Segments and Disaggregated Revenue (Revenue, Sam's Club) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2022	Oct. 31, 2021	Oct. 31, 2022	Oct. 31, 2021
Revenue from External Customer [Line Items]
Net sales	$ 151,469	$ 139,207	$ 443,138	$ 416,237
Sam's Club
Revenue from External Customer [Line Items]
Net sales	21,399	18,971	62,921	54,307
Sam's Club | Grocery and consumables
Revenue from External Customer [Line Items]
Net sales	13,846	12,335	39,539	35,018
Sam's Club | Fuel, tobacco and other categories
Revenue from External Customer [Line Items]
Net sales	3,680	2,932	11,779	8,047
Sam's Club | Home and apparel
Revenue from External Customer [Line Items]
Net sales	2,132	1,976	6,588	6,252
Sam's Club | Health and wellness
Revenue from External Customer [Line Items]
Net sales	1,085	1,037	3,101	2,934
Sam's Club | Technology, office and entertainment
Revenue from External Customer [Line Items]
Net sales	$ 656	$ 691	$ 1,914	$ 2,056