Restructuring and Other Costs - Schedule of Reconciliation of Accruals and Charges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring And Other Costs [Abstract]
Additional accruals and adjustments to accruals (see table above)			$ 34.4	$ 11.5
Acquisition costs			27.9	11.0
Integration costs			22.6	21.4
Divestiture costs			0.2	0.2
Net property, plant and equipment			5.2	7.5
Severance and other employee costs			6.9	1.4
Equipment and inventory relocation costs			3.9	5.2
Facility carrying costs			2.8	3.3
Other costs			3.2	3.6
Restructuring and other costs	$ 17.9	$ 17.1	$ 107.1	$ 65.1