Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Jun. 30, 2020
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 47.0	$ 50.4
Accrued postretirement benefits	14.0	14.0
Derivative financial instruments	7.0	11.1
Current portion of lease liabilities	11.1	11.5
Contract liabilities	11.3	12.3
Accrued interest expense	5.4	10.4
Accrued pension liabilities	27.3	20.2
Accrued income taxes	0.7	1.0
Other	26.5	27.0
Total accrued liabilities	$ 150.3	$ 157.9