Payables and Accrued Expenses - Components of Payables and Accrued Expenses (Details) - USD ($) $ in Millions	Jun. 30, 2020	Jun. 30, 2019
Other Liabilities Disclosure [Abstract]
Accounts payable	$ 151.8	$ 133.7
Employee compensation and benefits	260.4	232.2
Accrued broker fees	109.5	87.0
Accrued dividend payable	62.2	55.4
Managed services administration fees	59.4	53.1
Customer deposits	44.5	34.8
Accrued taxes	38.5	68.9
Operating lease liabilities	35.3
Other	68.6	46.6
Total	$ 829.9	$ 711.7