Segment Net Sales (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014
Segment Reporting Information [Line Items]
Net sales	$ 116,598	$ 118,076	$ 349,930	$ 351,579
Walmart U.S.
Segment Reporting Information [Line Items]
Net sales	72,712	70,025	216,916	208,478
Walmart International
Segment Reporting Information [Line Items]
Net sales	29,811	33,659	90,726	99,955
Sam's Club
Segment Reporting Information [Line Items]
Net sales	$ 14,075	$ 14,392	$ 42,288	$ 43,146