Variable Interest Entities - Consolidated VIEs (Details) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Carrying amounts of consolidated VIE assets and liabilities
Total assets	$ 282,580.6		$ 304,657.2
Total liabilities	272,837.2		288,198.9
Redeemable noncontrolling interest	255.1	$ 268.5	332.5	$ 343.3	$ 330.6	$ 255.6
Aggregate consolidated variable interest entities
Carrying amounts of consolidated VIE assets and liabilities
Total assets	32,569.3		37,269.2
Total liabilities	29,790.0		34,360.7
Redeemable noncontrolling interest	228.2		304.0
Mandatory retirement savings funds
Carrying amounts of consolidated VIE assets and liabilities
Total assets	29,985.2		34,687.0
Total liabilities	29,691.3		34,301.8
Real estate VIE
Carrying amounts of consolidated VIE assets and liabilities
Total assets	651.1		709.6
Total liabilities	48.3		36.1
Sponsored investment funds
Carrying amounts of consolidated VIE assets and liabilities
Total assets	434.7		609.4
Total liabilities	6.2		2.5
Redeemable noncontrolling interest	228.2		304.0
Residential mortgage loans VIE
Carrying amounts of consolidated VIE assets and liabilities
Total assets	1,498.3		1,263.2
Total liabilities	$ 44.2		$ 20.3