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Investments in Affiliates and Affiliate Sponsored Investment Products - Affiliate Accounted For Under Equity Method (Details) - Affiliates accounted for under the equity method - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Unconsolidated VIE Net Assets	$ 1,594.4	$ 1,047.6
Carrying Value and Maximum Exposure to Loss	$ 2,765.7	$ 2,846.8

X

- Definition

Difference between the carrying amount of assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the variable interest entity (VIE) and the reporting entity's maximum exposure to loss as a result of its involvement with the VIE, where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=77990344&loc=d3e5728-111685

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- Definition

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.

+ References

No definition available.

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- Definition

Net carrying amount of the assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), when the reporting entity is not the VIE's primary beneficiary.

+ References

No definition available.

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