Goodwill and Other Intangible Assets - Changes in Goodwill by Reportable Segment (Details) $ in Millions	9 Months Ended
Sep. 30, 2015 USD ($)
Goodwill [Roll Forward]
Balance, January 1, 2015	$ 1,075.2
Goodwill acquired	199.6
Currency and other impacts	(31.4)
Balance, September 30, 2015	1,243.4
Right Management
Goodwill [Roll Forward]
Balance, January 1, 2015	62.1
Balance, September 30, 2015	62.1
Reportable segments \| Americas
Goodwill [Roll Forward]
Balance, January 1, 2015	466.3
Goodwill acquired	51.2
Currency and other impacts	(2.1)
Balance, September 30, 2015	515.4
Reportable segments \| Americas \| United States \| Reportable subsegments
Goodwill [Roll Forward]
Balance, January 1, 2015	450.4
Balance, September 30, 2015	477.1
Reportable segments \| Southern Europe
Goodwill [Roll Forward]
Balance, January 1, 2015	100.5
Goodwill acquired	2.6
Currency and other impacts	(7.3)
Balance, September 30, 2015	95.8
Reportable segments \| Southern Europe \| France \| Reportable subsegments
Goodwill [Roll Forward]
Balance, January 1, 2015	76.9
Balance, September 30, 2015	71.0
Reportable segments \| Southern Europe \| Italy \| Reportable subsegments
Goodwill [Roll Forward]
Balance, January 1, 2015	5.0
Balance, September 30, 2015	4.6
Reportable segments \| Northern Europe
Goodwill [Roll Forward]
Balance, January 1, 2015	311.3
Goodwill acquired	136.7
Currency and other impacts	(17.5)
Balance, September 30, 2015	430.5
Reportable segments \| APME
Goodwill [Roll Forward]
Balance, January 1, 2015	70.1
Goodwill acquired	9.1
Currency and other impacts	(4.5)
Balance, September 30, 2015	74.7
Reportable segments \| Right Management
Goodwill [Roll Forward]
Balance, January 1, 2015	62.1
Goodwill acquired	0.0
Currency and other impacts	0.0
Balance, September 30, 2015	62.1
Corporate
Goodwill [Roll Forward]
Balance, January 1, 2015	64.9
Goodwill acquired	0.0
Currency and other impacts	0.0
Balance, September 30, 2015	64.9
Corporate \| Jefferson Wells
Goodwill [Roll Forward]
Balance, September 30, 2015	$ 55.5

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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

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-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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

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