Fair Value Measurements (Not Carried At Fair Value) (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Carrying Amount | ||
| Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items] | ||
| Long-term debt (excluding finance leases) | $ 37,106 | $ 37,627 |
| Fair Value | ||
| Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items] | ||
| Long-term debt (excluding finance leases) | 32,932 | 35,733 |
| Fair Value | Level 1 | ||
| Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items] | ||
| Long-term debt (excluding finance leases) | 0 | 0 |
| Fair Value | Level 2 | ||
| Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items] | ||
| Long-term debt (excluding finance leases) | 31,977 | 34,800 |
| Fair Value | Level 3 | ||
| Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items] | ||
| Long-term debt (excluding finance leases) | $ 955 | $ 933 |