CONSOLIDATED STATEMENT OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2025	Sep. 28, 2024	Sep. 27, 2025	Sep. 28, 2024
Income Statement [Abstract]
Net sales	$ 3,260	$ 3,233	$ 9,546	$ 9,625
Cost of goods sold	2,176	2,057	6,313	6,257
Selling, general and administrative expense	632	720	1,913	2,026
Operating profit	452	456	1,320	1,342
Interest expense	60	75	186	241
Other income (expense), net	8	21	28	97
Income before income taxes	400	402	1,162	1,198
Income taxes	89	34	245	213
Earnings (loss) from unconsolidated entities	3	2	8	3
Net income (loss)	314	370	925	988
Net income (loss) attributable to noncontrolling interests	5	3	13	10
Net income attributable to Kellanova	$ 309	$ 367	$ 912	$ 978
Earnings per common share - basic
Net earnings (loss) per common share - basic	$ 0.89	$ 1.07	$ 2.63	$ 2.86
Earnings per common share - diluted
Net earnings (loss) per common share - diluted	$ 0.88	$ 1.05	$ 2.61	$ 2.83
Average shares outstanding:
Basic (in shares)	348	343	347	342
Diluted (in shares)	350	347	350	345
Actual shares outstanding at period end (in shares)	348	345	348	345