Restructuring and Other Costs - Schedule of Changes in Restructuring Accrual Charges (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Restructuring And Other Costs [Abstract]
Accrual at beginning of fiscal year	$ 32.3	$ 31.6
Additional accruals	19.1	16.6
Payments	(18.4)	(9.8)
Adjustment to accruals	1.2	(1.9)
Foreign currency rate changes	0.1	0.2
Accrual at December 31	$ 34.3	$ 36.7