Restructuring (Schedule of Restructuring and Related Costs) (Details) $ in Millions	12 Months Ended
	Jan. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Asset impairment charges	$ 1,400
Restructuring charges	1,201
Walmart International
Restructuring Cost and Reserve [Line Items]
Restructuring charges	236
Sam's Club
Restructuring Cost and Reserve [Line Items]
Restructuring charges	665
Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	300
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges	789
Facility Closing [Member] | Walmart International
Restructuring Cost and Reserve [Line Items]
Asset impairment charges	193
Facility Closing [Member] | Sam's Club
Restructuring Cost and Reserve [Line Items]
Asset impairment charges	596
Facility Closing [Member] | Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges	0
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance costs	412
Employee Severance [Member] | Walmart International
Restructuring Cost and Reserve [Line Items]
Severance costs	43
Employee Severance [Member] | Sam's Club
Restructuring Cost and Reserve [Line Items]
Severance costs	69
Employee Severance [Member] | Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Severance costs	$ 300