Equity Method Investments in Affiliates - Schedule of Equity Method Investments in Affiliates (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Goodwill	$ 2,648.9	$ 2,648.7
Equity method investments in Affiliates (net)	1,920.2	2,139.5
Equity Method Investee
Schedule of Equity Method Investments [Line Items]
Goodwill	1,278.4	1,262.4
Definite-lived acquired client relationships (net)	462.0	479.4
Indefinite-lived acquired client relationships (net)	121.1	119.0
Undistributed earnings and tangible capital	58.7	278.7
Equity method investments in Affiliates (net)	$ 1,920.2	$ 2,139.5

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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