Related-Party Transactions (Narrative) (Detail) - USD ($)		1 Months Ended	12 Months Ended
		Jan. 31, 2023	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022	Jul. 31, 2023	Nov. 30, 2022
Related Party Transaction [Line Items]
Amounts due to Dominion, noncurrent			$ 1,352,000,000		$ 1,434,000,000
Other deferred credits and other liabilities			644,000,000		610,000,000
Revolving credit facility maximum borrowing capacity			6,000,000,000	[1],[2]	6,000,000,000	[2]		$ 600,000,000
Borrowing Interest Charges			29,000,000		80,000,000		$ 15,000,000
Dividend paid			2,239,000,000		2,233,000,000		$ 2,209,000,000
Revolving Credit Facility
Related Party Transaction [Line Items]
Revolving credit facility maximum borrowing capacity			6,000,000,000
Virginia Electric and Power Company
Related Party Transaction [Line Items]
Amounts due to Dominion, noncurrent	[3]		1,224,000,000		1,125,000,000
Revolving credit facility maximum borrowing capacity	[5]		6,000,000,000	[4]	6,000,000,000
Cost of Revenue, Related Party [Extensible Enumeration]		Affiliated Entity
Related party transaction costs		$ 240,000,000
Outstanding borrowings, net of repayments, under money pool for non-regulated subsidiaries			$ 0		0
Issuance of stock (in shares)			0				0
Dividend declared			$ 407,000,000
Commencing Period		20 months
Lease commencement term		2025-08
Affiliated current borrowings			500,000,000		500,000,000
Virginia Electric and Power Company | Affiliated Entity
Related Party Transaction [Line Items]
Derivative assets			19,000,000		1,000,000
Derivative liabilities			17,000,000		79,000,000
Virginia Electric and Power Company | Affiliated Entity | Pension Benefits | Amounts Associated With Dominion Pension Plan
Related Party Transaction [Line Items]
Other deferred credits and other liabilities			505,000,000		456,000,000
Virginia Electric and Power Company | Affiliated Entity | Medical Coverage for Local retirees | Amounts Associated with the Dominion Retiree Health and Welfare Plan
Related Party Transaction [Line Items]
Amounts due from Dominion, noncurrent			$ 663,000,000		$ 584,000,000
Virginia Electric and Power Company | Principal Owner | Short-Term Borrowing Arrangements
Related Party Transaction [Line Items]
Weighted- average interest rate percentage			4.71%		5.61%
Affiliated current borrowings			$ 500,000,000		$ 500,000,000
Virginia Electric and Power Company | Revolving Credit Facility
Related Party Transaction [Line Items]
Revolving credit facility maximum borrowing capacity									$ 3,000,000,000
Credit facility, maturity date			Dec. 31, 2027

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

[2] 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.

[3] See Note 25 for amounts attributable to affiliates.

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

[5] The full amount of the facility is available to Virginia Power, less any amounts outstanding to co-borrowers Dominion Energy and DESC. The sub-limit for Virginia Power is set pursuant to the terms of the facility but can be changed at the option of the borrowers multiple times per year. At December 31, 2024, the sub-limit for Virginia Power was $1.75 billion. If Virginia Power has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. This credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028. The credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $2.0 billion (or the sub-limit, whichever is less) of letters of credit.