Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						9 Months Ended
	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Oct. 31, 2020	Oct. 31, 2019
Numerator
Consolidated net income	$ 5,201	$ 6,439	$ 4,074	$ 3,321	$ 3,680	$ 3,906	$ 15,714	$ 10,907
Consolidated net income attributable to noncontrolling interest	(66)			(33)			(113)	(167)
Consolidated net income attributable to Walmart	$ 5,135			$ 3,288			$ 15,601	$ 10,740
Denominator
Weighted-average common shares outstanding, basic	2,833			2,843			2,832	2,855
Dilutive impact of share-based awards	16			18			17	17
Weighted-average common shares outstanding, diluted	2,849			2,861			2,849	2,872
Net income per common share attributable to Walmart
Basic	$ 1.81			$ 1.16			$ 5.51	$ 3.76
Diluted	$ 1.80			$ 1.15			$ 5.48	$ 3.74