Significant Financing Transactions (Narrative) (Detail) - USD ($)		1 Months Ended		3 Months Ended		12 Months Ended
		Mar. 31, 2024	Jan. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023		Oct. 31, 2023	Nov. 30, 2020
Debt Instrument [Line Items]
Facility Limit	[1]	$ 6,000,000,000		$ 6,000,000,000
Short-term debt		$ 3,626,000,000		3,626,000,000		$ 3,956,000,000	[2]
Line of credit issued				$ 3,000,000,000	$ 2,500,000,000
Preferred stock shares authorized		20,000,000		20,000,000
Issuance of common stock				$ 31,000,000	$ 43,000,000
Securities due within one year	[3]	$ 2,344,000,000		$ 2,344,000,000		6,589,000,000	[2]
Common Stock
Debt Instrument [Line Items]
Stock repurchased, shares				0
Issuance of stock (in shares)				0	1,000,000
Stock repurchase program, authorized amount		900,000,000		$ 900,000,000					$ 1,000,000,000
Series B Preferred Stock
Debt Instrument [Line Items]
Recorded dividend				$ 9,000,000	$ 9,000,000
Recorded dividends per share				$ 11.625	$ 11.625
Series C Preferred Stock
Debt Instrument [Line Items]
Recorded dividend				$ 11,000,000	$ 11,000,000
Recorded dividends per share				$ 10.875	$ 10.875
Various Programs
Debt Instrument [Line Items]
Issuance of common stock				$ 31,000,000	$ 43,000,000
Issuance of stock (in shares)					1,000,000
Various Programs | Maximum
Debt Instrument [Line Items]
Issuance of stock (in shares)				1,000,000
Floating Rate Demand Notes
Debt Instrument [Line Items]
Short-term debt		462,000,000		$ 462,000,000		409,000,000
Floating Rate Demand Notes | Shelf Registration for Sale of Demand Notes
Debt Instrument [Line Items]
Facility Limit						3,000,000,000
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
Virginia Electric and Power Company
Debt Instrument [Line Items]
Facility Limit	[4]	6,000,000,000		6,000,000,000
Short-term debt	[5]	0		$ 0		455,000,000	[6]
Issuance of stock (in shares)				0	0
Securities due within one year	[5]	$ 100,000,000		$ 100,000,000		$ 381,000,000	[6]
Dominion Energy
Debt Instrument [Line Items]
Preferred stock shares issued		1,800,000		1,800,000		1,800,000
Preferred stock shares outstanding		1,800,000		1,800,000		1,800,000
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		1,000,000		1,000,000
Preferred stock shares outstanding		1,000,000		1,000,000		1,000,000
Dominion Energy | Senior Notes Due In February 2024
Debt Instrument [Line Items]
Recorded interest expense				$ 10,000,000
Joint Revolving Credit Facility
Debt Instrument [Line Items]
Facility Limit		$ 6,000,000,000		6,000,000,000
Letter of Credit
Debt Instrument [Line Items]
Facility Limit					$ 100,000,000
Letters of credit issued and outstanding		58,000,000		58,000,000		$ 54,000,000
Letter of Credit | Credit Facility, Maturing in June 2024
Debt Instrument [Line Items]
Facility Limit		30,000,000		30,000,000
Letter of credit		0		$ 0		25,000,000
Line of credit facility, maturity date				Jun. 30, 2024
Letter of Credit | Virginia Electric and Power Company
Debt Instrument [Line Items]
Facility Limit			$ 125,000,000		$ 200,000,000
Letter of credit						0
Line of credit facility, maturity date			Jan. 31, 2026
Line of credit issued				$ 119,000,000		124,000,000
Letter of Credit | Virginia Electric and Power Company | Maximum
Debt Instrument [Line Items]
Letters of credit issued and outstanding						1,000,000
364 Term loan facility
Debt Instrument [Line Items]
Securities due within one year						2,500,000,000
364 Term loan facility | Credit Facility, Maturing In July 2024
Debt Instrument [Line Items]
Facility Limit			$ 2,500,000,000
Repayments of borrowings		2,500,000,000
364 Term loan facility | Credit Facility, Maturing In October 2024
Debt Instrument [Line Items]
Facility Limit								$ 2,250,000,000
Line of credit issued		500,000,000
Repayments of borrowings		1,800,000,000
Securities due within one year		976,000,000		$ 976,000,000		$ 2,250,000,000
364 Term loan facility | Credit Facility, Maturing In October 2024 | General Corporate Purposes
Debt Instrument [Line Items]
Line of credit issued		$ 500,000,000

[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, 2023 has been derived from the audited Consolidated Balance Sheet at that date.

[3] See Note 15 for amounts attributable to VIEs.

[4] 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 March 31, 2024, 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.

[5] See Note 15 for amounts attributable to VIEs.

[6] Virginia Power’s Consolidated Balance Sheet at December 31, 2023 has been derived from the audited Consolidated Balance Sheet at that date.