CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 30, 2024	Apr. 01, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 271	$ 302
Other comprehensive income (loss), pre-tax:
Foreign currency translation adjustments, pre-tax	(272)	42
Net investment hedges, pre-tax
Net investment hedge gain (loss), pre-tax	71	(57)
Cash flow hedges, pre-tax:
Net deferred gain (loss) on cash flow hedges, pre-tax	22	(18)
Reclassification to net income, pre-tax	2	3
Postretirement and postemployment benefits reclassification to net income, pre-tax:
Net experience (gain) loss		(1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	1
Available-for-sale securities, pre-tax
Unrealized gain (loss) on available-for-sale securities, pre-tax		1
Other comprehensive income (loss), pre-tax	(176)	(30)
Other comprehensive income (loss), tax (expense) benefit
Foreign currency translation adjustments, tax (expense) benefit	0	3
Net investment hedges, tax (expense) benefit
Net investment hedge gain (loss), tax (expense) benefit	(18)	15
Cash flow hedges, tax (expense) benefit:
Net deferred gain (loss) on cash flow hedges, tax (expense) benefit	(6)	5
Reclassification to net income, tax (expense) benefit	0	(1)
Postretirement and postemployment benefits reclassification to net income, tax (expense) benefit:
Net experience loss, tax (expense) benefit		0
Prior service cost, tax (expense) benefit	0
Available-for-sale securities, tax (expense) benefit
Unrealized gain (loss) on available-for-sale securities, tax (expense) benefit		0
Other comprehensive income (loss), tax (expense) benefit	(24)	22
Other comprehensive income (loss), after tax:
Foreign currency translation adjustments, after-tax	(272)	45
Net investment hedges, after tax
Net investment hedge gain (loss), after-tax	53	(42)
Cash flow hedges, after tax
Net deferred gain (loss) on cash flow hedges	16	(13)
Reclassification to net income, after tax	2	2
Postretirement and postemployment benefits reclassification to net income, after-tax:
Net experience (gain) loss, after-tax		(1)
Prior service cost, after-tax	1
Available-for-sale securities, after tax
Unrealized gain (loss) on available-for-sale securities, after-tax		1
Other comprehensive income (loss)	(200)	(8)
Comprehensive income	71	294
Net income attributable to noncontrolling interests	4	4
Other comprehensive income (loss) attributable to noncontrolling interests	(70)	(3)
Comprehensive income attributable to Kellanova	$ 137	$ 293