Fair Value Measurements, Investments and Notes Receivable - Narrative (Details) $ in Millions	12 Months Ended
Dec. 31, 2023 USD ($) aircraft
Fair Value [Line Items]
Investments in securities accounted for under the equity method	$ 230
Carrying amount of loan receivable	$ 103
Maximum \| Corporate Debt
Fair Value [Line Items]
Available for sale investment maturity term	15 months
Champlain
Fair Value [Line Items]
Number of regional aircraft \| aircraft	53
Republic
Fair Value [Line Items]
Number of regional aircraft \| aircraft	66
Champlain
Fair Value [Line Items]
Ownership stake	40.00%
Republic
Fair Value [Line Items]
Ownership stake	19.00%
UAV Fund
Fair Value [Line Items]
Ownership stake	38.00%
Fulcrum BioEnergy, Inc., Boom, Alder Fuels LLC, Heart Aerospace Incorporated and ZeroAvia, Inc.
Fair Value [Line Items]
Carrying value of other investment	$ 401

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Fair Value [Line Items]

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of investment in equity security without readily determinable fair value.

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Amortized cost, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Number of aircraft operated by the carrier.

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