v3.25.2
Fair Value of Financial Assets and Liabilities - Fair Value Assets Liabilities Measured On Recurring Basis Unobservable Input Reconciliation (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract]          
Mark-to-market derivative liabilities $ 24   $ 24   $ 29
Mark-to-market derivative liabilities (noncurrent liabilities) 119   119   103
Fair Value, Inputs, Level 3 [Member]          
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]          
Beginning Balance (129) $ (65) (110) $ (90)  
Total realized / unrealized gains (losses)          
Included in net income (1) (1) 1 (1)  
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Regulatory assets 16 (31) (3) (6)  
Purchases, sales, issuances and settlements          
Settlements 0 (21) 0 (21)  
Ending Balance (112) (116) (112) (116)  
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) 1 2 1 2  
Commonwealth Edison Co          
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract]          
Mark-to-market derivative liabilities 24   24   29
Mark-to-market derivative liabilities (noncurrent liabilities) 111   111   103
Commonwealth Edison Co | Fair Value, Recurring [Member]          
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract]          
Mark-to-market derivative liabilities 24   24   29
Mark-to-market derivative liabilities (noncurrent liabilities) 111   111   $ 103
Other current assets 0   0    
Other deferred debits (noncurrent assets) 0   0    
Commonwealth Edison Co | Derivative [Member] | Interest Rate Swap          
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract]          
Realized Investment Gains (Losses) 11 12 20 24  
Commonwealth Edison Co | Fair Value, Inputs, Level 3 [Member] | Derivative [Member]          
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]          
Beginning Balance (151) (108) (132) (133)  
Total realized / unrealized gains (losses)          
Included in net income 0 0 0 0  
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Regulatory assets 16 (31) (3) (6)  
Purchases, sales, issuances and settlements          
Settlements 0 0 0 0  
Ending Balance (135) (139) (135) (139)  
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) 0 0 0 0  
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract]          
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease) 5 (43) (17) (30)  
Pepco Holdings LLC | Fair Value, Inputs, Level 3 [Member] | 6311 Life Insurance [Member]          
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]          
Beginning Balance 21 41 21 41  
Total realized / unrealized gains (losses)          
Included in net income (1) (2) 1 2  
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Regulatory assets 0 0 0 0  
Purchases, sales, issuances and settlements          
Settlements 0 (21) 0 21  
Ending Balance 22 22 22 22  
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) 1 2 1 2  
Potomac Electric Power Company | Fair Value, Inputs, Level 3 [Member] | 6311 Life Insurance [Member]          
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]          
Beginning Balance 21 41 21 41  
Total realized / unrealized gains (losses)          
Included in net income (1) (2) 1 (2)  
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Regulatory assets 0 0 0 0  
Purchases, sales, issuances and settlements          
Settlements 0 (21) 0 (21)  
Ending Balance 22 22 22 22  
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) $ 1 $ 2 $ 1 $ 2