Segments and Disaggregated Revenue (Segment Revenues and Long-Lived Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Segment Reporting Information [Line Items]
Total revenues	$ 559,151	$ 523,964	$ 514,405
Total long-lived assets	109,848	127,049	111,395
UNITED STATES
Segment Reporting Information [Line Items]
Total revenues	436,649	402,532	392,265
Total long-lived assets	87,068	86,944	81,144
Walmart International [Member]
Segment Reporting Information [Line Items]
Total revenues	122,502	121,432	122,140
Total long-lived assets	$ 22,780	$ 40,105	$ 30,251