Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Parenthetical) (Detail) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Derivatives Fair Value [Line Items]
Current derivative assets	[1]	$ 122	$ 67
Noncurrent derivative assets	[2]	$ 491	330
Other Current Assets
Derivatives Fair Value [Line Items]
Current derivative assets			63
Other Deferred Charges and Other Assets
Derivatives Fair Value [Line Items]
Noncurrent derivative assets			330
Other Current Liabilities
Derivatives Fair Value [Line Items]
Current derivative liabilities			412
Other Deferred Credits and Other Liabilities
Derivatives Fair Value [Line Items]
Noncurrent derivative liabilities			$ 71

[1] At December 31, 2021, all current derivative assets are presented in other current assets in Dominion Energy’s Consolidated Balance Sheets. At December 31, 2020, $63 million is included in other current assets and the remainder is recorded in current assets held for sale.

[2] At December 31, 2021, all noncurrent derivative assets are presented in other deferred charges and other assets in Dominion Energy’s Consolidated Balance Sheets. At December 31, 2020, $330 million is included in other deferred charges and other assets and the remainder is recorded in noncurrent assets held for sale.