Geographic and Product Information (Revenue and Long-Lived Assets) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operations by Geographic Area
Total revenues	$ 2,563.3	$ 2,334.1	$ 2,277.8	$ 2,080.8	$ 2,085.5	$ 1,982.2	$ 1,872.7	$ 1,730.0	$ 9,256.0	$ 7,670.4	$ 6,493.9
Total long lived assets	814.1				642.6				814.1	642.6
United States
Operations by Geographic Area
Total revenues									5,604.0	4,482.8	3,862.1
Total long lived assets	585.5				406.1				585.5	406.1
Europe
Operations by Geographic Area
Total revenues									2,624.3	2,310.8	1,865.7
Total long lived assets	215.2				222.2				215.2	222.2
All other
Operations by Geographic Area
Total revenues									1,027.7	876.8	$ 766.1
Total long lived assets	$ 13.4				$ 14.3				$ 13.4	$ 14.3