Investments - Fair Value Investments (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Fair Value Investments | ||
| Carrying value | $ 1,099 | $ 1,090 |
| Air France-KLM | ||
| Fair Value Investments | ||
| Ownership interest (percent) | 9.00% | 9.00% |
| Carrying value | $ 418 | $ 408 |
| GOL | ||
| Fair Value Investments | ||
| Ownership interest (percent) | 0.00% | 9.00% |
| Carrying value | $ 0 | $ 213 |
| China Eastern | ||
| Fair Value Investments | ||
| Ownership interest (percent) | 3.00% | 3.00% |
| Carrying value | $ 258 | $ 259 |
| Hanjin-KAL | ||
| Fair Value Investments | ||
| Ownership interest (percent) | 10.00% | 0.00% |
| Carrying value | $ 205 | $ 0 |
| Other Investments | ||
| Fair Value Investments | ||
| Carrying value | $ 218 | $ 210 |