Employee Benefit Plans (Narrative) (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accumulated benefit obligation			$ 8,100,000,000	$ 7,700,000,000
Defined contribution plan, employer matching contributions			85,000,000	75,000,000	$ 65,000,000
Discontinued Operations
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost			18,000,000	25,000,000	28,000,000
Non-service cost			$ (46,000,000)	(43,000,000)	(34,000,000)
Common and Preferred Stocks
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, actual plan asset allocation percentages			26.00%
Non-U.S. Equity
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, actual plan asset allocation percentages			19.00%
Fixed Income Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, actual plan asset allocation percentages			32.00%
Real Assets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, actual plan asset allocation percentages			3.00%
Other than Securities Investment
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, actual plan asset allocation percentages			20.00%
Virginia Electric and Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, employer matching contributions			$ 26,000,000	22,000,000	20,000,000
Pension Plans and Post Retirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual return (loss) on pension and other postretirement plan assets			1,200,000,000	(3,000,000,000)
Expected return on pension and other postretirement plan assets			1,000,000,000	1,100,000,000
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual return (loss) on pension and other postretirement plan assets			882,000,000	(2,556,000,000)
Expected return on pension and other postretirement plan assets			864,000,000	886,000,000	834,000,000
Increase to net periodic benefit cost (credit)			(325,000,000)	(252,000,000)	(144,000,000)
Actuarial gains (losses) from increase decrease in discount rate			322,000,000	2,700,000,000
Contributions to qualified defined benefit pension plans			8,000,000	9,000,000
Expected contributions to qualified defined benefit pension plans in next fiscal year		$ 46,000,000
Service cost			96,000,000	142,000,000	170,000,000
Pension Benefits | Virginia Electric and Power Company | Amounts Associated With Dominion Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Payment made to Dominion				172,000,000	151,000,000
Pension Benefits | Virginia Electric and Power Company | Other Operations and Maintenance
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Increase to net periodic benefit cost (credit)			34,000,000	72,000,000	86,000,000
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actual return (loss) on pension and other postretirement plan assets			277,000,000	(416,000,000)
Expected return on pension and other postretirement plan assets			151,000,000	191,000,000	173,000,000
Increase to net periodic benefit cost (credit)			$ (118,000,000)	$ (172,000,000)	$ (140,000,000)
Health care cost trend decreased rate	[1]		5.00%	5.00%	5.00%
Actuarial gain (loss) by offset of decrease in discount rate from favorable claims and other			$ 28,000,000
Actuarial gains (losses) from increase decrease in capital claims expense and other expense			1,000,000
Actuarial gains (losses) from increase decrease in discount rate			29,000,000	$ 360,000,000
Contribution to voluntary employees beneficiary association					$ 0
Service cost			14,000,000	22,000,000	25,000,000
Other Postretirement Benefits | Virginia Electric and Power Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution to voluntary employees beneficiary association			0	0	0
Other Postretirement Benefits | Virginia Electric and Power Company | Forecast
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution to voluntary employees beneficiary association		$ 0
Other Postretirement Benefits | Virginia Electric and Power Company | Other Operations and Maintenance | Dominion Energy Retiree Health And Welfare Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Increase to net periodic benefit cost (credit)			$ (60,000,000)	$ (81,000,000)	$ (72,000,000)

[1] Assumptions used to determine net periodic cost for the following year.