Accrued Liabilities - Schedule of Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2023	Jun. 30, 2023
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 59.7	$ 92.4
Accrued postretirement benefits	16.1	16.1
Contract liabilities	11.0	14.0
Current portion of lease liabilities	8.8	9.1
Derivative financial instruments	6.7	6.4
Accrued interest expense	6.4	18.5
Accrued taxes	5.6	4.9
Accrued pension liabilities	3.3	3.3
Accrued income taxes	2.3	2.5
Other	13.2	14.1
Total accrued liabilities	$ 133.1	$ 181.3