Net Income Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011
Net Income Per Common Share [Line Items]
Income from continuing operations	$ 3,825	$ 3,501	$ 11,880	$ 11,016
Less consolidated net income attributable to noncontrolling interest	(190)	(157)	(487)	(444)
Income from continuing operations attributable to Walmart	$ 3,635	$ 3,344	$ 11,393	$ 10,572
Weighted-average common shares outstanding, basic	3,364	3,445	3,385	3,473
Dilutive impact of stock options and other share-based awards	15	13	15	14
Weighted-average common shares outstanding, diluted	3,379	3,458	3,400	3,487
Basic	$ 1.08	$ 0.97	$ 3.37	$ 3.04
Diluted	$ 1.08	$ 0.97	$ 3.35	$ 3.03
Stock Option [Member]
Net Income Per Common Share [Line Items]
Antidilutive stock options and share-based awards excluded from computation of diluted net income per common share				9