Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Net Income Per Common Share [Line Items]
Consolidated net Income	$ 10,523	$ 14,293	$ 15,080
Consolidated net income attributable to noncontrolling interest	(661)	(650)	(386)
Consolidated net income attributable to Walmart	$ 9,862	$ 13,643	$ 14,694
Weighted-average common shares outstanding, basic	2,995	3,101	3,207
Dilutive impact of stock options and other share-based awards	15	11	10
Weighted-average common shares outstanding, diluted	3,010	3,112	3,217
Basic net income per common share attributable to Walmart	$ 3.29	$ 4.40	$ 4.58
Diluted net income per common share attributable to Walmart	$ 3.28	$ 4.38	$ 4.57