Segments and Disaggregated Revenue Revenue from Contract with Customer Excluding Assessed Tax, International (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 International | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 28,775 | 30,260 |
| Mexico and Central America | Walmart International | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 7,837 | 7,684 |
| United Kingdom | Walmart International | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 7,077 | 7,515 |
| Canada | Walmart International | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 4,122 | 4,254 |
| China | Walmart International | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 3,063 | 3,205 |
| Other | Walmart International | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 6,676 | 7,602 |
| eCommerceMember | Walmart International | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | $ 2,500 | $ 1,000 |