Income Taxes (Reconciliation of Income Taxes at the U.S. Statutory Federal Income Tax Rate) (Detail)	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Effective Income Tax Computation [Line Items]
U.S. statutory rate	21.00%	21.00%
Increases (reductions) resulting from:
State taxes, net of federal benefit	3.20%	3.80%
Investment tax credits	(1.30%)	(1.20%)
Production tax credits	(2.20%)	(0.50%)
Reversal of excess deferred income taxes	(2.50%)	(2.00%)
AFUDC - equity	(0.70%)	(0.10%)
Other, net	0.40%	(1.30%)
Effective tax rate	17.90%	19.70%
Virginia Electric and Power Company
Effective Income Tax Computation [Line Items]
U.S. statutory rate	21.00%	21.00%
Increases (reductions) resulting from:
State taxes, net of federal benefit	4.40%	4.60%
Investment tax credits	(0.80%)	(0.80%)
Production tax credits	(2.00%)	(0.80%)
Reversal of excess deferred income taxes	(1.80%)	(2.30%)
AFUDC - equity	(0.60%)	(0.10%)
Other, net	0.40%	(0.50%)
Effective tax rate	20.60%	21.10%