Investments - Fair Value Investments (Details) - USD ($) $ in Millions |
Sep. 30, 2020 |
Jan. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|---|
| Fair Value Investments | |||
| Carrying value | $ 1,310 | $ 1,099 | |
| Hanjin-KAL | |||
| Fair Value Investments | |||
| Ownership interest (percent) | 15.00% | 10.00% | |
| Carrying value | $ 517 | $ 205 | |
| Air France-KLM | |||
| Fair Value Investments | |||
| Ownership interest (percent) | 9.00% | 9.00% | |
| Carrying value | $ 130 | $ 418 | |
| China Eastern | |||
| Fair Value Investments | |||
| Ownership interest (percent) | 3.00% | 3.00% | |
| Carrying value | $ 199 | $ 258 | |
| Wheels Up | |||
| Fair Value Investments | |||
| Ownership interest (percent) | 25.00% | 27.00% | 0.00% |
| Carrying value | $ 234 | $ 0 | |
| Other investments | |||
| Fair Value Investments | |||
| Carrying value | $ 230 | $ 218 |