Segment Net Sales (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Segment Reporting Information [Line Items]
Net sales	$ 118,076	$ 114,876	$ 351,579	$ 344,290
Walmart U.S.
Segment Reporting Information [Line Items]
Net sales	70,025	67,692	208,478	202,973
Walmart International
Segment Reporting Information [Line Items]
Net sales	33,659	33,109	99,955	98,839
Sam's Club
Segment Reporting Information [Line Items]
Net sales	$ 14,392	$ 14,075	$ 43,146	$ 42,478