Segments and Disaggregated Revenue Revenue from Contract with Customer Excluding Assessed Tax, Walmart US (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Apr. 30, 2019 |
Apr. 30, 2018 |
|
| Revenue from External Customer [Line Items] | ||
| Net sales | $ 122,949 | $ 121,630 |
| Walmart U.S. | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 80,344 | 77,748 |
| Walmart U.S. | Grocery | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 45,404 | 43,860 |
| Walmart U.S. | General merchandise | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 24,607 | 24,174 |
| Walmart U.S. | Health and wellness | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 9,518 | 9,128 |
| Walmart U.S. | Other categories | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 815 | 586 |
| eCommerceMember | Walmart U.S. | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | $ 4,300 | $ 3,200 |