Commitments and Contingencies - Employees (Details) $ in Millions		3 Months Ended	12 Months Ended
	Feb. 21, 2022	Dec. 31, 2022 USD ($) employeeGroup employee	Dec. 31, 2022 USD ($) employeeGroup employee	Dec. 31, 2021 USD ($)
Health Insurance Product Line
Concentration Risk [Line Items]
Accrued health care claims | $		$ 11.0	$ 11.0	$ 9.1
Air Line Pilots Association, International (ALPA)
Concentration Risk [Line Items]
Collective bargaining arrangement, term		2 years
Transport Workers Union of America (TWU)
Concentration Risk [Line Items]
Collective bargaining arrangement, term	5 years
Aircraft Mechanics Fraternal Association, Aircraft Maintenance Technicians
Concentration Risk [Line Items]
Number of employees included n union application (approximately) | employee		600	600
Number of employees, total | Unionized employees concentration risk
Concentration Risk [Line Items]
Union-represented employee groups | employeeGroup		5	5
Concentration of risk			81.00%
Number of employees, total | Unionized employees concentration risk | Air Line Pilots Association, International (ALPA)
Concentration Risk [Line Items]
Concentration of risk			27.00%
Number of employees, total | Unionized employees concentration risk | Association of Flight Attendants (AFA-CWA)
Concentration Risk [Line Items]
Concentration of risk			48.00%
Number of employees, total | Unionized employees concentration risk | Professional Airline Flight Control Association (PAFCA)
Concentration Risk [Line Items]
Concentration of risk			1.00%
Number of employees, total | Unionized employees concentration risk | International Association of Machinists and Aerospace Workers (IAMAW)
Concentration Risk [Line Items]
Concentration of risk			3.00%
Number of employees, total | Unionized employees concentration risk | Transport Workers Union of America (TWU)
Concentration Risk [Line Items]
Concentration of risk			2.00%