Restructuring and Other Costs - Schedule of Reconciliation of Accruals and Charges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Restructuring And Other Costs [Abstract]
Additional accruals and adjustments to accruals (see table above)			$ 25.6	$ 29.6
Acquisition costs			0.4	27.0
Integration costs			13.4	12.0
Divestiture costs				0.2
Net property, plant and equipment			3.0	6.9
Severance and other employee costs			(0.3)	6.3
Equipment and inventory relocation costs			1.4	2.1
Facility carrying costs			1.0	2.0
Other costs			2.0	3.1
Restructuring and other costs	$ 16.4	$ 34.8	$ 46.5	$ 89.2