v3.26.1
Risk Management - Derivative Liabilities Input Level (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount $ (416) $ (213)
Energy commodity derivative contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount (267) (75)
Contracts available for netting 40 68
Cash collateral posted 52  
Cash collateral posted   (2)
Net amount (175) (9)
Energy commodity derivative contracts | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount (10) (12)
Energy commodity derivative contracts | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount (257) (63)
Energy commodity derivative contracts | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount 0 0
Interest rate contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount (149) (136)
Contracts available for netting 7 6
Cash collateral posted 0 0
Net amount (142) (130)
Interest rate contracts | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount 0 0
Interest rate contracts | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount (149) (136)
Interest rate contracts | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount $ 0 0
Foreign currency contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount   (2)
Contracts available for netting   0
Cash collateral posted   0
Net amount   (2)
Foreign currency contracts | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount   0
Foreign currency contracts | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount   (2)
Foreign currency contracts | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Gross amount   $ 0