Segment Operating Income, Income Expense, Net And Income From Continuing Operations Before Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Segment Reporting Information [Line Items]
Operating income	$ 6,310	$ 6,093	$ 19,525	$ 19,145
Interest, net	580	546	1,662	1,586
Income from continuing operations before income taxes	5,730	5,547	17,863	17,559
Walmart U.S.
Segment Reporting Information [Line Items]
Operating income	5,123	4,841	15,973	15,122
Walmart International
Segment Reporting Information [Line Items]
Operating income	1,457	1,432	4,144	4,201
Sam's Club
Segment Reporting Information [Line Items]
Operating income	474	434	1,550	1,458
Corporate and support
Segment Reporting Information [Line Items]
Operating income	$ (744)	$ (614)	$ (2,142)	$ (1,636)