Other Current Liabilities - Schedule of Other Current Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016
Other current liabilities
Unrealized losses on foreign exchange contracts	$ 11.2	$ 31.3
Product warranty obligations	30.0	28.5	$ 27.2	$ 28.0
Taxes other than income taxes	39.3	42.7
Accrued interest	15.3	16.9
Dividends payable	113.3	0.0
Income taxes payable	55.5	32.6
Other	129.4	68.2
Other current liabilities	$ 394.0	$ 220.2