v3.25.2
Significant Financing Transactions (Commercial Paper, Bank Loans and Letters of Credit Outstanding) (Parenthetical) (Detail) - USD ($)
Jul. 31, 2025
Jun. 30, 2025
Apr. 30, 2025
Mar. 31, 2023
Line of Credit Facility [Line Items]        
Facility Limit   $ 8,000,000,000    
Virginia Electric and Power Company        
Line of Credit Facility [Line Items]        
Facility Limit   7,000,000,000    
Letter of Credit Matures in April 2032        
Line of Credit Facility [Line Items]        
Facility Limit   3,000,000,000    
Letter of Credit Matures in April 2032 | Virginia Electric and Power Company        
Line of Credit Facility [Line Items]        
Facility Limit   3,000,000,000 $ 1,750,000,000  
Letter of Credit Matures in April 2032 | Virginia Electric and Power Company | Subsequent Event        
Line of Credit Facility [Line Items]        
Facility Limit $ 4,000,000,000      
Letter of Credit        
Line of Credit Facility [Line Items]        
Facility Limit       $ 100,000,000
Letter of Credit | Virginia Electric and Power Company        
Line of Credit Facility [Line Items]        
Facility Limit   $ 3,000,000,000   $ 300,000,000