RESTRUCTURING - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 29, 2024 USD ($)	Jun. 29, 2024 USD ($)
Restructuring Cost and Reserve [Line Items]
Program costs to date	$ 109	$ 109
Restructuring charges	$ 8	109
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Cash implementation costs	1
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Cash implementation costs	5
North America
Restructuring Cost and Reserve [Line Items]
Program costs to date	$ 40	40
Restructuring charges	9	40
Employee Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Program costs to date	37	37
Restructuring charges	0	37
Asset related costs [Member]
Restructuring Cost and Reserve [Line Items]
Program costs to date	8	8
Restructuring charges	4	8
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]
Restructuring and related cost, expected cost	50	50
North America Frozen Supply Chain Network Reconfiguration | COGS
Restructuring Cost and Reserve [Line Items]
Restructuring charges	9	40
North America Frozen Supply Chain Network Reconfiguration | Employee Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	10	10
North America Frozen Supply Chain Network Reconfiguration | Asset related costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	30	30
North America Frozen Supply Chain Network Reconfiguration | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	10	10
European Cereal Supply Chain Network Reconfiguration
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	120	120
Restructuring charges		69
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