CONSOLIDATED STATEMENT OF EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Capital in excess of par value	Retained earnings	Treasury stock	Accumulated other comprehensive income (loss)	Total Kellanova equity	Non-controlling interests
Balance (in shares) at Dec. 31, 2022		421			79
Balance at Dec. 31, 2022		$ 105	$ 1,068	$ 9,197	$ (4,721)	$ (1,708)	$ 3,941	$ 434
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Dec. 31, 2022	$ 4,375
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	302			298			298	4
Dividends, Common Stock	(202)			(202)			(202)
Distributions to noncontrolling interest	(8)						0	(8)
Other comprehensive income (loss)	(8)					(5)	(5)	(3)
Stock compensation	22		22				22
Stock options exercised, issuance of other stock awards and other	(2)		(57)	0	$ 55		(2)
Stock options exercised and other (in shares)					(1)
Balance (in shares) at Apr. 01, 2023		421			78
Balance at Apr. 01, 2023		$ 105	1,033	9,293	$ (4,666)	(1,713)	4,052	427
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Apr. 01, 2023	$ 4,479
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 0.59
Balance (in shares) at Dec. 30, 2023		421			81
Balance at Dec. 30, 2023	$ 3,175	$ 105	1,101	8,804	$ (4,794)	(2,041)	3,175	194
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Dec. 30, 2023	3,369
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	271			267			267	4
Dividends, Common Stock	(191)			(191)			(191)
Distributions to noncontrolling interest	(2)						0	(2)
Other comprehensive income (loss)	(200)					(130)	(130)	(70)
Stock compensation	21		21				21
Stock options exercised, issuance of other stock awards and other	10		(59)	(2)	$ 71		10
Stock options exercised and other (in shares)					(1)
Balance (in shares) at Mar. 30, 2024		421			80
Balance at Mar. 30, 2024	3,152	$ 105	$ 1,063	$ 8,878	$ (4,723)	$ (2,171)	$ 3,152	$ 126
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Mar. 30, 2024	$ 3,278
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 0.56