Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Parenthetical) (Detail) - USD ($) $ in Millions		Sep. 30, 2020	Dec. 31, 2019
Derivatives Fair Value [Line Items]
Current derivative assets	[1]	$ 98	$ 68
Noncurrent derivative assets	[2]	154	25
Current derivative liabilities		223	394	[3]
Noncurrent derivative liabilities		537	329	[3]
Other Current Assets
Derivatives Fair Value [Line Items]
Current derivative assets		87	61
Other Deferred Charges and Other Assets
Derivatives Fair Value [Line Items]
Noncurrent derivative assets		154	16
Held for Sale
Derivatives Fair Value [Line Items]
Current derivative liabilities		$ 16	14
Noncurrent derivative liabilities			$ 3

[1] Current derivative assets include $87 million and $61 million in other current assets in Dominion Energy’s Consolidated Balance Sheets as of September 30, 2020 and December 31, 2019, respectively.  The remainder is recorded in current assets held for sale in Dominion Energy’s Consolidated Balance Sheets.

[2] Noncurrent derivative assets include $154 million and $16 million in other deferred charges and other assets in Dominion Energy’s Consolidated Balance Sheets as of September 30, 2020 and December 31, 2019, respectively.  The remainder is recorded in noncurrent assets held for sale in Dominion Energy’s Consolidated Balance Sheets.

[3] Dominion Energy’s Consolidated Balance Sheet at December 31, 2019 has been derived from the audited Consolidated Balance Sheet at that date.