Statement of Changes in Equity (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Mar. 08, 2019	Jan. 01, 2019	Mar. 31, 2019	Mar. 31, 2018
Cash dividend paid (in dollars per share)	$ 0.35
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		$ 551,519	$ 551,519	$ 992,461
Shares issued under stock-based compensation plans			0	70
Stock-based compensation expense			63,475	35,723
Temporary equity reclassification			6,947
Common stock issued under employee stock purchase plan			19,015	17,457
Stock repurchases, net			(93,805)	(750,000)
Restricted shares turned in for tax withholding			(60,106)	(46,917)
Other comprehensive income, net of tax			2,671	(4,068)
Cash dividends declared			(46,024)
Cumulative-effect adjustment from adoption of accounting standards		$ 800	838	132,778
Other				1,615
Net income			110,348	144,259
Ending balance			$ 554,878	$ 523,378
Beginning balance, treasury shares (in shares)		(178,327,000)	(178,327,000)
Restricted shares turned in for tax withholding (in shares)			(593,988)	(507,274)
Ending balance, treasury shares (in shares)			(179,832,000)
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)		309,761,000	309,761,000	305,751,000
Shares issued under stock compensation plans (shares)			1,755,000	1,572,000
Common stock issued under employee stock purchase plan (shares)			216,000	252,000
Ending balance (in shares)			311,732,000	307,575,000
Beginning balance		$ 310	$ 310	$ 306
Shares issued under stock-based compensation plans			2	2
Ending balance			312	308
Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		5,404,500	5,404,500	4,883,670
Shares issued under stock-based compensation plans			(2)	68
Stock-based compensation expense			63,475	35,723
Temporary equity reclassification			6,947
Common stock issued under employee stock purchase plan			19,015	17,457
Other			2,000	1,615
Ending balance			5,495,935	4,938,533
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		4,169,019	4,169,019	3,509,484
Cash dividends declared			(46,024)
Cumulative-effect adjustment from adoption of accounting standards			838	132,778
Other			(2,000)
Net income			110,348	144,259
Ending balance			4,232,181	3,786,521
Accumulated Other Comprehensive (Loss) Income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		(8,154)	(8,154)	(10,806)
Other comprehensive income, net of tax			2,671	(4,068)
Ending balance			(5,483)	(14,874)
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		$ (9,014,156)	(9,014,156)	(7,390,193)
Stock repurchases, net			(93,805)	(750,000)
Restricted shares turned in for tax withholding			(60,106)	(46,917)
Ending balance			$ (9,168,067)	$ (8,187,110)
Beginning balance, treasury shares (in shares)		(178,327,000)	(178,327,000)	(162,044,000)
Stock repurchases net (shares)			(911,000)	(7,880,000)
Restricted shares turned in for tax withholding (in shares)			(594,000)	(507,000)
Ending balance, treasury shares (in shares)			(179,832,000)	(170,431,000)