v3.26.3
Regulatory Matters - Schedule of Additional Significant Riders Associated with Virginia Power Projects (Parenthetical) (Detail) - Virginia Electric and Power Company
$ in Millions
 1 Months Ended 9 Months Ended 12 Months Ended
Mar. 31, 2027
USD ($)
Sep. 30, 2026
USD ($)
Agreement
Project
Dec. 31, 2025
USD ($)
Program
Sep. 30, 2025
USD ($)
Public Utilities, General Disclosures [Line Items]        
Additional total revenue requirement   $ 65    
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    
Electric Distribution Grid Transformation Projects        
Public Utilities, General Disclosures [Line Items]        
Total revenue requirement   196    
Underground Distribution Facilities        
Public Utilities, General Disclosures [Line Items]        
Total revenue requirement   172    
Underground Distribution Facilities        
Public Utilities, General Disclosures [Line Items]        
Total revenue requirement   230    
Rural Broadband Capacity Projects        
Public Utilities, General Disclosures [Line Items]        
Total revenue requirement   35    
Rural Broadband Capacity Projects        
Public Utilities, General Disclosures [Line Items]        
Total revenue requirement   37    
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   599    
Rider T1 | Transmission Component Of Virginia Powers | Virginia Regulation | Operating Segments        
Public Utilities, General Disclosures [Line Items]        
Total revenue requirement   940    
DSM Riders        
Public Utilities, General Disclosures [Line Items]        
Total revenue requirement [2],[4]   114    
DSM Riders | Virginia Regulation        
Public Utilities, General Disclosures [Line Items]        
Amount of cost cap recovery     $ 221  
Public utilities energy efficiency program cost exceed percentage     15.00%  
DSM Riders | Virginia Regulation | Operating Segments        
Public Utilities, General Disclosures [Line Items]        
Number of new demand response programs | Program     7  
DSM Riders | Energy Efficiency Program | Virginia Regulation | Operating Segments        
Public Utilities, General Disclosures [Line Items]        
Number of redesigned energy efficiency programs | Program     2  
DSM Riders | Virtual Power Plant Pilot Program | Virginia Regulation        
Public Utilities, General Disclosures [Line Items]        
Amount of cost cap recovery     $ 64  
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. Appeals have been filed with the Supreme Court of Virginia regarding this matter, which are currently pending.
[2] In addition, Virginia Power has riders associated with other projects with an aggregate total revenue requirement of approximately $65 million at September 30, 2026.
[3] Consists of $599 million for the transmission component of Virginia Power’s base rates and $940 million for Rider T1.
[4] Associated with two redesigned energy efficiency programs and seven new demand response programs with a $221 million cost cap, with the ability to exceed the cost cap by no more than 15%. Also, in December 2025, Virginia Power filed a petition requesting Virginia Commission approval to conduct a pilot program to evaluate methods to optimize system demand through various technology applications and distributed energy resources, including the establishment of a VPP, as required by the Community Energy Act. In its petition, Virginia Power sought to utilize certain programs previously approved by the Virginia Commission and incorporate newly proposed programs associated with the DSM Riders. The DSM Riders cost cap includes $64 million associated with the proposed VPP pilot program. The Virginia Commission consolidated the DSM Riders and VPP pilot program petitions and approved all related matters in August 2026.