Segments and Disaggregated Revenue (Net Sales) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020
Segment Reporting Information [Line Items]
Net sales	$ 139,871	$ 136,824	$ 277,030	$ 270,496
Walmart U.S.
Segment Reporting Information [Line Items]
Net sales	98,192	93,282	191,359	182,025
Walmart International
Segment Reporting Information [Line Items]
Net sales	23,035	27,167	50,335	56,933
Sam's Club
Segment Reporting Information [Line Items]
Net sales	$ 18,644	$ 16,375	$ 35,336	$ 31,538