Summary of Significant Accounting Policies and Adoption of New Accounting Pronouncements (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Accrued performance fees	$ 11.9	$ 15.8
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Noncontrolling interests	$ 1,805.7	$ 2,142.8
Minimum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of investments hedged	50.00%
Maximum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of investments hedged	100.00%
KWE [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Noncontrolling interests	$ 1,600.0
Percentage of investments hedged	84.40%

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- References

No definition available.

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For an unclassified balance sheet, the amount of fees and other revenue, excluding investment income receivable, earned but not yet received, which were recognized in conformity with revenue recognition criteria based on estimates or specific contractual terms.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.31)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 27

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 20

-Article 7

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