Segments and Disaggregated Revenue (Revenue from Contract with Customer Excluding Assessed Tax, International) (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Revenue from External Customer [Line Items]
Net sales	$ 555,233	$ 519,926	$ 510,329
Walmart International [Member]
Revenue from External Customer [Line Items]
Net sales	121,360	120,130	$ 120,824
Walmart International [Member] | E Commerce [Member]
Revenue from External Customer [Line Items]
Net sales	16,600	11,800
Mexico and Central America [Member] | Walmart International [Member]
Revenue from External Customer [Line Items]
Net sales	32,642	33,350
UNITED KINGDOM | Walmart International [Member]
Revenue from External Customer [Line Items]
Net sales	29,234	29,243
CANADA | Walmart International [Member]
Revenue from External Customer [Line Items]
Net sales	19,991	18,420
CHINA | Walmart International [Member]
Revenue from External Customer [Line Items]
Net sales	11,430	10,671
Other [Member] | Walmart International [Member]
Revenue from External Customer [Line Items]
Net sales	$ 28,063	$ 28,446