Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Jun. 30, 2021
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 41.3	$ 81.4
Accrued interest expense	16.2	16.2
Accrued postretirement benefits	14.4	14.4
Contract liabilities	12.8	8.6
Current portion of lease liabilities	9.7	9.0
Accrued pension liabilities	3.5	3.5
Accrued income taxes	1.8	0.5
Derivative financial instruments	0.1	4.2
Other	24.2	26.1
Total accrued liabilities	$ 124.0	$ 163.9