Derivatives and Risk Management - Not Designated Hedge Gains (Losses) (Details) - Not designated as hedges - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized	$ 235	$ (43)
Foreign currency exchange contracts | Gain/(loss) on investments, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized	19	11
Fuel hedge contracts | Aircraft fuel and related taxes
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives recognized	$ 216	$ (54)