Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2016	Jun. 30, 2016
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 36.2	$ 41.8
Derivative financial instruments	20.0	31.6
Accrued postretirement benefits	13.7	13.8
Deferred revenue	8.9	8.9
Accrued interest expense	5.6	11.2
Accrued pension liabilities	4.1	10.1
Accrued income taxes	0.8	1.5
Other	21.5	20.3
Total accrued liabilities	$ 110.8	$ 139.2