Supplementary Data Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Accrued Liabilities [Abstract]
Salaries, benefits and related expenses	$ 386.9	$ 502.4
Acquisition obligations	73.8	50.1
Office and related expenses	42.9	51.0
Interest	17.2	17.3
Other	110.9	139.5
Total accrued liabilities	$ 631.7	$ 760.3