Preferred Stock (Schedule of Equity Units) (Detail) - USD ($) shares in Millions, $ in Millions			1 Months Ended				12 Months Ended
		Jun. 14, 2019	Aug. 31, 2021	Jul. 31, 2021	Sep. 30, 2020	Aug. 31, 2019	Dec. 31, 2021	Dec. 31, 2019	Dec. 31, 2020
Capital Unit [Line Items]
Units Issued			0.6	1.4	4.1	18.5		6.1
Total Preferred Stock							$ 1,783		$ 2,387
Stock Purchase Contract Liability							$ 44		$ 129
Preferred Stock
Capital Unit [Line Items]
Units Issued							1.0	2.0
Preferred Stock | 2019 Series A Corporate Units
Capital Unit [Line Items]
Units Issued		16.0
Total Net Proceeds	[1]	$ 1,582
Total Preferred Stock	[2]	$ 1,610
Cumulative Dividend Rate		1.75%
Stock Purchase Contract Annual Rate		5.50%
Stock Purchase Contract Liability	[3]	$ 250
Stock Purchase Contract Settlement Date		Jun. 01, 2022

[1] Issuance costs of $28 million were recorded as a reduction to preferred stock ($14 million) and common stock ($14 million). In connection with the reclassification of the Series A Preferred Stock to mezzanine equity in 2021, the issuance costs originally recognized as a reduction to preferred stock were reclassified to common stock.

[2] Dominion Energy recorded dividends of $28 million ($17.50 per share), $28 million ($17.50 per share) and $15 million ($9.479 per share) for the years ended December 31, 2021, 2020 and 2019, respectively.

[3] Payments of $85 million, $83 million and $38 million were made in 2021, 2020 and 2019, respectively. The stock purchase contract liability was $44 million and $129 million at December 31, 2021 and 2020, respectively.