Leases (Weighted Average Remaining Lease Term and Weighted Discounted Rate for Finance and Operating Leases) (Detail)	Dec. 31, 2024	Dec. 31, 2023
Lessee Lease Disclosure [Line Items]
Weighted average remaining lease term - finance leases	5 years	5 years
Weighted average remaining lease term - operating leases	31 years	31 years
Weighted average discount rate - finance leases	5.61%	7.14%
Weighted average discount rate - operating leases	4.42%	4.11%
Virginia Electric and Power Company
Lessee Lease Disclosure [Line Items]
Weighted average remaining lease term - finance leases	5 years	5 years
Weighted average remaining lease term - operating leases	32 years	33 years
Weighted average discount rate - finance leases	6.71%	7.28%
Weighted average discount rate - operating leases	5.13%	4.18%