Segments and Disaggregated Revenue Revenue from Contract with Customer Excluding Assessed Tax, Sam's Club (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 |
| Sam's Club | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 13,830 | 13,622 |
| Sam's Club | Grocery and consumables | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 8,373 | 8,012 |
| Sam's Club | Fuel, tobacco and other categories | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 2,777 | 2,919 |
| Sam's Club | Home and apparel | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 1,178 | 1,202 |
| Sam's Club | Health and wellness | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 827 | 801 |
| Sam's Club | Technology, office and entertainment | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | 675 | 688 |
| eCommerceMember | Sam's Club | ||
| Revenue from External Customer [Line Items] | ||
| Net sales | $ 700 | $ 600 |