v3.26.1
Regulatory Matters - Schedule of Additional Significant Riders Associated with Virginia Power Projects (Parenthetical) (Detail) - Virginia Electric and Power Company
$ in Millions
 1 Months Ended 6 Months Ended
Mar. 31, 2027
USD ($)
Jun. 30, 2026
USD ($)
Project
Agreement
Sep. 30, 2025
USD ($)
Public Utilities, General Disclosures [Line Items]      
Public utilities requested rate increase annual revenue of pending applications approval   $ 20  
Additional total revenue requirement   45  
Forecast      
Public Utilities, General Disclosures [Line Items]      
Total revenue requirement $ 940    
Recovery period of costs 2 years    
Rider CE      
Public Utilities, General Disclosures [Line Items]      
Total revenue requirement [1],[2]   $ 280  
Public utilities number of solar generation projects | Project   4  
Non-jurisdictional generation facilities aggregate recorded cost     $ 251
Public utilities number of energy storage project | Project   1  
Public utilities number of power purchase agreements | Agreement   10  
Electric Distribution Grid Transformation Projects      
Public Utilities, General Disclosures [Line Items]      
Total revenue requirement   $ 120  
Underground Distribution Facilities      
Public Utilities, General Disclosures [Line Items]      
Total revenue requirement   172  
Rural Broadband Capacity Projects      
Public Utilities, General Disclosures [Line Items]      
Total revenue requirement   35  
Rider T1      
Public Utilities, General Disclosures [Line Items]      
Total revenue requirement [2],[3]   1,539  
Rider T1 | Virginia Regulation | Operating Segments      
Public Utilities, General Disclosures [Line Items]      
Total revenue requirement   999  
Rider T1 | Transmission Component Of Virginia Powers | Virginia Regulation | Operating Segments      
Public Utilities, General Disclosures [Line Items]      
Total revenue requirement   540  
Disallowance of Certain Strategic Undergrounding Costs      
Public Utilities, General Disclosures [Line Items]      
Impairment of assets and other charges   24  
Asset impairment charges after tax   $ 18  
[1] As approved, associated with four solar generation projects, including Bedford and Pumpkinseed (non-jurisdictional generation facilities with an aggregate recorded cost of $251 million at September 30, 2025), one energy storage project, 10 purchased power agreements and certain costs associated with expanding solar and storage facilities in addition to previously approved Rider CE projects.
[2] In addition, Virginia Power has riders associated with other projects with an aggregate total revenue requirement of approximately $45 million at June 30, 2026 and pending applications associated with such riders, which if approved, would result in an annual revenue requirement increase of approximately $20 million.
[3] Consists of $540 million for the transmission component of Virginia Power’s base rates and $999 million for Rider T1.