Segment Operating Income, Income Expense, Net and Income from Continuing Operations before Income Taxes (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]
Operating income (loss):	$ 5,714	$ 6,265	$ 17,463	$ 19,198
Interest, net	552	656	1,919	1,762
Income from continuing operations before income taxes	5,162	5,609	15,544	17,436
Walmart U.S.
Segment Reporting Information [Line Items]
Operating income (loss):	4,506	4,932	13,964	15,159
Walmart International
Segment Reporting Information [Line Items]
Operating income (loss):	1,338	1,430	3,685	4,121
Sam's Club
Segment Reporting Information [Line Items]
Operating income (loss):	539	493	1,394	1,466
Corporate and support
Segment Reporting Information [Line Items]
Operating income (loss):	$ (669)	$ (590)	$ (1,580)	$ (1,548)