Reportable Business Segments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	$ 224,483	$ 215,670	$ 655,453	$ 607,125
Interest expense	(16,048)	(15,166)	(47,126)	(44,014)
Stock-based compensation expense	(9,413)	(8,066)	(26,584)	(23,167)
Acquisition-related expenses	(2,537)		(2,537)
Income before income taxes	212,060	203,140	617,770	570,568
Segment operating income
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	245,824	233,214	713,250	657,793
Unallocated amount to segment
Reconciliation of segment operating income to consolidated income before income taxes
Interest expense	(16,048)	(15,166)	(47,126)	(44,014)
Interest Income	4,142	2,954	10,628	8,484
Stock-based compensation expense	(9,413)	(8,066)	(26,584)	(23,167)
Acquisition-related expenses	(2,537)		(2,537)
Other costs, net	(9,908)	(9,796)	(29,861)	(28,528)
Income before income taxes	$ 212,060	$ 203,140	$ 617,770	$ 570,568