Other Current Liabilities - Schedule of Other Current Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2021	Sep. 30, 2020
Other current liabilities
Unrealized losses on foreign exchange contracts	$ 41.5	$ 24.3
Product warranty obligations	19.1	20.8
Taxes other than income taxes	80.0	58.5
Accrued interest	29.9	14.9
Dividends payable	124.4	0.0
Income taxes payable	48.5	79.8
Operating lease liabilities	89.8	89.7
Other	105.2	88.5
Other current liabilities	$ 538.4	$ 376.5