Cover - USD ($) $ / shares in Units, $ in Billions	12 Months Ended
	Dec. 28, 2024	Jan. 25, 2025	Jun. 29, 2024
Entity Information [Line Items]
Document Type	10-K/A
Document Transition Report	false
Entity File Number	1-4171
Registrant Name	Kellanova
Document Period End Date	Dec. 28, 2024
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	38-0710690
Entity Address, Address Line One	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
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 16.6
MarketValuePerShare			$ 57.68
Entity Common Stock, Shares Outstanding		345,215,923
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2024
Current Fiscal Year End Date	--12-28
Amendment Description	EXPLANATORY NOTEThis Amendment No. 1 on Form 10-K/A, or this Form 10-K/A, to the Annual Report on Form 10-K of Kellanova (the "Company") for the fiscal year ended December 28, 2024, filed with the Securities and Exchange Commission, or the SEC, on February 21, 2025, or the Original Form 10-K, is being filed solely for the purpose of including the information required by Part III of Form 10-K that the Company did not include in the Original Form 10-K in reliance on General Instruction G(3) to Form 10-K. We are filing this Form 10-K/A to include Part III information in our Form 10-K because we do not intend to file a definitive proxy statement for an annual meeting of shareholders containing such information within 120 days after the end of our fiscal year ending December 28, 2024. In addition, in connection with the filing of this Form 10-K/A and pursuant to the rules of the SEC, we are including with this Form 10-K/A new certifications of our principal executive officer and principal financial officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. Item 15 of Part IV has also been amended to reflect the filing of these new certifications.Except as described above, this Form 10-K/A does not modify or update the disclosures in, or any exhibits to, the Original Form 10-K. Furthermore, this Form 10-K/A does not change any previously reported financial results, nor does it reflect any events which occurred subsequent to the filing of the Original Form 10-K. Information not affected by this Form 10-K/A remains unchanged and reflects the disclosures made at the time the Original Form 10-K was filed. Unless otherwise specified or indicated by the context, “Kellanova,” the “Company,” “we,” “us” and “our” refer to Kellanova, its divisions and subsidiaries.
Auditor Firm ID	238
Auditor Location	Chicago, Illinois
Auditor Name	PricewaterhouseCoopers LLP
Document Annual Report	true
Central Index Key	0000055067
Amendment Flag	true
Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $.25 par value per share
Trading Symbol	K
Security Exchange Name	NYSE
1.250% Senior Notes due 2025
Entity Information [Line Items]
Title of 12(b) Security	1.250% Senior Notes due 2025
Trading Symbol	K 25
Security Exchange Name	NYSE
0.500% Senior Notes due 2029
Entity Information [Line Items]
Title of 12(b) Security	0.500% Senior Notes due 2029
Trading Symbol	K 29
Security Exchange Name	NYSE
3.750% Senior Notes due 2034
Entity Information [Line Items]
Title of 12(b) Security	3.750% Senior Notes due 2034
Trading Symbol	K 34
Security Exchange Name	NYSE