Restructuring and Other Costs - Schedule of Restructuring and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring And Related Activities [Abstract]
Restructuring	$ 6.4	$ 6.9	$ 56.4	$ 32.5
Other	11.5	10.2	50.7	32.6
Restructuring and other costs	$ 17.9	$ 17.1	$ 107.1	$ 65.1