Related-Party Transactions (Narrative) (Detail) - USD ($)		1 Months Ended	12 Months Ended
		Jan. 31, 2023	Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021	Jul. 31, 2023	Nov. 30, 2022	Jun. 30, 2021
Related Party Transaction [Line Items]
Amounts due to Dominion, noncurrent			$ 1,434,000,000		$ 1,275,000,000
Revolving credit facility maximum borrowing capacity			6,000,000,000	[1]	6,000,000,000	[1]		$ 600,000,000
Payable to affiliates	[2]		1,732,000,000		1,695,000,000
Borrowing Interest Charges			80,000,000		15,000,000		$ 1,000,000
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]		1,125,000,000		1,040,000,000
Revolving credit facility maximum borrowing capacity	[4]		6,000,000,000		6,000,000,000
Payable to affiliates			908,000,000		826,000,000
Cost of Revenue, Related Party, Type [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		0
Commencing Period		20 months
Lease commencement term		2025-08
Virginia Electric and Power Company | Affiliated Entity
Related Party Transaction [Line Items]
Derivative assets			$ 1,000,000		$ 33,000,000
Derivative liabilities			79,000,000		31,000,000
Virginia Electric and Power Company | Affiliated Entity | Pension Benefits | Amounts Associated With Dominion Pension Plan
Related Party Transaction [Line Items]
Amounts due to Dominion, noncurrent			456,000,000		422,000,000
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			584,000,000		518,000,000
Virginia Electric and Power Company | Principal Owner | Short-Term Borrowing Arrangements
Related Party Transaction [Line Items]
Payable to affiliates			$ 500,000,000		$ 2,000,000,000
Weighted- average interest rate percentage			5.61%		4.68%
Virginia Electric and Power Company | Revolving Credit Facility
Related Party Transaction [Line Items]
Revolving credit facility maximum borrowing capacity									$ 3,000,000,000

[1] 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.

[2] See Note 9 for amounts attributable to related parties.

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

[4] The full amount of the facility is available to Virginia Power, less any amounts outstanding to co-borrowers Dominion Energy, Questar Gas 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, 2023, 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.