Payables and Accrued Expenses - Components of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2023	Jun. 30, 2022
Payables and Accruals [Abstract]
Accounts payable	$ 183.8	$ 244.9
Employee compensation and benefits	272.8	348.1
Accrued broker fees	110.1	154.1
Accrued dividend payable	85.4	75.0
Customer deposits	74.5	58.7
Business process outsourcing administration fees	61.5	65.5
Accrued taxes	50.2	40.9
Operating lease liabilities	38.9	45.4
Other	81.7	82.2
Total	$ 958.8	$ 1,114.9
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Total	Total