Accrued Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2017	Jun. 30, 2016
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 48.7	$ 41.8
Accrued postretirement benefits	13.8	13.8
Derivative financial instruments	11.7	31.6
Accrued interest expense	5.6	11.2
Other	36.9	40.8
Total accrued liabilities	$ 116.7	$ 139.2