REPORTABLE SEGMENTS - Supplemental product information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Jan. 01, 2022	Jan. 02, 2021
Segment Reporting Information [Line Items]
Net sales	$ 15,315	$ 14,181	$ 13,770
Snacks
Segment Reporting Information [Line Items]
Net sales	7,563	6,807	6,281
Retail Channel Cereal
Segment Reporting Information [Line Items]
Net sales	5,280	5,123	5,433
Frozen
Segment Reporting Information [Line Items]
Net sales	1,097	1,106	1,139
Noodles and other
Segment Reporting Information [Line Items]
Net sales	$ 1,375	$ 1,145	$ 917