v3.25.2
Operating Revenue (Schedule of Operating Revenue) (Parenthetical) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Public Utilities General Disclosures [Line Items]        
Operating revenue from contracts with customers $ 3,718 $ 3,455 $ 7,803 $ 6,979
Renewable Energy Investment Tax Credits        
Public Utilities General Disclosures [Line Items]        
Operating revenue from contracts with customers 5 7 15 12
Transition services agreements        
Public Utilities General Disclosures [Line Items]        
Other revenues 24 13 51 17
Alternative Revenue Programs        
Public Utilities General Disclosures [Line Items]        
Other revenues 60 33 82 61
Virginia Electric and Power Company        
Public Utilities General Disclosures [Line Items]        
Operating revenue from contracts with customers 2,660 2,468 5,411 4,885
Virginia Electric and Power Company | Renewable Energy Investment Tax Credits        
Public Utilities General Disclosures [Line Items]        
Operating revenue from contracts with customers 2 3 6 5
Virginia Electric and Power Company | Alternative Revenue Programs        
Public Utilities General Disclosures [Line Items]        
Other revenues $ 60 $ 33 $ 82 $ 61