Income Taxes (Narrative) (Detail) - USD ($)		1 Months Ended			12 Months Ended
		Sep. 30, 2023	Aug. 31, 2022	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jul. 31, 2023	Dec. 31, 2020
Income Taxes [Line Items]
State deferred income tax expense (benefit)					$ 282,000,000	$ 73,000,000	$ (49,000,000)
Income tax expense (benefit)				$ 173,000,000	575,000,000	113,000,000	(181,000,000)
Income tax expense (benefit) from discontinued operations					1,300,000,000	197,000,000	374,000,000
Discontinued operations, deferred tax liabilities		$ 939,000,000
Deferred income tax expense (benefit)					1,471,000,000	102,000,000	409,000,000
Income tax benefit associated with remeasurement of state deferred taxes					(45,000,000)	(35,000,000)	(42,000,000)
Unrecognized tax benefits				128,000,000	110,000,000	117,000,000	128,000,000		$ 167,000,000
Unrecognized tax benefits that would impact effective tax rate				$ 72,000,000	52,000,000	64,000,000	72,000,000
Pre-tax income					2,732,000,000	540,000,000	1,880,000,000
Maximum
Income Taxes [Line Items]
Decrease in Unrecognized tax benefits due to settlement negotiations and expiration of statutes of limitations					27,000,000
Amount that earnings could potentially increase if changes were to occur					$ 14,000,000
Cove Point
Income Taxes [Line Items]
Percentage of noncontrolling limited partnership interest retained	[1]				50.00%
Income tax expense (benefit) from discontinued operations					$ 31,000,000	92,000,000	$ 60,000,000
Four Brothers And Three Cedars
Income Taxes [Line Items]
Percentage of noncontrolling limited partnership interest retained				50.00%	50.00%		50.00%
East Ohio, PSNC and Questar Gas
Income Taxes [Line Items]
Discontinued operations, deferred tax liabilities		$ 825,000,000
East Ohio, PSNC and Questar Gas | Cove Point
Income Taxes [Line Items]
Percentage of noncontrolling limited partnership interest retained		50.00%			50.00%
Income tax expense (benefit)					$ 29,000,000
Virginia Electric and Power Company
Income Taxes [Line Items]
State deferred income tax expense (benefit)					107,000,000	108,000,000	$ 116,000,000
Income tax expense (benefit)					389,000,000	294,000,000	447,000,000
Deferred income tax expense (benefit)					504,000,000	141,000,000	207,000,000
Income tax benefit associated with remeasurement of state deferred taxes					0	0	0
Unrecognized tax benefits				$ 0	0	0	0
Hope Gas Inc [Member]
Income Taxes [Line Items]
Income tax expense (benefit)						34,000,000
Percentage of equity interests sold			100.00%
Discontinued Operations
Income Taxes [Line Items]
Unrecognized tax benefits that would impact effective tax rate				$ 33,000,000	38,000,000	33,000,000	33,000,000
Discontinued Operations | East Ohio [Member]
Income Taxes [Line Items]
Pre-tax income					104,000,000
Discontinued Operations | PSNC
Income Taxes [Line Items]
Income tax expense (benefit)					(59,000,000)	(38,000,000)
Pre-tax income						233,000,000
Discontinued Operations | Questar Gas [Member]
Income Taxes [Line Items]
Income tax expense (benefit)							(37,000,000)
Pre-tax income							218,000,000
Discontinued Operations | East Ohio, PSNC and Questar Gas
Income Taxes [Line Items]
Income tax charge		$ 886,000,000
Continuing Operations
Income Taxes [Line Items]
Increase (Decrease) in tax expense as a result of changes in unrecognized tax benefits					$ (8,000,000)	(7,000,000)	(34,000,000)
Deferred income tax expense (benefit)						(21,000,000)
Continuing Operations | Virginia Electric and Power Company
Income Taxes [Line Items]
Deferred income tax expense (benefit)						$ (16,000,000)
Continuing Operations | SCANA
Income Taxes [Line Items]
Increase (Decrease) in tax expense as a result of changes in unrecognized tax benefits							38,000,000
SBL Holdco
Income Taxes [Line Items]
Income tax expense (benefit)							196,000,000
BHE | East Ohio, PSNC and Questar Gas | Cove Point
Income Taxes [Line Items]
Income tax expense (benefit) from discontinued operations		$ 278,000,000
IRA
Income Taxes [Line Items]
Percentage of alternate minimum tax on GAAP net income			15.00%
IRA | Minimum
Income Taxes [Line Items]
Tax credit expiration year			2032
Annual financial statement income for tax years			$ 1,000,000,000
GT&S Transaction
Income Taxes [Line Items]
Income tax expense (benefit) from discontinued operations							19,000,000
GT&S Transaction | Cove Point
Income Taxes [Line Items]
Percentage of noncontrolling limited partnership interest retained						50.00%
GT&S Transaction | Discontinued Operations
Income Taxes [Line Items]
Income tax benefit related to finalizing income tax returns							(14,000,000)
GT&S Transaction | BHE | Cove Point
Income Taxes [Line Items]
Percentage of noncontrolling limited partnership interest retained								50.00%
Q-Pipe Group | Discontinued Operations
Income Taxes [Line Items]
Income tax expense (benefit) on non-deductible goodwill written off							$ 36,000,000

[1] Dominion Energy’s sold its remaining 50% noncontrolling limited partnership interest in September 2023. See discussion below. Presented in noncurrent assets held for sale in Dominion Energy’s Consolidated Balance Sheets at December 31, 2022.