Financial Derivative Instruments - Premiums for Fuel Derivative Contracts (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Fuel derivative contracts \| Designated as Hedging Instrument \| Fuel and oil
Derivative [Line Items]
Premium expense recognized in income on derivatives	$ 30	$ 26

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.

No definition available.

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