Derivatives and Hedge Accounting Activities (Schedule of Offsetting Assets) (Detail) - USD ($) $ in Millions		Jun. 30, 2024	Dec. 31, 2023
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	$ 1,352	$ 1,207
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		511	250
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	15
Net Amounts		841	942
Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	373	297
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		25	27
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		348	270
Commodity Contract | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	253	289
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		41	26
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		212	263
Commodity Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	160	112
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		19	13
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		141	99
Commodity Contract | Exchange
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	100	118
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		95	33
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	15
Net Amounts		5	70
Commodity Contract | Exchange | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	4	4
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		4	3
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]	1	800
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		1	191
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		0	609
Interest Rate Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	1	181
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		1	11
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		0	$ 170
Foreign currency exchange rate | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	998
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		374
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0
Net Amounts		624
Foreign currency exchange rate | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	208
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		1
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0
Net Amounts		$ 207

[1] Excludes derivative assets of $232 million and $143 million at Dominion Energy and $16 million and $1 million at Virginia Power at June 30, 2024 and December 31, 2023, respectively, which are not subject to master netting or other similar arrangements.