RESTRUCTURING - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2025	Sep. 28, 2024	Sep. 27, 2025	Sep. 28, 2024
Restructuring Cost and Reserve [Line Items]
Program costs to date	$ 165		$ 165
Restructuring charges	$ 7	$ 12	22	$ 121
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Activities, Description	1
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Activities, Description	5
North America
Restructuring Cost and Reserve [Line Items]
Program costs to date	$ 65		65
Restructuring charges	(1)	7	0	47
Employee Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Program costs to date	55		55
Restructuring charges	3	4	10	41
Asset related costs [Member]
Restructuring Cost and Reserve [Line Items]
Program costs to date	31		31
Restructuring charges	4	1	8	9
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges			4
North America Frozen Supply Chain Network Reconfiguration
Restructuring Cost and Reserve [Line Items]
Program costs to date	65		65
North America Frozen Supply Chain Network Reconfiguration | COGS
Restructuring Cost and Reserve [Line Items]
Restructuring charges		7		47
North America Frozen Supply Chain Network Reconfiguration | Employee Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Program costs to date	7		7
North America Frozen Supply Chain Network Reconfiguration | Asset related costs [Member]
Restructuring Cost and Reserve [Line Items]
Program costs to date	43		43
North America Frozen Supply Chain Network Reconfiguration | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Program costs to date	15		15
European Cereal Supply Chain Network Reconfiguration
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	120		120
Restructuring charges	8	$ 5	22	$ 74
European Cereal Supply Chain Network Reconfiguration | Employee Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	50		50
European Cereal Supply Chain Network Reconfiguration | Asset related costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	40		40
European Cereal Supply Chain Network Reconfiguration | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	$ 30		$ 30