Guarantees (Details) (USD $)	12 Months Ended
	Jan. 27, 2013		Jan. 29, 2012		Jan. 30, 2011
Notes to financial statements [Abstract]
Net Warranty charge	$ 475,900,000
Payments related to warranty accrual	3,000,000		73,300,000		149,800,000
Estimated product warranty liabilities
Balance at beginning of period	18,406,000		107,896,000		92,655,000
Additions	5,738,000	[1]	7,329,000	[1]	194,108,000	[1]
Deductions	(9,270,000)	[2]	(96,819,000)	[2]	(178,867,000)	[2]
Balance at end of period	14,874,000		18,406,000		107,896,000
Incremental repair and replacement costs for the weak die/packaging material set					$ 186,200,000

[1] Includes $186.2 million for fiscal year 2011 for incremental repair and replacement costs from a weak die/packaging material set.

[2] Includes $3.0 million, $73.3 million and $149.8 million for fiscal years 2013, 2012 and 2011, respectively, in payments related to the warranty accrual associated with incremental repair and replacement costs from a weak die/packaging material set.