Supplemental Information (Related Party Transactions) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Sep. 30, 2025
Related Party Transaction [Line Items]
Sales	$ 3,161.0	$ 3,022.7	$ 9,435.3	$ 8,870.4
Trade receivables, net	1,881.5		1,881.5		$ 1,901.2
Current portion of long-term debt	769.5		769.5		716.3
Mantle Ridge LP and Affiliates Transaction
Related Party Transaction [Line Items]
Reimbursement for costs incurred in connection with the proxy contest		24.7
Related Party
Related Party Transaction [Line Items]
Sales	85.0	90.0	275.0	$ 240.0
Trade receivables, net	200.0		200.0		105.0
Current portion of long-term debt	29.5		29.5		59.0
Related Party | Lu-An Clean Energy Company Transaction
Related Party Transaction [Line Items]
Total debt	$ 215.7		$ 215.7		$ 236.5
Affiliated Entity | Mantle Ridge LP and Affiliates Transaction
Related Party Transaction [Line Items]
Reimbursement for costs incurred in connection with the proxy contest		$ 24.7