CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions		Total	NRG Yield, Inc.	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Treasury Stock	Accumulated Other Comprehensive Loss	Noncontrolling Interest	Noncontrolling Interest NRG Yield, Inc.
Beginning 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	[1]	(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
Ending 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	[1]	(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
Ending balance at Jun. 30, 2018		2,071		4	8,481	(5,920)	(2,871)	(60)	2,437
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)		(48)				(72)			24
Other comprehensive (loss) income		2						2
Sale of assets to NRG Yield, Inc.		7			1				6
Share repurchases		(500)			(37)		(463)
Equity-based compensation		4			4
Issuance of common stock		4			4
Common stock dividends	[1]	(9)				(9)
Distributions to noncontrolling interest and dividends paid		(9)							(9)
Contributions from noncontrolling interests		1							1
Deconsolidation of Business		(2,459)							(2,459)
Ending balance at Sep. 30, 2018		(936)		4	8,453	(6,001)	(3,334)	(58)	$ 0
Beginning 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	[2]	(8)				(8)
Ending 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	[2]	(8)				(8)
Ending balance at Jun. 30, 2019		(1,648)		4	8,488	(5,355)	(4,686)	(99)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)		372				372
Other comprehensive (loss) income		(59)						(59)
Share repurchases		(234)					(234)
Equity-based compensation		5			5
Issuance of common stock		1			1
Common stock dividends	[2]	(8)				(8)
Ending balance at Sep. 30, 2019		$ (1,571)		$ 4	$ 8,494	$ (4,991)	$ (4,920)	$ (158)

[1] Dividends per common share were $0.03 for each of the quarters ended September 30, 2018, June 30, 2018 and March 31, 2018

[2] Dividends per common share were $0.03 for each of the quarters ended September 30, 2019, June 30, 2019 and March 31, 2019