Related-Party Transactions (Narrative) (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Borrowing Interest Charges		$ 21,000,000		$ 45,000,000
Virginia Electric and Power Company
Related Party Transaction [Line Items]
Payable to affiliates		2,330,000,000		2,330,000,000		$ 2,024,000,000	[1]
Outstanding borrowings, net of repayments, under money pool for non-regulated subsidiaries		$ 0		$ 0		0
Stock Issued During Period Shares New Issues		0	0	0	0
Commencing Period	20 months
Lease commencement term	2025-08
Related party transaction costs	$ 240,000,000
Virginia Electric and Power Company | Pension Benefits | Amounts Associated With Dominion Pension Plan
Related Party Transaction [Line Items]
Amounts due to Dominion, noncurrent		$ 439,000,000		$ 439,000,000		422,000,000
Virginia Electric and Power Company | 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		550,000,000		550,000,000		518,000,000
Virginia Electric and Power Company | Affiliated Entity
Related Party Transaction [Line Items]
Derivative assets		1,000,000		1,000,000		33,000,000
Derivative liabilities		89,000,000		89,000,000		31,000,000
Virginia Electric and Power Company | Principal Owner | Short-Term Borrowing Arrangements
Related Party Transaction [Line Items]
Payable to affiliates		$ 2,300,000,000		$ 2,300,000,000		$ 2,000,000,000.0

[1] Virginia Power’s Consolidated Balance Sheet at December 31, 2022 has been derived from the audited Consolidated Balance Sheet at that date.