Other Current Liabilities - Schedule of Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020
Other current liabilities
Unrealized losses on foreign exchange contracts	$ 60.0	$ 24.3
Product warranty obligations	19.7	20.8
Taxes other than income taxes	93.9	58.5
Accrued interest	29.8	14.9
Income taxes payable	111.4	79.8
Operating lease liabilities	94.0	89.7
Other	101.6	88.5
Other current liabilities	$ 510.4	$ 376.5