Investments - Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net Investment Income [Line Items]
Investment income (loss)	$ (0.4)	$ 0.3	$ (1.2)	$ 7.6
Consolidated Entity Excluding Consolidated Funds
Net Investment Income [Line Items]
Investment income (loss)	(0.4)	0.3	(1.2)	7.6
Consolidated Entity Excluding Consolidated Funds | Realized and unrealized gains (losses) on other investments held at fair value
Net Investment Income [Line Items]
Investment income (loss)	(0.4)	0.1	(1.2)	5.0
Consolidated Entity Excluding Consolidated Funds | Earnings from equity-accounted investment in Affiliate
Net Investment Income [Line Items]
Investment income (loss)	$ 0.0	$ 0.2	$ 0.0	$ 2.6