Consolidated Statement of Comprehensive Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Apr. 04, 2015	Mar. 29, 2014	Jan. 03, 2015
Consolidated Statement of Comprehensive Income [Abstract]
Net income	$ 227	$ 406	$ 633
Other comprehensive income, pre-tax:
Foreign currency translation adjustments, pre-tax	(62)	3
Cash flow hedges, pre-tax:
Unrealized gain (loss) on cash flow hedges, pre-tax	8	(1)
Reclassification to net income, pre-tax	(4)	(10)
Postretirement and postemployment benefit amounts arising during the period, pre-tax:
Prior service credit (cost), pre-tax	(1)
Postretirement and postemployment benefits reclassification to net income, pre-tax:
Net experience loss, pre-tax	1	1
Prior service cost, pre-tax	3	2
Other comprehensive income (loss), pre-tax	(55)	(5)
Other comprehensive income (loss), tax (expense) or benefit
Foreign currency translation adjustments, tax (expense) or benefit	(21)	0
Cash flow hedges, tax effect:
Unrealized gain (loss) on cash flow hedges, tax (expense) or benefit	(1)	0
Reclassification to net earnings - tax (expense) or benefit	0	3
Postretirement and postemployment benefit amounts arising during the period, tax effect:
Prior service credit (cost), tax (expense) or benefit	0
Postretirement and postemployment benefits reclassification to net income, tax effect:
Net experience loss, tax (expense) or benefit	0	0
Prior service cost, tax (expense) or benefit	(1)	(1)
Other comprehensive income (loss), tax (expense) or benefit	(23)	2
Other comprehensive income (loss), after tax
Foreign currency translation adjustments, after-tax	(83)	3
Cash flow hedges, after-tax:
Unrealized gain (loss) on cash flow hedges, after-tax	7	(1)
Reclassification to net income, after-tax	(4)	(7)
Postretirement and postemployment benefit amounts arising during the period, after-tax:
Prior service credit (cost), after-tax	(1)
Postretirement and postemployment benefits reclassification to net income, after-tax:
Net experience loss, after-tax	1	1
Prior service cost, after-tax	2	1
Other Comprehensive Income (Loss) Attributable to Kellogg	(78)	(3)
Other Comprehensive Income (Loss) Attributable to Noncontrolling Interest	(1)	0
Total comprehensive income	$ 148	$ 403