AOCI - Schedule of AOCI Components (Details) $ in Millions	3 Months Ended
Mar. 31, 2020 USD ($)
Fuel derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ (125)
Changes in fair value	(108)
Ending Balance	(209)
Interest rate derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(33)
Changes in fair value	(42)
Reclassification to earnings	0
Ending Balance	(75)
Defined Benefit Plan Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	20
Changes in fair value	0
Reclassification to earnings	0
Ending Balance	20
Other comprehensive income (loss) other changes net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	59
Changes in fair value	(37)
Reclassification to earnings	0
Ending Balance	22
Deferred Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	18
Changes in fair value	43
Reclassification to earnings	(5)
Ending Balance	56
AOCI Including Portion Attributable to Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(61)
Changes in fair value	(144)
Reclassification to earnings	19
Ending Balance	(186)
Reclassification out of Accumulated Other Comprehensive Income (Loss) \| Fuel derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification to earnings	$ 24

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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