Goodwill and Other Intangible Assets, Goodwill by Reporting Unit (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Goodwill [Line Items]
Goodwill	$ 1,056.8	[1]	$ 1,075.2	[1]
United States [Member]
Goodwill [Line Items]
Goodwill	505.9		505.9
Netherlands [Member]
Goodwill [Line Items]
Goodwill	93.7		85.9
United Kingdom [Member]
Goodwill [Line Items]
Goodwill	81.6		85.9
France [Member]
Goodwill [Line Items]
Goodwill	68.2		76.9
Right Management [Member]
Goodwill [Line Items]
Goodwill	62.1		62.1
Other reporting units [Member]
Goodwill [Line Items]
Goodwill	$ 245.3		$ 258.5

[1] Balances were net of accumulated impairment loss of $513.4 as of both March 31, 2015 and December 31, 2014.