Other Current Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015
Other current liabilities
Unrealized losses on foreign exchange contracts	$ 27.4	$ 15.6
Product warranty obligations	27.2	28.0	$ 27.0	$ 27.9
Taxes other than income taxes	40.1	43.1
Accrued interest	16.2	16.9
Dividends payable	97.6	0.0
Income taxes payable	47.3	28.6
Rocky Flats settlement (Note 14)	0.0	242.5
Other	58.7	72.9
Other current liabilities	$ 314.5	$ 447.6