Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Apr. 02, 2016	Apr. 04, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 175	$ 227
Other comprehensive income (loss), pre-tax:
Foreign currency translation adjustments, pre-tax	(55)	(62)
Cash flow hedges, pre-tax:
Unrealized gain (loss) on cash flow hedges, pre-tax	(57)	8
Reclassification to net income, pre-tax	2	(4)
Postretirement and postemployment benefit amounts arising during the period, pre-tax:
Prior service credit (cost), pre-tax	0	(1)
Postretirement and postemployment benefits reclassification to net income, pre-tax:
Net experience loss	1	1
Prior service cost	0	3
Other comprehensive income (loss), pre-tax	(109)	(55)
Other comprehensive income (loss), tax (expense) benefit
Foreign currency translation adjustments, tax (expense) benefit	29	(21)
Cash flow hedges, tax (expense) benefit:
Unrealized gain (loss) on cash flow hedges, tax (expense) benefit	23	(1)
Reclassification to net income, tax (expense) benefit	(1)	0
Postretirement and postemployment benefit amounts arising during the period, tax (expense) benefit:
Prior service credit (cost), tax (expense) benefit	0	0
Postretirement and postemployment benefits reclassification to net income, tax (expense) benefit:
Net experience loss, tax (expense) benefit	0	0
Prior service cost, tax (expense) benefit	0	(1)
Other comprehensive income (loss), tax (expense) benefit	51	(23)
Other comprehensive income (loss), after tax:
Foreign currency translation adjustments, after-tax	(26)	(83)
Cash flow hedges, after tax
Unrealized gain (loss) on cash flow hedges, after-tax	(34)	7
Reclassification to net income, after-tax	1	(4)
Postretirement and postemployment benefit amounts arising during the period, after-tax:
Prior service credit (cost), after-tax	0	(1)
Postretirement and postemployment benefits reclassification to net income, after-tax:
Net experience loss, after-tax	1	1
Prior service cost, after-tax	0	2
Other comprehensive income (loss)	(58)	(78)
Comprehensive income	117	149
Other comprehensive income (loss) attributable to noncontrolling interests	0	(1)
Comprehensive income attributable to Kellogg Company	$ 117	$ 148