INCOME TAXES - Change in Valuation Allowance Against Deferred Tax Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2023		Dec. 31, 2022	Jan. 01, 2022
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 263		$ 248	$ 192
Additions charged to income tax expense	65	[1]	44	59	[1]
Reductions credited to income tax expense	(34)		(3)	(6)
Acquisition of noncontrolling interest	0		0	13
Currency translation adjustments	6		(26)	(10)
Balance at end of year	300		$ 263	248
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	18			20
Deferred Income Tax [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	(18)			$ (20)
North America Cereal Business
Income Tax Disclosure [Abstract]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	21
Deferred Income Tax [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ (21)

[1] During 2021, the Company increased the valuation allowance $20 million to fully reserve for net deferred tax assets of a foreign subsidiary. During 2023, the Company established a state valuation allowance of $21 million due to projected, perpetual separate company losses for Kellanova post separation from the North America cereal business. Additionally, in 2023 the Company established a valuation allowance of $18 million related to the sale of a subsidiary.