Fair Value Measurements and Derivative Instruments - Summary of Effects on Consolidated Financial Statements of Designated As Cash Flow Hedges (Details) - Cash Flow Hedges - Designated - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Interest Rate Contracts
Derivative Instruments Gain Loss [Line Items]
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Interest Income (Expense), Operating	Interest Income (Expense), Operating
Income (Loss) recognized in Other comprehensive income (loss)	$ 13.1	$ (14.5)
Net income (loss) reclassified from Accumulated other comprehensive income (loss) into Interest expense	$ 2.0	$ 2.9
Fuel Contracts
Derivative Instruments Gain Loss [Line Items]
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of Goods and Services Sold	Cost of Goods and Services Sold
Income (Loss) recognized in Other comprehensive income (loss)	$ 0.0	$ 0.0
Net income (loss) reclassified from Accumulated other comprehensive income (loss) into Interest expense	$ (0.4)	$ 0.0