Consolidated Statements of Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid In Capital	Retained Earnings	Accumulated Other Comprehensive (loss) income	Common Stock in Treasury
Beginning balance at Dec. 31, 2011	$ 2,730,490	$ 283	$ 3,385,053	$ 2,211,471	$ (11,561)	$ (2,854,756)
Beginning balance, treasury shares (in shares) at Dec. 31, 2011						(96,960,000)
Beginning balance (in shares) at Dec. 31, 2011		282,774,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under stock-based compensation plans	108,409	3	108,406	0	0	0
Shares issued under stock-based compensation plans (in shares)		3,983,000				0
Stock-based compensation expense	145,967	0	145,967	0	0	0
Common stock issued under employee stock purchase plan	24,885	1	24,884	0	0	0
Common stock issued under employee stock purchase plan (in shares)		366,000				0
Tax deficiency from employer stock plans, net	24,839	0	24,839	0	0	0
Stock repurchases, net	(251,008)	0	0	0	0	(251,008)
Stock repurchases, net (in shares)	(3,550,817)	0				(3,551,000)
Restricted shares turned in for tax withholding	(20,170)	0	0	0	0	(20,170)
Restricted shares turned in for tax withholding (in shares)	(269,745)	0				(270,000)
Other	1,962	0	1,962	0	0	0
Other comprehensive income, net of tax	3,856	0	0	0	3,856	0
Net income	352,547	0	0	352,547	0	0
Ending balance at Dec. 31, 2012	3,121,777	287	3,691,111	2,564,018	(7,705)	(3,125,934)
Ending balance, treasury shares (in shares) at Dec. 31, 2012						(100,781,000)
Ending balance (in shares) at Dec. 31, 2012		287,123,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under stock-based compensation plans	73,658	3	73,655	0	0	0
Shares issued under stock-based compensation plans (in shares)		3,545,000				0
Stock-based compensation expense	179,098	0	179,098	0	0	0
Common stock issued under employee stock purchase plan	30,142	1	30,141	0	0	0
Common stock issued under employee stock purchase plan (in shares)		410,000				0
Tax deficiency from employer stock plans, net	(620)	0	(620)	0	0	0
Stock repurchases, net	(406,326)	0	0	0	0	(406,326)
Stock repurchases, net (in shares)	(6,563,986)	0				(6,564,000)
Restricted shares turned in for tax withholding	(31,013)	0	0	0	0	(31,013)
Restricted shares turned in for tax withholding (in shares)	(444,657)	0				(444,000)
Other	912	0	912	0	0	0
Other comprehensive income, net of tax	12,656	0	0	0	12,656	0
Net income	339,523	0	0	339,523	0	0
Ending balance at Dec. 31, 2013	3,319,807	291	3,974,297	2,903,541	4,951	(3,563,273)
Ending balance, treasury shares (in shares) at Dec. 31, 2013	(107,789,000)					(107,789,000)
Ending balance (in shares) at Dec. 31, 2013		291,078,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under stock-based compensation plans	46,621	3	46,618	0	0	0
Shares issued under stock-based compensation plans (in shares)		3,031,000				0
Stock-based compensation expense	164,040	0	164,040	0	0	0
Common stock issued under employee stock purchase plan	33,909	1	33,908	0	0	0
Common stock issued under employee stock purchase plan (in shares)		565,000				0
Tax deficiency from employer stock plans, net	(14,679)	0	(14,679)	0	0	0
Stock repurchases, net	(1,640,885)	0	0	0	0	(1,640,885)
Stock repurchases, net (in shares)		0				(25,549,000)
Restricted shares turned in for tax withholding	(33,672)	0	0	0	0	(33,672)
Restricted shares turned in for tax withholding (in shares)	(560,239)	0				(560,000)
Other comprehensive income, net of tax	(41,741)	0	0	0	(41,741)	0
Convertible note tax impact	8,166		8,166
Equity component of convertible note issuance	162,869	0	162,869	0	0	0
Purchase of convertible note hedges	(184,288)	0	(184,288)	0	0	0
Issuance of warrants	101,775	0	101,775	0	0	0
Net income	251,723	0	0	251,723	0	0
Ending balance at Dec. 31, 2014	$ 2,173,645	$ 295	$ 4,292,706	$ 3,155,264	$ (36,790)	$ (5,237,830)
Ending balance, treasury shares (in shares) at Dec. 31, 2014	(133,898,000)					(133,898,000)
Ending balance (in shares) at Dec. 31, 2014		294,674,000