Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jul. 29, 2016	Jul. 31, 2015	Jul. 29, 2016	Jul. 31, 2015
Net Income
Basic Earnings	$ 306,518	$ 282,349	$ 601,642	$ 535,584
Diluted Earnings	$ 306,518	$ 282,349	$ 601,642	$ 535,584
Shares
Shares outstanding, basic	283,130	295,679	284,508	298,440
Effect of dilutive share-based awards	986	849	1,039	868
Shares outstanding, diluted	284,116	296,528	285,547	299,308
Per Share Amount
Basic earnings per share (in dollars per share)	$ 1.08	$ 0.95	$ 2.11	$ 1.79
Diluted earnings per share (in dollars per share)	$ 1.08	$ 0.95	$ 2.11	$ 1.79
Share-based awards outstanding excluded from computation of diluted earnings per share	1,300	1,000	1,400	1,100

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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