Earnings per share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Feb. 03, 2012	Oct. 28, 2011	Jul. 29, 2011	Apr. 29, 2011	Jan. 28, 2011	Oct. 29, 2010	Jul. 30, 2010	Apr. 30, 2010	Feb. 03, 2012	Jan. 28, 2011	Jan. 29, 2010
Net Income
Basic earnings	$ 292,510	$ 171,164	$ 146,042	$ 156,969	$ 222,546	$ 128,120	$ 141,195	$ 135,996	$ 766,685	$ 627,857	$ 339,442
Diluted Earnings									$ 766,685	$ 627,857	$ 339,442
Shares
Shares outstanding, basic									341,234,000	341,047,000	322,778,000
Effect of dilutive share-based awards									3,883,000	3,753,000	2,058,000
Shares outstanding, diluted									345,117,000	344,800,000	324,836,000
Per Share Amount
Basic earnings per share (in dollars per share)	$ 0.86	$ 0.50	$ 0.43	$ 0.46	$ 0.65	$ 0.38	$ 0.41	$ 0.40	$ 2.25	$ 1.84	$ 1.05
Diluted earnings per share (in dollars per share)	$ 0.85	$ 0.50	$ 0.42	$ 0.45	$ 0.64	$ 0.37	$ 0.41	$ 0.39	$ 2.22	$ 1.82	$ 1.04
Shares of common stock outstanding excluded from computation of diluted earnings per share									0	400,000	200,000