Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Jul. 31, 2021	Apr. 30, 2021	Jul. 31, 2020	Apr. 30, 2020	Jul. 31, 2021	Jul. 31, 2020
Numerator
Consolidated net income	$ 4,364	$ 2,811	$ 6,439	$ 4,074	$ 7,175	$ 10,513
Consolidated net (income) loss attributable to noncontrolling interest	(88)		37		(169)	(47)
Consolidated net income attributable to Walmart	$ 4,276		$ 6,476		$ 7,006	$ 10,466
Denominator
Weighted-average common shares outstanding, basic (in shares)	2,799		2,832		2,807	2,832
Dilutive impact of share-based awards (in shares)	13		16		13	16
Weighted-average common shares outstanding, diluted (in shares)	2,812		2,848		2,820	2,848
Net income per common share attributable to Walmart
Basic (in dollars per share)	$ 1.53		$ 2.29		$ 2.50	$ 3.70
Diluted (in dollars per share)	$ 1.52		$ 2.27		$ 2.48	$ 3.67