REPORTABLE SEGMENTS - Supplemental product information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 30, 2023	Sep. 30, 2023	Jul. 01, 2023	Apr. 01, 2023	Dec. 31, 2022	Oct. 01, 2022	Jul. 02, 2022	Apr. 02, 2022	Dec. 30, 2023	Dec. 31, 2022	Jan. 01, 2022
Segment Reporting Information [Line Items]
Net sales	$ 3,174	$ 3,255	$ 3,351	$ 3,342	$ 3,164	$ 3,251	$ 3,181	$ 3,057	$ 13,122	$ 12,653	$ 11,747
Snacks
Segment Reporting Information [Line Items]
Net sales									8,105	7,563	6,807
Retail Channel Cereal
Segment Reporting Information [Line Items]
Net sales									2,736	2,618	2,689
Frozen
Segment Reporting Information [Line Items]
Net sales									1,095	1,097	1,106
Noodles and other
Segment Reporting Information [Line Items]
Net sales									$ 1,186	$ 1,375	$ 1,145