Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Net Income Per Common Share [Line Items]
Income from continuing operations	$ 3,152	$ 3,216
Consolidated net income attributable to noncontrolling interest	(113)	(137)
Income from continuing operations attributable to Walmart	$ 3,039	$ 3,079
Weighted-average common shares outstanding, basic	3,035	3,144
Dilutive impact of stock options and other share-based awards	12	10
Weighted-average common shares outstanding, diluted	3,047	3,154
Basic income per common share from continuing operations attributable to Walmart	$ 1.00	$ 0.98
Diluted income per common share from continuing operations attributable to Walmart	$ 1.00	$ 0.98