Payables and Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued compensation	$ 418.5	$ 455.0
Unsettled fund share payables	83.2	76.6
Accrued income taxes	87.7	67.9
Accrued professional fees	26.1	31.4
Other	113.8	98.5
Accounts payable and accrued liabilities	$ 729.3	$ 729.4