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Discontinued Operations - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Jun. 02, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jul. 22, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations, net of tax		$ 0.0	$ 1.2	$ 0.0	$ 76.5
Income tax expense		$ 0.0	0.4	$ 0.0	4.1
Interests In Landmark
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Redemption of co-investments	$ 31.5
Discontinued Operations, Disposed of by Sale \| Interests In Landmark
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration	690.0
Income from discontinued operations, net of tax					509.2
Income tax expense					176.6
Discontinued Operations, Disposed of by Sale \| Thompson Siegel & Walmsley, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration						$ 240.0
Income from discontinued operations, net of tax			185.4		185.4
Income tax expense			$ 74.0		$ 74.0
Discontinued Operations, Held-for-sale \| Landmark Partners, LLC , Carried Interest And Co-Investments
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration	$ 31.5