Leases (Weighted Average Remaining Lease Term and Weighted Discounted Rate for Finance and Operating Leases) (Detail)	Dec. 31, 2023	Dec. 31, 2022
Lessee Lease Disclosure [Line Items]
Weighted average remaining lease term - finance leases	5 years	4 years
Weighted average remaining lease term - operating leases	31 years	29 years
Weighted average discount rate - finance leases	7.14%	5.77%
Weighted average discount rate - operating leases	4.11%	3.91%
Virginia Electric and Power Company
Lessee Lease Disclosure [Line Items]
Weighted average remaining lease term - finance leases	5 years	6 years
Weighted average remaining lease term - operating leases	33 years	30 years
Weighted average discount rate - finance leases	7.28%	6.12%
Weighted average discount rate - operating leases	4.18%	3.90%