v3.25.2
Fair Value (Unobservable Inputs Related to Level 3 Assets and Liabilities) (Details)
$ in Millions
Jun. 30, 2025
USD ($)
$ / MMBTU
$ / MWh
Dec. 31, 2024
USD ($)
$ / MMBTU
$ / MWh
Unobservable Inputs Valuation Techniques [Line Items]    
Derivative Assets $ 711 $ 694
Derivative Liabilities (627) (605)
Natural gas    
Unobservable Inputs Valuation Techniques [Line Items]    
Derivative Assets 327 428
Derivative Liabilities (321) (410)
Electricity    
Unobservable Inputs Valuation Techniques [Line Items]    
Derivative Assets 253 187
Derivative Liabilities $ (225) $ (150)
Level 3 | Natural gas | Forward basis price | Minimum | Discounted Cash Flow    
Unobservable Inputs Valuation Techniques [Line Items]    
Forward basis price | $ / MMBTU (1.60) (1.24)
Level 3 | Natural gas | Forward basis price | Maximum | Discounted Cash Flow    
Unobservable Inputs Valuation Techniques [Line Items]    
Forward basis price | $ / MMBTU 2.58 9.96
Level 3 | Natural gas | Forward basis price | Weighted Average | Discounted Cash Flow    
Unobservable Inputs Valuation Techniques [Line Items]    
Forward basis price | $ / MMBTU (0.19) (0.05)
Level 3 | Electricity | Forward basis price | Minimum | Discounted Cash Flow    
Unobservable Inputs Valuation Techniques [Line Items]    
Forward basis price | $ / MWh (18.45) (16.34)
Level 3 | Electricity | Forward basis price | Maximum | Discounted Cash Flow    
Unobservable Inputs Valuation Techniques [Line Items]    
Forward basis price | $ / MWh 18.15 17.28
Level 3 | Electricity | Forward basis price | Weighted Average | Discounted Cash Flow    
Unobservable Inputs Valuation Techniques [Line Items]    
Forward basis price | $ / MWh (4.25) (2.74)
Recurring | Level 3    
Unobservable Inputs Valuation Techniques [Line Items]    
Derivative Assets $ 166 $ 166
Recurring | Level 3 | Natural gas    
Unobservable Inputs Valuation Techniques [Line Items]    
Derivative Assets 95 105
Derivative Liabilities (104) (123)
Recurring | Level 3 | Electricity    
Unobservable Inputs Valuation Techniques [Line Items]    
Derivative Assets 40 51
Derivative Liabilities $ (48) $ (27)