REPORTABLE SEGMENTS - Supplemental Product Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 28, 2024	Sep. 30, 2023	Sep. 28, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Net sales	$ 3,233	$ 3,255	$ 9,625	$ 9,948
Snacks
Segment Reporting Information [Line Items]
Net sales	2,069	2,040	6,153	6,114
Cereal
Segment Reporting Information [Line Items]
Net sales	690	684	2,066	2,070
Frozen
Segment Reporting Information [Line Items]
Net sales	276	281	828	838
Noodles and other
Segment Reporting Information [Line Items]
Net sales	$ 198	$ 250	$ 578	$ 926