Reportable Business Segments (Details 2) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	$ 294.8	$ 267.8	$ 815.7	$ 755.8
Interest expense	(17.0)	(21.1)	(51.1)	(60.2)
Stock-based compensation expense	(11.8)	(10.1)	(32.1)	(29.4)
Acquisition-related expenses		(2.5)	(5.7)	(4.6)
Income before income taxes	282.0	251.5	777.1	708.6
Operating Segment
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	317.6	291.1	886.5	820.4
Unallocated amount to segment
Reconciliation of segment operating income to consolidated income before income taxes
Interest expense	(17.0)	(21.1)	(51.1)	(60.2)
Interest Income	4.9	5.3	14.3	14.6
Stock-based compensation expense	(11.8)	(10.1)	(32.1)	(29.4)
Acquisition-related expenses		(2.5)	(5.7)	(4.6)
Other costs, net	(11.7)	(11.2)	(34.8)	(32.2)
Income before income taxes	$ 282.0	$ 251.5	$ 777.1	$ 708.6