Employee Benefit Plans (Net Periodic Benefit Cost (Credit)) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 35	$ 43	$ 106	$ 127
Interest cost		83	80	250	238
Expected return on plan assets		(221)	(209)	(667)	(625)
Amortization of net actuarial loss		39	48	119	145
Settlements and curtailment	[1]				5
Net periodic benefit (credit) cost		(64)	(38)	(192)	(110)
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost		5	6	16	18
Interest cost		11	11	34	35
Expected return on plan assets		(47)	(43)	(143)	(130)
Amortization of prior service cost (credit)		(10)	(11)	(29)	(32)
Amortization of net actuarial loss			1	(1)	3
Settlements and curtailment	[1]	(8)		(8)
Net periodic benefit (credit) cost		$ (49)	$ (36)	$ (131)	$ (106)

[1] 2022 amounts relate primarily to Dominion Energy’s sale of Hope. 2021 amounts relate primarily to the Dominion Energy executive nonqualified pension plan.