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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Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Financial Derivative Instruments - Premiums for Fuel Derivative Contracts (Details) - Fuel derivative contracts - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Designated as Hedging Instrument \| Fuel and oil
Derivative [Line Items]
Premium (benefit) expense recognized in income on derivatives			$ 105	$ 57	$ 64
Not Designated as Hedging Instrument, Economic Hedge \| Other (gains)/losses, net
Derivative [Line Items]
Premium (benefit) expense recognized in income on derivatives	$ (28)	$ 43			$ 34