Investments (Equity and Fixed Income Securities, Insurance Contracts and Cash Equivalents in Decommissioning Trust Funds) (Detail) - USD ($) $ in Millions		6 Months Ended	12 Months Ended
		Jun. 30, 2022	Dec. 31, 2021
Investment Holdings [Line Items]
Fixed income securities Fair Value		$ 1,884
Amortized Cost, Total		3,614	$ 4,235
Total Unrealized Gains		2,412	3,815
Total Unrealized Losses	[1]	(154)	(100)
Allowance for Credit Losses, Total		0	0
Fair Value, Total		5,872	7,950	[2]
Net assets related to pending sales of securities		8
Net assets related to pending purchases of securities			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		1,054
Amortized Cost, Total		1,994	1,997
Total Unrealized Gains		1,268	1,753
Total Unrealized Losses	[3]	(102)	(16)
Allowance for Credit Losses, Total		0	0
Fair Value, Total		3,160	3,734	[4]
Net assets related to pending sales of securities		4	5
Fair value of securities in an unrealized loss position		897	425
U.S.
Investment Holdings [Line Items]
Equity securities Amortized Cost	[5]	1,372	1,567
Equity securities Total Unrealized Gains	[5]	2,406	3,734
Equity securities Total Unrealized Losses	[5]	(24)	(13)
Equity securities Fair Value	[5]	3,754	5,288
U.S. | Virginia Electric and Power Company
Investment Holdings [Line Items]
Equity securities Amortized Cost	[5]	858	841
Equity securities Total Unrealized Gains	[5]	1,265	1,720
Equity securities Total Unrealized Losses	[5]	(20)	(11)
Equity securities Fair Value	[5]	2,103	2,550
Common/collective trust funds | Fixed Income
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	60	168
Fixed income securities Total Unrealized Gains	[6]		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]	60	172
Common/collective trust funds | Fixed Income | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	47	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]	47	53
Corporate debt instruments | Fixed Income
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	687	854
Fixed income securities Total Unrealized Gains	[6]	1	32
Fixed income securities Total Unrealized Losses	[6]	(70)	(5)
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	618	881
Corporate debt instruments | Fixed Income | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	474	517
Fixed income securities Total Unrealized Gains	[6]	1	17
Fixed income securities Total Unrealized Losses	[6]	(56)	(3)
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	419	531
Government Securities | Fixed Income
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	1,261	1,382
Fixed income securities Total Unrealized Gains	[6]	5	43
Fixed income securities Total Unrealized Losses	[6]	(60)	(7)
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	1,206	1,418
Government Securities | Fixed Income | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[6]	612	584
Fixed income securities Total Unrealized Gains	[6]	2	16
Fixed income securities Total Unrealized Losses	[6]	(26)	(2)
Fixed income securities Allowance for Credit Losses	[6]	0	0
Fixed income securities Fair Value	[6]	588	598
Insurance Contracts
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total		224	255
Fixed income securities Total Unrealized Gains		0	0
Fixed income securities Total Unrealized Losses		0	0
Fixed income securities Fair Value		224	255
Cash equivalents and other
Investment Holdings [Line Items]
Cash equivalents and other, Amortized Cost	[7]	10	9
Cash equivalents and other, Total Unrealized Gains	[7]		2
Cash equivalents and other, Total Unrealized Losses	[7]		(75)
Cash equivalents and other, Allowance for Credit Losses	[7]	0	0
Cash equivalents and other, Fair Value	[7]	10	(64)
Cash equivalents and other | Virginia Electric and Power Company
Investment Holdings [Line Items]
Cash equivalents and other, Amortized Cost	[8]	3	2
Cash equivalents and other, Allowance for Credit Losses	[8]	0	0
Cash equivalents and other, Fair Value	[8]	$ 3	$ 2

[1] The fair value of securities in an unrealized loss position was $1.6 billion and $883 million at June 30, 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 $897 million and $425 million at June 30, 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 sales of securities of $8 million at June 30, 2022, and pending purchases of securities of $35 million at December 31, 2021.

[8] Includes pending sales of securities of $4 million and $5 million at June 30, 2022 and December 31, 2021, respectively.