Investments (Equity and Fixed Income Securities, Insurance Contracts and Cash Equivalents in Decommissioning Trust Funds) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Fair Value		$ 2,082
Cash equivalents and other, Amortized Cost	[1]	84	$ 43
Cash equivalents and other, Total Unrealized Gains	[1]	0	0
Cash equivalents and other, Total Unrealized Losses	[1]	0	0
Cash equivalents and other, Allowance for Credit Losses	[1]	0	0
Cash equivalents and other, Fair Value	[1]	84	43
Amortized Cost, Total		3,699	3,632
Total Unrealized Gains		3,308	2,506
Total Unrealized Losses	[2]	(61)	(181)
Allowance for Credit Losses, Total		0	0
Fair Value, Total		6,946	5,957
Fair value of securities in an unrealized loss position		764	1,600
Net assets related to pending sale of securities		49	42
Virginia Electric and Power Company
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Fair Value		1,214
Cash equivalents and other, Amortized Cost	[1]	47	23
Cash equivalents and other, Total Unrealized Gains	[1]	0	0
Cash equivalents and other, Total Unrealized Losses	[1]	0	0
Cash equivalents and other, Fair Value	[1]	47	23
Amortized Cost, Total		2,033	2,012
Total Unrealized Gains		1,726	1,307
Total Unrealized Losses	[2]	(43)	(117)
Allowance for Credit Losses, Total		0	0
Fair Value, Total		3,716	3,202
Fair value of securities in an unrealized loss position		384	946
Net assets related to pending sale of securities		27	24
Corporate Debt Fixed Income Securities
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Amortized Cost, Total	[3]	508	640
Fixed income securities Total Unrealized Gains	[3]	10	1
Fixed income securities Total Unrealized Losses	[3]	(27)	(65)
Fixed income securities Allowance for Credit Losses	[3]	0	0
Fixed income securities Fair Value	[3]	491	576
Corporate Debt Fixed Income Securities | Virginia Electric and Power Company
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Amortized Cost, Total	[3]	292	406
Fixed income securities Total Unrealized Gains	[3]	3	1
Fixed income securities Total Unrealized Losses	[3]	(21)	(47)
Fixed income securities Allowance for Credit Losses	[3]	0	0
Fixed income securities Fair Value	[3]	274	360
Government Debt Fixed Income Securities
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Amortized Cost, Total	[3]	1,426	1,252
Fixed income securities Total Unrealized Gains	[3]	28	4
Fixed income securities Total Unrealized Losses	[3]	(24)	(70)
Fixed income securities Allowance for Credit Losses	[3]	0	0
Fixed income securities Fair Value	[3]	1,430	1,186
Government Debt Fixed Income Securities | Virginia Electric and Power Company
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Amortized Cost, Total	[3]	811	664
Fixed income securities Total Unrealized Gains	[3]	17	2
Fixed income securities Total Unrealized Losses	[3]	(12)	(35)
Fixed income securities Allowance for Credit Losses	[3]	0	0
Fixed income securities Fair Value	[3]	816	631
Insurance Contracts
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Amortized Cost, Total		244	221
Fixed income securities Total Unrealized Gains		0	0
Fixed income securities Total Unrealized Losses		0	0
Fixed income securities Fair Value		244	221
U.S.
Debt Securities, Available-for-Sale [Line Items]
Equity securities Amortized Cost	[4]	1,276	1,378
Equity securities Total Unrealized Gains	[4]	3,270	2,501
Equity securities Total Unrealized Losses	[4]	(10)	(46)
Equity securities Fair Value	[4]	4,536	3,833
U.S. | Virginia Electric and Power Company
Debt Securities, Available-for-Sale [Line Items]
Equity securities Amortized Cost	[4]	759	858
Equity securities Total Unrealized Gains	[4]	1,706	1,304
Equity securities Total Unrealized Losses	[4]	(10)	(35)
Equity securities Fair Value	[4]	2,455	2,127
Common/collective trust funds | Fixed Income
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Amortized Cost, Total	[3]	161	98
Fixed income securities Total Unrealized Gains	[3]	0	0
Fixed income securities Total Unrealized Losses	[3]	0	0
Fixed income securities Allowance for Credit Losses	[3]	0	0
Fixed income securities Fair Value	[3]	161	98
Common/collective trust funds | Fixed Income | Virginia Electric and Power Company
Debt Securities, Available-for-Sale [Line Items]
Fixed income securities Amortized Cost, Total	[3]	124	61
Fixed income securities Total Unrealized Gains	[3]	0	0
Fixed income securities Total Unrealized Losses	[3]	0	0
Fixed income securities Allowance for Credit Losses	[3]	0	0
Fixed income securities Fair Value	[3]	$ 124	$ 61

[1] Dominion Energy includes pending sales of securities of $49 million and $42 million at December 31, 2023 and 2022, respectively. Virginia Power includes pending sales of securities of $27 million and $24 million at December 31, 2023 and 2022, respectively.

[2] Dominion Energy’s fair value of securities in an unrealized loss position was $764 million and $1.6 billion at December 31, 2023 and 2022, respectively. Virginia Power’s fair value of securities in an unrealized loss position was $384 million and $946 million at December 31, 2023 and 2022, respectively.

[3] Unrealized gains and losses on fixed income securities are included in AOCI and the nuclear decommissioning trust regulatory liability as discussed in Note 2. Changes in allowance for credit losses are included in other income

[4] Unrealized gains and losses on equity securities are included in other income and the nuclear decommissioning trust regulatory liability as discussed in Note 2.