Investments - Variable Interest Entity (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Variable Interest Entity
Total Assets	$ 26,708.5	$ 27,619.0
Total Liabilities	13,312.0	13,954.9
RMMC/RMBC
Variable Interest Entity
Total Assets	234.7	204.9
Total Liabilities	22.7	19.1
Other
Variable Interest Entity
Total Assets	45.1	70.8
Total Liabilities	$ 15.1	$ 14.8