Summary of Significant Accounting Policies - Concentrations of Risk (Details)	12 Months Ended
Dec. 31, 2023 employeeGroup lessor vendor	Dec. 31, 2022	Dec. 31, 2021
Concentration Risk [Line Items]
Number of union-represented employee groups \| employeeGroup	7
Amount of employees represented by unions	86.00%
Number of lessors with capitalized maintenance deposits \| lessor	1
Number of vendors with pre-delivery deposits for flight equipment \| vendor	1
Cost Risk \| Operating Expense \| Aircraft Fuel Cost
Concentration Risk [Line Items]
Concentration risk	31.00%	34.00%	26.00%

Aircraft Maintenance Deposits, Number Of Lessors

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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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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Percentage of entity's employees covered by collective-bargaining arrangement (CBA) to all entity's employees in multiemployer pension plan determined to be individually significant.

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