v3.26.3
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 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract]          
Mark-to-market derivative liabilities $ 21   $ 21   $ 30
Mark-to-market derivative liabilities (noncurrent liabilities) 96   96   106
Fair Value, Inputs, Level 3 [Member]          
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]          
Beginning Balance (109) $ (112) (110) $ (110)  
Total realized / unrealized gains (losses)          
Included in net income 0 1 0 2  
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Regulatory assets 11 7 14 4  
Purchases, sales, issuances and settlements          
Settlements 0 1 2 1  
Ending Balance (98) (105) (98) (105)  
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) 0 (1) 0 1  
Commonwealth Edison Co          
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract]          
Mark-to-market derivative liabilities 21   21   25
Mark-to-market derivative liabilities (noncurrent liabilities) 96   96   106
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 21   21   25
Mark-to-market derivative liabilities (noncurrent liabilities) 96   96   $ 106
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) 3 6 22 33  
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 (128) (135) (131) (132)  
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 11 7 14 4  
Purchases, sales, issuances and settlements          
Settlements 0 0 0 0  
Ending Balance (117) (128) (117) (128)  
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) 8 1 8 29  
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 19 22 20 21  
Total realized / unrealized gains (losses)          
Included in net income 0 0 0 1  
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Regulatory assets 0 0 0 0  
Purchases, sales, issuances and settlements          
Settlements 0 1 (1) (1)  
Ending Balance 19 21 19 21  
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) 0 0 0 1  
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 19 22 20 21  
Total realized / unrealized gains (losses)          
Included in net income 0 0 0 1  
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Regulatory assets 0 0 0 0  
Purchases, sales, issuances and settlements          
Settlements 0 1 (1) 1  
Ending Balance 19 21 19 21  
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) $ 0 $ 0 $ 0 $ 1