CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jul. 29, 2012	Jul. 31, 2011
Cash flows from operating activities:
Net income	$ 179,483	$ 286,792
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	110,686	99,923
Stock based compensation expense	67,824	67,689
Deferred income taxes	13,791	20,082
Excess Tax benefit from stock based compensation	(18,154)	(25,021)
Other	32,496	10,695
Changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable	(109,218)	(57,511)
Inventories	(46,834)	(2,169)
Prepaid expenses and other current assets	(3,912)	2,255
Other assets	494	(992)
Accounts payable	65,646	(8,366)
Accrued liabilities and other long-term liabilities	(100,624)	(139,156)
Net cash provided by operating activities	191,678	254,221
Cash flows from investing activities:
Purchases of marketable securities	(1,247,664)	(711,674)
Proceeds from sales and maturities of marketable securities	918,856	591,242
Purchases of property and equipment and intangible assets	(90,867)	(54,518)
Acquisition of businesses, net of cash acquired	0	(348,884)
Other	(82)	(1,890)
Net cash used in investing activities	(419,757)	(525,724)
Cash flows from financing activities:
Proceeds from issuance of common stock under employee stock plans	42,678	124,785
Payments under capital lease obligations	(1,011)	(731)
Excess Tax benefit from Stock based compensation	18,154	25,021
Payment of notes payable assumed from acquisition	0	(10,319)
Net cash provided by financing activities	59,821	138,756
Change in cash and cash equivalents	(168,258)	(132,747)
Cash and cash equivalents at beginning of period	667,876	665,361
Cash and cash equivalents at end of period	499,618	532,614
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net		2,854
Proceeds from Income Tax Refunds	(43,149)
Cash paid for interest on capital lease obligations	1,474	1,510
Other non-cash activities:
Assets acquired by assuming related liabilities	54,230	13,673
Change in unrealized gains (losses) from marketable securities	$ 545	$ 4,163