Payables and Accrued Expensess - Components of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Jun. 30, 2020
Payables and Accruals [Abstract]
Accounts payable	$ 120.0	$ 151.8
Employee compensation and benefits	156.6	260.4
Accrued dividend payable	66.4	62.2
Accrued broker fees	65.2	109.5
Managed services administration fees	56.0	59.4
Operating lease liabilities	40.7	35.3
Customer deposits	36.7	44.5
Accrued taxes	22.5	38.5
Other	68.3	68.6
Total	$ 632.3	$ 829.9