Payables and Accrued Expenses - Components of Payables and Accrued Expenses (Details) - USD ($) $ in Millions	Jun. 30, 2021	Jun. 30, 2020
Other Liabilities Disclosure [Abstract]
Accounts payable	$ 248.9	$ 151.8
Employee compensation and benefits	343.7	260.4
Accrued broker fees	136.0	109.5
Accrued dividend payable	66.8	62.2
Business process outsourcing administration fees	66.1	59.4
Customer deposits	55.5	44.5
Accrued taxes	42.6	38.5
Operating lease liabilities	40.2	35.3
Other	102.9	68.6
Total	$ 1,102.7	$ 829.9