Segment Operating Income, Income Expense, Net And Income From Continuing Operations Before Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Apr. 30, 2015	Apr. 30, 2014
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ 5,680	$ 6,193
Interest, net	824	568
Income from continuing operations before income taxes	4,856	5,625
Walmart U.S.
Segment Reporting Information [Line Items]
Operating Income (Loss)	4,639	4,975
Walmart International
Segment Reporting Information [Line Items]
Operating Income (Loss)	1,070	1,202
Sam's Club
Segment Reporting Information [Line Items]
Operating Income (Loss)	427	479
Corporate and support
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ (456)	$ (463)