Segment Reporting (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Revenue $ 3,469.2 $ 3,502.2
Americas    
Revenue 2,151.0 2,081.3
Long-lived assets and goodwill 6,136.3 6,101.2
UNITED STATES    
Revenue 1,958.2 1,871.8
EMEA    
Revenue 961.4 1,061.6
Long-lived assets and goodwill 2,635.6 3,009.0
Asia Pacific    
Revenue 356.8 359.3
Long-lived assets and goodwill $ 549.4 $ 608.5