Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Parenthetical) (Detail) - USD ($) $ in Millions		Mar. 31, 2021	Dec. 31, 2020
Derivatives Fair Value [Line Items]
Current derivative assets	[1]	$ 36	$ 67
Current derivative liabilities	[2]	221	415
Other Current Assets
Derivatives Fair Value [Line Items]
Current derivative assets		31	63
Other Current Liabilities
Derivatives Fair Value [Line Items]
Current derivative liabilities		$ 217	$ 412

[1] Current derivative assets include $31 million and $63 million in other current assets in Dominion Energy’s Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020, respectively.  The remainder is recorded in current assets held for sale in Dominion Energy’s Consolidated Balance Sheets.

[2] Current derivative liabilities include $217 million and $412 million at March 31, 2021 and December 31, 2020, respectively, presented in other current liabilities in Dominion Energy’s Consolidated Balance Sheets. The remainder is in current liabilities held for sale in Dominion Energy’s Consolidated Balance Sheets.