Accrued Liabilities (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Accrued Liabilities [Abstract]
Salaries, benefits and related expenses	$ 420.1	$ 470.0
Office and related expenses	51.7	62.0
Acquisition obligations	10.1	63.5
Interest	24.2	41.5
Professional fees	17.3	24.6
Other	100.6	118.9
Total accrued liabilities	$ 624.0	$ 780.5