Consolidated Statement of Income (Unaudited) - USD ($) shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Oct. 01, 2022	Sep. 30, 2023	Oct. 01, 2022
Income Statement [Abstract]
Net sales	$ 3,939	$ 3,946	$ 12,033	$ 11,482
Cost of goods sold	2,596	2,793	8,147	8,027
Selling, general and administrative expense	861	785	2,455	2,155
Operating profit	482	368	1,431	1,300
Interest expense	83	39	245	149
Other income (expense), net	(24)	54	38	188
Income before income taxes	375	383	1,224	1,339
Income tax expense (benefit)	104	74	294	283
Earnings (loss) from unconsolidated entities	(1)	3	4	6
Net income	270	312	934	1,062
Net income attributable to noncontrolling interests	1	2	10	4
Net income attributable to Kellanova	$ 269	$ 310	$ 924	$ 1,058
Per share amounts:
Basic earnings (in dollars per share)	$ 0.79	$ 0.91	$ 2.70	$ 3.11
Diluted earnings (in dollars per share)	$ 0.78	$ 0.90	$ 2.68	$ 3.09
Average shares outstanding:
Basic (in shares)	342,000	341,000	342,000	340,000
Diluted (in shares)	345,000	344,000	345,000	343,000
Actual shares outstanding at period end (in shares)	343,000	341,000	343,000	341,000