Segment Net Sales (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 114,876	$ 113,077	$ 344,290	$ 338,644
Walmart U.S.
Segment Reporting Information [Line Items]
Net sales	67,692	66,113	202,973	199,789
Walmart International
Segment Reporting Information [Line Items]
Net sales	33,109	33,046	98,839	96,922
Sam's Club
Segment Reporting Information [Line Items]
Net sales	$ 14,075	$ 13,918	$ 42,478	$ 41,933