Acquisitions QS Investors Acquisition - Fair Value Assumptions (Details) - QS Investors [Domain]	3 Months Ended
Dec. 31, 2014
Fund management contracts [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Fair Value, Inputs, Level 3 [Member] \| Fund management contracts [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Attrition Rate	10.00%
Fair Value Inputs, Discount Rate	15.00%
Minimum [Member] \| Fair Value, Inputs, Level 3 [Member] \| Contingent Consideration Liability
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Long-term Revenue Growth Rate	0.00%
Maximum [Member] \| Fair Value, Inputs, Level 3 [Member] \| Contingent Consideration Liability
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Long-term Revenue Growth Rate	10.00%
Weighted Average [Member] \| Fair Value, Inputs, Level 3 [Member] \| Contingent Consideration Liability
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Long-term Revenue Growth Rate	6.00%
Contingent payment due on second anniversary of acquisition \| Fair Value, Inputs, Level 3 [Member] \| Contingent Consideration Liability
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	1.20%
Contingent payment due on fourth anniversary of acquisition [Member] \| Fair Value, Inputs, Level 3 [Member] \| Contingent Consideration Liability
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	2.10%

Amount used to represent the attrition when calculating the fair value of amortizable asset management contracts

No definition available.

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- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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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.

+ References

No definition available.

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- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Percentage of assumed long-term growth in revenues, used as an input to measure fair value.

+ References

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