Long-Term Debt (Total Long Term Debt) (Parenthetical) (Detail) - USD ($) $ in Millions		1 Months Ended
		Aug. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Jul. 31, 2016
Debt Instrument [Line Items]
Total principal	[1]		$ 37,694	$ 35,496
Sustainability Revolving Credit Agreement
Debt Instrument [Line Items]
Debt instrument, face amount			900
Sustainability Revolving Credit Agreement | June Twenty Twenty One
Debt Instrument [Line Items]
Debt, amount redeemed			250
Sustainability Revolving Credit Agreement | August Twenty Twenty One
Debt Instrument [Line Items]
Debt, amount redeemed			650
Junior Subordinated Debt
Debt Instrument [Line Items]
Interest Rate					5.25%
Debt instrument, face amount					$ 800
Term loans
Debt Instrument [Line Items]
Estimated mandatory prepayments due within one year				22
Virginia Electric and Power Company
Debt Instrument [Line Items]
Total principal			13,863	13,314
2.30% to 8.875%, due 2022 to 2051 | Virginia Electric and Power Company | Senior Notes
Debt Instrument [Line Items]
Total principal			$ 13,238	12,689
2.30% to 8.875%, due 2022 to 2051 | Minimum | Virginia Electric and Power Company | Senior Notes
Debt Instrument [Line Items]
Interest Rate			2.30%
2.30% to 8.875%, due 2022 to 2051 | Maximum | Virginia Electric and Power Company | Senior Notes
Debt Instrument [Line Items]
Interest Rate			8.875%
0.45% to 1.90%, due 2032 to 2041 | Virginia Electric and Power Company | Tax-Exempt Financings
Debt Instrument [Line Items]
Total principal	[2]		$ 625	625
0.45% to 1.90%, due 2032 to 2041 | Minimum | Virginia Electric and Power Company | Tax-Exempt Financings
Debt Instrument [Line Items]
Interest Rate			0.45%
0.45% to 1.90%, due 2032 to 2041 | Maximum | Virginia Electric and Power Company | Tax-Exempt Financings
Debt Instrument [Line Items]
Interest Rate			1.90%
1.45% to 7.0%, due 2021 to 2049 | Senior Notes
Debt Instrument [Line Items]
Total principal	[3]		$ 11,238	9,938
1.45% to 7.0%, due 2021 to 2049 | Minimum | Senior Notes
Debt Instrument [Line Items]
Interest Rate			1.45%
1.45% to 7.0%, due 2021 to 2049 | Maximum | Senior Notes
Debt Instrument [Line Items]
Interest Rate			7.00%
2.715% to 4.104%, Due 2021 and 2024 | Junior Subordinated Debt
Debt Instrument [Line Items]
Total principal			$ 700	1,950
2.715% to 4.104%, Due 2021 and 2024 | Minimum | Junior Subordinated Debt
Debt Instrument [Line Items]
Interest Rate			2.715%
2.715% to 4.104%, Due 2021 and 2024 | Maximum | Junior Subordinated Debt
Debt Instrument [Line Items]
Interest Rate			4.104%
8.4% due 2031 | Junior Subordinated Debt
Debt Instrument [Line Items]
Interest Rate			8.40%
Total principal			$ 10	10
5.25% and 5.75%, due 2054 and 2076 | Enhanced Junior Subordinated Notes
Debt Instrument [Line Items]
Total principal	[4]		$ 685	1,485
5.25% and 5.75%, due 2054 and 2076 | Minimum | Enhanced Junior Subordinated Notes
Debt Instrument [Line Items]
Interest Rate			5.25%
5.25% and 5.75%, due 2054 and 2076 | Maximum | Enhanced Junior Subordinated Notes
Debt Instrument [Line Items]
Interest Rate			5.75%
2.21% to 7.20%, due 2024 to 2051 | Minimum | Questar Gas Company
Debt Instrument [Line Items]
Interest Rate			2.21%
2.21% to 7.20%, due 2024 to 2051 | Maximum | Questar Gas Company
Debt Instrument [Line Items]
Interest Rate			7.20%
1.30% to 3.00%, due 2025 to 2050 | Minimum | East Ohio
Debt Instrument [Line Items]
Interest Rate			1.30%
1.30% to 3.00%, due 2025 to 2050 | Maximum | East Ohio
Debt Instrument [Line Items]
Interest Rate			3.00%
3.10% to 7.45%, due 2021 to 2051 | Minimum | PSNC
Debt Instrument [Line Items]
Interest Rate			3.10%
3.10% to 7.45%, due 2021 to 2051 | Maximum | PSNC
Debt Instrument [Line Items]
Interest Rate			7.45%
First mortgage bonds, 2.30% to 6.625%, due 2021 to 2065 | Minimum | DESC
Debt Instrument [Line Items]
Interest Rate			2.30%
First mortgage bonds, 2.30% to 6.625%, due 2021 to 2065 | Maximum | DESC
Debt Instrument [Line Items]
Interest Rate			6.625%
3.625% and 4.00%, due 2028 and 2033 | Tax-Exempt Financings
Debt Instrument [Line Items]
Total principal	[5]		$ 54	54
3.625% and 4.00%, due 2028 and 2033 | Minimum | Tax-Exempt Financings
Debt Instrument [Line Items]
Interest Rate			3.625%
3.625% and 4.00%, due 2028 and 2033 | Maximum | Tax-Exempt Financings
Debt Instrument [Line Items]
Interest Rate			4.00%
4.82%, due 2042
Debt Instrument [Line Items]
Interest Rate			4.82%
Total principal	[6]		$ 314	331
Tax-Exempt Financing, 1.7% due 2033
Debt Instrument [Line Items]
Interest Rate			1.70%
Tax-Exempt Financing, 1.7% due 2033 | Tax-Exempt Financings
Debt Instrument [Line Items]
Total principal			$ 27	$ 27
July2016 Hybrids | Junior Subordinated Debt
Debt Instrument [Line Items]
Debt instrument, face amount		$ 800
Debt instrument maturity year		2076
Industrial Revenue Bonds
Debt Instrument [Line Items]
Total principal			$ 68

[1] Excludes amounts classified as held for sale at December 31, 2020. See Note 3.

[2] These financings relate to certain pollution control equipment at Virginia Power’s generating facilities.

[3] Includes debt assumed by Dominion Energy from the merger of its former CNG subsidiary.

[4] In August 2021, Dominion Energy redeemed the remaining principal outstanding of $800 million of its July 2016 hybrids, which would have otherwise matured in 2076.

[5] Industrial revenue bonds totaling $68 million are secured by letters of credit that expire, subject to renewal, in the fourth quarter of 2022.

[6] Represents debt associated with Eagle Solar. The debt is nonrecourse to Dominion Energy and is secured by Eagle Solar’s interest in certain solar facilities.