Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Net Income Per Common Share [Line Items]
Income from continuing operations	$ 1,904	$ 3,202	$ 8,160	$ 10,307
Consolidated net income attributable to noncontrolling interest	(155)	(168)	(473)	(421)
Income from continuing operations attributable to Walmart	$ 1,749	$ 3,034	$ 7,687	$ 9,886
Weighted-average common shares outstanding, basic	2,981	3,089	3,008	3,114
Dilutive impact of stock options and other share-based awards	15	11	13	10
Weighted-average common shares outstanding, diluted	2,996	3,100	3,021	3,124
Basic income per common share from continuing operations attributable to Walmart	$ 0.59	$ 0.98	$ 2.56	$ 3.17
Diluted income per common share from continuing operations attributable to Walmart	$ 0.58	$ 0.98	$ 2.54	$ 3.16