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]
Common stock repurchased	(60)				$ (60)		(60)
Common stock repurchased (in shares)					1
Net income	664			655			655	9
Dividends, Common Stock	(404)			(404)			(404)
Distributions to noncontrolling interest	(13)						0	(13)
Other comprehensive income (loss)	(409)					(235)	(235)	(174)
Stock compensation	43		43				43
Stock options exercised, issuance of other stock awards and other	25		(55)	(1)	$ 81		25
Stock options exercised and other (in shares)					(1)
Balance (in shares) at Jul. 01, 2023		421			79
Balance at Jul. 01, 2023		$ 105	1,056	9,447	$ (4,700)	(1,943)	3,965	256
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jul. 01, 2023	$ 4,221
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 1.18
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, Beginning Balance at Apr. 01, 2023	$ 4,479
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased	(60)				$ (60)		(60)
Common stock repurchased (in shares)					1
Net income	362			357			357	5
Dividends, Common Stock	(202)			(202)			(202)
Distributions to noncontrolling interest	(5)						0	(5)
Other comprehensive income (loss)	(401)					(230)	(230)	(171)
Stock compensation	21		21				21
Stock options exercised, issuance of other stock awards and other	27		2	(1)	$ 26		27
Stock options exercised and other (in shares)					0
Balance (in shares) at Jul. 01, 2023		421			79
Balance at Jul. 01, 2023		$ 105	1,056	9,447	$ (4,700)	(1,943)	3,965	256
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jul. 01, 2023	$ 4,221
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	618			611			611	7
Dividends, Common Stock	(383)			(383)			(383)
Distributions to noncontrolling interest	(3)						0	(3)
Other comprehensive income (loss)	(245)					(167)	(167)	(78)
Stock compensation	41		41				41
Stock options exercised, issuance of other stock awards and other	30		(60)	(5)	$ 95		30
Stock options exercised and other (in shares)					(2)
Balance (in shares) at Jun. 29, 2024		421			79
Balance at Jun. 29, 2024	3,307	$ 105	1,082	9,027	$ (4,699)	(2,208)	3,307	120
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 29, 2024	$ 3,427
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 1.12
Balance (in shares) at Mar. 30, 2024		421			80
Balance at Mar. 30, 2024		$ 105	1,063	8,878	$ (4,723)	(2,171)	3,152	126
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Mar. 30, 2024	$ 3,278
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	347			344			344	3
Dividends, Common Stock	(192)			(192)			(192)
Distributions to noncontrolling interest	(1)						0	(1)
Other comprehensive income (loss)	(45)					(37)	(37)	(8)
Stock compensation	20		20				20
Stock options exercised, issuance of other stock awards and other	20		(1)	(3)	$ 24		20
Stock options exercised and other (in shares)					(1)
Balance (in shares) at Jun. 29, 2024		421			79
Balance at Jun. 29, 2024	3,307	$ 105	$ 1,082	$ 9,027	$ (4,699)	$ (2,208)	$ 3,307	$ 120
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 29, 2024	$ 3,427
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 0.56