Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended
	Oct. 28, 2012	Oct. 30, 2011	Oct. 28, 2012	Oct. 30, 2011	Jan. 29, 2012
Revenue by Operating Segment and Geographic Region
Revenue	$ 1,204,110,000	$ 1,066,180,000	$ 3,173,257,000	$ 3,044,736,000
Depreciation and amortization expense	57,148,000	52,387,000	167,834,000	152,310,000
Operating income (loss)	252,217,000	197,090,000	464,666,000	525,982,000
Revenue from significant customers (in percent)	14.00%	11.00%	12.00%	11.00%
Number of customers with significant revenue	1	1	1	1
Accounts receivable from significant customers (in percent)	19.00%		19.00%		20.00%
Number of customers with significant accounts receivable balance	1		1		1
Charitable contribution	25,000,000		25,000,000
Net present value, charitable contribution	20,127,000
China [Member]
Revenue by Operating Segment and Geographic Region
Revenue	205,636,000	209,986,000	580,934,000	732,202,000
Taiwan [Member]
Revenue by Operating Segment and Geographic Region
Revenue	403,769,000	293,171,000	1,020,232,000	857,717,000
Other Asia Pacific [Member]
Revenue by Operating Segment and Geographic Region
Revenue	192,814,000	223,597,000	583,858,000	561,708,000
United States [Member]
Revenue by Operating Segment and Geographic Region
Revenue	257,551,000	180,245,000	557,561,000	442,733,000
Other Americas [Member]
Revenue by Operating Segment and Geographic Region
Revenue	81,463,000	84,868,000	239,291,000	228,223,000
Europe [Member]
Revenue by Operating Segment and Geographic Region
Revenue	62,877,000	74,313,000	191,381,000	222,153,000
GPU [Member]
Revenue by Operating Segment and Geographic Region
Revenue	739,652,000	644,802,000	1,987,671,000	1,920,935,000
Depreciation and amortization expense	32,351,000	29,547,000	96,481,000	89,238,000
Operating income (loss)	193,226,000	146,843,000	434,818,000	406,833,000
PSB [Member]
Revenue by Operating Segment and Geographic Region
Revenue	220,557,000	230,295,000	629,527,000	642,425,000
Depreciation and amortization expense	4,278,000	5,427,000	13,109,000	17,414,000
Operating income (loss)	100,895,000	95,887,000	283,520,000	235,635,000
CPB [Member]
Revenue by Operating Segment and Geographic Region
Revenue	243,901,000	191,083,000	556,059,000	481,376,000
Depreciation and amortization expense	20,519,000	17,413,000	58,244,000	45,658,000
Operating income (loss)	(41,904,000)	(45,640,000)	(233,545,000)	(116,486,000)
All Other [Member]
Revenue by Operating Segment and Geographic Region
Revenue	0	0	0	0
Depreciation and amortization expense	0	0	0	0
Operating income (loss)	$ 0	$ 0	$ (20,127,000)	$ 0