Summary of Significant Accounting Policies - Other Investments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cost method investments - jetblue tech ventures	$ 45	$ 40
Measurement alternative, ownership percentage	10.00%
Cost method investments - TWA flight center hotel	$ 14	$ 14

Ownership Interest, Measurement Alternative, Percentage

No definition available.

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