v3.25.0.1
Indebtedness: (Fair Value of Outstanding Long-Term Debt, Excluding Finance Leases) (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value of outstanding long-term debt, excluding finance leases $ 41,431 $ 38,259
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value of outstanding long-term debt, excluding finance leases $ 3,011 $ 6,687