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Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis (Details) - Fair Value Measured on a Recurring Basis - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financial Assets
Investments in marketable securities	$ 74.9	$ 59.4
Derivative financial instruments	3.5	7.9
Financial Liabilities
Affiliate equity repurchase obligations	22.0	19.8
Derivative financial instruments	4.2	1.0
Level 1
Financial Assets
Investments in marketable securities	25.7	24.4
Derivative financial instruments	0.0	0.0
Financial Liabilities
Affiliate equity repurchase obligations	0.0	0.0
Derivative financial instruments	0.0	0.0
Level 2
Financial Assets
Investments in marketable securities	49.2	35.0
Derivative financial instruments	3.5	7.9
Financial Liabilities
Affiliate equity repurchase obligations	0.0	0.0
Derivative financial instruments	4.2	1.0
Level 3
Financial Assets
Investments in marketable securities	0.0	0.0
Derivative financial instruments	0.0	0.0
Financial Liabilities
Affiliate equity repurchase obligations	22.0	19.8
Derivative financial instruments	$ 0.0	$ 0.0

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Due to Related Parties, Fair Value Disclosure

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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