Derivatives and Hedge Accounting Activities (Schedule of Offsetting Liabilities) (Detail) - USD ($) $ in Millions		Dec. 31, 2024	Dec. 31, 2023
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	$ 505	$ 697
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		301	250
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		20	30
Net Amounts		184	417
Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	208	240
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		45	27
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	30
Net Amounts		163	183
Commodity Contract | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	42	266
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		20	26
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	30
Net Amounts		22	210
Commodity Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	15	153
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		14	13
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	30
Net Amounts		1	110
Commodity Contract | Exchange
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	74	33
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		54	33
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		20	0
Net Amounts		0	0
Commodity Contract | Exchange | Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	1	3
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		1	3
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		0	0
Interest Rate Contract | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	197	359
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		197	186
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		0	173
Interest Rate Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	0	45
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		0	6
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		0	39
Foreign Currency Exchange Rate Contract | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	192	39
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		30	5
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		162	34
Foreign Currency Exchange Rate Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	192	39
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		30	5
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		$ 162	$ 34

[1] Excludes derivative liabilities of $7 million at Dominion Energy at December 31, 2024, which are not subject to master netting or similar arrangements. Dominion Energy did not have any derivative liabilities at December 31, 2023 which were not subject to master netting or similar arrangements. Excludes derivative liabilities of $17 million and $76 million at Virginia Power at December 31, 2024 and 2023, respectively, which are not subject to master netting or similar arrangements.