Business Combinations, Goodwill by Segment (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
BUSINESS COMBINATIONS, GOODWILL AND OTHER INTANGIBLE ASSETS [Abstract]
Intangible Assets, Net (Including Goodwill)	$ 3,008.7
Goodwill	307.4	$ 299.5	$ 295.0
Finite-Lived Intangible Assets, Net	298.6
Identifiable intangibles with indefinite useful lives	8.8
Goodwill [Roll Forward]
Goodwill	2,579.3	2,141.5
Goodwill Additions, net of adjustments	29.6	450.6
Goodwill, Translation Adjustments	92.4	(45.3)
Goodwill	2,701.3	2,546.8
Investment Management [Member]
Goodwill [Roll Forward]
Goodwill	15.4	17.6
Goodwill Additions, net of adjustments	0.0	0.0
Goodwill, Translation Adjustments	1.0	(1.5)
Goodwill	16.4	16.1
Americas [Member] \| Reportable Subsegments [Member]
Goodwill [Roll Forward]
Goodwill	1,406.1	1,161.1
Goodwill Additions, net of adjustments	5.2	174.2
Goodwill, Translation Adjustments	0.9	0.8
Goodwill	1,412.2	1,336.1
EMEA [Member] \| Reportable Subsegments [Member]
Goodwill [Roll Forward]
Goodwill	851.7	696.2
Goodwill Additions, net of adjustments	17.9	239.8
Goodwill, Translation Adjustments	80.5	(50.8)
Goodwill	950.1	885.2
Asia Pacific [Member] \| Reportable Subsegments [Member]
Goodwill [Roll Forward]
Goodwill	306.1	266.6
Goodwill Additions, net of adjustments	6.5	36.6
Goodwill, Translation Adjustments	10.0	6.2
Goodwill	$ 322.6	$ 309.4

-- None. No documentation exists for this element. --

No definition available.

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- Definition

The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation. Also includes purchase price allocation adjustment for allocations not yet complete at the prior year end.

+ References

No definition available.

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

+ References

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Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance.

+ References

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