Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Other current liabilities
Unrealized losses on foreign exchange contracts	$ 15.4	$ 15.6
Product warranty obligations	27.2	28.0	$ 27.6	$ 27.9
Taxes other than income taxes	45.2	43.1
Accrued interest	16.2	16.9
Income taxes payable	60.5	28.6
Rocky Flats settlement (Note 13)	242.5	242.5
Other	64.5	72.9
Other current liabilities	$ 471.5	$ 447.6