Employee Benefit Plans - Components of Net Pension (Income)/Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Service cost – benefits earned during the period	$ 1.3	$ 1.2	$ 2.6	$ 2.3
Interest cost on projected benefits	21.1	19.5	42.3	39.0
Expected return on plan assets	(29.0)	(31.8)	(58.0)	(63.7)
Net amortization and deferral	0.8	0.4	1.5	1.0
Settlement charges and special termination benefits	0.0	0.0	0.0	1.4
Net pension (income)/expense	$ (5.8)	$ (10.7)	$ (11.6)	$ (20.0)