Investments (Narrative) (Detail 2) - USD ($)	1 Months Ended		3 Months Ended		12 Months Ended
	Jul. 31, 2023	Feb. 28, 2022	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022		Feb. 29, 2024	Sep. 30, 2023	Sep. 30, 2014
Schedule of Equity Method Investments [Line Items]
Earnings (losses) from equity method investees					$ 3,000,000	[1]	$ (26,000,000)	[2]	$ 21,000,000	[3]
Distributions received from investment					140,000,000		245,000,000		355,000,000
Income tax expense (benefit) from discontinued operations					31,000,000		1,300,000,000		207,000,000
Contributions to equity method affiliates					20,000,000		104,000,000		43,000,000
Current liabilities					0		8,885,000,000
Facility Limit	$ 600,000,000				6,000,000,000	[4],[5]	6,000,000,000	[5]
Income tax expense					308,000,000	[6]	568,000,000	[7]	59,000,000	[8]
Impairment of certain property, plant and equipment					(600,000,000)		(307,000,000)		$ (1,401,000,000)
Investment company received distribution amount											$ 126,000,000
364 Term loan facility
Schedule of Equity Method Investments [Line Items]
Credit facility, outstanding amount	2,200,000,000
364 Term Loan Facility One
Schedule of Equity Method Investments [Line Items]
Credit facility, outstanding amount	750,000,000
Revolving Credit Facility
Schedule of Equity Method Investments [Line Items]
Facility Limit					6,000,000,000
Wrangler Retail Gas Holdings LLC | Gas Supply, Inc.
Schedule of Equity Method Investments [Line Items]
Ownership interest percentage of limited partner interests									15.00%
Cash consideration from sale of noncontrolling interest									$ 85,000,000
Amount of gain from sale									11,000,000
Amount of gain from sale, after tax									8,000,000
Dominion Energy Virginia
Schedule of Equity Method Investments [Line Items]
Cash consideration from sale of noncontrolling interest		$ 120,000,000							215,000,000
Limited partnership interest sale transaction, proceeds received		$ 60,000,000	$ 108,000,000						$ 108,000,000
Percentage ownership in total units		50.00%	50.00%						50.00%
Initial fair value		$ 60,000,000	$ 107,000,000						$ 107,000,000
Amount of gain from sale			133,000,000	$ 23,000,000
Amount of gain from sale, after tax			$ 99,000,000	$ 16,000,000
Agreement entered date		2022-02
Cove Point
Schedule of Equity Method Investments [Line Items]
Distributions received from investment							227,000,000		344,000,000
Income tax expense (benefit) from discontinued operations							31,000,000		92,000,000
Discontinued operations, interest income									(160,000,000)
Discontinued operations, interest expense							120,000,000
Cove Point | Discontinued Operations
Schedule of Equity Method Investments [Line Items]
Earnings (losses) from equity method investees							218,000,000		277,000,000
Cove Point | Cove Point | GT&S Transaction
Schedule of Equity Method Investments [Line Items]
Percentage of noncontrolling limited partnership interest retained												50.00%
Cove Point | BHE | GT&S Transaction
Schedule of Equity Method Investments [Line Items]
Cash consideration from sale of noncontrolling interest	$ 3,300,000,000
Percentage of noncontrolling limited partnership interest retained	50.00%
Amount of gain from sale	$ 626,000,000
Amount of gain from sale, after tax	348,000,000
Proceeds from settlement of related interest rate derivatives, fair value	$ 199,000,000
Cove Point | East Ohio, PSNC and Questar Gas | GT&S Transaction
Schedule of Equity Method Investments [Line Items]
Percentage of noncontrolling limited partnership interest retained												50.00%
Atlantic Coast Pipeline
Schedule of Equity Method Investments [Line Items]
Earnings (losses) from equity method investees					(13,000,000)		15,000,000		(7,000,000)
Contributions to equity method affiliates					12,000,000		95,000,000		3,000,000
Equity in earnings (losses) on investments after tax					(10,000,000)		11,000,000		$ (5,000,000)
Atlantic Coast Pipeline | Other Current Liabilities
Schedule of Equity Method Investments [Line Items]
Current liabilities					$ 7,000,000		4,000,000
Atlantic Coast Pipeline | Dominion Energy Gas Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage acquired													5.00%
Percentage ownership in total units													53.00%
Align RNG, LLC
Schedule of Equity Method Investments [Line Items]
Percentage of noncontrolling limited partnership interest retained					50.00%
Impairment of certain property, plant and equipment							(35,000,000)
Asset impairment charges after tax							$ 26,000,000

[1] Items designated are other segment items for each reportable segment.

[2] Items designated are other segment items for each reportable segment.

[3] Items designated are other segment items for each reportable segment.

[4] In May 2024, the joint revolving credit facility was amended to remove Questar Gas as a co-borrower.

[5] This credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028, and can be used by the borrowers under the credit facility to support bank borrowings and the issuance of commercial paper, as well as to support up to a combined $2.0 billion of letters of credit.

[6] The significant expense categories and amounts in the segment information presented above align with the segment-level information that is regularly provided to Dominion Energy’s CODM.

[7] The significant expense categories and amounts in the segment information presented above align with the segment-level information that is regularly provided to Dominion Energy’s CODM.

[8] The significant expense categories and amounts in the segment information presented above align with the segment-level information that is regularly provided to Dominion Energy’s CODM.