Stock-Based Employee Compensation (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Number of Options
Outstanding at January 1, 2012	5,671,658
Granted	7,576
Exercised	(906,011)
Canceled	(324,450)
Outstanding at December 31, 2012	4,448,773	5,671,658
Vested and expected to vest at December 31, 2012	4,367,468
Options Exercisable at December 31, 2012	3,329,335
Weighted-Average Exercise Price
Outstanding at January 1, 2012	$ 30.62
Granted	$ 26.06
Exercised	$ 16.24
Canceled	$ 30.40
Outstanding at December 31, 2012	$ 33.56	$ 30.62
Vested and expected to vest at December 31, 2012	$ 33.54
Options Exercisable at December 31, 2012	$ 36.24
Weighted-Average Remaining Contractual Term
Outstanding at January 1, 2012	4 years 6 months 18 days	6 years 1 month 24 days
Outstanding at December 31, 2012	4 years 6 months 18 days	6 years 1 month 24 days
Vested and expected to vest at December 31, 2012	4 years 6 months
Options Exercisable at December 31, 2012	3 years 9 months 29 days
Aggregate Intrinsic Value
Outstanding at January 1, 2012	$ 21,887,000
Outstanding at December 31, 2012	25,522,000	21,887,000
Vested and expected to vest at December 31, 2012	25,113,000
Options Exercisable at December 31, 2012	12,565,000
Weighted-average estimated fair value of stock options granted	$ 9.90	$ 21.39	$ 11.69
Total intrinsic value of stock options exercised	15,300,000	17,300,000	26,900,000
Stock Option
Aggregate Intrinsic Value
Total unrecognized compensation cost	$ 2,600,000
Weighted-average period of unrecognized compensation cost to be recognized	7 months 6 days