Goodwill and Other Intangible Assets, Goodwill by Reporting Unit (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Goodwill [Line Items]
Goodwill	$ 1,028.5	[1]	$ 984.7	[1]
United States [Member]
Goodwill [Line Items]
Goodwill	504.0		503.8
Netherlands (Vitae) [Member]
Goodwill [Line Items]
Goodwill	78.7		79.3
France [Member]
Goodwill [Line Items]
Goodwill	70.5		42.1
Right Management [Member]
Goodwill [Line Items]
Goodwill	62.2		60.3
Other reporting units [Member]
Goodwill [Line Items]
Goodwill	313.1	[2]	299.2	[2]
Elan [Member]
Goodwill [Line Items]
Goodwill			$ 123.8

[1] Balances were net of accumulated impairment loss of $513.4 as of both January 1, 2012 and September 30, 2012.

[2] Elan reporting unit, which carried $123.8 of goodwill as of December 31, 2011, was integrated into other reporting units within our Northern Europe reportable segment as of January 1, 2012.