Business Acquisitions and Dispositions Business Acquisitions and Dispositions - Alta Wind (Details 2) $ in Millions			7 Months Ended
	Aug. 13, 2014 USD ($)	Jul. 30, 2014 USD ($) shares	Aug. 11, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Aug. 12, 2014 USD ($) MW	Aug. 05, 2014 USD ($)
Business Acquisition [Line Items]
Long-term Debt				$ 19,406	$ 19,620
Alta Wind Portfolio [Member]
Business Acquisition [Line Items]
Percentage of Ownership							100.00%
Power Generation Capacity, Megawatts | MW							947
Payments to Acquire Businesses, Gross	$ 923
Business Acquisitions, Consideration Transferred, Purchase Price							$ 870
Business Acquisition, Consideration Transferred, Working Capital							$ 53
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents			$ 22			$ 22
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Cash			0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current and Non-Current Assets						49
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Assets			(2)
Business Acquisition, Purchase Price Allocation, Other Assets, Adjusted			47
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment						1,304
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment			6
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment, Adjusted			1,310
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						1,177
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles			(6)
Business Acquisition, Purchase Price Allocation, Intangible Assets, Other than Goodwill, Adjusted			1,171
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets						2,552
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Total Assets			(2)
Business Acquisition, Purchase Price Allocation, Assets Acquired, Adjusted			2,550
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 Liabilities						38
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Current and Noncurrent Liabilities			(2)
Business Acquisition, Purchase Price Allocation, Current and Non-current Liabilities, Adjusted			36
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities						1,629
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities			(2)
Business Acquisition, Purchase Price Allocation, Liabilities Assumed, Adjusted			1,627
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net						$ 923
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 I - V Lease financing arrangement [Member]
Business Acquisition [Line Items]
Lessor Leasing Arrangements, Operating Leases, Term of Contract	21 years
Alta Wind X and Alta Wind XI, due 2020 [Member]
Business Acquisition [Line Items]
Lessor Leasing Arrangements, Operating Leases, Term of Contract	22 years
NRG Yield, Inc. [Member] | Common Class A [Member]
Business Acquisition [Line Items]
Shares, Issued | shares		12,075,000
Proceeds from Issuance or Sale of Equity		$ 630
NRG Yield Operating LLC [Member]
Business Acquisition [Line Items]
Long-term Debt								$ 500
Debt Instrument, Interest Rate, Stated Percentage								5.375%