Significant Financing Transactions (Narrative) (Detail) - USD ($)				1 Months Ended									3 Months Ended			9 Months Ended
		Sep. 01, 2022	May 05, 2022	Oct. 31, 2022	Aug. 31, 2022	Jun. 30, 2022	May 31, 2022	Apr. 30, 2022	Jan. 31, 2022	Aug. 31, 2021	Jul. 31, 2021	Jun. 30, 2020	Sep. 30, 2022	Aug. 31, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021		Nov. 30, 2020	Jul. 31, 2020
Debt Instrument [Line Items]
Facility Limit	[1]												$ 6,000,000,000			$ 6,000,000,000
Short-term debt													2,943,000,000			2,943,000,000		$ 2,314,000,000	[2]
Debt repurchased value					$ 154,000,000								$ 149,000,000	$ 154,000,000		$ 149,000,000
Preferred stock shares authorized													20,000,000			20,000,000
Stock purchase contract liability																		44,000,000
Corporate units stock purchase contract liability payments																$ 44,000,000	$ 64,000,000
Issuance of common stock																1,744,000,000	144,000,000
Issuance of stock													$ 44,000,000		$ 195,000,000	$ 1,847,000,000	$ 292,000,000
Common Stock
Debt Instrument [Line Items]
Stock repurchased, shares																0
Issuance of stock (in shares)						400,000	900,000			600,000	1,400,000		1,000,000		3,000,000	23,000,000	4,000,000
Issuance of stock						$ 30,000,000	$ 72,000,000			$ 45,000,000	$ 104,000,000		$ 44,000,000		$ 195,000,000	$ 1,847,000,000	$ 292,000,000
Stock repurchase program, authorized amount																				$ 1,000,000,000.0	$ 3,000,000,000.0
2019 Series A Corporate Units
Debt Instrument [Line Items]
Short-term deposit							2,000,000,000.0
2019 Series A Corporate Units | Common Stock
Debt Instrument [Line Items]
Issuance of stock (in shares)						19,400,000
Issuance of stock						$ 1,600,000,000
2019 Series A Corporate Units | Maximum
Debt Instrument [Line Items]
Short-term deposit							2,000,000,000.0
2019 Series A Corporate Units | Minimum
Debt Instrument [Line Items]
Short-term deposit							$ 1,600,000,000
Series A Preferred Stock
Debt Instrument [Line Items]
Debt repurchased value													1,600,000,000			1,600,000,000
Recorded dividend															$ 7,000,000	$ 12,000,000	$ 21,000,000
Recorded dividends per share															$ 4.375	$ 7.292	$ 13.125
Interest expense													5,000,000			$ 7,000,000
Series A Preferred Stock | 2019 Series A Corporate Units
Debt Instrument [Line Items]
Stock repurchased, shares							1,600,000
Preferred stock dividend rate percentage							1.75%							1.75%
Preferred stock dividend rate increase percentage		6.75%
Series B Preferred Stock
Debt Instrument [Line Items]
Recorded dividend													$ 9,000,000		$ 9,000,000	$ 27,000,000	$ 27,000,000
Recorded dividends per share													$ 11.625		$ 11.625	$ 34.875	$ 34.875
Series C Preferred Stock
Debt Instrument [Line Items]
Recorded dividend													$ 11,000,000			$ 33,000,000
Recorded dividends per share													$ 10.875			$ 32.625
Interest Rate Swap
Debt Instrument [Line Items]
Derivative notional value												$ 2,000,000,000.0
Derivative maturity month and year												2024-12
Interest And Related Charges
Debt Instrument [Line Items]
Gain on early redemption of senior notes													$ 17,000,000			$ 17,000,000
Gain on early redemption of senior notes, after-tax													13,000,000			13,000,000
Subsequent Event
Debt Instrument [Line Items]
Debt repurchased value				$ 61,000,000
Various Programs
Debt Instrument [Line Items]
Issuance of common stock																$ 134,000,000	$ 292,000,000
Issuance of stock (in shares)																2,000,000	4,000,000
Floating Rate Demand Notes
Debt Instrument [Line Items]
Short-term debt													343,000,000			$ 343,000,000		431,000,000
Floating Rate Demand Notes | Shelf Registration for Sale of Demand Notes
Debt Instrument [Line Items]
Facility Limit																		3,000,000,000.0
DESC
Debt Instrument [Line Items]
Facility Limit													500,000,000			500,000,000
Questar Gas Company
Debt Instrument [Line Items]
Facility Limit													250,000,000			250,000,000
Questar Gas Company | Senior Notes Due in 2032 | Private Placement
Debt Instrument [Line Items]
Total Long-term Debt					$ 125,000,000									$ 125,000,000
Interest rate percentage					4.39%									4.39%
Debt maturity year					2032
Questar Gas Company | Senior Notes Due in 2052 | Private Placement
Debt Instrument [Line Items]
Total Long-term Debt					$ 125,000,000									$ 125,000,000
Interest rate percentage					4.70%									4.70%
Debt maturity year					2052
Virginia Electric and Power Company
Debt Instrument [Line Items]
Facility Limit	[3]												6,000,000,000			6,000,000,000
Short-term debt													$ 1,009,000,000			$ 1,009,000,000		$ 745,000,000	[4]
Interest rate percentage								1.65%
Aggregate outstanding principal								$ 138,000,000
Debt, maturity month and year								2024-05
Issuance of stock (in shares)													0		0	0	0
Virginia Electric and Power Company | Senior Notes Due in 2032
Debt Instrument [Line Items]
Total Long-term Debt									$ 600,000,000
Interest rate percentage									2.40%
Debt maturity year									2032
Virginia Electric and Power Company | Senior Notes Due in 2051
Debt Instrument [Line Items]
Total Long-term Debt									$ 400,000,000
Interest rate percentage									2.95%
Debt maturity year									2051
Virginia Electric and Power Company | Senior Notes Due in 2027
Debt Instrument [Line Items]
Total Long-term Debt							$ 600,000,000
Interest rate percentage							3.75%
Debt maturity year							2027
Virginia Electric and Power Company | Senior Notes Due in 2052
Debt Instrument [Line Items]
Total Long-term Debt							$ 600,000,000
Interest rate percentage							4.625%
Debt maturity year							2052
Dominion Energy
Debt Instrument [Line Items]
Preferred stock shares issued													1,800,000			1,800,000		3,400,000
Preferred stock shares outstanding													1,800,000			1,800,000		3,400,000
Dominion Energy | Series A Preferred Stock
Debt Instrument [Line Items]
Preferred stock shares issued																		1,600,000
Preferred stock shares outstanding																		1,600,000
Dominion Energy | Series B Preferred Stock
Debt Instrument [Line Items]
Preferred stock shares issued													800,000			800,000		800,000
Preferred stock shares outstanding													800,000			800,000		800,000
Dominion Energy | Series C Preferred Stock
Debt Instrument [Line Items]
Preferred stock shares issued													1,000,000.0			1,000,000.0		1,000,000.0
Preferred stock shares outstanding													1,000,000.0			1,000,000.0		1,000,000.0
Dominion Energy | Senior Notes Due in 2032
Debt Instrument [Line Items]
Total Long-term Debt					$ 400,000,000									$ 400,000,000
Interest rate percentage					4.35%									4.35%
Debt maturity year					2032
Dominion Energy | Senior Notes Due in 2052
Debt Instrument [Line Items]
Total Long-term Debt					$ 600,000,000									$ 600,000,000
Interest rate percentage					4.85%									4.85%
Debt maturity year					2052
Dominion Energy | Series 2003 due 2033 | Subsequent Event
Debt Instrument [Line Items]
Aggregate outstanding principal				$ 27,000,000
Debt instrument re-evaluation date				Oct. 31, 2024
Dominion Energy | Series 2003 due 2033 | Subsequent Event | Coupon Rate
Debt Instrument [Line Items]
Interest rate percentage				3.80%
East Ohio | Senior Notes Due in 2032 | Private Placement | Subsequent Event
Debt Instrument [Line Items]
Total Long-term Debt				$ 250,000,000
Interest rate percentage				6.19%
Debt maturity year				2032
East Ohio | Senior Notes Due in 2052 | Private Placement | Subsequent Event
Debt Instrument [Line Items]
Total Long-term Debt				$ 250,000,000
Interest rate percentage				6.38%
Debt maturity year				2052
Joint Revolving Credit Facility
Debt Instrument [Line Items]
Facility Limit													$ 6,000,000,000.0			$ 6,000,000,000.0
Letter of Credit
Debt Instrument [Line Items]
Facility Limit													2,000,000,000.0			2,000,000,000.0
Letter of Credit | Credit Facility, Maturing in June 2022
Debt Instrument [Line Items]
Facility Limit						30,000,000
Credit facility, outstanding amount													20,000,000			$ 20,000,000		$ 29,000,000
Line of credit facility, maturity date																Jun. 30, 2022
Line of credit facility, extended maturity date								Jun. 30, 2025
Letter of Credit | Amended and Restated Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maturity date							Jun. 30, 2024
Letter of Credit | Virginia Electric and Power Company
Debt Instrument [Line Items]
Facility Limit													$ 2,000,000,000.0			$ 2,000,000,000.0
Sustainability Revolving Credit Facility | Dominion Energy
Debt Instrument [Line Items]
Facility Limit			$ 900,000,000
Debt maturity year			2024
Sustainability Revolving Credit Facility | Dominion Energy | Environmental Sustainability And Social Investment Initiatives
Debt Instrument [Line Items]
Proceeds from borrowings			$ 450,000,000
Sustainability Revolving Credit Facility | Dominion Energy | General Corporate Purposes
Debt Instrument [Line Items]
Proceeds from borrowings			$ 450,000,000
Repayments of borrowings						$ 450,000,000

[1] This credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028, and can be used by the borrowers under the credit facility to support bank borrowings and the issuance of commercial paper, as well as to support up to a combined $2.0 billion of letters of credit.

[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 full amount of the facility is available to Virginia Power, less any amounts outstanding to co-borrowers Dominion Energy, Questar Gas and DESC. The sub-limit for Virginia Power is set pursuant to the terms of the facility but can be changed at the option of the borrowers multiple times per year. At September 30, 2022, the sub-limit for Virginia Power was $1.75 billion. If Virginia Power has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. This credit facility matures in June 2026, with the potential to be extended by the borrowers to June 2028. The credit facility can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $2.0 billion (or the sub-limit, whichever is less) of letters of credit.

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