Significant Accounting Policies (Reconciliation of Total Cash, Restricted Cash and Equivalents) (Detail) - USD ($) $ in Millions		Mar. 31, 2024	Dec. 31, 2023		Mar. 31, 2023	Dec. 31, 2022
Cash Cash Equivalents And Restricted Cash [Line Items]
Cash and cash equivalents	[1]	$ 306	$ 217		$ 1,792	$ 153
Cash and cash equivalents		265	184	[2]
Restricted cash and equivalents	[3],[4]	30	84		164	188
Restricted cash and equivalents		4	4		1	2
Cash, restricted cash and equivalents shown in the Consolidated Statements of Cash Flows		336	301		1,956	341
Virginia Electric and Power Company
Cash Cash Equivalents And Restricted Cash [Line Items]
Cash and cash equivalents		119	90	[5]	21	22
Restricted cash and equivalents	[4],[6]	6			1	2
Cash, restricted cash and equivalents shown in the Consolidated Statements of Cash Flows		$ 125	$ 90		$ 22	$ 24

[1] At March 31, 2024, March 31, 2023, December 31, 2023 and December 31, 2022, Dominion Energy had $41 million, $40 million, $33 million and $34 million, respectively, of cash and cash equivalents included in current assets held for sale.

[2] Dominion Energy’s Consolidated Balance Sheet at December 31, 2023 has been derived from the audited Consolidated Balance Sheet at that date.

[3] At March 31, 2024, March 31, 2023, December 31, 2023 and December 31, 2022, Dominion Energy had $4 million, $1 million, $4 million and $2 million, respectively, of restricted cash and equivalents included in current assets held for sale with the remaining balances presented within other current assets in Dominion Energy’s Consolidated Balance Sheets.

[4] Includes $6 million attributable to VIEs at March 31, 2024.

[5] Virginia Power’s Consolidated Balance Sheet at December 31, 2023 has been derived from the audited Consolidated Balance Sheet at that date.

[6] Restricted cash and equivalents balances are presented within other current assets in Virginia Power’s Consolidated Balance Sheets.