Discontinued Operations - Schedule of Divestitures and Assets Held for Sale (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Revenues	$ 0.0	$ 5.6	$ 0.0	$ 115.1
Compensation and benefits	0.0	3.6	0.0	91.2
General and administrative expenses	0.0	0.4	0.0	8.1
Amortization of intangibles	0.0	0.0	0.0	2.7
Depreciation and amortization	0.0	0.0	0.0	0.5
Consolidated Funds’ expense	0.0	0.0	0.0	0.1
Total operating expenses	0.0	4.0	0.0	102.6
Operating income	0.0	1.6	0.0	12.5
Investment gains of consolidated Funds	0.0	0.0	0.0	68.1
Income from discontinued operations before taxes	0.0	1.6	0.0	80.6
Income tax expense	0.0	0.4	0.0	4.1
Income from discontinued operations, net of tax	0.0	1.2	0.0	76.5
Gain on disposal of discontinued operations, net of tax	0.0	185.4	0.0	694.6
Tax effect	0.0	74.0	0.0	250.6
Income from discontinued operations, net of tax	0.0	186.6	0.0	771.1
Income from discontinued operations attributable to non-controlling interests	0.0	0.0	0.0	68.0
Net income from discontinued operations attributable to controlling interests	$ 0.0	$ 186.6	$ 0.0	$ 703.1