Net Income Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Net Income Per Common Share [Line Items]
Income from continuing operations	$ 3,826	$ 3,870	$ 11,626	$ 12,007
Less income from continuing operations attributable to noncontrolling interest	(115)	(143)	(410)	(443)
Income from continuing operations attributable to Walmart	$ 3,711	$ 3,727	$ 11,216	$ 11,564
Weighted-average common shares outstanding, basic	3,229	3,257	3,231	3,279
Dilutive impact of stock options and other share-based awards	11	14	12	14
Weighted-average common shares outstanding, diluted	3,240	3,271	3,243	3,293
Basic income per common share from continuing operations attributable to Walmart	$ 1.15	$ 1.14	$ 3.47	$ 3.53
Diluted income per common share from continuing operations attributable to Walmart	$ 1.15	$ 1.14	$ 3.46	$ 3.51