v3.26.1
Fair Value (Nonrecurring Measurements) (Details) - USD ($)
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Other Asset Impairment Charges $ 12,000,000 $ 49,000,000    
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs (236,000,000) (130,000,000) $ (245,000,000) $ (115,000,000)
Commodity Contract [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs (27,000,000) 2,000,000 $ (40,000,000) $ (21,000,000)
Other Contract [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs (3,000,000)      
Commodity Option        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs (24,000,000)      
Mong Duong Subsidiary [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Selling Expense   5,000,000    
Weighted Average [Member] | Commodity        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Derivative, Commodity prices $ 50.22      
Derivative, Underlying 47.98      
Maximum [Member] | Commodity        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Derivative, Commodity prices $ 132.82      
Derivative, Underlying 91.39      
Minimum [Member] | Commodity        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Derivative, Commodity prices $ 5.85      
Derivative, Underlying 22.76      
Long Lived Assets Held For Sale | Mong Duong held-for-sale        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Assets Carrying Amount Disclosure Nonrecurring   383,000,000    
Other Asset Impairment Charges   17,000,000    
Long Lived Assets Held For Sale | Mong Duong held-for-sale | Level 1 [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Assets Carrying Amount Disclosure Nonrecurring   0    
Long Lived Assets Held For Sale | Mong Duong held-for-sale | Level 2 [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Assets Carrying Amount Disclosure Nonrecurring   371,000,000    
Long Lived Assets Held For Sale | Mong Duong held-for-sale | Level 3 [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Assets Carrying Amount Disclosure Nonrecurring   $ 0