Investments (Equity and Fixed Income Securities, Insurance Contracts and Cash Equivalents in Decommissioning Trust Funds) (Detail) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2022	Dec. 31, 2021
Investment Holdings [Line Items]
Fixed income securities Fair Value		$ 2,317
Amortized Cost, Total		4,238	$ 4,235
Total Unrealized Gains		3,529	3,815
Total Unrealized Losses	[1]	(153)	(100)
Allowance for Credit Losses, Total		0	0
Fair Value, Total		7,614	7,950	[2]
Net assets related to pending purchases of securities		1	35
Fair value of securities in an unrealized loss position		1,600	883
Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Fair Value		1,117
Amortized Cost, Total		2,011	1,997
Total Unrealized Gains		1,627	1,753
Total Unrealized Losses	[3]	(61)	(16)
Allowance for Credit Losses, Total		0	0
Fair Value, Total		3,577	3,734	[4]
Net assets related to pending purchases of securities		2	5
Fair value of securities in an unrealized loss position		863	425
U.S.
Investment Holdings [Line Items]
Equity securities Amortized Cost	[5]	1,586	1,567
Equity securities Total Unrealized Gains	[5]	3,498	3,734
Equity securities Total Unrealized Losses	[5]	(13)	(13)
Equity securities Fair Value	[5]	5,071	5,288
U.S. | Virginia Electric and Power Company
Investment Holdings [Line Items]
Equity securities Amortized Cost	[5]	857	841
Equity securities Total Unrealized Gains	[5]	1,619	1,720
Equity securities Total Unrealized Losses	[5]	(12)	(11)
Equity securities Fair Value	[5]	2,464	2,550
Common/collective trust funds | Fixed Income
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	150	168
Fixed income securities Total Unrealized Gains	[6]	3	4
Fixed income securities Total Unrealized Losses	[6]	0	0
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	153	172
Common/collective trust funds | Fixed Income | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	55	53
Fixed income securities Total Unrealized Gains	[6]	0	0
Fixed income securities Total Unrealized Losses	[6]	0	0
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	55	53
Corporate debt instruments | Fixed Income
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	876	854
Fixed income securities Total Unrealized Gains	[6]	9	32
Fixed income securities Total Unrealized Losses	[6]	(45)	(5)
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	840	881
Corporate debt instruments | Fixed Income | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	535	517
Fixed income securities Total Unrealized Gains	[6]	4	17
Fixed income securities Total Unrealized Losses	[6]	(30)	(3)
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	509	531
Government Securities | Fixed Income
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	1,358	1,382
Fixed income securities Total Unrealized Gains	[6]	14	43
Fixed income securities Total Unrealized Losses	[6]	(48)	(7)
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	1,324	1,418
Government Securities | Fixed Income | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	568	584
Fixed income securities Total Unrealized Gains	[6]	4	16
Fixed income securities Total Unrealized Losses	[6]	(19)	(2)
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	553	598
Insurance Contracts
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total		242	255
Fixed income securities Total Unrealized Gains		0	0
Fixed income securities Total Unrealized Losses		0	0
Fixed income securities Fair Value		242	255
Cash equivalents and other
Investment Holdings [Line Items]
Cash equivalents and other, Amortized Cost	[7]	26	9
Cash equivalents and other, Total Unrealized Gains	[7]	5	2
Cash equivalents and other, Total Unrealized Losses	[7]	(47)	(75)
Cash equivalents and other, Allowance for Credit Losses	[7]	0	0
Cash equivalents and other, Fair Value	[7]	(16)	(64)
Cash equivalents and other | Virginia Electric and Power Company
Investment Holdings [Line Items]
Cash equivalents and other, Amortized Cost	[8]	(4)	2
Cash equivalents and other, Allowance for Credit Losses	[8]	0	0
Cash equivalents and other, Fair Value	[8]	$ (4)	$ 2

[1] The fair value of securities in an unrealized loss position was $1.6 billion and $883 million at March 31, 2022 and December 31, 2021, respectively.

[2] Dominion Energy’s Consolidated Balance Sheet at December 31, 2021 has been derived from the audited Consolidated Balance Sheet at that date.

[3] The fair value of securities in an unrealized loss position was $863 million and $425 million at March 31, 2022 and December 31, 2021, respectively.

[4] Virginia Power’s Consolidated Balance Sheet at December 31, 2021 has been derived from the audited Consolidated Balance Sheet at that date.

[5] Unrealized gains and losses on equity securities are included in other income and the nuclear decommissioning trust regulatory liability.

[6] Unrealized gains and losses on fixed income securities are included in AOCI and the nuclear decommissioning trust regulatory liability. Changes in allowance for credit losses are included in other income.

[7] Includes pending purchases of securities of $1 million and $35 million at March 31, 2022 and December 31, 2021, respectively.

[8] Includes pending purchases of securities of $2 million at March 31, 2022, and pending sales of securities of $5 million at December 31, 2021.