| Cover Page Cover Page | Nov. 08, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Nov. 08, 2023 |
| Entity Registrant Name | WK Kellogg Co |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-41755 |
| Entity Tax Identification Number | 92-1243173 |
| Entity Address, Address Line One | One Kellogg Square, P.O. Box 3599 |
| Entity Address, City or Town | Battle Creek |
| Entity Address, State or Province | MI |
| Entity Address, Postal Zip Code | 49016-3599 |
| City Area Code | 269 |
| Local Phone Number | 401-3000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Title of 12(b) Security | Common Stock, $.0001 par value per share |
| Trading Symbol | KLG |
| Security Exchange Name | NYSE |
| Entity Central Index Key | 0001959348 |
| Amendment Flag | false |
| Document Year Focus | 2023 |
| Document Fiscal Period Focus | Q3 |
