v3.25.2
Fair Value of Financial Assets and Liabilities - Fair Value Inputs Assets Quantitative Information (Details) - Fair Value, Inputs, Level 3 [Member] - Derivative [Member] - USD ($)
Jun. 30, 2025
Dec. 31, 2024
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Amount Not Offset Against Collateral $ (135,000,000) $ (132,000,000)
Discounted Cash Flow [Member] | Minimum [Member]    
Derivatives, Fair Value [Line Items]    
Fair Value Inputs Forward Power Price 28.24 30.31
Discounted Cash Flow [Member] | Maximum [Member]    
Derivatives, Fair Value [Line Items]    
Fair Value Inputs Forward Power Price 62.10 59.88
Discounted Cash Flow [Member] | Arithmetic Average [Member]    
Derivatives, Fair Value [Line Items]    
Fair Value Inputs Forward Power Price 40.28 42.08
Commonwealth Edison Co    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Amount Not Offset Against Collateral $ (135,000,000) $ (132,000,000)
Commonwealth Edison Co | Discounted Cash Flow [Member] | Minimum [Member]    
Derivatives, Fair Value [Line Items]    
Fair Value Inputs Forward Power Price 28.24 30.31
Commonwealth Edison Co | Discounted Cash Flow [Member] | Maximum [Member]    
Derivatives, Fair Value [Line Items]    
Fair Value Inputs Forward Power Price 62.10 59.88
Commonwealth Edison Co | Discounted Cash Flow [Member] | Arithmetic Average [Member]    
Derivatives, Fair Value [Line Items]    
Fair Value Inputs Forward Power Price 40.28 42.08