Cover Page - shares	9 Months Ended
	Sep. 28, 2024	Nov. 01, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 28, 2024
Document Transition Report	false
Entity File Number	001-41755
Entity Registrant Name	WK Kellogg Co
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	92-1243173
Entity Address, Address Line One	One Kellogg Square
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
Title of 12(b) Security	Common Stock, $.0001 par value per share
Trading Symbol	KLG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		86,125,244
Amendment Flag	false
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2024
Entity Central Index Key	0001959348
Current Fiscal Year End Date	--12-28