Derivatives and Hedge Accounting Activities (Schedule of Offsetting Liabilities) (Detail) - USD ($) $ in Millions		Mar. 31, 2024	Dec. 31, 2023
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	$ 819	$ 697
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		430	250
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	30
Net Amounts		389	417
Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	233	240
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		48	27
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	30
Net Amounts		185	183
Commodity Contract | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	163	266
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		46	26
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	30
Net Amounts		117	210
Commodity Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	100	153
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		34	13
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	30
Net Amounts		66	110
Commodity Contract | Exchange
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	65	33
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		65	33
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	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]	4	3
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		4	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]	108	39
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		3	5
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		105	34
Interest Rate Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	108	39
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		3	5
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		105	34
Foreign currency exchange rate | Over-the-counter
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	483	359
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		316	186
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		167	173
Foreign currency exchange rate | Over-the-counter | Virginia Electric and Power Company
Offsetting Liabilities [Line Items]
Gross Liabilities Presented in the Consolidated Balance Sheet	[1]	21	45
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		7	6
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral		0	0
Net Amounts		$ 14	$ 39

[1] Excludes derivative liabilities of $3 million at Dominion Energy at March 31, 2024 and $56 million and $76 million at Virginia Power at March 31, 2024 and December 31, 2023, respectively, 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.