Segment Operating Income, Income Expense, Net And Income From Continuing Operations Before Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Segment Reporting Information [Line Items]
Operating income	$ 6,456	$ 6,387
Interest, net	530	535
Income before income taxes	5,926	5,852
Walmart U.S.
Segment Reporting Information [Line Items]
Operating income	5,329	5,033
Walmart International
Segment Reporting Information [Line Items]
Operating income	1,256	1,318
Sam's Club
Segment Reporting Information [Line Items]
Operating income	525	489
Corporate and support
Segment Reporting Information [Line Items]
Operating income	$ (654)	$ (453)