Segment Net Sales (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2015	Jul. 31, 2014
Segment Reporting Information [Line Items]
Net sales	$ 119,330	$ 119,336	$ 233,332	$ 233,503
Walmart U.S.
Segment Reporting Information [Line Items]
Net sales	73,959	70,601	144,204	138,453
Walmart International
Segment Reporting Information [Line Items]
Net sales	30,637	33,872	60,915	66,296
Sam's Club
Segment Reporting Information [Line Items]
Net sales	$ 14,734	$ 14,863	$ 28,213	$ 28,754