Accrued Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Jun. 30, 2019
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 44.1	$ 71.2
Accrued postretirement benefits	14.7	14.7
Derivative financial instruments	14.5	16.7
Current portion of lease liabilities	11.7
Contract liabilities	11.0	10.5
Contract liabilities		10.5
Accrued interest expense	3.9	10.4
Accrued pension liabilities	3.4	3.4
Accrued income taxes	2.5	4.2
Other	30.6	26.5
Total accrued liabilities	$ 136.4	$ 157.6