Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Net Income Per Common Share [Line Items]
Income from continuing operations	$ 3,202	$ 3,414	$ 10,307	$ 10,332
Consolidated net income attributable to noncontrolling interest	(168)	(110)	(421)	(212)
Income from continuing operations attributable to Walmart	$ 3,034	$ 3,304	$ 9,886	$ 10,120
Weighted-average common shares outstanding, basic	3,089	3,210	3,114	3,221
Dilutive impact of stock options and other share-based awards	11	9	10	10
Weighted-average common shares outstanding, diluted	3,100	3,219	3,124	3,231
Basic income per common share from continuing operations attributable to Walmart	$ 0.98	$ 1.03	$ 3.17	$ 3.14
Diluted income per common share from continuing operations attributable to Walmart	$ 0.98	$ 1.03	$ 3.16	$ 3.13