Equity Method Investments in Affiliates - Schedule of Equity Method Investments in Affiliates (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Goodwill	$ 2,689.2	$ 2,661.4	$ 2,651.7
Equity method investments in Affiliates (net)	2,134.4	2,074.8
Equity Method Investee
Schedule of Equity Method Investments [Line Items]
Goodwill	1,264.4	1,251.6
Definite-lived acquired client relationships (net)	470.1	479.5
Indefinite-lived acquired client relationships (net)	174.4	173.1
Undistributed earnings and tangible capital	225.5	170.6
Equity method investments in Affiliates (net)	$ 2,134.4	$ 2,074.8	$ 2,195.6

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

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