Comprehensive Income Statement - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 695	$ 614	$ 633
Other comprehensive income (loss), pre-tax:
Foreign currency translation adjustment before tax	(230)	(170)	(231)
Cash flow hedges, pre-tax:
Unrealized gain (loss) on cash flow hedges, pre-tax	(55)	8	(35)
Reclassifications to net income, pre-tax	11	(23)	(10)
Postretirement and postemployment benefit amounts arising during the period, pre-tax:
Net experience gain (loss)	0	0	(8)
Prior service credit (cost)	21	63	10
Postretirement and postemployment benefits reclassification to net income, pre-tax:
Net experience loss, pre-tax	3	3	3
Prior service cost, pre-tax	5	9	10
Venezuela deconsolidation loss, pre-tax	63	0	0
Other comprehensive income (loss), pre-tax	(182)	(110)	(261)
Other comprehensive income (loss), tax (expense) benefit:
Foreign currency translation adjustments tax (expense) benefit	(24)	(26)	(32)
Cash flow hedges, tax (expense) benefit:
Unrealized gain (loss) on cash flow hedges, tax (expense) benefit	22	(3)	18
Reclassifications to net income, tax (expense) benefit	(6)	3	2
Postretirement and postemployment benefit amounts arising during the period, tax (expense) benefit:
Net experience gain (loss), tax (expense) benefit	0	0	3
Prior service credit (cost), tax (expense) benefit	(7)	(24)	(3)
Postretirement and postemployment benefits reclassification to net income, tax (expense) benefit:
Net experience loss, tax (expense) benefit	(1)	(1)	(1)
Prior service cost, tax (expense) benefit	(1)	(3)	(3)
Venezuela deconsolidation loss, tax (expense) benefit	0	0	0
Other comprehensive income (loss), tax (expense) benefit	(17)	(54)	(16)
Other comprehensive income (loss), after-tax
Foreign currency translation adjustments after tax	(254)	(196)	(263)
Cash flow hedges, after-tax:
Unrealized gain (loss) on cash flow hedges, after-tax	(33)	5	(17)
Reclassification to net income, after-tax	5	(20)	(8)
Postretirement and postemployment benefit amounts arising during the period, after-tax
Net experience gain (loss), after tax	0	0	(5)
Prior service credit (cost), after-tax	14	39	7
Postretirement and postemployment benefits reclassification to net income, after-tax
Net experience loss, after-tax	2	2	2
Prior service cost, after-tax	4	6	7
Venezuela deconsolidation loss related to CTA, net of tax	63	0	0
Other comprehensive income (loss)	(199)	(164)	(277)
Comprehensive income	496	450	356
Net income (loss) attributable to noncontrolling interests	1	0	1
Other comprehensive income (loss) attributable to noncontrolling interests	0	(1)	0
Comprehensive income attributable to Kellogg Company	$ 495	$ 451	$ 355