Segment Net Sales (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]
Net sales	$ 116,216	$ 113,520	$ 229,645	$ 225,784
Walmart U.S.
Segment Reporting Information [Line Items]
Net sales	68,728	67,343	135,281	133,676
Walmart International
Segment Reporting Information [Line Items]
Net sales	32,956	32,016	65,961	64,093
Sam's Club
Segment Reporting Information [Line Items]
Net sales	$ 14,532	$ 14,161	$ 28,403	$ 28,015