v3.26.1
Fair Value Measurements (Assets and Liabilities Accounted for at Fair Value on Recurring Basis) (Detail) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash collateral netted with derivative liabilities   $ 10
Fair Value, Recurring    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Contingent consideration $ 235 236
Fair Value, Recurring | Commodity derivatives    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Commodity derivative instruments, assets - netting and collateral (1,647) (226)
Derivative asset, net carrying value on balance sheet 133 17
Commodity derivative instruments, assets - collateral pledged not offset 0 10
Commodity derivative instruments, liabilities - netting and collateral (1,610) (236)
Derivative liability, net carrying value on balance sheet 981 0
Commodity derivative instruments, liabilities - collateral pledged not offset 0 0
Fair Value, Recurring | Embedded derivatives in commodity contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Commodity derivative instruments, liabilities - netting and collateral 0 0
Derivative liability, net carrying value on balance sheet 47 41
Commodity derivative instruments, liabilities - collateral pledged not offset 0 0
Fair Value, Recurring | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Contingent consideration 0 0
Fair Value, Recurring | Level 1 | Commodity derivatives    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Commodity derivative instruments, assets - gross 1,780 243
Commodity derivative instruments, liabilities - gross 1,610 236
Fair Value, Recurring | Level 1 | Embedded derivatives in commodity contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Commodity derivative instruments, liabilities - gross 0 0
Fair Value, Recurring | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Contingent consideration 0 0
Fair Value, Recurring | Level 2 | Commodity derivatives    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Commodity derivative instruments, assets - gross 0 0
Commodity derivative instruments, liabilities - gross 973 0
Fair Value, Recurring | Level 2 | Embedded derivatives in commodity contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Commodity derivative instruments, liabilities - gross 0 0
Fair Value, Recurring | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Contingent consideration 235 236
Fair Value, Recurring | Level 3 | Commodity derivatives    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Commodity derivative instruments, assets - gross 0 0
Commodity derivative instruments, liabilities - gross 8 0
Fair Value, Recurring | Level 3 | Embedded derivatives in commodity contracts    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Commodity derivative instruments, liabilities - gross $ 47 $ 41