v3.26.3
Operating Revenue (Schedule of Operating Revenue) (Parenthetical) (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Public Utilities General Disclosures [Line Items]        
Operating revenue from contracts with customers $ 5,592 $ 4,510 $ 15,139 $ 12,313
Renewable Energy Investment Tax Credits        
Public Utilities General Disclosures [Line Items]        
Operating revenue from contracts with customers 28 8 78 23
Transition services agreements        
Public Utilities General Disclosures [Line Items]        
Other revenues 13 23 61 74
Alternative Revenue Programs        
Public Utilities General Disclosures [Line Items]        
Other revenues 38 35 174 117
Virginia Electric and Power Company        
Public Utilities General Disclosures [Line Items]        
Operating revenue from contracts with customers 4,179 3,279 11,153 8,690
Virginia Electric and Power Company | Renewable Energy Investment Tax Credits        
Public Utilities General Disclosures [Line Items]        
Operating revenue from contracts with customers 7 4 18 10
Virginia Electric and Power Company | Alternative Revenue Programs        
Public Utilities General Disclosures [Line Items]        
Other revenues $ 38 $ 35 $ 174 $ 117