| Cover Document | Dec. 09, 2020 |
| Cover [Abstract] | |
| Entity Central Index Key | 0000016732 |
| Title of 12(b) Security | Capital Stock, par value $.0375 |
| Entity Incorporation, State or Country Code | NJ |
| Document Type | 8-K |
| Document Period End Date | Dec. 9, 2020 |
| Entity Registrant Name | CAMPBELL SOUP CO |
| Entity File Number | 1-3822 |
| Entity Tax Identification Number | 21-0419870 |
| Entity Address, Address Line One | One Campbell Place |
| Entity Address, City or Town | Camden |
| Entity Address, State or Province | NJ |
| Entity Address, Postal Zip Code | 08103 |
| City Area Code | 856 |
| Local Phone Number | 342-4800 |
| Trading Symbol | CPB |
| Security Exchange Name | NYSE |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
