Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2015	Jun. 30, 2015
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 44.3	$ 44.3
Derivative financial instruments	42.2	32.7
Accrued postretirement benefits	14.0	14.0
Accrued income taxes	9.3	8.7
Accrued interest expense	5.6	11.2
Accrued pension liabilities	3.3	3.3
Other	40.3	38.4
Total accrued liabilities	$ 159.0	$ 152.6