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No definition available.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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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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- Definition

Amount, after accumulated amortization, of debt discount.

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- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as current. Excludes lease obligation.

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Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation.

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Debt and Other Obligations - Schedule of Long-term Debt (Details) $ in Millions	Sep. 30, 2024 USD ($) aircraft	Dec. 31, 2023 USD ($)	Sep. 30, 2023	Apr. 30, 2021	May 12, 2020
Debt Instrument [Line Items]
Long-term debt	$ 3,287.2	$ 3,439.1
Less current maturities	1,253.2	315.3
Less unamortized discounts, net	47.6	69.0
Total	$ 1,986.4	$ 3,054.8
Aircraft
Debt Instrument [Line Items]
Failed aircraft sale leaseback \| aircraft	18
8.00% senior secured notes due 2025 \| 8.00% Senior Secured Notes Due 2025
Debt Instrument [Line Items]
Stated interest rate percentage	8.00%	8.00%	8.00%
Long-term debt	$ 1,110.0	$ 1,110.0
Weighted-average interest rate	8.00%	8.00%
Fixed-rate loans due through 2039
Debt Instrument [Line Items]
Long-term debt	$ 1,011.8	$ 1,093.3
Weighted-average interest rate	6.44%	5.83%
Unsecured term loans due in 2031 \| Unsecured term loans
Debt Instrument [Line Items]
Long-term debt	$ 136.3	$ 136.3
Weighted-average interest rate	1.00%	1.00%
Fixed-rate class A 2015-1 EETC due through 2028
Debt Instrument [Line Items]
Long-term debt	$ 245.6	$ 256.6
Weighted-average interest rate	4.10%	4.10%
Fixed-rate class B 2015-1 EETC due through 2024
Debt Instrument [Line Items]
Long-term debt	$ 0.0	$ 40.0
Weighted-average interest rate	4.45%	4.45%
Fixed-rate class AA 2017-1 EETC due through 2030
Debt Instrument [Line Items]
Long-term debt	$ 160.3	$ 172.2
Weighted-average interest rate	3.38%	3.38%
Fixed-rate class A 2017-1 EETC due through 2030
Debt Instrument [Line Items]
Long-term debt	$ 53.4	$ 57.4
Weighted-average interest rate	3.65%	3.65%
Fixed-rate class B 2017-1 EETC due through 2026
Debt Instrument [Line Items]
Long-term debt	$ 44.7	$ 48.2
Weighted-average interest rate	3.80%	3.80%
Convertible Notes \| Convertible notes due 2025
Debt Instrument [Line Items]
Stated interest rate percentage	4.75%	4.75%			4.75%
Long-term debt	$ 25.1	$ 25.1
Weighted-average interest rate	4.75%	4.75%
Convertible Notes \| Convertible notes due 2026
Debt Instrument [Line Items]
Stated interest rate percentage	1.00%	1.00%		1.00%
Long-term debt	$ 500.0	$ 500.0
Weighted-average interest rate	1.00%	1.00%
Less unamortized discounts, net	$ 18.7
Total	$ 481.3