PAYABLES AND ACCRUED EXPENSES - Components of Payables and Accrued Expenses (Details) - USD ($) $ in Millions	Jun. 30, 2025	Jun. 30, 2024
Payables and Accruals [Abstract]
Accounts payable	$ 220.3	$ 314.0
Employee compensation and benefits	372.8	354.4
Accrued broker fees	137.0	126.3
Accrued dividend payable	103.1	93.4
Customer deposits	84.4	52.7
Accrued taxes	60.1	112.5
Business process outsourcing administration fees	52.6	59.9
Operating lease liabilities	$ 37.2	$ 38.0
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Payables and accrued expenses	Payables and accrued expenses
Other	$ 45.4	$ 43.3
Total	$ 1,112.8	$ 1,194.4