Net Income (Loss) Per Share (Details) (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Aug. 01, 2010	Jul. 31, 2011	Aug. 01, 2010
Numerator:
Net income (loss)	$ 151,573	$ (140,961)	$ 286,792	$ (3,367)
Denominator:
Denominator for basic net income/(loss) per share, weighted average shares (in shares)	601,340	572,764	598,077	569,971
Effect of dilutive securities:
Equity awards outstanding (in shares)	12,594	0	17,475	0
Denominator for diluted net income (loss) per share, weighted average shares (in shares)	613,934	572,764	615,552	569,971
Net income (loss) per share:
Basic net income (loss) per share	$ 0.25	$ (0.25)	$ 0.48	$ (0.01)
Diluted net income (loss) per share	$ 0.25	$ (0.25)	$ 0.47	$ (0.01)
Anti-dilutive common equivalent shares from stock options and RSUs (in shares)	13,500,000.0		14,300,000.0