Earnings Per Share (Calculation of Basic and Diluted EPS) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income from continuing operations		$ 781	$ 589	$ 1,021	$ 1,828
Preferred stock dividends (see Note 16)		(20)	(16)	(72)	(48)
Net income attributable to Dominion Energy from continuing operations – Basic		761	573	949	1,780
Dilutive effect of 2019 Equity Units	[1]			12
Net income attributable to Dominion Energy from continuing operations - Diluted		761	573	961	1,780
Net income attributable to Dominion Energy		$ (3)	$ 65	$ 15	$ 119
Average shares of common stock outstanding – Basic		832.6	808.7	820.6	807.1
Net effect of dilutive securities	[2]	0.6	1.3	12.1	0.5
Average shares of common stock outstanding – Diluted		833.2	810.0	832.7	807.6
EPS from continuing operations – Basic		$ 0.91	$ 0.71	$ 1.16	$ 2.20
EPS from discontinued operations – Basic			0.08	0.02	0.15
Net income attributable to Dominion Energy		0.91	0.79	1.18	2.35
EPS from continuing operations – Diluted		0.91	0.71	1.15	2.20
EPS from discontinued operations – Diluted			0.08	0.02	0.15
Net income attributable to Dominion Energy		$ 0.91	$ 0.79	$ 1.17	$ 2.35

[1] As discussed in Note 16, effective in June 2022 through its settlement in September 2022, the Series A Preferred Stock was considered to be mandatorily redeemable and was classified in current liabilities. In accordance with revised accounting standards effective January 2022, a fair value adjustment, if dilutive, of the Series A Preferred Stock was no longer included in applying the if converted method to the 2019 Equity Units. In addition, diluted net income was no longer reduced by the Series A Preferred Stock dividends. No fair value adjustment was necessary for the three and nine months ended September 30, 2021.

[2] Dilutive securities for the three and nine months ended September 30, 2022 consist primarily of the 2019 Equity Units through their settlement in June 2022 (applying the if converted method as updated effective January 2022), stock potentially to be issued to satisfy the obligation under a settlement agreement with the SCDOR (applying the if converted method) as well as forward sales agreements entered into in November 2021 (applying the treasury stock method). See Notes 16 and 17 for additional information