Significant Accounting Policies (Depreciation Rates and Estimated Useful Life) (Detail)		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Nonregulated Generation-Nuclear | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives	[1]	54 years
Nonregulated Generation-Nuclear | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives	[1]	64 years
Nonregulated Generation Solar | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives	[1]	30 years
Nonregulated Generation Solar | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives	[1]	35 years
General and Other | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives	[1]	5 years
General and Other | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives	[1]	50 years
Generation
Public Utility, Property, Plant and Equipment [Line Items]
Average composite depreciation rates on utility property, plant and equipment (percentage)	[2]	2.65%	2.71%	2.63%
Generation | Virginia Electric and Power Company
Public Utility, Property, Plant and Equipment [Line Items]
Average composite depreciation rates on utility property, plant and equipment (percentage)		2.75%	2.84%	2.69%
Transmission
Public Utility, Property, Plant and Equipment [Line Items]
Average composite depreciation rates on utility property, plant and equipment (percentage)	[2]	2.32%	2.32%	2.52%
Transmission | Virginia Electric and Power Company
Public Utility, Property, Plant and Equipment [Line Items]
Average composite depreciation rates on utility property, plant and equipment (percentage)		2.29%	2.29%	2.51%
Distribution
Public Utility, Property, Plant and Equipment [Line Items]
Average composite depreciation rates on utility property, plant and equipment (percentage)	[2]	2.72%	2.80%	2.85%
Distribution | Virginia Electric and Power Company
Public Utility, Property, Plant and Equipment [Line Items]
Average composite depreciation rates on utility property, plant and equipment (percentage)		2.78%	2.76%	3.18%
General and Other
Public Utility, Property, Plant and Equipment [Line Items]
Average composite depreciation rates on utility property, plant and equipment (percentage)	[2]	4.20%	4.31%	4.36%
General and Other | Virginia Electric and Power Company
Public Utility, Property, Plant and Equipment [Line Items]
Average composite depreciation rates on utility property, plant and equipment (percentage)		4.60%	4.78%	5.08%

[1] The estimated useful life for a generation station is made on a unit basis if the facility has multiple generating units and represents the period the unit was placed in service or acquired until the end of its license or estimated service period.

[2] Excludes rates for depreciation reported as discontinued operations.