Fair Value Measurements (Financial Instruments' Carrying Amounts and Fair Values) (Detail) - USD ($) $ in Millions		Dec. 31, 2024	Dec. 31, 2023
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	[1]	$ 34,533	$ 42,526
Supplemental 364-Day credit facility borrowings			450
Securitization bonds		1,217
Junior subordinated notes	[1]	3,223	1,388
Estimate of Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	[1],[2]	32,167	40,539
Supplemental 364-Day credit facility borrowings	[2]		450
Securitization bonds	[2]	1,218
Junior subordinated notes	[2]	3,372	1,374	[1]
Virginia Electric and Power Company | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	[1]	19,224	17,392
Securitization bonds		1,217
Virginia Electric and Power Company | Estimate of Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	[1],[2]	17,578	$ 16,418
Securitization bonds	[2]	$ 1,218

[1] Carrying amount includes current portions included in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium. There were no fair value hedges associated with fixed-rate debt at December 31, 2024 and December 31, 2023. Additionally, Dominion Energy carrying amounts include portions classified as liabilities held for sale at December 31, 2023. (3) Carrying amount includes current portions included in securities due within one year.

[2] Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.