Derivatives and Hedge Accounting Activities (Schedule of Offsetting Assets) (Detail) - USD ($) $ in Millions		Mar. 31, 2025	Dec. 31, 2024
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	$ 898	$ 1,157
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		277	301
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		621	856
Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	82	357
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		18	45
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		64	312
Commodity Contract | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	153	197
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		8	20
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		145	177
Commodity Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	32	95
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		7	14
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		25	81
Commodity Contract | Exchange
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	82	55
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		82	54
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		0	1
Commodity Contract | Exchange | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	1	2
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		1	1
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		0	1
Interest Rate Contract | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	654	875
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		178	197
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		476	678
Interest Rate Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	40	230
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		1	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		39	230
Foreign Currency Exchange Rate Contract | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	9	30
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		9	30
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		0	0
Foreign Currency Exchange Rate Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	9	30
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		9	30
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		$ 0	$ 0

[1] Excludes derivative assets of $166 million and $242 million at Dominion Energy and $30 million and $18 million at Virginia Power at March 31, 2025 and December 31, 2024, respectively, which are not subject to master netting or other similar arrangements.