Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Numerator
Consolidated net income	$ 4,074	$ 3,906
Consolidated net income attributable to noncontrolling interest	(84)	(64)
Consolidated net income attributable to Walmart	$ 3,990	$ 3,842
Denominator
Weighted-average common shares outstanding, basic (in shares)	2,831	2,869
Dilutive impact of share-based awards (in shares)	18	17
Weighted-average common shares outstanding, diluted (in shares)	2,849	2,886
Net income per common share attributable to Walmart
Basic (in dollars per share)	$ 1.41	$ 1.34
Diluted (in dollars per share)	$ 1.40	$ 1.33