CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Oct. 28, 2012	Oct. 30, 2011
Cash flows from operating activities:
Net income	$ 388,563	$ 465,065
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	167,834	152,310
Stock based compensation expense	100,893	100,918
Deferred income taxes	42,684	14,242
Excess Tax benefit from stock based compensation	(25,646)	(52,703)
Other	39,978	13,689
Changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable	(109,008)	(8,834)
Inventories	(88,378)	39,748
Prepaid expenses and other current assets	(16,786)	35
Other assets	4,784	(2,992)
Accounts payable	49,099	9,218
Accrued liabilities and other long-term liabilities	(180,854)	(232,058)
Net cash provided by operating activities	373,163	498,638
Cash flows from investing activities:
Purchases of marketable securities	(1,729,307)	(1,324,350)
Proceeds from sales and maturities of marketable securities	1,262,167	953,808
Purchases of property and equipment and intangible assets	(135,551)	(93,553)
Acquisition of businesses, net of cash acquired	0	(348,884)
Other	135	(1,890)
Net cash used in investing activities	(602,556)	(814,869)
Cash flows from financing activities:
Proceeds from issuance of common stock under employee stock plans	62,781	176,490
Payments under capital lease obligations	(1,522)	(1,188)
Excess Tax benefit from Stock based compensation	25,646	52,703
Payment of notes payable assumed from acquisition	0	(10,319)
Net cash provided by financing activities	86,905	217,686
Change in cash and cash equivalents	(142,488)	(98,545)
Cash and cash equivalents at beginning of period	667,876	665,361
Cash and cash equivalents at end of period	525,388	566,816
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net		3,857
Proceeds from Income Tax Refunds	(40,442)
Cash paid for interest on capital lease obligations	2,189	2,254
Other non-cash activities:
Assets acquired by assuming related liabilities	43,792	12,064
Change in unrealized gains (losses) from marketable securities	$ 246	$ (1,274)