Investments (Narrative) (Detail) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023		Feb. 29, 2024
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investees			$ 2
Net earnings (losses) from discontinued operations including noncontrolling interest	[1]	$ (114)	(281)
Distributions received from investment		131	85
Equity method affiliates includes cash and accrued amounts of contributions		3	10
Current liabilities		4,386		$ 8,885	[2]
Contributions to equity method affiliates		7	10
Income tax expense (benefit) from discontinued operations		51	56
Investment company received distribution amount						$ 126
Discontinued operations
Schedule of Equity Method Investments [Line Items]
Net earnings (losses) from discontinued operations including noncontrolling interest		(10)	76
Atlantic Coast Pipeline
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investees		(11)	(1)
Atlantic Coast Pipeline | Other Current Liabilities
Schedule of Equity Method Investments [Line Items]
Current liabilities		14		4
Cove Point
Schedule of Equity Method Investments [Line Items]
Distributions received from investment			83
Discontinued operations, interest expense			62
Income tax expense (benefit) from discontinued operations			3
Cove Point | Discontinued operations
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investees			$ 76
Finite Lived Equity Method Investment Basis Difference
Schedule of Equity Method Investments [Line Items]
Carrying amount of investment that exceeded share of underlying equity		13		18
Equity method investment goodwill		9		9
Capitalized interest		(2)		(3)
Trading Securities
Schedule of Equity Method Investments [Line Items]
Rabbi trust securities		141		$ 119
Maximum
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investees		$ 1

[1] Includes income tax expense of $51 million and $56 million for the three months ended March 31, 2024 and 2023, respectively.

[2] Dominion Energy’s Consolidated Balance Sheet at December 31, 2023 has been derived from the audited Consolidated Balance Sheet at that date.