Restructuring and Other Costs - Schedule of Changes in Restructuring Accrual Charges (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Restructuring And Other Costs [Abstract]
Accrual at beginning of fiscal year	$ 13.4	$ 17.2
Additional accruals	24.1	12.1
Payments	(8.2)	(14.7)
Adjustment to accruals	(0.8)	(2.1)
Foreign currency rate changes and other	(0.2)	(1.8)
Accrual at June 30	$ 28.3	$ 10.7