Derivatives and Hedge Accounting Activities (Schedule of Offsetting Assets) (Detail) - USD ($) $ in Millions		Mar. 31, 2024	Dec. 31, 2023
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	$ 1,241	$ 1,207
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		430	250
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	15
Net Amounts		811	942
Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	275	297
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		48	27
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		227	270
Commodity Contract | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	229	289
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		51	26
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		178	263
Commodity Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	96	112
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		39	13
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		57	99
Commodity Contract | Exchange
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	114	118
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		65	33
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	15
Net Amounts		49	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]	895	800
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		311	191
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		584	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]	172	181
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		2	11
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		170	$ 170
Foreign currency exchange rate | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	3
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		3
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0
Net Amounts		0
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]	3
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		3
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0
Net Amounts		$ 0

[1] Excludes derivative assets of $203 million and $143 million at Dominion Energy and $4 million and $1 million at Virginia Power at March 31, 2024 and December 31, 2023, respectively, which are not subject to master netting or other similar arrangements.