Net Income Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Net Income Per Common Share [Line Items]
Consolidated net income	$ 3,945	$ 3,894
Less consolidated net income attributable to noncontrolling interest	(161)	(152)
Consolidated net income attributable to Walmart	$ 3,784	$ 3,742
Weighted-average common shares outstanding, basic	3,301	3,409
Dilutive impact of stock options and other share-based awards	17	16
Weighted-average common shares outstanding, diluted	3,318	3,425
Basic net income per common share attributable to Walmart	$ 1.15	$ 1.10
Diluted net income per common share attributable to Walmart	$ 1.14	$ 1.09