Derivatives and Risk Management - Not Designated Hedge Gains (Losses) (Details) - Not designated as hedging instrument - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gain (loss) on derivatives recognized | $ (31) | $ 48 | $ (81) |
| Foreign currency exchange contracts | Gain/(loss) on investments, net | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gain (loss) on derivatives recognized | 10 | (4) | 0 |
| Fuel hedge contracts | Aircraft fuel and related taxes | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gain (loss) on derivatives recognized | $ (41) | $ 52 | $ (81) |