Net Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 29, 2012	Oct. 30, 2011	Jul. 31, 2011	May 01, 2011	Jan. 30, 2011	Oct. 31, 2010	Jul. 31, 2010	May 02, 2010	Jan. 29, 2012	Jan. 30, 2011	Jan. 31, 2010
Numerator:
Net income (loss)	$ 116,025	$ 178,273	$ 151,573	$ 135,219	$ 171,651	$ 84,862	$ (140,961)	$ 137,594	$ 581,090	$ 253,146	$ (67,987)
Denominator:
Denominator for basic net income per share, weighted average shares (in shares)									603,646,000	575,177,000	549,574,000
Effect of dilutive securities:
Equity awards outstanding (in shares)									12,725,000	13,507,000	0
Denominator for diluted net income per share, weighted average shares (in shares)									616,371,000	588,684,000	549,574,000
Net income per share:
Basic net income (loss) per share	$ 0.19	$ 0.29	$ 0.25	$ 0.23	$ 0.29	$ 0.15	$ (0.25)	$ 0.24	$ 0.96	$ 0.44	$ (0.12)
Diluted net income (loss) per share	$ 0.19	$ 0.29	$ 0.25	$ 0.22	$ 0.29	$ 0.15	$ (0.25)	$ 0.23	$ 0.94	$ 0.43	$ (0.12)
Anti-dilutive common equivalent shares from stock options and RSUs (in shares)									22,617,213	24,646,398	29,313,489