Consolidated Statements of Equity - USD ($) shares in Millions, $ in Millions	Total	NRG Energy, Inc	Common Units	Preferred Stock	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total Shareholders' Equity	Noncontrolling Interests	Noncontrolling Interests NRG Energy, Inc	Noncontrolling Interests Common Units
Beginning balance at Dec. 31, 2016	$ 16,840				$ 8,550	$ 6,854	$ (799)	$ 14,605	$ 2,235
Beginning balance (in shares) at Dec. 31, 2016					628.0
Net income (loss) including noncontrolling interests	3,120					2,999		2,999	121
Contributions to Four Brothers and Three Cedars		$ 9								$ 9
Issuance of common stock	1,302				$ 1,302			1,302
Issuance of common stock (in shares)					17.0
Sale of Dominion Energy Midstream common units—net of offering costs			$ 18								$ 18
Stock awards (net of change in unearned compensation)	22				$ 22			22
Dividends and distributions	(2,087)					(1,931)		(1,931)	(156)
Other comprehensive income (loss), net of tax	141						140	140	1
Other	5				(9)	14		5
Ending balance at Dec. 31, 2017	19,370				$ 9,865	7,936	(659)	17,142	2,228
Ending Balance (in shares) at Dec. 31, 2017					645.0
Cumulative-effect of changes in accounting principles	6				$ (127)	1,029	(1,023)	(121)	127
Net income (loss) including noncontrolling interests	2,549					2,447		2,447	102
Issuance of common stock	2,461				$ 2,461			2,461
Issuance of common stock (in shares)					36.0
Sale of Dominion Energy Midstream common units—net of offering costs	4								4
Stock awards (net of change in unearned compensation)	22				$ 22			22
Remeasurement of noncontrolling interest in Dominion Energy Midstream					375			375	(375)
Dividends and distributions	(2,331)					(2,185)		(2,185)	(146)
Other comprehensive income (loss), net of tax	(17)						(18)	(18)	1
Other	(16)				(8)	(8)		(16)
Ending balance at Dec. 31, 2018	22,048				$ 12,588	9,219	(1,700)	20,107	1,941
Ending Balance (in shares) at Dec. 31, 2018					681.0
Net income (loss) including noncontrolling interests	1,376					1,358		1,358	18
Issuance of common stock	$ 5,401			$ 2,387	$ 3,014			5,401
Issuance of common stock (in shares)	6.1			2.0	39.0
Stock purchase contract component of 2019 Equity Units	$ (264)				$ (264)			(264)
Acquisition of SCANA	6,818				$ 6,818			6,818
Acquisition of SCANA (in shares)					96.0
Acquisition of public interest in Dominion Energy Midstream (in shares)					22.0
Acquisition of public interest in Dominion Energy Midstream	(40)				$ 1,181			1,181	(1,221)
Stock awards (net of change in unearned compensation)	24				24			24
Other comprehensive income (loss), net of tax	(93)						(93)	(93)
Other	(14)				(13)	(1)		(14)
Sale of interest in Cove Point	1,862				476			476	1,386
Preferred stock dividends	(17)					(17)		(17)
Common dividends and distributions	(3,068)					(2,983)		(2,983)	(85)
Ending balance at Dec. 31, 2019	$ 34,033			$ 2,387	$ 23,824	$ 7,576	$ (1,793)	$ 31,994	$ 2,039
Ending Balance (in shares) at Dec. 31, 2019				2.0	838.0