Segments (Segment Operating Income, Income Expense, Net And Income From Continuing Operations Before Income Taxes) (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Operating income	$ 6,383	$ 6,190	$ 12,279	$ 11,927
Interest expense, net	(578)	(485)	(1,096)	(956)
Income from continuing operations before income taxes	5,805	5,705	11,183	10,971
Walmart U.S. [Member]
Operating income	4,985	4,881	9,635	9,496
Walmart International [Member]
Operating income	1,415	1,299	2,511	2,382
Sam's Club [Member]
Operating income	492	428	951	857
Other [Member]
Operating income	$ (509)	$ (418)	$ (818)	$ (808)