Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Jul. 31, 2020	Apr. 30, 2020	Jul. 31, 2019	Apr. 30, 2019	Jul. 31, 2020	Jul. 31, 2019
Numerator
Consolidated net income	$ 6,439	$ 4,074	$ 3,680	$ 3,906	$ 10,513	$ 7,586
Consolidated net (income) loss attributable to noncontrolling interest	37		(70)		(47)	(134)
Consolidated net income attributable to Walmart	$ 6,476		$ 3,610		$ 10,466	$ 7,452
Denominator
Weighted-average common shares outstanding, basic (in shares)	2,832		2,853		2,832	2,861
Dilutive impact of share-based awards (in shares)	16		16		16	17
Weighted-average common shares outstanding, diluted (in shares)	2,848		2,869		2,848	2,878
Net income per common share attributable to Walmart
Basic (in dollars per share)	$ 2.29		$ 1.27		$ 3.70	$ 2.60
Diluted (in dollars per share)	$ 2.27		$ 1.26		$ 3.67	$ 2.59