| Document and Entity Information | Oct. 21, 2024 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 21, 2024 |
| Entity Registrant Name | Kellanova |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-4171 |
| Entity Tax Identification Number | 38-0710690 |
| Entity Address Address Line 1 | 412 N. Wells Street |
| Entity Address City Or Town | Chicago |
| Entity Address State Or Province | IL |
| Entity Address Postal Zip Code | 60654 |
| City Area Code | 269 |
| Local Phone Number | 961-2000 |
| Written Communications | false |
| Soliciting Material | true |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000055067 |
| Amendment Flag | false |
| Common Stock [Member] | |
| Entity Information [Line Items] | |
| Security 12b Title | Common Stock, $.25 par value per share |
| Trading Symbol | K |
| Security Exchange Name | NYSE |
| 1.250% Senior Notes Due 2025 [Member] | |
| Entity Information [Line Items] | |
| Security 12b Title | 1.250% Senior Notes due 2025 |
| Trading Symbol | K25 |
| Security Exchange Name | NYSE |
| 0.500% Senior Notes Due 2029 [Member] | |
| Entity Information [Line Items] | |
| Security 12b Title | 0.500% Senior Notes due 2029 |
| Trading Symbol | K29 |
| Security Exchange Name | NYSE |
| 3.750% Senior Notes Due 2034 [Member] | |
| Entity Information [Line Items] | |
| Security 12b Title | 3.750% Senior Notes due 2034 |
| Trading Symbol | K34 |
| Security Exchange Name | NYSE |
