Summary of Significant Accounting Policies - Investments in Unconsolidated Variable Interest Entities (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Investments	$ 897.2	$ 931.6
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Investments	482.5	511.8
Receivables	13.9	3.7
Maximum Exposure to Loss	$ 496.4	$ 515.5

For an unclassified balance sheet, the amount due from customers or clients for goods or services that have been delivered or sold in the normal course of business, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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Sum of the carrying amounts as of the balance sheet date of all investments.

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The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

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