Financial Derivative Instruments and Risk Management - Effect of Fuel and Interest Rate Derivative Instruments (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fuel Derivative Contracts
Derivative [Line Items]
Losses on fuel derivative and interest rate derivative contracts	$ 0	$ (26)	$ (17)
Losses on fuel derivative contracts	0	(56)	0
Cash flow hedge reclassification net of tax impact	0	(11)	0
Interest Rate Swap
Derivative [Line Items]
Losses on fuel derivative and interest rate derivative contracts	1	1	0
Cash flow hedge reclassification net of tax impact	$ 1	$ 0	$ 0

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The amount of net gain (loss) reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

+ References

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Gain (loss) incurred in hedging activities.

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Amount, after tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

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-Publisher FASB
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-Topic 220
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