Investments - Schedule of Consolidated Investments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Variable Interest Entity
Total Assets	$ 26,064.3	$ 26,375.1
Total Liabilities	12,611.6	12,940.0
RMMC/RMBC
Variable Interest Entity
Total Assets	230.3	261.6
Total Liabilities	29.8	24.7
Other
Variable Interest Entity
Total Assets	0.0	2.8
Total Liabilities	$ 0.0	$ 3.3