Supplementary Data Accrued Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Accrued Liabilities [Abstract]
Salaries, benefits and related expenses	$ 301.7	$ 499.0
Acquisition obligations	91.1	77.5
Office and related expenses	46.7	46.7
Interest	17.2	17.3
Other	115.3	153.5
Total accrued liabilities	$ 572.0	$ 794.0