Investments (Equity and Fixed Income Securities, Insurance Contracts and Cash Equivalents in Decommissioning Trust Funds) (Detail) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2022	Dec. 31, 2021
Investment Holdings [Line Items]
Fixed income securities Fair Value		$ 1,816
Amortized Cost, Total		3,604	$ 4,235
Total Unrealized Gains		2,210	3,815
Total Unrealized Losses	[1]	(224)	(100)
Allowance for Credit Losses, Total		0	0
Fair Value, Total		5,590	7,950	[2]
Net assets related to pending sales of securities		13
Net assets related to pending purchases of securities			35
Fair value of securities in an unrealized loss position		1,900	883
Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Fair Value		1,023
Amortized Cost, Total		1,995	1,997
Total Unrealized Gains		1,151	1,753
Total Unrealized Losses	[3]	(142)	(16)
Allowance for Credit Losses, Total		0	0
Fair Value, Total		3,004	3,734	[4]
Net assets related to pending sales of securities		6	5
Fair value of securities in an unrealized loss position		1,100	425
Corporate Debt Fixed Income Securities
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[5]	649	854
Fixed income securities Total Unrealized Gains	[5]	0	32
Fixed income securities Total Unrealized Losses	[5]	(86)	(5)
Fixed income securities Allowance for Credit Losses	[5]	0	0
Fixed income securities Fair Value	[5]	563	881
Corporate Debt Fixed Income Securities | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[5]	434	517
Fixed income securities Total Unrealized Gains	[5]	0	17
Fixed income securities Total Unrealized Losses	[5]	(62)	(3)
Fixed income securities Allowance for Credit Losses	[5]	0	0
Fixed income securities Fair Value	[5]	372	531
Government Debt Fixed Income Securities
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[5]	1,291	1,382
Fixed income securities Total Unrealized Gains	[5]	1	43
Fixed income securities Total Unrealized Losses	[5]	(101)	(7)
Fixed income securities Allowance for Credit Losses	[5]	0	0
Fixed income securities Fair Value	[5]	1,191	1,418
Government Debt Fixed Income Securities | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[5]	654	584
Fixed income securities Total Unrealized Gains	[5]	0	16
Fixed income securities Total Unrealized Losses	[5]	(48)	(2)
Fixed income securities Allowance for Credit Losses	[5]	0	0
Fixed income securities Fair Value	[5]	606	598
Insurance Contracts
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total		214	255
Fixed income securities Total Unrealized Gains		0	0
Fixed income securities Total Unrealized Losses		0	0
Fixed income securities Fair Value		214	255
U.S.
Investment Holdings [Line Items]
Equity securities Amortized Cost	[6]	1,375	1,567
Equity securities Total Unrealized Gains	[6]	2,209	3,734
Equity securities Total Unrealized Losses	[6]	(37)	(13)
Equity securities Fair Value	[6]	3,547	5,288
U.S. | Virginia Electric and Power Company
Investment Holdings [Line Items]
Equity securities Amortized Cost	[6]	856	841
Equity securities Total Unrealized Gains	[6]	1,151	1,720
Equity securities Total Unrealized Losses	[6]	(32)	(11)
Equity securities Fair Value	[6]	1,975	2,550
Common/collective trust funds | Fixed Income
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[5]	62	168
Fixed income securities Total Unrealized Gains	[5]	0	4
Fixed income securities Total Unrealized Losses	[5]	0	0
Fixed income securities Allowance for Credit Losses	[5]	0	0
Fixed income securities Fair Value	[5]	62	172
Common/collective trust funds | Fixed Income | Virginia Electric and Power Company
Investment Holdings [Line Items]
Fixed income securities Amortized Cost, Total	[5]	45	53
Fixed income securities Total Unrealized Gains	[5]	0	0
Fixed income securities Total Unrealized Losses	[5]	0	0
Fixed income securities Allowance for Credit Losses	[5]	0	0
Fixed income securities Fair Value	[5]	45	53
Cash equivalents and other
Investment Holdings [Line Items]
Cash equivalents and other, Amortized Cost	[7]	13	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]	13	(64)
Cash equivalents and other | Virginia Electric and Power Company
Investment Holdings [Line Items]
Cash equivalents and other, Amortized Cost	[8]	6	2
Cash equivalents and other, Allowance for Credit Losses	[8]	0	0
Cash equivalents and other, Fair Value	[8]	$ 6	$ 2

[1] The fair value of securities in an unrealized loss position was $1.9 billion and $883 million at September 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 $1.1 billion and $425 million at September 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 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.

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

[7] Includes pending sales of securities of $13 million at September 30, 2022, and pending purchases of securities of $35 million at December 31, 2021.

[8] Includes pending sales of securities of $6 million and $5 million at September 30, 2022 and December 31, 2021, respectively.