Derivatives and Hedge Accounting Activities (Schedule of Offsetting Assets) (Detail) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	$ 1,207	$ 1,975
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		250	435
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		15	0
Net Amounts		942	1,540
Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	297	852
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		27	45
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		270	807
Commodity Contract | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	289	408
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		26	28
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		263	380
Commodity Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	112	238
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		13	7
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		99	231
Commodity Contract | Exchange
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	118	160
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		33	159
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		15	0
Net Amounts		70	1
Commodity Contract | Exchange | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	4	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		3	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		1	0
Interest Rate Contract | Over-the-counter
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	800	1,407
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		191	248
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		609	1,159
Interest Rate Contract | Over-the-counter | Virginia Electric and Power Company
Offsetting Assets [Line Items]
Gross Assets Presented in the Consolidated Balance Sheet	[1]	181	614
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments		11	38
Gross Amounts Not Offset in the Consolidated Balance Sheet, Cash Collateral Received		0	0
Net Amounts		$ 170	$ 576

[1] Excludes derivative assets of $143 million and $201 million at Dominion Energy, and $1 million and $30 million at Virginia Power, at December 31, 2023 and 2022, respectively, which are not subject to master netting or similar arrangements.