Restructuring and Other Costs - Schedule of Reconciliation of Accruals and Charges (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Restructuring And Other Costs [Abstract]
Additional accruals and adjustments to accruals (see table above)	$ 18.1	$ 9.9
PP&E and related costs	(3.1)	(1.6)
Severance and other employee costs	0.2	0.1
Acquisition costs	1.9	11.0
Integration costs	0.6	4.3
Divestiture costs	0.3	1.4
Other restructuring costs	47.5	7.0
Restructuring and other costs, net	$ 65.5	$ 32.1