Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
Numerator
Consolidated net income	$ 2,811	$ 4,074
Consolidated net income attributable to noncontrolling interest	(81)	(84)
Consolidated net income attributable to Walmart	$ 2,730	$ 3,990
Denominator
Weighted-average common shares outstanding, basic (in shares)	2,815	2,831
Dilutive impact of share-based awards (in shares)	14	18
Weighted-average common shares outstanding, diluted (in shares)	2,829	2,849
Net income per common share attributable to Walmart
Basic (in dollars per share)	$ 0.97	$ 1.41
Diluted (in dollars per share)	$ 0.97	$ 1.40