Segment Net Sales (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2016	Apr. 30, 2015
Segment Reporting Information [Line Items]
Net sales	$ 114,986	$ 114,002
Walmart U.S.
Segment Reporting Information [Line Items]
Net sales	73,295	70,245
Walmart International
Segment Reporting Information [Line Items]
Net sales	28,083	30,278
Sam's Club
Segment Reporting Information [Line Items]
Net sales	$ 13,608	$ 13,479