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Assets and Liabilities Measured at Fair Value - Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring - USD ($) $ in Millions | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Financial assets |  |
Fuel derivative | $ 0.2 | $ 0.2
Deferred compensation plan assets | 15.2 | 14.9
Financial liabilities |  |
Fair value, net asset (liability) | (10.4) | (11.2)
Deferred compensation plan liabilities |  |
Financial liabilities |  |
Deferred compensation plan liabilities | (25.8) | (26.3)
Level 1 |  |
Financial assets |  |
Fuel derivative | 0.0 | 0.0
Deferred compensation plan assets | 15.2 | 14.9
Financial liabilities |  |
Fair value, net asset (liability) | (10.6) | (11.4)
Level 1 | Deferred compensation plan liabilities |  |
Financial liabilities |  |
Deferred compensation plan liabilities | (25.8) | (26.3)
Level 2 |  |
Financial assets |  |
Fuel derivative | 0.0 | 0.0
Deferred compensation plan assets | 0.0 | 0.0
Financial liabilities |  |
Fair value, net asset (liability) | 0.0 | 0.0
Level 2 | Deferred compensation plan liabilities |  |
Financial liabilities |  |
Deferred compensation plan liabilities | 0.0 | 0.0
Level 3 |  |
Financial assets |  |
Fuel derivative | 0.2 | 0.2
Deferred compensation plan assets | 0.0 | 0.0
Financial liabilities |  |
Fair value, net asset (liability) | 0.2 | 0.2
Level 3 | Deferred compensation plan liabilities |  |
Financial liabilities |  |
Deferred compensation plan liabilities | $ 0.0 | $ 0.0

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