Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 643,491	$ 527,374
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	89,876	80,558
Provision for doubtful accounts	3,533	8,050
Deferred income taxes	(26,204)	39,721
Stock-based compensation expense	64,244	42,044
Excess tax benefit on stock-based compensation plans	(30,966)	(59,497)
Other	24,019	(9,486)
Changes in assets and liabilities:
Trade accounts receivable	(207,242)	(291,817)
Other current assets	(41,680)	(98,477)
Other assets	(20,884)	(22,259)
Accounts payable	(2,654)	36,567
Other current and noncurrent liabilities	94,553	119,582
Net cash provided by operating activities	590,086	372,360
Cash flows from investing activities:
Purchases of property and equipment	(163,660)	(110,961)
Purchases of investments	(1,181,460)	(665,949)
Proceeds from maturity or sale of investments	743,111	516,030
Acquisitions, net of cash acquired	(75,040)	(31,705)
Net cash used in investing activities	(677,049)	(292,585)
Cash flows from financing activities:
Issuance of common stock under stock-based compensation plans	57,277	87,070
Excess tax benefit on stock-based compensation plans	30,966	59,497
Repurchases of common stock	(364,974)	(12,096)
Net cash (used in) provided by financing activities	(276,731)	134,471
Effect of currency translation on cash and cash equivalents	3,944	1,901
(Decrease) increase in cash and cash equivalents	(359,750)	216,147
Cash and cash equivalents, beginning of year	1,540,969	1,100,930
Cash and cash equivalents, end of period	$ 1,181,219	$ 1,317,077