Acquisitions and Dispositions (Schedule of Major Classes of Assets and Liabilities Held for Sale in Discontinued Operations) (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	[1]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Current assets held for sale	$ 969	$ 25
Current liabilities held for sale	217
Ullico Inc
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Current assets held for sale	58
Property, plant and equipment, net	481
Other deferred charges and other assets, including goodwill and intangible assets	305
Current liabilities held for sale	39
Long-term debt	2
Deferred credits and other liabilities	$ 174

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