Variable Interest Entities - Consolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Carrying amounts of consolidated VIE assets and liabilities
Total assets	$ 313,663.6	$ 305,046.7
Total liabilities	302,194.6	293,836.1
Redeemable noncontrolling interest	337.7	248.9	$ 262.0	$ 332.5
Aggregate consolidated variable interest entities
Carrying amounts of consolidated VIE assets and liabilities
Total assets	35,834.9	37,511.3
Total liabilities	33,051.8	34,778.5
Redeemable noncontrolling interest	309.9	226.4
Mandatory retirement savings funds
Carrying amounts of consolidated VIE assets and liabilities
Total assets	33,130.4	35,034.4
Total liabilities	32,802.2	34,688.3
Real estate VIE
Carrying amounts of consolidated VIE assets and liabilities
Total assets	814.3	829.1
Total liabilities	69.4	63.0
Sponsored investment funds
Carrying amounts of consolidated VIE assets and liabilities
Total assets	833.7	523.8
Total liabilities	160.3	6.3
Redeemable noncontrolling interest	309.9	226.4
Residential mortgage loans VIE
Carrying amounts of consolidated VIE assets and liabilities
Total assets	806.5	874.7
Total liabilities	19.9	20.9
Asset-backed limited partnership
Carrying amounts of consolidated VIE assets and liabilities
Total assets	$ 250.0	$ 249.3