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Equity Method Investment, Measurement Input

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of liabilities classified as other.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Equity Method Investments in Affiliates - Additional Information (Details) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2021 USD ($) affiliate	Dec. 31, 2020 USD ($) affiliate	Mar. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) affiliate	Dec. 31, 2020 USD ($) affiliate	Dec. 31, 2019 USD ($)
Estimated Future Amortization Expense of Finite-Lived Intangibles
Contingent payment obligation	$ 709.2	$ 452.2		$ 709.2	$ 452.2
Number of affiliates accounted for under the equity method \| affiliate	21	18		21	18
Acquired Client Relationships
Schedule of Equity Method Investments [Line Items]
Intangible amortization expense				$ 35.7	$ 69.8
Estimated Future Amortization Expense of Finite-Lived Intangibles
Intangible future amortization expense in 2022	$ 50.0			50.0
Intangible future amortization expense in 2023	50.0			50.0
Intangible future amortization expense in 2024	35.0			35.0
Intangible future amortization expense in 2025	30.0			30.0
Intangible future amortization expense in 2026	30.0			30.0
Equity Method Investee
Estimated Future Amortization Expense of Finite-Lived Intangibles
Impairment expense	52.0	$ 45.0	$ 140.0
Deferred payment obligations payable in 2022	50.8			50.8
Equity Method Investee \| Achievement of Specified Financial Targets
Estimated Future Amortization Expense of Finite-Lived Intangibles
Contingent payment obligation	$ 43.0			$ 43.0
Equity Method Investee \| Growth rate period
Estimated Future Amortization Expense of Finite-Lived Intangibles
Measurement input	5	5	5	5	5
Equity Method Investee \| Growth rate
Estimated Future Amortization Expense of Finite-Lived Intangibles
Measurement input	0.003	(0.05)	(0.02)	0.003	(0.05)
Equity Method Investee \| Market participant tax rates
Estimated Future Amortization Expense of Finite-Lived Intangibles
Measurement input	0.25	0.25	0.25	0.25	0.25
Equity Method Investee \| Discount rates, asset based fees
Estimated Future Amortization Expense of Finite-Lived Intangibles
Measurement input	0.11	0.11	0.11	0.11	0.11
Equity Method Investee \| Discount rates, performance based fees
Estimated Future Amortization Expense of Finite-Lived Intangibles
Measurement input	0.20	0.20	0.20	0.20	0.20
Equity Method Investee \| Acquired Client Relationships
Schedule of Equity Method Investments [Line Items]
Intangible amortization expense				$ 123.0	$ 147.0	$ 142.4
Estimated Future Amortization Expense of Finite-Lived Intangibles
Intangible future amortization expense in 2022	$ 80.0			80.0
Intangible future amortization expense in 2023	80.0			80.0
Intangible future amortization expense in 2024	50.0			50.0
Intangible future amortization expense in 2025	50.0			50.0
Intangible future amortization expense in 2026	$ 50.0			$ 50.0