Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2015	Aug. 01, 2014	Jul. 31, 2015	Aug. 01, 2014
Net Income
Basic Earnings	$ 282,349	$ 251,260	$ 535,584	$ 473,658
Diluted Earnings	$ 282,349	$ 251,260	$ 535,584	$ 473,658
Shares
Shares outstanding, basic	295,679	303,015	298,440	306,173
Effect of dilutive share-based awards	849	873	868	918
Shares outstanding, diluted	296,528	303,888	299,308	307,091
Per Share Amount
Basic earnings per share (in dollars per share)	$ 0.95	$ 0.83	$ 1.79	$ 1.55
Diluted earnings per share (in dollars per share)	$ 0.95	$ 0.83	$ 1.79	$ 1.54
Share-based awards outstanding excluded from computation of diluted earnings per share	1,000	1,700	1,100	1,600