs are expensed as incurred.
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 amounts of assets and liabilities as of the date of the financial statements. They also impact the reported amount of net earnings during the reporting period. Actual results could be different from these estimates.
	In recording transactions and balances resulting from business operations, the Company uses estimates based on the best information available. Estimates are used for such items as plant depreciable lives, tax provisions, uncollectible accounts, environmental liabilities, acquisition accounting and legal costs incurred in connection with recorded loss contingencies, among others. As better information becomes available or actual amounts are determinable, the recorded estimates are revised. Consequently, operating results can be affected by revisions to prior accounting estimates.
Segment Reporting	The Company’s segment structure reflects how management currently makes financial decisions and allocates resources. Its 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.
Recent Accounting Developments	Recent Accounting Developments
	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 is currently evaluating the impact of the standard on the Company's results of operations, cash flows and financial position.
	ASU 2014-09 - In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU No. 2014-09. The amendments of ASU No. 2014-09 complete the joint effort between the FASB and the 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 considerations 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.
	ASU 2013-11 - In July 2013, the FASB issued ASU No. 2013-11, Income Taxes (Topic 740) Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists, or ASU No. 2013-11.  The amendments of ASU 2013-11, require an entity to present an unrecognized tax benefit, or a portion of an unrecognized tax benefit, as a reduction of a deferred tax asset for an NOL, a similar tax loss or tax credit carryforwards rather than a liability when the uncertain tax position would reduce the NOL or other carryforward under the tax law of the applicable jurisdiction and the entity intends to use the deferred tax asset for that purpose.  The guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The Company adopted this standard effective January 1, 2014. The adoption of this standard did not impact the Company's results of operations or cash flows as the Company has no uncertain tax benefits as of December 31, 2014.

Nature_of_Business_Nature_of_B

Nature of Business Nature of Business (Tables)	12 Months Ended
	Dec. 31, 2014
Nature of Business Disclosure [Abstract]
IPO of NRG Yield	The following table represents the structure of the Company as of December 31, 2014, with the retrospective application of the stock split that took place on May 14, 2015:
The Company's operating assets are comprised of the following projects:	he 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
	RE 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	%	124	Various	Various
	Total net capacity (excluding equivalent MWt)			3,754
	(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 December 31, 2014.
	(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.

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	The Company’s major classes of property, plant, and equipment were as follows:
		December 31, 2014			December 31, 2013			Depreciable Lives
		(In millions)
	Facilities and equipment	$	4,709		$	2,373		2 - 40 Years
	Land and improvements	87			86
	Construction in progress	8			6
	Total property, plant and equipment	4,804			2,465
	Accumulated depreciation	(338		)	(174		)
	Net property, plant and equipment	$	4,466		$	2,291

Investments_Accounted_for_by_t1

Investments Accounted for by the Equity Method and Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2014
CVSR
Schedule of Equity Method Investments
Summarized financial information of equity method investment	The following table presents summarized financial information for CVSR:
		Year Ended December 31,
		2014		2013		2012
	Income Statement Data:	(In millions)
	Operating revenues	$	82	$	47	$	2
	Operating income	40		22		1
	Net income	17		4		1
				As of December 31,
				2014		2013
				(In millions)
	Balance Sheet Data:
	Current assets			$	173	$	455
	Non-current assets			868		932
	Current liabilities			33		412
	Non-current liabilities			799		769
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:
		Year ended December 31,
		2014		2013		2012
	Income Statement Data:	(In millions)
	Operating revenues	$	82	$	80	$	78
	Operating income	40		44		45
	Net income	28		31		29
		December 31, 2014		December 31, 2013
	Balance Sheet Data:	(In millions)
	Current assets	$	33	$	32
	Non-current assets	438		454
	Current liabilities	20		18
	Non-current liabilities	223		232
	The following table presents undistributed equity earnings for the Company's three equity method investments:
		As of December 31,
		2014		2013
		(In millions)
	Undistributed earnings from equity investments	$	22	$	19

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2014										Dec. 31, 2013
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 December 31, 2014					As of December 31, 2013
		Carrying Amount			Fair Value		Carrying Amount		Fair Value
		(In millions)
	Assets:
	Notes receivable, including current portion — affiliate	$	—		$	—	$	2	$	2
	Notes receivable, including current portion	21			21		27		27
	Liabilities:
	Long-term debt, including current portion	4,787			4,873		1,783		1,785
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 December 31, 2013
		As of December 31, 2014										Fair Value (a)
		Fair Value (a)									(In millions)	Level 2		Level 3		Total
	(In millions)	Level 2									Derivative assets:
	Derivative assets:										Commodity contracts	$	1	$	—	$	1
	Commodity contracts	$	—
											Interest rate contracts	20		—		20
	Interest rate contracts	2
											Total assets	21		—		21
	Total assets	$	2
											Derivative liabilities:
	Derivative liabilities:										Commodity contracts	1		1		2
	Commodity contracts	$	3
											Interest rate contracts	45		—		45
	Interest rate contracts	114
											Total liabilities	$	46	$	1	$	47
	Total liabilities	$	117
Reconciliation of beginning and ending balances for financial instruments that are recognized at fair value in the consolidated financial statements at least annually using significant unobservable inputs	The following table reconciles, for the year ended December 31, 2014, the beginning and ending balances for derivative instruments that are recognized at fair value in the consolidated financial statements, at least annually, using significant unobservable inputs:
		Fair Value Measurement Using Significant Unobservable Inputs (Level 3)
	(In millions)	Year ended December 31, 2014
		Derivatives
	Beginning balance	$	(1	)
	Total gains and losses (realized/unrealized) included in earnings	1
	Ending balance as of December 31, 2014	$	—

Accounting_for_Derivative_Inst1

Accounting for Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2014
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 December 31, 2014, and 2013.
				Total Volume
				December 31, 2014				December 31, 2013
	Commodity	Units		(In millions)
	Natural Gas	MMBtu		2				2
	Interest	Dollars		$	2,817			$	1,234
	The increase in the interest rate position was primarily the result of the interest rate swaps acquired with the Alta Wind Portfolio.
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
		December 31, 2014				December 31, 2013				December 31, 2014			December 31, 2013
		(In millions)
	Derivatives Designated as Cash Flow Hedges:
	Interest rate contracts current	$	—			$	—			$	40		$	26
	Interest rate contracts long-term	2				14				49			16
	Total Derivatives Designated as Cash Flow Hedges	2				14				89			42
	Derivatives Not Designated as Cash Flow Hedges:
	Interest rate contracts current	—				—				5			3
	Interest rate contracts long-term	—				6				20			—
	Commodity contracts current	—				1				3			2
	Total Derivatives Not Designated as Cash Flow Hedges	—				7				28			5
	Total Derivatives	$	2			$	21			$	117		$	47
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 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	)
		Gross Amounts Not Offset in the Statement of Financial Position
	As of December 31, 2013	Gross Amounts of Recognized Assets/Liabilities				Derivative Instruments				Net Amount
	Commodity contracts:	(In millions)
	Derivative assets	$	1			$	—			$	1
	Derivative liabilities	(2		)		—				(2		)
	Total commodity contracts	(1		)		—				(1		)
	Interest rate contracts:
	Derivative assets	20				(12		)		8
	Derivative liabilities	(45		)		12				(33		)
	Total interest rate contracts	(25		)		—				(25		)
	Total derivative instruments	$	(26	)		$	—			$	(26	)
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 other comprehensive loss, or OCL, balance attributable to interest rate swaps designated as cash flow hedge derivatives, net of tax:
		Year ended December 31,
		2014				2013				2012
		(In millions)
	Accumulated OCL beginning balance	$	—			$	(48	)		$	(28	)
	Reclassified from accumulated OCL to income due to realization of previously deferred amounts	13				13				5
	Mark-to-market of cash flow hedge accounting contracts	(65		)		35				(25		)
	Accumulated OCL ending balance, net of income tax benefit of $6, $1 and $17, respectively	$	(52	)		$	—			$	(48	)
	Accumulated OCL attributable to NRG	(43		)		—
	Accumulated OCL attributable to NRG Yield, Inc.	$	(9	)		$	—
	Losses expected to be realized from OCL during the next 12 months, net of income tax of $3	$	(27	)

Intangible_Assets_Tables

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of the components of the Company's intangible assets subject to amortization	The following tables summarize the components of intangible assets subject to amortization:
	Year ended December 31, 2014	Emission Allowances			Development			Customer Contracts			Customer			PPAs			Leasehold Rights			Other		Total
					Rights						Relationships
					(In millions)
	1-Jan-14	$	8		$	4		$	15		$	66		$	14		$	—		$	3	$	110
	Acquisition of Alta Wind Portfolio	—			—			—			—			1,091			86			—		1,177
	Transfer of EME-NYLD-Eligible Assets	7			—			—			—			160			—			—		167
	Other	1			—			—			—			4			—			—		5
	31-Dec-14	16			4			15			66			1,269			86			3		1,459
	Less accumulated amortization	—			(1		)	(5		)	(2		)	(26		)	(2		)	—		(36		)
	Net carrying amount	$	16		$	3		$	10		$	64		$	1,243		$	84		$	3	$	1,423
	Year ended December 31, 2013	Emission			Development Rights			Customer Contracts			Customer Relationships			PPAs			Leasehold Rights			Other		Total
		Allowances
		(In millions)
	1-Jan-13	$	8		$	4		$	15		$	7		$	4		$	—		$	3	$	41
	Business acquisition/transfer	—			—			—			59			10			—			—		69
	31-Dec-13	8			4			15			66			14			—			3		110
	Less accumulated amortization	—			(1		)	(4		)	(1		)	(1		)	—			—		(7		)
	Net carrying amount	$	8		$	3		$	11		$	65		$	13		$	—		$	3	$	103
Schedule of estimated amortization of NRG's intangible assets for each of the next five years	The following table presents estimated amortization of the Company's intangible assets for each of the next five years:
	Year Ended December 31,		Total
			(In millions)
	2015		$	58
	2016		71
	2017		71
	2018		71
	2019		72

Longterm_Debt_Tables

Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of Effective Interest Rate [Table Text Block]	During the years ended December 31, 2014, the Company recorded the following expense in relation to the Convertible Notes at the effective rate of 5.00%:
	(In millions)
	Interest expense at 3.5% coupon rate		11
	Debt discount amortization		4
	Debt issuance costs amortization		1
			$	16
Schedule of long-term debt	The Company's borrowings, including short term and long term portions consisted of the following:
		December 31, 2014				December 31, 2013			Interest rate % (a)
		(In millions, except rates)
	Convertible Notes, due 2019 (b)	$	326			—			3.5
	Senior Notes, due 2024	500				—			5.375
	Project-level debt:
	Alta Wind I, lease financing arrangement, due 2034	261				—			7.015
	Alta Wind II, lease financing arrangement, due 2034	205				—			5.696
	Alta Wind III, lease financing arrangement, due 2034	212				—			6.067
	Alta Wind IV, lease financing arrangement, due 2034	138				—			5.938
	Alta Wind V, lease financing arrangement, due 2035	220				—			6.071
	Alta Wind X, due 2021	300				—			L+2.00
	Alta Wind XI, due 2021	191				—			L+2.00
	Alta Realty Investments, due 2031	34				—			7
	Alta Wind Asset Management, due 2031	20				—			L+2.375
	NRG West Holdings LLC, due 2023	506				512			L+2.25 - L+2.875; L+2.25 - L+2.75
	NRG Marsh Landing LLC, due 2017 and 2023	464				473			L+ 1.75 - L+1.875; L+2.75 - L+3.00
	Walnut Creek Energy LLC, due 2023	391				—			L+1.625
	Tapestry Wind LLC, due 2021	192				—			L+1.625
	NRG Solar Alpine LLC, due 2014 and 2022	163				221			L+1.75 - L+2.50; L+2.25 - L+2.50
	NRG Energy Center Minneapolis LLC, due 2017 and 2025	121				127			5.95 -7.31
	Laredo Ridge LLC, due 2026	108				—			L+1.875
	NRG Solar Borrego LLC, due 2024 and 2038	75				78			L+ 2.50/5.65
	South Trent Wind LLC, due 2020	65				69			L+2.75;L+2.625
	NRG Solar Avra Valley LLC, due 2031	63				63			L+1.75; L+2.25
	TA High Desert LLC, due 2023 and 2033	55				80			L+2.50/5.15
	WCEP Holdings LLC, due 2023	46				—			L+3.00
	NRG Roadrunner LLC, due 2031	42				44			L+2.01
	NRG Solar Kansas South LLC, due 2031	35				58			L+2.00;L+2.625
	NRG Solar Blythe LLC, due 2028	22				24			L+2.75
	PFMG and related subsidiaries financing agreement, due 2030	31				32			6
	NRG Energy Center Princeton LLC, due 2017	1				2			5.95
	Subtotal project-level debt:	3,961				1,783
	Total debt	4,787				1,783
	Less current maturities	214				214
	Total long-term debt	$	4,573			$	1,569
	(a) As of December 31, 2014, L+ equals 3 month LIBOR plus x%, except for RE Kansas South where L+ equals 6 month LIBOR plus x%.
Summary of swaps related to the Company's project level debt	The following table summarizes the swaps, some of which are forward starting as indicated, related to the Company's project level debt as of December 31, 2014.
			% of Principal		Fixed Interest Rate		Floating Interest Rate	Notional Amount at December 31, 2014		Effective Date	Maturity Date
								(In millions)
	NRG Marsh Landing LLC		75%		3.24%		3-Month LIBOR	$	431	June 28, 2013	June 30, 2023
	NRG West Holdings LLC		75%		2.42%		3-Month LIBOR	384		November 30, 2011	August 31, 2023
	South Trent Wind LLC		75%		3.26%		3-Month LIBOR	48		June 15, 2010	June 14, 2020
	South Trent Wind LLC		75%		4.95%		3-Month LIBOR	21		June 30, 2020	June 14, 2028
	NRG Solar Roadrunner LLC		75%		4.31%		3-Month LIBOR	31		September 30, 2011	December 31, 2029
	NRG Solar Blythe LLC		75%		3.56%		3-Month LIBOR	17		June 25, 2010	June 25, 2028
	NRG Solar Avra Valley LLC		85%		2.33%		3-Month LIBOR	54		November 30, 2012	November 30, 2030
	NRG Solar Alpine LLC		85%		2.74%		3-Month LIBOR	129		various	December 31, 2029
	NRG Solar Alpine LLC		85%		2.42%		3-Month LIBOR	10		June 24, 2014	June 30, 2025
	Kansas South LLC		75%		2.37%		3-Month LIBOR	26		June 28, 2013	December 31, 2030
	NRG Solar Borrego LLC		75%		1.13%		3-Month LIBOR	11		April 3, 2013	June 30, 2020
	Alta X		100%		various		3-Month LIBOR	174		December 31, 2013	December 31, 2015
	Alta X		100%		various		3-Month LIBOR	126		December 31, 2013	December 31, 2025
	Alta X		100%		various		3-Month LIBOR	162		December 31, 2015	December 31, 2020
	Alta X		100%		various		3-Month LIBOR	103		December 31, 2020	December 31, 2025
	Alta XI		100%		various		3-Month LIBOR	138		December 31, 2013	December 31, 2015
	Alta XI		100%		various		3-Month LIBOR	54		December 31, 2013	December 31, 2025
	Alta XI		100%		various		3-Month LIBOR	103		December 31, 2015	December 31, 2020
	Alta XI		100%		various		3-Month LIBOR	65		December 31, 2020	December 31, 2025
	AWAM		100%		2.47%		3-Month LIBOR	20		May 22, 2013	May 15, 2031
	Laredo Ridge		90%		2.31%		3-Month LIBOR	86		31-Mar-11	31-Mar-26
	Tapestry		90%		2.21%		3-Month LIBOR	172		30-Dec-11	21-Dec-21
	Tapestry		50%		3.57%		3-Month LIBOR	60		21-Dec-21	21-Dec-29
	Walnut Creek Energy		90%		various		3-Month LIBOR	345		28-Jun-13	31-May-23
	WCEP Holdings		90%		4.00%		3-Month LIBOR	47		28-Jun-13	31-May-23
	Total							$	2,817
Schedule of annual payments based on the maturities of NRG Yield's debt	Annual payments based on the maturities of the Company's debt, for the years ending after December 31, 2014, are as follows:
		(In millions)
	2015	$	214
	2016	246
	2017	259
	2018	264
	2019	625
	Thereafter	3,198
	Total	$	4,806

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
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 earnings per share is shown in the following table, after giving effect to the stock split as described in Note 1, Nature of Business:
		Class A Common Stock				Class C Common Stock
		Year ended December 31, 2014		Period from July 23, 2013 to December 31, 2013		Year ended December 31, 2014		Period from July 23, 2013 to December 31, 2013
	(In millions, except per share data)
	Basic and diluted earnings per share attributable to NRG Yield, Inc. common stockholders
	Net income attributable to NRG Yield, Inc.	$	8	$	7	$	8	$	7
	Weighted average number of common shares outstanding	28		23		28		23
	Earnings per weighted average common share — basic and diluted	$	0.3	$	0.29	$	0.3	$	0.29

Stockholders_Equity_Stockholde

Stockholders' Equity Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Attributable to Parent [Abstract]
Schedule of Distributions Paid [Table Text Block]	The following table lists the distributions paid to NRG during the year ended December 31, 2014:
		Fourth Quarter 2014		Third Quarter 2014		Second Quarter 2014		First Quarter 2014
	Distributions per unit	$	0.375	$	0.365	$	0.35	$	0.33
Schedule of Dividends Paid [Table Text Block]	The following table lists the dividends paid on the Company's Class A common stock during the year ended December 31, 2014:
		Fourth Quarter 2014		Third Quarter 2014		Second Quarter 2014		First Quarter 2014
	Dividends per share	$	0.375	$	0.365	$	0.35	$	0.33

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2014																Dec. 31, 2013																Dec. 31, 2011
Segment Reporting [Abstract]
Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]	The Company generated more than 10% of its revenues from the following customers for the years ended December 31, 2014, and 2013. For the year ended December 31, 2012, there were no customers from whom the Company derived more than 10% of consolidated revenue.
		2014			2013
	Customer	Conventional (%)		Renewables (%)	Conventional (%)		Renewables (%)
	Southern California Edison	28%		9%	15%		4%
	Pacific Gas and Electric	18%		4%	22%		7%
Schedule of Segment Reporting Information, by Segment
		Year ended December 31, 2014																Year ended December 31, 2013																Year ended December 31, 2012
																	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total			(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total
	(In millions)	Conventional Generation			Renewables			Thermal			Corporate			Total			Operating revenues	$	138		$	89		$	152		$	—		$	379		Operating revenues	$	—		$	33		$	142		$	—		$	175
	Operating revenues	$	317		$	177		$	195		$	—		$	689		Cost of operations	23			11			110			—			144			Cost of operations	2			9			103			—			114
	Cost of operations	55			45			139			—			239			Depreciation and amortization	20			26			15			—			61			Depreciation and amortization	—			10			15			—			25
	Depreciation and amortization	82			66			18			—			166			General and administrative — affiliate	—			—			—			7			7			General and administrative — affiliate	—			—			—			7			7
	General and administrative — affiliate	—			—			—			8			8			Operating income (loss)	95			52			27			(7		)	167			Operating income (loss)	(2		)	14			24			(7		)	29
	Acquisition-related transaction and integration costs	—			—			—			4			4			Equity in earnings of unconsolidated affiliates	16			6			—			—			22			Equity in earnings of unconsolidated affiliates	15			4			—			—			19
	Operating income (loss)	180			66			38			(12		)	272			Other income, net	1			2			—			—			3			Other income, net	1			1			—			—			2
	Equity in earnings of unconsolidated affiliates	14			13			—			—			27			Interest expense	(25		)	(20		)	(7		)	—			(52		)	Interest expense	—			(20		)	(8		)	—			(28		)
	Other income, net	—			2			—			1			3			Income (loss) before income taxes	87			40			20			(7		)	140			Income (loss) before income taxes	14			(1		)	16			(7		)	22
	Interest expense	(53		)	(96		)	(7		)	(30		)	(186		)	Income tax expense	—			—			—			8			8			Income tax expense	—			—			—			10			10
	Income (loss) before income taxes	141			(15		)	31			(41		)	116			Net Income (Loss)	$	87		$	40		$	20		$	(15	)	$	132		Net Income (Loss)	$	14		$	(1	)	$	16		$	(17	)	$	12
	Income tax expense	—			—			—			4			4			Balance Sheet
																	Equity investments in affiliates	$	118		$	109		$	—		$	—		$	227
	Net Income (Loss)	$	141		$	(15	)	$	31		$	(45	)	$	112
																	Capital expenditures (a)	168			30			15			—			213
	Balance Sheet
																	Total Assets	$	1,584		$	1,046		$	436		$	172		$	3,238
	Equity investment in affiliates	$	114		$	113		$	—		$	—		$	227
	Capital expenditures(a)	6			(1		)	7			—			12
	Total Assets	$	2,194		$	3,856		$	437		$	478		$	6,965

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income tax provision from continuing operations	The income tax provision from continuing operations consisted of the following amounts:
		Year Ended December 31,
		2014			2013			2012
		(In millions, except percentages)
	Current
	U.S. Federal	$	—		$	—		$	7
	Total — current	—			—			7
	Deferred
	U.S. Federal	2			14			1
	State	2			(6		)	2
	Total — deferred	4			8			3
	Total income tax expense	$	4		$	8		$	10
	Effective tax rate	3.4		%	5.7		%	45.7		%
Reconciliation of the U.S. federal statutory rate to the Company's effective rate	A reconciliation of the U.S. federal statutory rate of 35% to the Company's effective rate is as follows:
		Year Ended December 31,
		2014			2013 (a)			2012 (b)
		(In millions, except percentages)
	Income Before Income Taxes	116			140			22
	Tax at 35%	41			49			8
	State taxes, net of federal benefit	1			(6		)	2
	Impact of non-taxable equity earnings	(33		)	(35		)	—
	Production tax credits	(6		)	—			—
	Change in state effective tax rate	1			—			—
	Income tax expense	$	4		$	8		$	10
	Effective income tax rate	3.4		%	5.7		%	45.7		%
Company's deferred tax assets and liabilities	The following table summarizes the Company's net deferred tax position:
		As of December 31,
		2014			2013
		(In millions)
	Net deferred tax asset — current	$	16		$	—
	Net deferred tax asset — noncurrent	118			146
	Net deferred tax asset	$	134		$	146
	The temporary differences, which gave rise to the Company's deferred tax assets, consisted of the following:
		As of December 31,
		2014			2013
		(In millions)
	Deferred tax assets:
	Investment in projects	$	47		$	81
	Production tax credits carryforwards	6			—
	U.S. Federal net operating loss carryforwards	74			61
	State net operating loss carryforwards	7			4
	Total deferred tax assets	134			146
	Net deferred tax asset	$	134		$	146

Commitments_and_Contingencies_1

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Long-term Purchase Commitment [Table Text Block]	As of December 31, 2014, the Company's commitments under such outstanding agreements are estimated as follows:
	Period	(In millions)
	2015	$	15
	2016	4
	2017	3
	2018	3
	2019	2
	Thereafter	26
	Total	$	53
Future minimum lease commitments under operating leases	Future minimum lease commitments under operating leases for the years ending after December 31, 2014, are as follows:
	Period	(In millions)
	2015	$	12
	2016	11
	2017	7
	2018	7
	2019	7
	Thereafter	133
	Total	$	177

Unaudited_Quarterly_Financial_1

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Summary of Unaudited Quarterly Financial Data	Summarized unaudited quarterly financial data is as follows:
		Quarter Ended
		December 31, (a)			September 30, (a)		June 30, (a)		March 31, (c)
		2014
	(As recast)	(In millions, except per share data)
	Operating Revenues	$	192		$	184	$	173	$	140
	(As previously reported in 2014 Form 10-K)
	Operating Revenues	148			161		134		140
	(Change )	44			23		39		—
	(As recast)
	Operating Income	70			84		64		54
	(As previously reported in 2014 Form 10-K)
	Operating Income	46			70		51		54
	Change	24			14		13		—
	(As recast)
	Net Income	5			40		41		26
	(As previously reported in 2014 Form 10-K)
	Net (Loss) Income	$	(10	)	$	31	$	34	$	26
	(Change)	15			9		7		—
	Net Income Attributable to NRG Yield, Inc.	$	—		$	6	$	6	$	4
	Weighted average number of Class A common shares outstanding - basic and diluted (b)	35			31		23		23
	Earnings per Weighted Average Class A Common Share - Basic and Diluted (b)	$	0.01		$	0.1	$	0.13	$	0.09
	Weighted average number of Class C common shares outstanding - basic and diluted (b)	35			31		23		23
	Earnings per Weighted Average Class C Common Share - Basic and Diluted (b)	$	0.01		$	0.1	$	0.13	$	0.09
	(a) The Company's unaudited quarterly financial data was recast for the effect of the EME-NYLD-Eligible Assets, from the date the entities were under common control or April 1, 2014.
	(b) Adjusted to give effect to the stock split, as described in Note 1, Nature of Business.
	(c) The Acquired ROFO Assets were purchased on June 30, 2014, and accordingly the Company had previously reported operating revenues of $110 million, operating income of $38 million and net income of $18 million for the three months ended March 31, 2014.
		Quarter Ended
		December 31, (c)			September 30, (a) (c)		June 30, (c)		March 31, (c)
		2013
	(As recast)	(In millions, except per share data)
	Operating Revenues	$	118		$	126	$	82	$	53
	(As previously reported in 2013 Form 10-K)
	Operating Revenues	86			95		79		53
	(Change )	32			31		3		—
	(As recast)
	Operating Income	54			63		38		12
	(As previously reported in 2013 Form 10-K)
	Operating Income	33			45		38		12
	(Change )	21			18		—		—
	(As recast)
	Net Income	37			49		35		11
	(As previously reported in 2013 Form 10-K)
	Net Income	$	24		40		$	34	$	11
	(Change )	13			9		1		—
	Net Income Attributable to NRG Yield, Inc.	$	4		$	9	n/a		n/a
	Weighted average number of Class A common shares outstanding - basic and diluted	23			23		n/a		n/a
	Weighted average number of Class C common shares outstanding - basic and diluted	23			23		n/a		n/a
	Earnings per Weighted Average Class A Common Share - Basic and Diluted (b)	$	0.09		$	0.2	n/a		n/a
	Earnings per Weighted Average Class C Common Share - Basic and Diluted (b)	$	0.09		$	0.2	n/a		n/a
	(a) Earnings per weighted average class A and Class C common share are calculated for the period of July 22, 2013 to September 30, 2013.
	(b) Adjusted to give effect to the stock split, as described in Note 1, Nature of Business.
	(c) The Company's unaudited quarterly financial data was recast for the effect of the Acquired ROFO Assets.

Nature_of_Business_Details

Nature of Business (Details) (USD $)

0 Months Ended

7 Months Ended

12 Months Ended

0 Months Ended

2 Months Ended

1 Months Ended

0 Months Ended

6 Months Ended

In Millions, except Share data, unless otherwise specified

Jul. 22, 2013

Jul. 22, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Jul. 29, 2014

Sep. 30, 2013

Jul. 31, 2013

Jun. 30, 2014

Dec. 31, 2013

Dec. 14, 2012

MW

MW

Nature of Business

Megawatts Thermal Equivalent, Available Under right-to-use Provisions

134

Proceeds from issuance of Class A common stock

$468

$468

$0

Power Generation Capacity (in MWs)

3,754

Allocation of Corporate Expenses

4

Business Acquisitions, Consideration Transferred, Purchase Price

901

120

0

Common Stock, Par or Stated Value Per Share

$0.01

0.01

Conventional

Nature of Business

Power Generation Capacity (in MWs)

1,945

[1]

Utility-Scale Solar

Nature of Business

Power Generation Capacity (in MWs)

343

[1]

Distributed Solar

Nature of Business

Power Generation Capacity (in MWs)

10

[1]

Wind

Nature of Business

Power Generation Capacity (in MWs)

1,332

Thermal

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

124

[1]

Steam and Chilled Water Capacity, Megawatts Thermal Equivalent

1,310

[1]

Common Class C [Member]

Nature of Business

Common Stock, Voting Rights

1/100th

Common Stock, Par or Stated Value Per Share

$0.01

Common Class A [Member]

Nature of Business

Proceeds from Issuance Initial Public Offering

468

Common Stock, Par or Stated Value Per Share

$0.01

$0.01

$0.01

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

Nature of Business

Sale of Stock, Number of Shares Issued in Transaction

22,511,250

12,075,000

Proceeds from issuance of Class A common stock

630

Economic Interest in Entity

100.00%

NRG

Nature of Business

Payments to Acquire Interest in Subsidiaries and Affiliates

395

NRG Yield LLC | Class A Common Stockholders [Member]

Nature of Business

Economic Interest in Entity

100.00%

NRG Yield LLC | NRG Yield, Inc.

Nature of Business

Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest

34.50%

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

65.50%

55.30%

55.30%

65.50%

65.50%

GenConn Middletown | Conventional

Nature of Business

Equity Method Investment, Ownership Percentage

49.95%

Power Generation Capacity (in MWs)

95

[1]

GenConn Devon [Member] | Conventional

Nature of Business

Equity Method Investment, Ownership Percentage

49.95%

Power Generation Capacity (in MWs)

95

[1]

Marsh Landing

Nature of Business

Power Generation Capacity (in MWs)

720

Marsh Landing | Conventional

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

720

[1]

El Segundo [Member] | Conventional

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

550

Walnut Creek [Member] | Conventional

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

485

Alpine | Utility-Scale Solar

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

66

[1]

Avenal | Utility-Scale Solar

Nature of Business

Equity Method Investment, Ownership Percentage

49.95%

Power Generation Capacity (in MWs)

23

[1]

Avra Valley | Utility-Scale Solar

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

25

[1]

NRG Solar Blythe LLC [Member] | Utility-Scale Solar

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

21

[1]

Borrego | Utility-Scale Solar

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

26

[1]

Roadrunner | Utility-Scale Solar

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

20

[1]

CVSR | Utility-Scale Solar

Nature of Business

Equity Method Investment, Ownership Percentage

48.95%

[2]

Power Generation Capacity (in MWs)

122

[1],[2]

RE Kansas South [Member] | Utility-Scale Solar

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

20

TA - High Desert LLC [Member] | Utility-Scale Solar

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

20

AZ DG Solar Projects | Distributed Solar

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

5

[1]

PFMG DG Solar Projects | Distributed Solar

Nature of Business

Percentage of Ownership

51.00%

Power Generation Capacity (in MWs)

5

[1]

Alta I [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

150

Alta II [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

150

Alta III [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

150

Alta IV [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

102

Alta V [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

168

Alta X [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

137

Alta XI [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

90

South Trent | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

101

[1]

Laredo Ridge [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

80

Taloga [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

130

Pinnacle [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

55

Buffalo Bear [Member] | Wind

Nature of Business

Percentage of Ownership

100.00%

Power Generation Capacity (in MWs)

19

Drop-down Acquisition [Member]

Nature of Business

Business Acquisitions, Consideration Transferred, Purchase Price

357

Business Acquisitions, Consideration Transferred, Purchase Price

349

Affiliated Entity [Member]

Nature of Business

General and administrative — affiliate

$8

$7

[3]

$7

[3]

3

[1]

Net capacity represents the maximum, or rated, generating capacity of the facility multiplied by the Company's percentage ownership in the facility as of December 31, 2014.

[2]

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.

[3]

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

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Contingent Rental Income Associated with PPAs	$194	$105	$33
Interest Costs Capitalized	0	18	31
Income Taxes, Threshold Percentage	50.00%
Asset Retirement Obligation	$27	$9

Business_Acquisitions_Details

Business Acquisitions (Details) (USD $)	0 Months Ended	3 Months Ended												7 Months Ended	9 Months Ended	12 Months Ended						1 Months Ended	0 Months Ended		2 Months Ended	5 Months Ended		0 Months Ended				6 Months Ended		0 Months Ended
In Millions, except Share data, unless otherwise specified	Jul. 22, 2013	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jul. 22, 2013	Sep. 30, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		31-May-13	Aug. 05, 2014	Aug. 13, 2014	Sep. 30, 2014	Dec. 31, 2014		Jun. 30, 2014	Dec. 31, 2013		Jul. 29, 2014	Dec. 31, 2013		Jan. 02, 2015	Dec. 14, 2012	Aug. 12, 2014	Jul. 30, 2014
		MW														MW																			MW
Business Acquisition
Current assets		$606							$378	[1]						$606		$378	[1]							$606			$378	[1]		378	[1]
Total operating revenues		192	[2]	184	[2]	173	[2]	140	118		126	82	53		379	689		379	[1]	175	[1]
Property, Plant and Equipment, Net		4,466							2,291	[1]						4,466		2,291	[1]							4,466			2,291	[1]		2,291	[1]
Business Combination, Integration Related Costs																4		0	[1]	0	[1]
Business Combination, Consideration Transferred																901		120		0
Non-current assets									569									569											569			569
Working Capital									1									1											1			1
Power Generation Capacity (in MWs)		3,754														3,754										3,754
Proceeds from issuance of Class A common stock	468																	468		0
Long-term Debt		4,806							1,783							4,806		1,783								4,806			1,783			1,783
Assets		6,965							3,238	[1]						6,965		3,238	[1]							6,965			3,238	[1]		3,238	[1]
Other Liabilities									203									203											203			203
Liabilities		5,080							1,986	[1]						5,080		1,986	[1]							5,080			1,986	[1]		1,986	[1]
Operating Income (Loss)		70	[2]	84	[2]	64	[2]	54	54		63	38	12		167	272		167	[1]	29	[1]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		5	[2]	40	[2]	41	[2]	26	37		49	35	11	54	132	112		132	[1]	12	[1]
Other Comprehensive Income (Loss), Net of Tax																52		-48	[1]	20	[1]
Marsh Landing
Business Acquisition
Power Generation Capacity (in MWs)																																			720
Power Purchase Agreement Period																						10 years
5.375% Senior Notes due in 2024 [Member]
Business Acquisition
Debt Instrument, Interest Rate, Stated Percentage		5.38%														5.38%										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%
Marsh Landing Term Loan Facility | Marsh Landing
Business Acquisition
Line of Credit Facility, Maximum Borrowing Capacity																																			650
RE Kansas South [Member]
Business Acquisition
Total operating revenues																		2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets						1			25									25										1	25			25
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment						50			51									51										50	51			51
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted						16																						16
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets						53			79									79										53	79			79
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities						37			63									63										37	63			63
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets						2			3									3										2	3			3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt						35			58									58										35	58			58
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Current and Non-Current Liabilities						2			5									5										2	5			5
Operating Income (Loss)																		1
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest																		-1
Alta Wind Portfolio [Member]
Business Acquisition
Business Acquisition, Pro Forma Revenue																821		531
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, Integration Related Costs																2
Business Combination, Consideration Transferred																								870
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment																																				1,057
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles																																				1,420
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles																										-243
Business Acquisition, Purchase Price Allocation, Intangible Assets, Other than Goodwill, Adjusted																																				1,177
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																										247
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment, Adjusted																																				1,304
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																										0
Business Acquisition, Purchase Price Allocation, Other Assets, Adjusted																																				49
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets																																				2,548
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Assets																										4
Business Acquisition, Purchase Price Allocation, Assets Acquired, Adjusted																																				2,552
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current and Non-Current Liabilities																																				34
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Current and Noncurrent Liabilities																										4
Business Acquisition, Purchase Price Allocation, Current and Non-current Liabilities, Adjusted																																				38
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities																																				1,625
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities																										4
Business Acquisition, Purchase Price Allocation, Liabilities Assumed, Adjusted																																				1,629
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual																									49
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual																									39
Business Acquisition, Pro Forma Net Income(Loss), Including Portion Attributable to Noncontrolling Interest																94		87
Business Acquisition, Pro Forma Net Income (Loss)																7		8
Business Acquisition, Pro Forma Earnings Per Share, Basic and Diluted																$0.10		$0.12
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
EME-NYLD Assets [Member]
Business Acquisition
Business Acquisition, Pro Forma Revenue																715		513
Business Acquisition, Pro Forma Net Income(Loss), Including Portion Attributable to Noncontrolling Interest																97		145
Business Acquisition, Pro Forma Net Income (Loss)																21		16
Business Acquisition, Pro Forma Earnings Per Share, Basic and Diluted																$0.38		$0.35
Drop-down Acquisition [Member]
Business Acquisition
Business Combination, Consideration Transferred																												357
Working Capital						8																						8
Business Combination, Consideration Transferred, Liabilities Incurred																												612
Business Acquisitions, Consideration Transferred, Purchase Price						349																						349
Alta Wind Holdings [Member]
Business Acquisition
Power Generation Capacity (in MWs)																																				947
Energy Systems
Business Acquisition
Payments to Acquire Businesses, Gross																													120
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment									60									60											60			60
Energy Systems | Customer Contracts
Business Acquisition
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles									59									59											59			59
Marsh Landing
Business Acquisition
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment																																			537
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted																				138
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment																				73
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment, Adjusted																				610
Marsh Landing | NRG [Member]
Business Acquisition
Business Acquisition, Percentage of Voting Interests Acquired																																			100.00%
TA - High Desert LLC [Member]
Business Acquisition
Total operating revenues																		8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets						3			28									28										3	28			28
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment						67			63									63										67	63			63
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted						26																						26
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets						83			101									101										83	101			101
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities						57			83									83										57	83			83
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets						13			10									10										13	10			10
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt						57			80									80										57	80			80
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Current and Non-Current Liabilities						0			3									3										0	3			3
Operating Income (Loss)																		4
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest																		1
El Segundo [Member]
Business Acquisition
Total operating revenues																		56
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets						43			58									58										43	58			58
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment						625			636									636										625	636			636
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Adjusted						194																						194
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets						744			745									745										744	745			745
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities						550			538									538										550	538			538
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets						76			51									51										76	51			51
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt						520			512									512										520	512			512
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Current and Non-Current Liabilities						30			26									26										30	26			26
Operating Income (Loss)																		34
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest																		23
NRG [Member] | NRG Yield LLC [Member]
Business Acquisition
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	65.50%															55.30%												65.50%			55.30%	65.50%
Utility-Scale Solar [Member]
Business Acquisition
Power Generation Capacity (in MWs)		343	[3]													343	[3]									343	[3]
Utility-Scale Solar [Member] | CVSR [Member]
Business Acquisition
Power Generation Capacity (in MWs)		122	[3],[4]													122	[3],[4]									122	[3],[4]
Equity Method Investment, Ownership Percentage		48.95%	[4]													48.95%	[4]									48.95%	[4]
Common Class A [Member] | Public Shareholders [Member]
Business Acquisition
Sale of Stock, Number of Shares Issued in Transaction	22,511,250																														12,075,000
Share Price																																					$54
Proceeds from issuance of Class A common stock																															630
Scenario, Previously Reported [Member]
Business Acquisition
Current assets									267									267											267			267
Total operating revenues		148		161		134		110	86		95	79	53					313
Property, Plant and Equipment, Net									1,541									1,541											1,541			1,541
Non-current assets									505									505											505			505
Long-term Debt									1,133									1,133											1,133			1,133
Assets									2,313									2,313											2,313			2,313
Other Liabilities									169									169											169			169
Liabilities									1,302									1,302											1,302			1,302
Operating Income (Loss)		46		70		51		38	33		45	38	12					128
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		-10		31		34		18	24		40	34	11					109
Subsequent Event [Member] | 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
Subsequent Event [Member] | 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
Subsequent Event [Member] | 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
Subsequent Event [Member] | EME-NYLD Assets [Member]
Business Acquisition
Working Capital																																		9
Business Combination, Consideration Transferred, Liabilities Incurred																																		737
Business Acquisitions, Consideration Transferred, Purchase Price																																		489
Business Combination, Separately Recognized Transactions, Net Gains and Losses																																		61
Other Comprehensive Income (Loss), Net of Tax																																		$23
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	The Company's unaudited quarterly financial data was recast for the effect of the EME-NYLD-Eligible Assets, from the date the entities were under common control or April 1, 2014.
[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 December 31, 2014.
[4]	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.

Property_Plant_and_Equipment_D

Property, Plant and Equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012	Sep. 30, 2013	16-May-13
Property, Plant and Equipment
Property, plant and equipment, gross	$4,804,000,000	$2,465,000,000	[1]
Under construction	8,000,000	6,000,000
Less accumulated depreciation	-338,000,000	-174,000,000
Property, Plant and Equipment, Net	4,466,000,000	2,291,000,000	[1]
Proceeds from renewable energy grants	137,000,000	25,000,000		28,000,000
Support Equipment and Facilities [Member]
Property, Plant and Equipment
Property, plant and equipment, gross	4,709,000,000	2,373,000,000
Land and improvements
Property, Plant and Equipment
Property, plant and equipment, gross	87,000,000	86,000,000
Borrego
Property, Plant and Equipment
Renewable energy grant, gross						39,000,000
Renewable energy grants, net					36,000,000
Deferred tax asset, renewable energy grant					10,000,000
Proceeds from renewable energy grants	30,000,000
TA - High Desert LLC [Member]
Property, Plant and Equipment
Renewable energy grant, gross						25,000,000
Deferred Tax Assets, Deferred Income					6,000,000
Renewable energy grants, net					20,000,000
Proceeds from renewable energy grants	20,000,000
Kansas South [Member]
Property, Plant and Equipment
Renewable energy grant, gross						23,000,000
Deferred Tax Assets, Deferred Income					6,000,000
Renewable energy grants, net					21,000,000
Proceeds from renewable energy grants	$21,000,000
Minimum | Support Equipment and Facilities [Member]
Property, Plant and Equipment
Property, plant and equipment, useful life	2 years
Maximum | Support Equipment and Facilities [Member]
Property, Plant and Equipment
Property, plant and equipment, useful life	40 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												7 Months Ended	9 Months Ended	12 Months Ended						1 Months Ended		12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jul. 22, 2013	Sep. 30, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2010	Jun. 30, 2011	Apr. 30, 2010	Dec. 31, 2011	Jan. 31, 2014	Sep. 22, 2010	Sep. 30, 2011
	MW														MW					generatingunit	generatingunit
Variable Interest Entity
Power Generation Capacity (in MWs)	3,754														3,754
Long-term Debt	$4,806,000,000							$1,783,000,000							$4,806,000,000	$1,783,000,000
Operating revenues	192,000,000	[1]	184,000,000	[1]	173,000,000	[1]	140,000,000	118,000,000		126,000,000	82,000,000	53,000,000		379,000,000	689,000,000	379,000,000	[2]	175,000,000	[2]
Operating income	70,000,000	[1]	84,000,000	[1]	64,000,000	[1]	54,000,000	54,000,000		63,000,000	38,000,000	12,000,000		167,000,000	272,000,000	167,000,000	[2]	29,000,000	[2]
Net Income	5,000,000	[1]	40,000,000	[1]	41,000,000	[1]	26,000,000	37,000,000		49,000,000	35,000,000	11,000,000	54,000,000	132,000,000	112,000,000	132,000,000	[2]	12,000,000	[2]
Current assets	606,000,000							378,000,000	[2]						606,000,000	378,000,000	[2]
Non-current assets								569,000,000								569,000,000
Current liabilities	389,000,000							369,000,000	[2]						389,000,000	369,000,000	[2]
Non-current liabilities	4,691,000,000							1,617,000,000	[2]						4,691,000,000	1,617,000,000	[2]
Equity investments in affiliates	227,000,000							227,000,000	[2]						227,000,000	227,000,000	[2]
GenConn Energy LLC
Variable Interest Entity
Power Generation Capacity (in MWs)	190														190
Power Generation Units, Number	2														2
GenConn Energy LLC | GenConn Devon
Variable Interest Entity
Number of Units Reached Commercial Operation at Peaking Generation Facilities																				4
GenConn Energy LLC | GenConn Middletown
Variable Interest Entity
Number of Units Reached Commercial Operation at Peaking Generation Facilities																					4
CVSR
Variable Interest Entity
Renewable energy grant, gross																								307
Renewable energy grants, net																								285
Avenal
Variable Interest Entity
Economic interest in equity method investments (as a percent)	49.95%														49.95%
Power Generation Capacity (in MWs)	45														45
Power Purchase Agreement Period																						20 years
Notes and Loans Payable	2,000,000														2,000,000										35,000,000
Interest rate																									4.50%
Equity investments in affiliates	11,000,000														11,000,000
Avenal | Syndicate of Banks
Variable Interest Entity
Long-term Debt	107,000,000							112,000,000							107,000,000	112,000,000									209,000,000
Avenal | NRG
Variable Interest Entity
Economic interest in equity method investments (as a percent)	0.05%														0.05%
Avenal | Eurus Energy
Variable Interest Entity
Economic interest in equity method investments (as a percent)	50.00%														50.00%
CVSR
Variable Interest Entity
Economic interest in equity method investments (as a percent)	48.95%														48.95%
Power Generation Capacity (in MWs)	250														250
Power Purchase Agreement Period															25 years
Operating revenues															82,000,000	47,000,000							2,000,000
Operating income															40,000,000	22,000,000							1,000,000
Net Income															17,000,000	4,000,000							1,000,000
Current assets	173,000,000														173,000,000			455,000,000
Non-current assets	868,000,000														868,000,000			932,000,000
Current liabilities	33,000,000														33,000,000			412,000,000
Non-current liabilities	799,000,000														799,000,000			769,000,000
Equity investments in affiliates	102,000,000														102,000,000
CVSR | NRG
Variable Interest Entity
Economic interest in equity method investments (as a percent)	51.05%														51.05%
GCE Holdings LLC
Variable Interest Entity
Economic interest in equity method investments (as a percent)	49.95%														49.95%
Operating revenues															82,000,000	80,000,000							78,000,000
Operating income															40,000,000	44,000,000							45,000,000
Net Income															28,000,000	31,000,000							29,000,000
Current assets	33,000,000														33,000,000			32,000,000
Non-current assets	438,000,000														438,000,000			454,000,000
Current liabilities	20,000,000														20,000,000			18,000,000
Non-current liabilities	223,000,000														223,000,000			232,000,000
Retained Earnings, Undistributed Earnings from Equity Method Investees	22,000,000							19,000,000							22,000,000	19,000,000
GenConn Energy LLC
Variable Interest Entity
Equity investments in affiliates	114,000,000														114,000,000
GenConn Energy LLC | Fixed Rate Notes
Variable Interest Entity
Long-term Debt	228,000,000														228,000,000
Interest rate	4.73%														4.73%
Line of Credit Facility, Maximum Borrowing Capacity	237,000,000														237,000,000
GenConn Energy LLC | Working Capital Facility [Member]
Variable Interest Entity
Interest rate	1.88%														1.88%
Line of Credit Facility, Maximum Borrowing Capacity	35,000,000														35,000,000
CVSR Financing Agreement
Variable Interest Entity
Other Borrowings	815,000,000														815,000,000			1,104,000,000
CVSR Financing Agreement | High Plains Ranch II
Variable Interest Entity
Line of Credit Facility, Maximum Borrowing Capacity																										$1,200,000,000
Basis spread on variable rate															0.38%
[1]	The Company's unaudited quarterly financial data was recast for the effect of the EME-NYLD-Eligible Assets, from the date the entities were under common control or April 1, 2014.
[2]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Fair Value of Financial Instruments
Derivative Asset, 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	$1,000,000
Derivative Assets	2,000,000		21,000,000	[1]
Long-term debt, including current portion	4,806,000,000		1,783,000,000
Derivative Liabilities	117,000,000		47,000,000
Concentration of Credit Risk
Credit risk exposure under certain long-term agreements for the next five years	2,200,000,000
Period of credit risk exposure under certain long-term agreements (in years)	5 years
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	0		0
Interest rate contracts
Fair Value of Financial Instruments
Derivative Assets	2,000,000		20,000,000
Derivative Liabilities	114,000,000		45,000,000
Commodity contracts
Fair Value of Financial Instruments
Derivative Assets	0		1,000,000
Derivative Liabilities	3,000,000		2,000,000
Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments
Derivative Assets	2,000,000	[1]	21,000,000	[1]
Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments
Derivative Assets			0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	0		-1,000,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Purchases	1,000,000
Reported Value Measurement [Member]
Fair Value of Financial Instruments
Financing Receivable, Net	21,000,000
Notes receivable, including current portion			27,000,000
Long-term debt, including current portion	4,787,000,000		1,783,000,000
Estimate of Fair Value Measurement [Member]
Fair Value of Financial Instruments
Notes receivable, including current portion	21,000,000		27,000,000
Long-term debt, including current portion	4,873,000,000		1,785,000,000
Fair Value, Measurements, Recurring [Member]
Fair Value of Financial Instruments
Derivative Liabilities			47,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Interest rate contracts
Fair Value of Financial Instruments
Derivative Assets			20,000,000	[1]
Derivative Liabilities			45,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Commodity contracts
Fair Value of Financial Instruments
Derivative Assets			1,000,000	[1]
Derivative Liabilities			2,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments
Derivative Liabilities	117,000,000	[1]	46,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest rate contracts
Fair Value of Financial Instruments
Derivative Assets	2,000,000	[1]	20,000,000	[1]
Derivative Liabilities	114,000,000	[1]	45,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commodity contracts
Fair Value of Financial Instruments
Derivative Assets	0	[1]	1,000,000	[1]
Derivative Liabilities	3,000,000	[1]	1,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Financial Instruments
Derivative Assets (Liabilities), at Fair Value, Net	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments
Derivative Assets (Liabilities), at Fair Value, Net			0
Derivative Liabilities			1,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contracts
Fair Value of Financial Instruments
Derivative Assets			0	[1]
Derivative Liabilities			0	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commodity contracts
Fair Value of Financial Instruments
Derivative Assets			0	[1]
Derivative Liabilities			1,000,000	[1]
Affiliated Entity [Member] | Reported Value Measurement [Member]
Fair Value of Financial Instruments
Notes receivable — affiliate	0		2,000,000	[2]
Affiliated Entity [Member] | Estimate of Fair Value Measurement [Member]
Fair Value of Financial Instruments
Financing Receivable, Net	$0		$2,000,000
[1]	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of December 31, 2014.
[2]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Accounting_for_Derivative_Inst2

Accounting for Derivative Instruments and Hedging Activities (Details) (USD $)	6 Months Ended		7 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Jul. 22, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012	Apr. 03, 2013
Derivative
Long-term Debt	$1,783			$4,806	$1,783
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3				0
Derivative, Notional Amount								15
Fair Value of Derivative Instruments
Derivative Liabilities	-47			-117	-47
Derivative Assets	21	[1]		2	21	[1]
Derivative instruments	1	[2]		0	1	[2]
Fair Value of Gross Derivative Assets/(Liabilities), Net	-26			-115	-26
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0			0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	-26			-115	-26
Accumulated Other Comprehensive Income (Loss), Net of Tax
Accumulated OCL beginning balance			-48	0	-48		-28
Mark-to-market of cash flow hedge accounting contracts				-65	35		-25
Accumulated OCL ending balance, net of income tax benefit of $6, $1 and $17, respectively	0			-52	0		-48
Accumulated OCL ending balance, net of income tax benefit of $6, $1 and $17, respectively	1			6	1		17
Loss expected to be realized from OCI during the next 12 months, net of tax				-27
Summary of Derivative Instruments Impact on Results of Operations
Unrealized gain/(loss) on derivatives	6		38	-52			-20
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3				0
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	0			0	0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	0			0	0
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount	0			0	0
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount	0			0	0
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months, Tax				3
Derivative, Collateral, Right to Reclaim Cash	0			0	0
Derivative, Collateral, Obligation to Return Cash	0			0	0
Reclassification out of Accumulated Other Comprehensive Income
Derivative
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net				13	13		5
Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-42			-89	-42
Derivative Assets	14			2	14
Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-5			-28	-5
Derivative Assets	7			0	7
Interest rate contracts current | Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-26			-40	-26
Derivative Assets	0			0	0
Interest rate contracts current | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-3			-5	-3
Derivative Assets	0			0	0
Interest rate contracts long-term | Derivatives Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-16			-49	-16
Derivative Assets	14			2	14
Interest rate contracts long-term | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	0			-20	0
Derivative Assets	6			0	6
Commodity contracts current | Derivatives Not Designated as Cash Flow Hedges
Fair Value of Derivative Instruments
Derivative Liabilities	-2			-3	-2
Derivative Assets	1				1
Commodity contracts
Derivative
Derivative Liability	-2			-3	-2
Fair Value of Derivative Instruments
Derivative Liabilities	-2			-3	-2
Derivative Assets	1			0	1
Derivative instruments	1			0	1
Fair Value of Gross Derivative Assets/(Liabilities), Net	-1			-3	-1
Derivative Liability, Fair Value, Gross Asset	0			0	0
Derivative Asset, Fair Value, Gross Liability	0			0	0
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0			0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	-1			-3	-1
Interest rate contracts
Derivative
Derivative Liability	-33			-112	-33
Fair Value of Derivative Instruments
Derivative Liabilities	-45			-114	-45
Derivative Assets	20			2	20
Derivative instruments	8			0	8
Fair Value of Gross Derivative Assets/(Liabilities), Net	-25			-112	-25
Derivative Liability, Fair Value, Gross Asset	12			2	12
Derivative Asset, Fair Value, Gross Liability	-12			-2	-12
Derivative Asset Fair Value Gross Liability Net Of Derivative Liability Fair Value Gross Asset	0			0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral Net Of Derivative Liability, Fair Value, Amount Offset Against Collateral	-25			-112	-25
Summary of Derivative Instruments Impact on Results of Operations
Unrealized gain/(loss) on derivatives				22	13
MMbtu | Natural Gas [Member]
Derivative
Underlying, Derivative				2,000,000	2,000,000
Dollars | Interest
Derivative
Derivative, Notional Amount	1,234			2,817	1,234
Successor
Accumulated Other Comprehensive Income (Loss), Net of Tax
Accumulated OCL ending balance, net of income tax benefit of $6, $1 and $17, respectively	0			-9	0
Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss), Net of Tax
Accumulated OCL beginning balance				0
Accumulated OCL ending balance, net of income tax benefit of $6, $1 and $17, respectively	0			-43	0
Summary of Derivative Instruments Impact on Results of Operations
Unrealized gain/(loss) on derivatives				-43	9
Fair Value, Measurements, Recurring [Member]
Fair Value of Derivative Instruments
Derivative Liabilities	-47	[1]			-47	[1]
Fair Value, Measurements, Recurring [Member] | Commodity contracts
Fair Value of Derivative Instruments
Derivative Liabilities	-2	[1]			-2	[1]
Derivative Assets	1	[1]			1	[1]
Fair Value, Measurements, Recurring [Member] | Interest rate contracts
Fair Value of Derivative Instruments
Derivative Liabilities	-45	[1]			-45	[1]
Derivative Assets	$20	[1]			$20	[1]
[1]	(a) There were no assets or liabilities classified as Level 1 or Level 3 as of December 31, 2014.
[2]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Intangible_Assets_Details

Intangible Assets (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Finite-Lived Intangible Assets
Gross amount at the beginning of the period	$110	$41
Acquisition of Alta Wind Portfolio		69
Gross amount at the end of the period	1,459	110		41
Less accumulated amortization	-36	-7
Net carrying amount	1,423	103	[1]
Amortization of Intangible Assets	29	4		1
Finite-Lived Intangible Asset, Useful Life	20 years
Finite-Lived Intangible Assets, Other Changes	5
Contra Revenue Intangibles Amortization	28	0		0
Accumulated Amortization of Out of Market Contracts	2
Out of Market Contracts Amortization Expense	0
Estimated amortization related to the Company's finite-lived intangible assets
Estimated intangible assets amortization, 2015	58
Estimated intangible assets amortization, 2016	71
Estimated intangible assets amortization, 2017	71
Estimated intangible assets amortization, 2018	71
Estimated intangible assets amortization, 2019	72
Customer Contracts
Finite-Lived Intangible Assets
Gross amount at the beginning of the period	15	15
Acquisition of Alta Wind Portfolio		0
Gross amount at the end of the period	15	15
Less accumulated amortization	-5	-4
Net carrying amount	10	11
Finite-Lived Intangible Assets, Other Changes	0
Customer Relationships
Finite-Lived Intangible Assets
Gross amount at the beginning of the period	66	7
Acquisition of Alta Wind Portfolio		59
Gross amount at the end of the period	66	66
Less accumulated amortization	-2	-1
Net carrying amount	64	65
Finite-Lived Intangible Assets, Other Changes	0
Supply Commitment Arrangement [Domain]
Finite-Lived Intangible Assets
Gross amount at the beginning of the period	14	4
Acquisition of Alta Wind Portfolio		10
Gross amount at the end of the period	1,269	14
Less accumulated amortization	-26	-1
Net carrying amount	1,243	13
Finite-Lived Intangible Assets, Other Changes	4
Other Intangible Assets [Member]
Finite-Lived Intangible Assets
Gross amount at the beginning of the period	3	3
Acquisition of Alta Wind Portfolio		0
Gross amount at the end of the period	3	3
Less accumulated amortization	0	0
Net carrying amount	3	3
Finite-Lived Intangible Assets, Other Changes	0
Emission Allowances [Member]
Finite-Lived Intangible Assets
Gross amount at the beginning of the period	8	8
Acquisition of Alta Wind Portfolio		0
Gross amount at the end of the period	16	8
Less accumulated amortization	0	0
Net carrying amount	16	8
Finite-Lived Intangible Assets, Other Changes	1
Research and Development Expense [Member]
Finite-Lived Intangible Assets
Gross amount at the beginning of the period	4	4
Acquisition of Alta Wind Portfolio		0
Gross amount at the end of the period	4	4
Less accumulated amortization	-1	-1
Net carrying amount	3	3
Finite-Lived Intangible Assets, Other Changes	0
Leasehold Rights [Member]
Finite-Lived Intangible Assets
Gross amount at the beginning of the period	0	0
Acquisition of Alta Wind Portfolio		0
Gross amount at the end of the period	86	0
Less accumulated amortization	-2	0
Net carrying amount	84	0
Finite-Lived Intangible Assets, Other Changes	0
Out of Market Contracts [Member]
Finite-Lived Intangible Assets
Amortization	1
NRG Solar Blythe LLC [Member]
Finite-Lived Intangible Assets
Out of Market Contracts	5
Alta Wind XI [Member]
Finite-Lived Intangible Assets
Out of Market Contracts	5
EME-NYLD Assets [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	167
EME-NYLD Assets [Member] | Customer Contracts
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
EME-NYLD Assets [Member] | Customer Relationships
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
EME-NYLD Assets [Member] | Supply Commitment Arrangement [Domain]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	160
EME-NYLD Assets [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
EME-NYLD Assets [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	7
EME-NYLD Assets [Member] | Research and Development Expense [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
EME-NYLD Assets [Member] | Leasehold Rights [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
Alta Wind Portfolio [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	1,177
Alta Wind Portfolio [Member] | Customer Contracts
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
Alta Wind Portfolio [Member] | Customer Relationships
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
Alta Wind Portfolio [Member] | Supply Commitment Arrangement [Domain]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	1,091
Weighted average remaining amortization period (in years)	22 years
Alta Wind Portfolio [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
Alta Wind Portfolio [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
Alta Wind Portfolio [Member] | Research and Development Expense [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	0
Alta Wind Portfolio [Member] | Leasehold Rights [Member]
Finite-Lived Intangible Assets
Acquisition of Alta Wind Portfolio	$86
Weighted average remaining amortization period (in years)	21 years
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Longterm_Debt_Details

Long-term Debt (Details) (USD $)

12 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

1 Months Ended

0 Months Ended

1 Months Ended

0 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 17, 2014

Oct. 21, 2014

Jul. 27, 2011

Dec. 21, 2011

Mar. 31, 2014

Mar. 31, 2013

Mar. 28, 2013

Mar. 31, 2013

Apr. 30, 2014

Aug. 05, 2014

Aug. 31, 2011

Jul. 09, 2014

Feb. 05, 2015

Jul. 17, 2014

Sep. 26, 2014

Nov. 12, 2014

Apr. 03, 2013

Sep. 30, 2013

Dec. 14, 2012

31-May-13

Jan. 15, 2013

Mar. 16, 2012

Jun. 24, 2014

Feb. 11, 2014

Jul. 27, 2010

Apr. 25, 2014

Aug. 23, 2011

Jan. 31, 2011

Jun. 30, 2013

Jan. 02, 2015

Long-term Debt Disclosure

Additional Paid in Capital

$1,240,000,000

$621,000,000

[1]

Long-term Debt

4,806,000,000

1,783,000,000

Convertible Debt, Fair Value Disclosures

0

Common Stock Closing Price

$47.14

Long-term debt, current maturities

214,000,000

214,000,000

Long-term debt, excluding current maturities

4,573,000,000

1,569,000,000

Variable rate basis

3 month LIBOR

Debt Instrument, Convertible, Carrying Amount of Equity Component

19,000,000

Notional Amount of Interest Rate Derivatives

15,000,000

Annual Payments Based on Maturities, 2015

214,000,000

Annual Payments Based on Maturities, 2016

246,000,000

Annual Payments Based on Maturities, 2017

259,000,000

Annual Payments Based on Maturities, 2018

264,000,000

Annual Payments Based on Maturities, 2019

625,000,000

Annual Payments Based on Maturities, Thereafter

3,198,000,000

Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt

23,000,000

Letters of Credit, Drawn Amount

0

Interest Rate Swaps

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

2,817,000,000

Affiliated Entity [Member]

Long-term Debt Disclosure

Proceeds from Contributions from Parent

2,000,000

171,000,000

355,000,000

Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

4,787,000,000

1,783,000,000

NRG Wind LLC [Member]

Long-term Debt Disclosure

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

33,000,000

NRG Yield LLC [Member]

Long-term Debt Disclosure

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

29,000,000

Borrego

Long-term Debt Disclosure

Renewable energy grants, net

36,000,000

Kansas South [Member]

Long-term Debt Disclosure

Renewable energy grants, net

21,000,000

WCEP Holdings LLC [Member]

Long-term Debt Disclosure

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

6,000,000

Alta Wind I - V Lease financing arrangement [Member] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

1,036,000,000

Interest Rate Swap Maturity - June 30, 2023 | NRG West Holdings LLC [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

2.42%

Notional Amount of Interest Rate Derivatives

384,000,000

Interest Rate Swap Maturity - June 30, 2023 | Marsh Landing [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

3.24%

Notional Amount of Interest Rate Derivatives

431,000,000

Interest Rate Swap Maturity - June 30, 2023 | Kansas South [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

2.37%

Notional Amount of Interest Rate Derivatives

26,000,000

Interest Rate Swap Maturity - June 14, 2020 | South Trent Wind LLC

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

3.27%

Notional Amount of Interest Rate Derivatives

48,000,000

Interest Rate Swap Maturity - June 14, 2028 | South Trent Wind LLC

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

4.95%

Notional Amount of Interest Rate Derivatives

21,000,000

Interest Rate Swap Maturity - December 31, 2029 | Borrego

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

1.13%

Notional Amount of Interest Rate Derivatives

11,000,000

Interest Rate Swap Maturity - December 31, 2029 | NRG Solar Roadrunner LLC

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

4.31%

Notional Amount of Interest Rate Derivatives

31,000,000

Interest Rate Swap Maturity - December 31, 2029 | NRG Solar Alpine LLC

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

85.00%

Derivative, Fixed Interest Rate

2.74%

Notional Amount of Interest Rate Derivatives

129,000,000

Maturity - June 30, 2025 [Member] | NRG Solar Alpine LLC

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

85.00%

Derivative, Fixed Interest Rate

2.42%

Notional Amount of Interest Rate Derivatives

10,000,000

Interest Rate Swap Maturity - June 25, 2028 | NRG Solar Blythe LLC

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

3.56%

Notional Amount of Interest Rate Derivatives

17,000,000

Interest Rate Swap Maturity - November 30, 2030 | NRG Solar Avra Valley LLC

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

85.00%

Derivative, Fixed Interest Rate

2.33%

Notional Amount of Interest Rate Derivatives

54,000,000

3.5% Convertible Notes due 2019 [Member]

Long-term Debt Disclosure

Interest Expense, Debt

11,000,000

Convertible Debt, Fair Value Disclosures

349,000,000

Debt Instrument, Interest Rate, Effective Percentage

5.00%

Long-term Debt

326,000,000

[2]

Long-term Debt, Fair Value

395,000,000

Amortization of Debt Discount (Premium)

4,000,000

Amortization of Debt Issuance Costs

1,000,000

Interest Expense at Effective Rate

16,000,000

Alta Wind XI term loan after March 2018 [Member] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Basis spread on variable rate

2.25%

Alta Wind X term loan after March 2018 [Member] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Basis spread on variable rate

2.25%

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

Long-term Debt Disclosure

Interest rate

7.01%

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

Long-term Debt Disclosure

Interest rate

7.00%

NRG Marsh Landing LLC, due 2017 and 2023 | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

464,000,000

473,000,000

NRG Marsh Landing LLC, due 2017 and 2023 | Marsh Landing [Member]

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

650,000,000

NRG Marsh Landing LLC, due 2017 and 2023 | Letter of Credit

Long-term Debt Disclosure

Letters of Credit Outstanding, Amount

22,000,000

NRG Marsh Landing LLC, due 2017 and 2023 | Term Loan Facility

Long-term Debt Disclosure

Debt Instrument, Face Amount

34,000,000

Letters of Credit Outstanding, Amount

24,000,000

NRG Marsh Landing LLC, due 2023

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

1.88%

3.00%

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

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

1.63%

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

Long-term Debt Disclosure

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

90.00%

Derivative, Fixed Interest Rate

4.00%

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

Long-term Debt Disclosure

Long-term Debt

391,000,000

0

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

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

90.00%

Notional Amount of Interest Rate Derivatives

345,000,000

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

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

117,000,000

Letters of Credit Outstanding, Amount

41,000,000

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

Long-term Debt Disclosure

Long-term Debt

442,000,000

Debt Issuance Cost

4,000,000

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, Maximum Borrowing Capacity

5,000,000

Line of Credit Facility, Fair Value of Amount Outstanding

0

Line of Credit Facility, Commitment Fee Percentage

0.50%

0.63%

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] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

192,000,000

0

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

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

90.00%

Derivative, Fixed Interest Rate

2.21%

Notional Amount of Interest Rate Derivatives

172,000,000

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

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

20,000,000

Letters of Credit Outstanding, Amount

20,000,000

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, Maximum Borrowing Capacity

8,000,000

Line of Credit Facility, Fair Value of Amount Outstanding

0

Line of Credit Facility, Commitment Fee Percentage

0.75%

Marsh Landing Tranche A due December 2017 [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

1.75%

2.75%

Marsh Landing Tranche A due December 2017 [Member] | Term Loan Facility

Long-term Debt Disclosure

Long-term Debt

108,000,000

Marsh Landing Term Loan Due 2023 [Member] | Term Loan Facility

Long-term Debt Disclosure

Long-term Debt

356,000,000

NRG Solar Alpine LLC, due 2013 and 2022 | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

163,000,000

221,000,000

NRG Solar Alpine LLC, due 2013 and 2022 | Cash Grant Loan

Long-term Debt Disclosure

Long-term Debt

63,000,000

68,000,000

Variable rate basis

6 month LIBOR

Line of Credit Facility, Increase, Additional Borrowings

62,000,000

Repayments of Debt

62,000,000

NRG Solar Alpine LLC, due 2013 and 2022 | Construction Loans

Long-term Debt Disclosure

Long-term Debt

166,000,000

Line of Credit Facility, Increase, Additional Borrowings

164,000,000

NRG Solar Alpine, due 2022

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Alpine [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

3 month LIBOR

Basis spread on variable rate

2.00%

1.75%

Debt Instrument, Face Amount

13,000,000

Line of Credit Facility, Increase, Additional Borrowings

11,000,000

Debt Issuance Cost

2,000,000

NRG Yield, Inc. | Convertible Debt [Member]

Long-term Debt Disclosure

Convertible Debt

345,000,000

NRG Energy Center Minneapolis LLC, senior secured notes, due 2013, 2017, and 2025 | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

121,000,000

127,000,000

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%

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] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

108,000,000

0

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

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

90.00%

Derivative, Fixed Interest Rate

2.31%

Notional Amount of Interest Rate Derivatives

86,000,000

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

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

9,000,000

Letters of Credit Outstanding, Amount

10,000,000

Credit Facility, Maximum Borrowing Capacity, Amendment

1,000,000

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

Long-term Debt

75,000,000

Debt Issuance Cost

8,000,000

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, Maximum Borrowing Capacity

3,000,000

Line of Credit Facility, Fair Value of Amount Outstanding

0

Line of Credit Facility, Commitment Fee Percentage

0.50%

Credit Facility, Maximum Borrowing Capacity, Amendment

-1,000,000

NRG Solar Borrego I LLC, due 2024 and 2038 | Interest Rate Swaps

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

75.00%

Derivative, Fixed Interest Rate

1.13%

NRG Solar Borrego I LLC, due 2024 and 2038 | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

75,000,000

78,000,000

NRG Solar Borrego I LLC, due 2024 and 2038 | Letter of Credit

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

5,000,000

Line of Credit Facility, Unused Capacity, Commitment Fee Percentage

100.00%

Letters of Credit Outstanding, Amount

5,000,000

NRG Solar Borrego I LLC, due 2024 and 2038 | Fixed Rate Notes

Long-term Debt Disclosure

Long-term Debt

45,000,000

45,000,000

Interest rate

5.65%

NRG Solar Borrego I LLC, due 2024 and 2038 | Term Loan Facility

Long-term Debt Disclosure

Long-term Debt

30,000,000

36,000,000

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.50%

Debt Instrument, Incremental Escalation On Basis Spread, Percentage

0.25%

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%

2.63%

South Trent Wind LLC, due 2020 | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

65,000,000

69,000,000

NRG Solar Avra Valley LLC, due 2031 | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

63,000,000

63,000,000

High Desert Facility [Member] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

55,000,000

80,000,000

High Desert Facility [Member] | Revolving Credit Facility [Member]

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

12,000,000

12,000,000

Letters of Credit Outstanding, Amount

8,000,000

Line of Credit Facility, Maximum Borrowing Capacity Available for Issuance of Letters of Credit

9,000,000

9,000,000

High Desert Facility [Member] | Fixed Rate Notes

Long-term Debt Disclosure

Long-term Debt

53,000,000

53,000,000

Interest rate

5.15%

5.15%

High Desert Facility [Member] | Floating Rate Notes [Member]

Long-term Debt Disclosure

Long-term Debt

7,000,000

7,000,000

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.50%

High Desert Facility [Member] | Bridge Loan [Member]

Long-term Debt Disclosure

Long-term Debt

22,000,000

22,000,000

Variable rate basis

1 month LIBOR

Basis spread on variable rate

2.50%

Extinguishment of Debt, Amount

20,000,000

High Desert Facility [Member] | Bridge Loan [Member] | NRG [Member]

Long-term Debt Disclosure

Extinguishment of Debt, Amount

2,000,000

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] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

46,000,000

0

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

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

90.00%

Derivative, Fixed Interest Rate

4.00%

Notional Amount of Interest Rate Derivatives

47,000,000

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-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

42,000,000

44,000,000

Kansas South Facility, due 2031 [Member]

Long-term Debt Disclosure

Basis spread on variable rate

2.00%

2.63%

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

Long-term Debt Disclosure

Long-term Debt

35,000,000

58,000,000

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-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

22,000,000

24,000,000

PFMG and related subsidiaries, due 2030 | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

31,000,000

32,000,000

Interest rate

6.00%

NRG Energy Center Princeton LLC, due 2017 | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

1,000,000

2,000,000

Interest rate

5.95%

NRG Yield Revolving Credit Facility

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

60,000,000

450,000,000

NRG Yield Revolving Credit Facility | Revolving Credit Facility [Member]

Long-term Debt Disclosure

Letters of Credit, Issued Amount

38,000,000

NRG Yield Revolving Credit Facility | Revolving Credit Facility [Member] | Alta X [Member]

Long-term Debt Disclosure

Letters of Credit, Issued Amount

3,000,000

NRG Yield Revolving Credit Facility | Revolving Credit Facility [Member] | Alta Wind Asset Management [Member]

Long-term Debt Disclosure

Letters of Credit, Issued Amount

1,000,000

NRG Yield Revolving Credit Facility | Revolving Credit Facility [Member] | Alta XI [Member]

Long-term Debt Disclosure

Letters of Credit, Issued Amount

3,000,000

NRG Yield Revolving Credit Facility | Revolving Credit Facility [Member] | Alta Realty Investments, LLC [Member]

Long-term Debt Disclosure

Letters of Credit, Issued Amount

2,000,000

NRG Yield Revolving Credit Facility | Revolving Credit Facility [Member] | Alta Wind I - V Lease financing arrangement [Member]

Long-term Debt Disclosure

Letters of Credit, Issued Amount

29,000,000

Convertible Debt [Member]

Long-term Debt Disclosure

Interest rate

3.50%

Debt Instrument, Convertible, Conversion Price

$46.55

Debt Instrument, Convertible, Conversion Ratio

21.4822

Debt Instrument, Face Amount

1,000

5.375% Senior Notes due in 2024 [Member]

Long-term Debt Disclosure

Interest rate

5.38%

Senior Notes

500,000,000

0

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

Alta Wind Asset Management, due 2031 [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

100.00%

Derivative, Fixed Interest Rate

2.47%

Alta Wind Asset Management, due 2031 [Member] | Non-affiliated Entity [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

3-Month LIBOR

3-month LIBOR

Line of Credit Facility, Maximum Borrowing Capacity

540,000,000

West Holdings Credit Agreement [Member] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

506,000,000

512,000,000

Alta Wind X, due 2020 [Member]

Long-term Debt Disclosure

Debt Service Loan Commitment

17,000,000

Alta Wind X, due 2020 [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

100.00%

Alta Wind X, due 2020 [Member] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.00%

Line of Credit Facility, Commitment Fee Percentage

0.75%

Alta Wind X, due 2020 [Member] | Letter of Credit

Long-term Debt Disclosure

Long-term Debt

5,000,000

Line of Credit Facility, Maximum Borrowing Capacity Available for Issuance of Letters of Credit

20,000,000

Alta Wind XI, due 2020 [Member]

Long-term Debt Disclosure

Debt Service Loan Commitment

11,000,000

Alta Wind XI, due 2020 [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

100.00%

Alta Wind XI, due 2020 [Member] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.00%

Line of Credit Facility, Commitment Fee Percentage

0.75%

Alta Wind XI, due 2020 [Member] | Letter of Credit

Long-term Debt Disclosure

Long-term Debt

0

Line of Credit Facility, Maximum Borrowing Capacity Available for Issuance of Letters of Credit

10,000,000

Alta Wind I - V Lease financing arrangement [Member] | Letter of Credit

Long-term Debt Disclosure

Long-term Debt

114,000,000

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

Long-term Debt Disclosure

Interest rate

5.70%

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

Long-term Debt Disclosure

Interest rate

6.07%

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

Long-term Debt Disclosure

Interest rate

5.94%

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

Long-term Debt Disclosure

Interest rate

6.07%

Project [Domain] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Long-term Debt

3,961,000,000

1,783,000,000

West Holdings Credit Agreement Tranche A [Member]

Long-term Debt Disclosure

Long-term Debt

447,000,000

Line of Credit Facility, Maximum Borrowing Capacity

480,000,000

Debt Instrument, Incremental Escalation On Basis Spread, Percentage

0.13%

West Holdings Credit Agreement Tranche B [Member]

Long-term Debt Disclosure

Long-term Debt

59,000,000

Line of Credit Facility, Maximum Borrowing Capacity

60,000,000

West Holdings PPA [Member]

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

90,000,000

Letters of Credit Outstanding, Amount

33,000,000

West Holding Collateral Agent [Member]

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

48,000,000

West Holdings Working Capital Facility [Member]

Long-term Debt Disclosure

Line of Credit Facility, Maximum Borrowing Capacity

10,000,000

Letters of Credit Outstanding, Amount

1,000,000

West Holdings Working Capital Facility [Member] | Letter of Support of Debt Service [Member]

Long-term Debt Disclosure

Letters of Credit Outstanding, Amount

48,000,000

Kansas South [Member] | Revolving Credit Facility [Member]

Long-term Debt Disclosure

Letters of Credit, Issued Amount

4,000,000

Kansas South [Member] | Fixed Rate Notes

Long-term Debt Disclosure

Long-term Debt

38,000,000

38,000,000

Kansas South [Member] | Bridge Loan [Member]

Long-term Debt Disclosure

Long-term Debt

21,000,000

21,000,000

Variable rate basis

1 month LIBOR

Basis spread on variable rate

2.00%

Kansas South Facility [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Kansas South Facility [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

6 month LIBOR

Basis spread on variable rate

2.63%

Avra Valley [Member]

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Basis spread on variable rate

1.75%

2.25%

Avra Valley [Member] | Floating Rate Notes [Member]

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

3 month LIBOR

Basis spread on variable rate

1.75%

2.25%

Debt Instrument, Face Amount

3,000,000

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%

Tapestry Wind LLC due in 2029 [Member] | EME [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Variable rate basis

3-Month LIBOR

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

50.00%

Derivative, Fixed Interest Rate

3.57%

Notional Amount of Interest Rate Derivatives

60,000,000

December 31, 2015 [Member] | Alta Wind X, due 2020 [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

174,000,000

December 31, 2015 [Member] | Alta Wind XI, due 2020 [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

138,000,000

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

Long-term Debt Disclosure

Long-term Debt

261,000,000

0

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

Long-term Debt Disclosure

Long-term Debt

205,000,000

0

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

Long-term Debt Disclosure

Long-term Debt

212,000,000

0

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

Long-term Debt Disclosure

Long-term Debt

138,000,000

0

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

Long-term Debt Disclosure

Long-term Debt

34,000,000

0

30,000,000

May 15, 2031 [Member] | Alta Wind Asset Management, due 2031 [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

20,000,000

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

Long-term Debt Disclosure

Long-term Debt

20,000,000

0

20,000,000

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

Long-term Debt Disclosure

Long-term Debt

300,000,000

0

337,000,000

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

Long-term Debt Disclosure

Long-term Debt

191,000,000

0

212,000,000

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

Long-term Debt Disclosure

Long-term Debt

220,000,000

0

December 31, 2025 [Member] | Alta Wind X, due 2020 [Member] | Forward Interest Rate Swap [Member]

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

103,000,000

December 31, 2025 [Member] | Alta Wind X, due 2020 [Member] | Current Interest Rate Swap [Member]

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

126,000,000

December 31, 2025 [Member] | Alta Wind XI, due 2020 [Member] | Forward Interest Rate Swap [Member]

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

65,000,000

December 31, 2025 [Member] | Alta Wind XI, due 2020 [Member] | Current Interest Rate Swap [Member]

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

54,000,000

December 31, 2020 [Member] | Alta Wind X, due 2020 [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

162,000,000

December 31, 2020 [Member] | Alta Wind XI, due 2020 [Member] | Interest Rate Swaps

Long-term Debt Disclosure

Notional Amount of Interest Rate Derivatives

103,000,000

Minimum [Member] | Alpine [Member]

Long-term Debt Disclosure

Basis spread on variable rate

1.75%

2.25%

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

Long-term Debt Disclosure

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

90.00%

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

Long-term Debt Disclosure

Basis spread on variable rate

2.25%

2.25%

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

Long-term Debt Disclosure

Debt Instrument, Incremental Escalation On Basis Spread, Percentage

0.13%

Minimum [Member] | Kansas South [Member]

Long-term Debt Disclosure

Debt Instrument, Incremental Escalation On Basis Spread, Percentage

0.25%

Maximum [Member] | Alpine [Member]

Long-term Debt Disclosure

Basis spread on variable rate

2.50%

2.50%

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

Long-term Debt Disclosure

Derivative, Minimum Percent of Outstanding Notional Amount Required to Have Fixed Interest Rate

100.00%

Maximum [Member] | Alta Wind Asset Management, due 2031 [Member] | Non-affiliated Entity [Member]

Long-term Debt Disclosure

Basis spread on variable rate

2.88%

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

Long-term Debt Disclosure

Basis spread on variable rate

2.88%

2.75%

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

Long-term Debt Disclosure

Debt Instrument, Incremental Escalation On Basis Spread, Percentage

0.25%

LIBOR Floor [Member] | High Desert Facility [Member] | Floating Rate Notes [Member]

Long-term Debt Disclosure

Basis spread on variable rate

1.50%

Subsequent Event [Member] | 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

October 8, 2013 to July 17, 2014 [Member] | NRG Marsh Landing LLC, due 2023 | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

3.00%

October 8, 2013 to July 17, 2014 [Member] | Marsh Landing Tranche A due December 2017 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.75%

July 17, 2014 to December 31, 2017 [Member] | NRG Marsh Landing LLC, due 2023 | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

1.88%

July 17, 2014 to December 31, 2017 [Member] | Marsh Landing Tranche A due December 2017 [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

1.75%

January 1, 2018 to December 31, 2020 [Member] | NRG Marsh Landing LLC, due 2023 | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.13%

January 1, 2021 and thereafter [Member] | NRG Marsh Landing LLC, due 2023 | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

3 month LIBOR

Basis spread on variable rate

2.38%

September 26, 2014 to September 30, 2019 [Member] | Kansas South Facility [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

6 month LIBOR

Basis spread on variable rate

2.00%

October 1, 2019 to September 30, 2031 [Member] | Kansas South Facility [Member] | Term Loan Facility

Long-term Debt Disclosure

Variable rate basis

6 month LIBOR

Basis spread on variable rate

2.25%

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%

[1]

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

[2]

Net of discount of $19 million as of December 31, 2014.

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	2 Months Ended	3 Months Ended					12 Months Ended
	Sep. 30, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net income attributable to NRG Yield, Inc.	$9,000,000	$0	$6,000,000	$6,000,000	$4,000,000	$4,000,000	$16,000,000	$13,000,000
Common Class C [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount							6,000,000
Numerator:
Net income attributable to NRG Yield, Inc.							8,000,000	6,500,000
Denominator:
Weighted average number of common shares outstanding							28,000,000	23,000,000
Basic and diluted loss per share:
Earnings per weighted average common share — basic and diluted							$0.30	$0.29
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount							6,000,000
Numerator:
Net income attributable to NRG Yield, Inc.							$8,000,000	$6,500,000
Denominator:
Weighted average number of common shares outstanding							28,000,000	23,000,000
Basic and diluted loss per share:
Earnings per weighted average common share — basic and diluted							$0.30	$0.29

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	0 Months Ended	3 Months Ended				6 Months Ended		7 Months Ended	12 Months Ended				1 Months Ended	0 Months Ended
In Millions, except Share data, unless otherwise specified	Jul. 22, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Jul. 22, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012	Jul. 31, 2013	Jul. 29, 2014	Jun. 30, 2014	Feb. 17, 2015	Jan. 02, 2015
Statement of Stockholders' Equity
Common Stock, Par or Stated Value Per Share						$0.01				$0.01
Proceeds from issuance of Class A common stock	$468									$468		$0
Expense Related to Distribution or Servicing and Underwriting Fees	27
Dividends Per Class A Common Share		$0.38	$0.37	$0.35	$0.33
Preferred Stock, Shares Authorized	10,000,000	10,000,000				10,000,000		10,000,000	10,000,000	10,000,000
Preferred Stock, Par or Stated Value Per Share	$0.01	$0.01				$0.01		$0.01	$0.01	$0.01
Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued		0				0	[1]		0	0	[1]
Payments of Capital Distribution								312	84			72
Proceeds from Contributions from Affiliates						14			16
Common Class B [Member]
Statement of Stockholders' Equity
Common Stock, Shares Authorized	500,000,000	500,000,000				500,000,000		500,000,000	500,000,000	500,000,000
Common Stock, Par or Stated Value Per Share	$0.01	$10,000						$0.01	$10,000
Common Class C [Member]
Statement of Stockholders' Equity
Common Stock, Shares Authorized		1,000,000,000				1,000,000,000			1,000,000,000	1,000,000,000
Common Stock, Par or Stated Value Per Share		$0.01							$0.01
Common Stock, Voting Rights									1/100th
NRG
Statement of Stockholders' Equity
Payments to Acquire Interest in Subsidiaries and Affiliates													395
NRG | Common Class B [Member]
Statement of Stockholders' Equity
Sale of Stock, Number of Shares Issued in Transaction	42,738,750
NRG Yield LLC | NRG
Statement of Stockholders' Equity
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	65.50%					65.50%			55.30%					55.30%	65.50%
NRG Yield LLC | NRG Yield, Inc.
Statement of Stockholders' Equity
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	34.50%								44.70%					44.70%
TA High Desert, RE Kansas South, and El Segundo Energy Center [Member]
Statement of Stockholders' Equity
Business Combination, Separately Recognized Transactions, Net Gains and Losses															113
NRG [Member]
Statement of Stockholders' Equity
Payments of Capital Distribution									86
NRG [Member] | El Segundo [Member]
Statement of Stockholders' Equity
Payments of Capital Distribution									23
NRG [Member] | EME-NYLD Assets [Member]
Statement of Stockholders' Equity
Payments of Capital Distribution									41
NRG Repowering Holdings LLC [Member] | TA - High Desert LLC [Member]
Statement of Stockholders' Equity
Proceeds from Contributions from Affiliates									2
Dividend Declared [Member]
Statement of Stockholders' Equity
Common Stock, Dividends, Per Share, Declared																$0.39
Subsequent Event [Member] | EME-NYLD Assets [Member]
Statement of Stockholders' Equity
Business Combination, Separately Recognized Transactions, Net Gains and Losses																	$61
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Segment_Reporting_Details

Segment Reporting (Details) (USD $)	3 Months Ended												7 Months Ended	9 Months Ended	12 Months Ended						6 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jul. 22, 2013	Sep. 30, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013
Segment Reporting
Total operating revenues	$192	[1]	$184	[1]	$173	[1]	$140	$118		$126	$82	$53		$379	$689		$379	[2]	$175	[2]
Cost of operations															239		144		114
Depreciation and amortization															166		61	[2]	25	[2]
Operating income	70	[1]	84	[1]	64	[1]	54	54		63	38	12		167	272		167	[2]	29	[2]
Equity in earnings of unconsolidated affiliates															27		22	[2]	19	[2]
Other Nonoperating Income (Expense)															3		3	[2]	2	[2]
Interest Expense															-186		-52	[2]	-28	[2]
Income Before Income Taxes															116	[3]	140	[2],[4]	22	[2],[4]
Income tax expense															4	[3]	8	[2],[4]	10	[2],[4]
Net Income	5	[1]	40	[1]	41	[1]	26	37		49	35	11	54	132	112		132	[2]	12	[2]
Equity investments in affiliates	227							227	[2]						227		227	[2]			227	[2]
Capital Expenditures	12	[5]						213	[6]						12	[5]	213	[6]			213	[6]
Total Assets	6,965							3,238	[2]						6,965		3,238	[2]			3,238	[2]
Conventional Generation
Segment Reporting
Total operating revenues															317		138		0
Cost of operations															55		23		2
Depreciation and amortization															82		20		0
Operating income															180		95		-2
Equity in earnings of unconsolidated affiliates															14		16		15
Other Nonoperating Income (Expense)															0		1		1
Interest Expense															-53		-25		0
Income Before Income Taxes															141		87		14
Income tax expense															0		0		0
Net Income															141		87		14
Equity investments in affiliates	114							118							114		118				118
Total Assets	2,194							1,584							2,194		1,584				1,584
Renewables
Segment Reporting
Total operating revenues															177		89		33
Cost of operations															45		11		9
Depreciation and amortization															66		26		10
Operating income															66		52		14
Equity in earnings of unconsolidated affiliates															13		6		4
Other Nonoperating Income (Expense)															2		2		1
Interest Expense															-96		-20		-20
Income Before Income Taxes															-15		40		-1
Income tax expense															0		0		0
Net Income															-15		40		-1
Equity investments in affiliates	113							109							113		109				109
Capital Expenditures	-1	[5]						30	[6]						-1	[5]	30	[6]			30	[6]
Total Assets	3,856							1,046							3,856		1,046				1,046
Thermal
Segment Reporting
Total operating revenues															195		152		142
Cost of operations															139		110		103
Depreciation and amortization															18		15		15
Operating income															38		27		24
Equity in earnings of unconsolidated affiliates															0		0		0
Other Nonoperating Income (Expense)															0		0		0
Interest Expense															-7		-7		-8
Income Before Income Taxes															31		20		16
Income tax expense															0		0		0
Net Income															31		20		16
Equity investments in affiliates	0							0							0		0				0
Capital Expenditures	7	[5]						15	[6]						7	[5]	15	[6]			15	[6]
Total Assets	437							436							437		436				436
Corporate
Segment Reporting
Total operating revenues															0		0		0
Cost of operations															0		0		0
Depreciation and amortization															0		0		0
Operating income															-12		-7		-7
Equity in earnings of unconsolidated affiliates															0		0		0
Other Nonoperating Income (Expense)															1		0		0
Interest Expense															-30		0		0
Income Before Income Taxes															-41		-7		-7
Income tax expense															4		8		10
Net Income															-45		-15		-17
Equity investments in affiliates	0							0							0		0				0
Capital Expenditures	0	[5]						0	[6]						0	[5]	0	[6]			0	[6]
Total Assets	478							172							478		172				172
Affiliated Entity [Member]
Segment Reporting
General and administrative — affiliate															8		7	[2]	7	[2]	3
Business Combination, Acquisition Related Costs															4
Affiliated Entity [Member] | Conventional Generation
Segment Reporting
General and administrative — affiliate															0		0		0
Business Combination, Acquisition Related Costs															0
Capital Expenditures	6	[5]						168	[6]						6	[5]	168	[6]			168	[6]
Affiliated Entity [Member] | Renewables
Segment Reporting
General and administrative — affiliate															0		0		0
Business Combination, Acquisition Related Costs															0
Affiliated Entity [Member] | Thermal
Segment Reporting
General and administrative — affiliate															0		0		0
Business Combination, Acquisition Related Costs															0
Affiliated Entity [Member] | Corporate
Segment Reporting
General and administrative — affiliate															8		7		7
Business Combination, Acquisition Related Costs															$4
Southern California Edison [Member] | Conventional Generation
Segment Reporting
Customer's Percentage of Total Revenue															28.00%		15.00%
Southern California Edison [Member] | Renewables
Segment Reporting
Customer's Percentage of Total Revenue															9.00%		4.00%
PG&E [Member] | Conventional Generation
Segment Reporting
Customer's Percentage of Total Revenue															18.00%		22.00%
PG&E [Member] | Renewables
Segment Reporting
Customer's Percentage of Total Revenue															4.00%		7.00%
[1]	The Company's unaudited quarterly financial data was recast for the effect of the EME-NYLD-Eligible Assets, from the date the entities were under common control or April 1, 2014.
[2]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[3]	(a) - Represents 34.5% ownership for the period July 22, 2013 through December 31, 2013
[4]	(b) - Represents pro forma tax provision for NRG Yield LLC
[5]	cludes accruals
[6]	(a) Includes accruals

Income_Taxes_Provision_Details

Income Taxes (Provision) (Details) (USD $)	3 Months Ended											7 Months Ended	9 Months Ended	12 Months Ended						0 Months Ended			6 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jul. 22, 2013	Sep. 30, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Jul. 29, 2014	Jun. 30, 2014	Jul. 22, 2013	Dec. 31, 2013
Income Tax Disclosure
Unrecognized Tax Benefits	$0													$0
State net operating loss carryforwards	7,000,000							4,000,000						7,000,000		4,000,000							4,000,000
Deferred Tax Assets, Derivative Instruments	6,000,000							0						6,000,000		0							0
Deferred Tax Assets, Net	134,000,000							146,000,000						134,000,000		146,000,000							146,000,000
Current
U.S. Federal														0		0		7,000,000
Total — current														0		0		7,000,000
Deferred
U.S. Federal														2,000,000		14,000,000		1,000,000
State														2,000,000		-6,000,000		2,000,000
Total — deferred														4,000,000		8,000,000		3,000,000
Income tax expense														4,000,000	[1]	8,000,000	[2],[3]	10,000,000	[2],[3]
Effective tax rate (as a percent)														3.40%	[1]	5.70%	[2]	45.70%	[2]
Income Taxes Receivable	6,000,000													6,000,000
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														116,000,000	[1]	140,000,000	[2],[3]	22,000,000	[2],[3]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	5,000,000	[4]	40,000,000	[4]	41,000,000	[4]	26,000,000	37,000,000	49,000,000	35,000,000	11,000,000	54,000,000	132,000,000	112,000,000		132,000,000	[3]	12,000,000	[3]
Tax at 35%														41,000,000	[1]	49,000,000	[2]	8,000,000	[2]
State taxes, net of federal benefit														-1,000,000	[1]	6,000,000	[2]	-2,000,000	[2]
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount														-33,000,000	[1]
Impact of non-taxable equity earnings																-35,000,000	[2]	0	[2]
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount														-6,000,000		0		0
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount														$1,000,000		$0		$0
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%	65.50%	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%		34.50%
[1]	(a) - Represents 34.5% ownership for the period July 22, 2013 through December 31, 2013
[2]	(b) - Represents pro forma tax provision for NRG Yield LLC
[3]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[4]	The Company's unaudited quarterly financial data was recast for the effect of the EME-NYLD-Eligible Assets, from the date the entities were under common control or April 1, 2014.

Income_Taxes_Deferred_Details_

Income Taxes (Deferred) (Details 2) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Company's deferred tax assets and liabilities
Deferred Tax Assets, Derivative Instruments	$6	$0
Deferred tax assets:
Deferred Tax Assets, Other	47	81
U.S. Federal net operating loss carryforwards	74	61
State net operating loss carryforwards	7	4
Total deferred tax assets	134	146
The Company's net deferred tax position
Net deferred tax asset — current	16	0	[1]
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	118	146
Deferred Tax Assets, Net	134	146
Domestic Tax Authority
Operating Loss Carryforwards
Operating Loss Carryforwards	74
State and Local Jurisdiction
Operating Loss Carryforwards
Operating Loss Carryforwards	$7
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	12 Months Ended		6 Months Ended	12 Months Ended				3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2013		Dec. 31, 2012		Mar. 31, 2014	Sep. 30, 2013
Management Services Agreement with NRG
Related Party Transaction
Management Services Fee, Increase	$2
Plan | Management Services Agreement with NRG
Related Party Transaction
Management Services Fee, Annual	6
Affiliated Entity [Member]
Related Party Transaction
General and administrative — affiliate	8		3	7	[1]	7	[1]
NRG Repowering Holdings LLC [Member]
Related Party Transaction
Payments			18	18
Receipt of payments								11
coal, gas purchases						2
Cost of Natural Gas Purchases	10			5
El Segundo [Member] | NRG El Segundo Operations, Inc. [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	4			5		1
Related Party Costs, Capitalized Amount				2		1
El Segundo [Member] | NRG Construction Services LLC [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	1			4		4
El Segundo [Member] | NRG El Segundo Operations, Inc. [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party				1		1
El Segundo [Member] | NRG Power Marketing LLC [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	1			12
Related Party Costs, Capitalized Amount				9
CVSR [Member] | NRG Renew LLC [Member]
Related Party Transaction
Capital contributions percentage									100.00%
Due to Affiliate			14	14
CVSR [Member] | Utility-Scale Solar [Member]
Related Party Transaction
Equity Method Investment, Ownership Percentage	48.95%	[2]
Thermal [Member] | NRG [Member]
Related Party Transaction
Due to Related Parties	22
Related Party Transaction, Expenses from Transactions with Related Party	27			24
NRG Yield, Inc. [Member] | NRG [Member]
Related Party Transaction
Due to Related Parties	5
Interest Due to Related Parties	0
GCE Holding LLC [Member] | NRG [Member]
Related Party Transaction
Related Party Transaction, Expenses from Transactions with Related Party	6			5		5
Marsh Landing [Member] | GenOn Energy Services LLC [Member]
Related Party Transaction
Due to Related Parties	4		2	2
Related Party Transaction, Expenses from Transactions with Related Party	13			36		2
Related Party Costs, Capitalized Amount	$2			$29		$2
[1]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[2]	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.

Commitments_and_Contingencies_2

Commitments and Contingencies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Utilities Operating Expense, Purchased Power under Long-term Contracts	$55	$40	$30
Operating Leases, Rent Expense	5	2	2
Operating Leases, Future Minimum Payments Due, Next Twelve Months	12
Operating Leases, Future Minimum Payments, Due in Two Years	11
Operating Leases, Future Minimum Payments, Due in Three Years	7
Operating Leases, Future Minimum Payments, Due in Four Years	7
Operating Leases, Future Minimum Payments, Due in Five Years	7
Operating Leases, Future Minimum Payments, Due Thereafter	133
Operating Leases, Future Minimum Payments Due	177
Purchase Obligation, Due in Next Twelve Months	15
Unrecorded Unconditional Purchase Obligation, Due within Two Years	4
Unrecorded Unconditional Purchase Obligation, Due within Three Years	3
Unrecorded Unconditional Purchase Obligation, Due within Four Years	3
Unrecorded Unconditional Purchase Obligation, Due within Five Years	2
Unrecorded Unconditional Purchase Obligation, Due after Five Years	26
Purchase Obligation	$53

Unaudited_Quarterly_Financial_2

Unaudited Quarterly Financial Data (Details) (USD $)	2 Months Ended		3 Months Ended													7 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2013		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jul. 22, 2013	Sep. 30, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Net income attributable to NRG Yield, Inc.	$9,000,000		$0		$6,000,000		$6,000,000		$4,000,000		$4,000,000							$16,000,000	$13,000,000
Net Income			5,000,000	[1]	40,000,000	[1]	41,000,000	[1]	26,000,000		37,000,000		49,000,000	35,000,000	11,000,000	54,000,000	132,000,000	112,000,000	132,000,000	[2]	12,000,000	[2]
Operating Income (Loss)			70,000,000	[1]	84,000,000	[1]	64,000,000	[1]	54,000,000		54,000,000		63,000,000	38,000,000	12,000,000		167,000,000	272,000,000	167,000,000	[2]	29,000,000	[2]
Operating revenues			192,000,000	[1]	184,000,000	[1]	173,000,000	[1]	140,000,000		118,000,000		126,000,000	82,000,000	53,000,000		379,000,000	689,000,000	379,000,000	[2]	175,000,000	[2]
Scenario, Previously Reported [Member]
Net Income			-10,000,000		31,000,000		34,000,000		18,000,000		24,000,000		40,000,000	34,000,000	11,000,000				109,000,000
Operating Income (Loss)			46,000,000		70,000,000		51,000,000		38,000,000		33,000,000		45,000,000	38,000,000	12,000,000				128,000,000
Operating revenues			148,000,000		161,000,000		134,000,000		110,000,000		86,000,000		95,000,000	79,000,000	53,000,000				313,000,000
Net Income (Loss) [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Reconciling to Previously Reported Results			15,000,000		9,000,000		7,000,000		0		13,000,000		9,000,000	1,000,000	0
Operating Income (Loss) [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Reconciling to Previously Reported Results			24,000,000		14,000,000		13,000,000		0		21,000,000		18,000,000	0	0
Operating Revenues [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Reconciling to Previously Reported Results			44,000,000		23,000,000		39,000,000		0		32,000,000		31,000,000	3,000,000	0
Common Class A [Member]
Net Income/(Loss) per Weighted Average Common Share - Basic (in dollars per share)	$0.20	[3],[4]	$0.01	[4]	$0.10	[4]	$0.13	[4]	$0.09	[4]	$0.09	[4]
Weighted average number of common shares outstanding - basic (in shares)	23,000,000	[3],[4]	35	[4]	31	[4]	23,000,000	[4]	23,000,000	[4]	23,000,000	[4]
Net income attributable to NRG Yield, Inc.																		8,000,000	6,500,000
Common Class C [Member]
Net Income/(Loss) per Weighted Average Common Share - Basic (in dollars per share)	$0.20	[3],[4]	$0.01	[4]	$0.10	[4]	$0.13	[4]	$0.09	[4]	$0.09	[4]
Weighted average number of common shares outstanding - basic (in shares)	23,000,000	[3],[4]	35	[4]	31	[4]	23,000,000	[4]	23,000,000	[4]	23,000,000	[4]
Net income attributable to NRG Yield, Inc.																		$8,000,000	$6,500,000
[1]	The Company's unaudited quarterly financial data was recast for the effect of the EME-NYLD-Eligible Assets, from the date the entities were under common control or April 1, 2014.
[2]	Retrospectively adjusted as discussed in Note 1, Nature of Business.
[3]	Earnings per weighted average class A and Class C common share are calculated for the period of July 22, 2013 to September 30, 2013
[4]	Adjusted to give effect to the stock split, as described in Note 1, Nature of Business.

Background_and_Basis_of_Presen1

Background and Basis of Presentation - Yield, Inc (Parent) (Details) (USD $)	0 Months Ended	7 Months Ended	12 Months Ended			1 Months Ended	0 Months Ended	2 Months Ended	0 Months Ended	6 Months Ended
In Millions, except Share data, unless otherwise specified	Jul. 22, 2013	Jul. 22, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 31, 2013	Jul. 29, 2014	Sep. 30, 2013	Jun. 30, 2014	Dec. 31, 2013
Proceeds from Issuance of Common Stock	$468			$468	$0
Common Stock, Par or Stated Value Per Share				$0.01						0.01
Payments of Capital Distribution		312	84		72
Common Class A [Member]
Common Stock, Par or Stated Value Per Share	$0.01	$0.01	$0.01
NRG [Member]
Payments to Acquire Interest in Subsidiaries and Affiliates						395
Public Shareholders [Member] | Common Class A [Member]
Sale of Stock, Number of Shares Issued in Transaction	22,511,250						12,075,000
Proceeds from Issuance of Common Stock							630
Economic Interest in Entity								100.00%
NRG Yield, Inc. [Member] | Common Class A [Member]
Common Stock, Par or Stated Value Per Share			$0.01		$0
NRG Yield, Inc. [Member] | NRG Yield LLC [Member]
Payments of Capital Distribution			$41	$5
NRG Yield LLC [Member] | NRG [Member]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	65.50%		55.30%				55.30%		65.50%	65.50%
NRG Yield LLC [Member] | NRG Yield, Inc. [Member]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	34.50%		44.70%				44.70%
NRG Yield LLC [Member] | Class A Common Stockholders [Member]
Economic Interest in Entity							100.00%

Environmental_Matters_Details

Environmental Matters (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Environmental Remediation Obligations [Abstract]
Litigation Settlement, Amount	$123,000