Regulatory Matters - Schedule of Additional Significant Riders Associated with Virginia Power Projects (Parenthetical) (Detail) $ in Millions		1 Months Ended	6 Months Ended
		Jul. 31, 2023 USD ($)	Jun. 30, 2024 USD ($) Project Program Agreement
Virginia Electric and Power Company
Public Utilities, General Disclosures [Line Items]
Additional total revenue requirement			$ 20
Rider T1 | Virginia Electric and Power Company
Public Utilities, General Disclosures [Line Items]
Total revenue requirement	[1],[2]		1,170
Rider T1 | Operating Segments | Virginia Electric and Power Company | Virginia Regulation
Public Utilities, General Disclosures [Line Items]
Total revenue requirement			638
Rider T1 | Operating Segments | Virginia Electric and Power Company | Virginia Regulation | Transmission Component Of Virginia Powers
Public Utilities, General Disclosures [Line Items]
Total revenue requirement			$ 532
Rider CE
Public Utilities, General Disclosures [Line Items]
Public utilities number of power purchase agreements | Agreement			13
Rider CE | Virginia Electric and Power Company
Public Utilities, General Disclosures [Line Items]
Total revenue requirement	[2],[3]		$ 133
Public utilities number of solar generation projects | Project			4
Rider U | Virginia Electric and Power Company
Public Utilities, General Disclosures [Line Items]
Total revenue requirement	[2],[4]		$ 150
Rider U | Virginia Electric and Power Company | Virginia Regulation | Previous Phase
Public Utilities, General Disclosures [Line Items]
Projected capital investment			72
Rider U | Virginia Electric and Power Company | Virginia Regulation | Seven Phase
Public Utilities, General Disclosures [Line Items]
Projected capital investment			78
Consolidation of Riders BW, GV and Four Other Riders | Virginia Electric and Power Company
Public Utilities, General Disclosures [Line Items]
Total revenue requirement			348
DSM Riders | Virginia Electric and Power Company
Public Utilities, General Disclosures [Line Items]
Total revenue requirement	[2],[5]		86
DSM Riders | Virginia Electric and Power Company | Virginia Regulation
Public Utilities, General Disclosures [Line Items]
Amount of cost cap recovery			$ 102
Public utilities energy efficiency program cost exceed percentage			15.00%
DSM Riders | Operating Segments | Virginia Electric and Power Company | Virginia Regulation
Public Utilities, General Disclosures [Line Items]
Number of new demand response programs | Program			1
DSM Riders | Operating Segments | Virginia Electric and Power Company | Virginia Regulation | Energy Efficiency Program
Public Utilities, General Disclosures [Line Items]
Number of new energy efficiency programs | Program			3
Base Rate Case | Virginia Electric and Power Company | Virginia Regulation
Public Utilities, General Disclosures [Line Items]
Total revenue requirement		$ 350

[1] Consists of $532 million for the transmission component of Virginia Power’s base rates and $638 million for Rider T1.

[2] In addition, Virginia Power has various riders associated with other projects with an aggregate total annual revenue requirement of approximately $20 million as of June 30, 2024.

[3] The Virginia Commission approved four solar generation projects and 13 power purchase agreements in addition to previously approved Rider CE projects. In addition, the approved total revenue requirement includes amounts which had previously been collected under a separate rider.

[4] Consists of $72 million for previously approved phases and $78 million for phase seven costs for Rider U. In addition, the Virginia Commission approved Virginia Power’s request to extend existing rates for Rider U through July 2024.

[5] Associated with an additional three new energy efficiency programs and one new demand response program with a $102 million cost cap, with the ability to exceed the cost cap by no more than 15%.