Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Parenthetical) (Detail) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Derivatives Fair Value [Line Items]
Derivative assets	$ 596,000,000	$ 122,000,000	[1]
Derivative liabilities	982,000,000	359,000,000	[1]
Other Current Assets
Derivatives Fair Value [Line Items]
Derivative assets	1,000,000	0
Other Current Liabilities
Derivatives Fair Value [Line Items]
Derivative liabilities	$ 2,000,000	$ 0

[1] Dominion Energy’s Consolidated Balance Sheet at December 31, 2021 has been derived from the audited Consolidated Balance Sheet at that date.