Earnings per share (Details) (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Jul. 29, 2011	Jul. 30, 2010	Jul. 29, 2011	Jul. 30, 2010
Net Income
Basic earnings	$ 146,042	$ 141,195	$ 303,011	$ 277,191
Diluted Earnings	$ 146,042	$ 141,195	$ 303,011	$ 277,191
Shares
Shares outstanding, basic (in shares)	341,534,000	341,001,000	341,528,000	340,910,000
Effect of dilutive share-based awards (in shares)	4,091,000	3,745,000	3,981,000	3,662,000
Shares outstanding, diluted (in shares)	345,625,000	344,746,000	345,509,000	344,572,000
Per Share Amount
Basic earnings per share (in dollars per share)	$ 0.43	$ 0.41	$ 0.89	$ 0.81
Diluted earnings per share (in dollars per share)	$ 0.42	$ 0.41	$ 0.88	$ 0.80
Shares of common stock outstanding excluded from computation of diluted earnings per share (in shares)	300,000	400,000