Investments - Schedule of Consolidated Investments (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entity
Total Assets	$ 27,619.0	$ 27,331.1
Total Liabilities	13,954.9	14,709.8
RMMC/RMBC
Variable Interest Entity
Total Assets	204.9	239.3
Total Liabilities	19.1	17.9
Other
Variable Interest Entity
Total Assets	70.8	93.4
Total Liabilities	$ 14.8	$ 18.0