| Document and Entity Information Document | Oct. 02, 2020 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 2, 2020 |
| Entity Registrant Name | Walmart Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-06991 |
| Entity Tax Identification Number | 71-0415188 |
| Entity Address, Address Line One | 702 S.W. 8th Street |
| Entity Address, City or Town | Bentonville |
| Entity Address, State or Province | AR |
| Entity Address, Postal Zip Code | 72716-0215 |
| City Area Code | 479 |
| Local Phone Number | 273-4000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000104169 |
| Amendment Flag | false |
| Common Stock, par value $0.10 per share [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, par value $0.10 per share |
| Trading Symbol | WMT |
| Security Exchange Name | NYSE |
| 2.550% Notes Due 2026 [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 2.550% Notes Due 2026 |
| Trading Symbol | WMT26 |
| Security Exchange Name | NYSE |
| 1.900% Notes Due 2022 [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 1.900% Notes Due 2022 |
| Trading Symbol | WMT22 |
| Security Exchange Name | NYSE |
