Commitments and Contingencies - Employees (Details) $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2021	Dec. 31, 2021 USD ($) employeeGroup	Dec. 31, 2020 USD ($)
Health Insurance Product Line
Concentration Risk [Line Items]
Accrued health care claims | $		$ 9.1	$ 7.3
International Association of Machinists and Aerospace Workers (IAMAW)
Concentration Risk [Line Items]
Collective bargaining arrangement, term	5 years
Unionized employees concentration risk | Number of employees, total
Concentration Risk [Line Items]
Union-represented employee groups | employeeGroup		5
Concentration of risk		81.00%
Unionized employees concentration risk | Number of employees, total | Air Line Pilots Association, International (ALPA)
Concentration Risk [Line Items]
Concentration of risk		28.00%
Unionized employees concentration risk | Number of employees, total | Association of Flight Attendants (AFA-CWA)
Concentration Risk [Line Items]
Concentration of risk		47.00%
Unionized employees concentration risk | Number of employees, total | Professional Airline Flight Control Association (PAFCA)
Concentration Risk [Line Items]
Concentration of risk		1.00%
Unionized employees concentration risk | Number of employees, total | International Association of Machinists and Aerospace Workers (IAMAW)
Concentration Risk [Line Items]
Concentration of risk		3.00%
Unionized employees concentration risk | Number of employees, total | Transport Workers Union of America (TWU)
Concentration Risk [Line Items]
Concentration of risk		2.00%