Restructuring and Other Costs - Schedule of Restructuring and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Restructuring And Related Activities [Abstract]
Restructuring									$ 93.7	$ 111.0	$ 39.5
Other									19.0	62.7	65.9
Restructuring and Other Costs	$ 56.5	$ 9.7	$ 16.4	$ 30.1	$ 66.6	$ 17.9	$ 34.8	$ 54.4	$ 112.7	$ 173.7	$ 105.4