Segment Operating Income, Income Expense, Net And Income From Continuing Operations Before Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Segment Reporting Information [Line Items]
Operating income	$ 6,793	$ 6,698	$ 13,249	$ 13,085
Interest, net	553	505	1,083	1,040
Income before income taxes	6,240	6,193	12,166	12,045
Walmart U.S.
Segment Reporting Information [Line Items]
Operating income	5,521	5,248	10,850	10,281
Walmart International
Segment Reporting Information [Line Items]
Operating income	1,465	1,484	2,721	2,802
Sam's Club
Segment Reporting Information [Line Items]
Operating income	551	535	1,076	1,024
Corporate and support
Segment Reporting Information [Line Items]
Operating income	$ (744)	$ (569)	$ (1,398)	$ (1,022)