Variable Interest Entities - Assets and Liabilities of Funds that are VIEs (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Assets
Total assets	$ 555.2	$ 611.4
Liabilities
Total liabilities	559.0	561.9
VIEs, Consolidated Funds
Assets
Investments	71.2	33.9
Other assets of consolidated Funds	21.4	1.3
Total assets	92.6	35.2
Liabilities
Liabilities of consolidated Funds	7.5	4.3
Total liabilities	$ 7.5	$ 4.3