Significant Financing Transactions (Narrative) (Detail)			1 Months Ended						3 Months Ended
		Jun. 14, 2019 USD ($) $ / shares shares	Jun. 30, 2022 shares	Apr. 30, 2020 USD ($)	Mar. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares		Jan. 31, 2019 USD ($) shares	Mar. 31, 2020 USD ($) $ / shares shares	Mar. 31, 2019 USD ($) shares	Dec. 15, 2024 $ / shares	Feb. 29, 2020 USD ($)	Sep. 30, 2019 USD ($)
Debt Instrument [Line Items]
Facility Limit	[1]				$ 6,000,000,000				$ 6,000,000,000
Short-term debt					2,190,000,000	$ 911,000,000	[2]		2,190,000,000
Shares of common stock issued in acquisition, value										$ 6,818,000,000
Amount of income taxes recognized in equity primarily attributable to establishing additional regulatory liabilities										$ (40,000,000)
Total Preferred Stock					$ 2,387,000,000	$ 2,387,000,000	[2]		$ 2,387,000,000
Preferred Stock, Redemption Price Per Share | $ / shares						$ 1,020
Shelf Registration for Sale of Common Stock through At-the-market Program
Debt Instrument [Line Items]
Issuance of common stock (in shares) | shares					0
Maximum | Shelf Registration for Sale of Common Stock through At-the-market Program
Debt Instrument [Line Items]
Sale Of Stock Authorized Amount					$ 500,000,000
Scenario Forecast
Debt Instrument [Line Items]
Preferred Stock, Redemption Price Per Share | $ / shares											$ 1,000
Common Stock
Debt Instrument [Line Items]
Shares of common stock issued in acquisition | shares										96,000,000
Shares of common stock issued in acquisition, value										$ 6,818,000,000
Amount of income taxes recognized in equity primarily attributable to establishing additional regulatory liabilities										$ 1,181,000,000
Issuance of common stock (in shares) | shares									1,000,000	3,000,000
2019 Corporate Units
Debt Instrument [Line Items]
Total Long-term Debt		$ 1,600,000,000
Percentage of interest in undivided beneficial ownership		10.00%
Total Preferred Stock	[3]	$ 1,610,000,000
Dividend rate percentage		1.75%
Issuance of common stock (in shares) | shares		16,000,000
2019 Corporate Units | Scenario Forecast | Maximum
Debt Instrument [Line Items]
Shares to be issued under purchase contracts | shares			21,800,000
2019 Corporate Units | Common Stock
Debt Instrument [Line Items]
Purchase price to be paid under stock purchase contracts | $ / shares		$ 100
SCANA
Debt Instrument [Line Items]
Debt Instrument, Maturity Date, Description									The notes would have otherwise matured in May 2021 and February 2022, respectively.
Shares of common stock issued in acquisition | shares								95,600,000
Shares of common stock issued in acquisition, value								$ 6,800,000,000
June 2006 Hybrids
Debt Instrument [Line Items]
Debt, amount redeemed												$ 111,000,000
September 2006 Hybrids
Debt Instrument [Line Items]
Debt, amount redeemed												$ 286,000,000
June 2006 and September 2006 Hybrids | Interest and Related Charges
Debt Instrument [Line Items]
Expenses related to early redemption of hybrids									$ 10,000,000
DESC
Debt Instrument [Line Items]
Facility Limit					500,000,000				500,000,000
Short-term indebtedness outstanding									$ 2,200,000,000
Debt maturity month and year									2021-03
Questar Gas
Debt Instrument [Line Items]
Facility Limit					$ 250,000,000				$ 250,000,000
GESC
Debt Instrument [Line Items]
Short-term indebtedness outstanding									$ 200,000,000
Debt maturity month and year									2021-03
Dominion Energy Midstream Partners, LP
Debt Instrument [Line Items]
Shares of common stock issued in acquisition | shares								22,500,000
Shares of common stock issued in acquisition, value								$ 1,600,000,000
Common units conversion ratio								0.2492
Gain or loss recognized in equity transaction								$ 0
Amount of income taxes recognized in equity primarily attributable to establishing additional regulatory liabilities								$ 40,000,000
Dominion Energy
Debt Instrument [Line Items]
Dividend rate percentage						2.993%
Dominion Energy | Series B Preferred Stock
Debt Instrument [Line Items]
Preferred stock shares authorized | shares						800,000
Total Preferred Stock						$ 791,000,000
Issuance of costs						9,000,000
Preferred stock liquidation value						$ 1,000
Dividend rate percentage						4.65%
Dividend stock									$ 9,000,000
Dividends Payable, Amount Per Share | $ / shares					$ 11.625				$ 11.625
Credit Facilities, Maturing in December 2017 with 1 year Automatic Renewals through 2023 | SBL Holdco
Debt Instrument [Line Items]
Facility Limit					$ 30,000,000				$ 30,000,000
Automatic renewal period									1 year
Short-term debt					0				$ 0
Credit Facilities, Maturing in May 2018 with 1 year Automatic Renewals through 2024 | Dominion Solar Projects III, Inc
Debt Instrument [Line Items]
Facility Limit					25,000,000				$ 25,000,000
Automatic renewal period									1 year
Short-term debt					0				$ 0
Term Loan Credit Agreement
Debt Instrument [Line Items]
Credit facility, outstanding amount					$ 500,000,000				500,000,000
Debt Instrument, Term					364 days
Term Loan Credit Agreement | Subsequent Event
Debt Instrument [Line Items]
Credit facility, outstanding amount				$ 625,000,000
Debt Instrument, Term				364 days
Floating rate senior notes | SCANA
Debt Instrument [Line Items]
Debt, amount redeemed					$ 66,000,000				$ 66,000,000
Debt Instrument, Maturity Date, Description									The notes would have otherwise matured in June 2034.
Floating rate senior notes | Interest and Related Charges | SCANA
Debt Instrument [Line Items]
Expenses related to early redemption of hybrids									$ 7,000,000
4.75% Medium Term Notes | SCANA
Debt Instrument [Line Items]
Debt, amount redeemed					$ 183,000,000				$ 183,000,000
Interest Rate					4.75%				4.75%
4.125% Medium Term Notes | SCANA
Debt Instrument [Line Items]
Debt, amount redeemed					$ 155,000,000				$ 155,000,000
Interest Rate					4.125%				4.125%
4.75% and 4.125% Medium Term Notes | Interest and Related Charges | SCANA
Debt Instrument [Line Items]
Expenses related to early redemption of hybrids									$ 14,000,000
Senior Notes Due in 2025 | Senior Notes
Debt Instrument [Line Items]
Interest Rate					3.30%				3.30%
Total Long-term Debt					$ 400,000,000				$ 400,000,000
Debt maturity year					2025
Senior Notes Due in 2025 | Subsequent Event | Senior Notes
Debt Instrument [Line Items]
Interest Rate				3.375%
Total Long-term Debt				$ 1,500,000,000
Debt maturity year				2030
Senior Notes Due in 2027 | Senior Notes
Debt Instrument [Line Items]
Interest Rate					3.60%				3.60%
Total Long-term Debt					$ 350,000,000				$ 350,000,000
Debt maturity year					2027
Senior Notes Due in 2030 | PSNC
Debt Instrument [Line Items]
Interest Rate					4.05%				4.05%
Total Long-term Debt					$ 200,000,000				$ 200,000,000
Debt maturity year					2030
2.579% Junior Subordinated Notes | Subsequent Event | Unsecured Junior Subordinated Notes
Debt Instrument [Line Items]
Debt maturity month and year				2020-07
Interest Rate				2.579%
Debt instrument repurchased and canceled amount				$ 7,000,000
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 2020
Debt Instrument [Line Items]
Facility Limit					21,000,000				$ 21,000,000
Credit facility, outstanding amount													$ 21,000,000
Line of credit facility, termination date									Jun. 30, 2020
364-day Revolving Credit Facility
Debt Instrument [Line Items]
Facility Limit					900,000,000				$ 900,000,000
Credit facility, outstanding amount					$ 0				$ 0
Debt Instrument, Term					364 days
364-day Revolving Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Credit facility borrowings				$ 225,000,000

[1] This credit facility matures in March 2023 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, 2019 has been derived from the audited Consolidated Balance Sheet at that date.

[3] Dominion Energy recorded dividends of $7 million ($4.375 per share) for the three months ended March 31, 2020.