CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	NRG Yield, Inc.	Common Stock	Additional Paid-In Capital	Additional Paid-In Capital NRG Yield, Inc.	Accumulated Deficit	Treasury Stock	Accumulated Other Comprehensive Loss	Noncontrolling Interest	Noncontrolling Interest NRG Yield, Inc.
Balance at Dec. 31, 2017	$ 1,968		$ 4	$ 8,376		$ (6,268)	$ (2,386)	$ (72)	$ 2,314
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	249					279			(30)
Other comprehensive (loss) income	11							11
Sale of assets to NRG Yield, Inc.		$ 12			$ 8					$ 4
ESPP share purchases	3			(2)			5
Share repurchases	(93)						(93)
Equity-based compensation	(10)			(10)
Issuance of common stock	7			7
Common stock dividends	(10)					(10)
Distributions to noncontrolling interest and dividends paid	(19)	(30)							(19)	(30)
Contributions from noncontrolling interests	153								153
Adoption of new accounting standards	17					17
Balance at Mar. 31, 2018	2,258		4	8,379		(5,982)	(2,474)	(61)	2,392
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	104					72			32
Other comprehensive (loss) income	1							1
Sale of assets to NRG Yield, Inc.		(2)								(2)
ESPP share purchases	(1)						(1)
Share repurchases	(407)			(11)			(396)
Equity-based compensation	8			8
Issuance of common stock	4			4
Common stock dividends	(9)					(9)
Distributions to noncontrolling interest and dividends paid	(15)	$ (31)							(15)	$ (31)
Contributions from noncontrolling interests	150								150
Adoption of new accounting standards	(1)					(1)
Deconsolidation of Business	(89)								(89)
Equity component of convertible senior notes	101			101
Balance at Jun. 30, 2018	2,071		4	8,481		(5,920)	(2,871)	(60)	$ 2,437
Balance at Dec. 31, 2018	(1,234)		4	8,510		(6,022)	(3,632)	(94)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	482					482
Other comprehensive (loss) income	(2)							(2)
Share repurchases	(749)			(10)			(739)
Equity-based compensation	(32)			(32)
Issuance of common stock	5			5
Common stock dividends	(8)					(8)
Balance at Mar. 31, 2019	(1,538)		4	8,473		(5,548)	(4,371)	(96)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)	201					201
Other comprehensive (loss) income	(3)							(3)
Share repurchases	(305)			10			(315)
Equity-based compensation	5			5
Common stock dividends	(8)					(8)
Balance at Jun. 30, 2019	$ (1,648)		$ 4	$ 8,488		$ (5,355)	$ (4,686)	$ (99)