Earnings Per Share (Calculation of Basic and Diluted EPS) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net Income from continuing operations	$ 259	$ 863	$ 1,239	$ 397
Preferred stock dividends (see Note 16)	(16)	(16)	(32)	(32)
Net income attributable to Dominion Energy from continuing operations – Basic	243	847	1,207	365
Dilutive effect of Series A Preferred Stock		(92)		(64)
Net income attributable to Dominion Energy from continuing operations - Diluted	243	755	1,207	301
Net Income (Loss) from discontinued operations	$ 26	$ (2,032)	$ 54	$ (1,836)
Average shares of common stock outstanding – Basic	806.6	839.4	806.2	838.8
Net effect of dilutive securities			0.1
Average shares of common stock outstanding – Diluted	806.6	839.4	806.3	838.8
EPS from continuing operations – Basic	$ 0.30	$ 1.01	$ 1.49	$ 0.43
EPS from discontinued operations – Basic	0.03	(2.42)	0.07	(2.18)
EPS attributable to Dominion Energy – Basic	0.33	(1.41)	1.56	(1.75)
EPS from continuing operations – Diluted	0.30	0.90	1.49	0.35
EPS from discontinued operations – Diluted	0.03	(2.42)	0.07	(2.18)
EPS attributable to Dominion Energy – Diluted	$ 0.33	$ (1.52)	$ 1.56	$ (1.83)