Financial Derivative Instruments - Premiums for Fuel Derivative Contracts (Details) - Fuel derivative contracts - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Designated as Hedging Instrument \| Fuel and oil
Derivative [Line Items]
Premium expense recognized in income on derivatives	$ 57	$ 64	$ 95
Not Designated as Hedging Instrument, Economic Hedge \| Other (gains)/losses, net
Derivative [Line Items]
Premium expense recognized in income on derivatives	$ 43	$ 34	$ 0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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