Income Taxes - Provision for Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Federal:
Current	$ 792,148	$ 488,031	$ 518,309
Deferred	(79,943)	14,333	4,170
Federal, total	712,205	502,364	522,479
State:
Current	74,064	70,676	49,488
Deferred	(12,308)	(45,272)	(20,419)
State, total	61,756	25,404	29,069
Foreign:
Current	168,959	101,101	120,287
Deferred	(25,322)	11,516	(33,538)
Foreign, total	143,637	112,617	86,749
Total provision for income taxes	$ 917,598	$ 640,385	$ 638,297