Reportable Segments (Reportable Segment Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Net sales	$ 3,714	$ 3,474	$ 7,575	$ 6,914
Operating profit	570	519	1,073	1,046
Reportable segments information			The Company currently manages its operations through eight operating segments that are based on product category or geographic location. These operating segments are evaluated for similarity with regards to economic characteristics, products, production processes, types or classes of customers, distribution methods and regulatory environments to determine if they can be aggregated into reportable segments.  Beginning in the first quarter of 2013, the Kashi operating segment, which was formerly aggregated with the U.S. Morning Foods operating segment and reported as U.S. Morning Foods and Kashi, was eliminated due to a reorganization of the business. Kashi operating segment results of prior periods were recast between U.S. Morning Foods and U.S. Snacks to conform to the current presentation.  The reportable segments are discussed in greater detail below.
Number of operating segments			8
Number of reportable segments			3
U.S. Morning Foods [Member]
Segment Reporting Information [Line Items]
Net sales	863	892	1,774	1,789
Operating profit	180	178	343	331
Reportable segments information			U.S. Morning Foods includes cereal, toaster pastries, health and wellness bars, and beverages generally marketed under the Kellogg’s name.
U.S. Snacks [Member]
Segment Reporting Information [Line Items]
Net sales	917	850	1,818	1,636
Operating profit	130	121	236	244
Reportable segments information			U.S. Snacks includes products such as cookies, crackers, cereal bars, savory snacks and fruit-flavored snacks.
U.S. Specialty [Member]
Segment Reporting Information [Line Items]
Net sales	272	252	651	600
Operating profit	62	56	140	127
Reportable segments information			U.S. Specialty primarily represents the food service, convenience and Girl Scouts businesses. The food service business is mostly non-commercial, servicing institutions such as schools and hospitals.
North America Other [Member]
Segment Reporting Information [Line Items]
Net sales	388	369	791	737
Operating profit	78	70	153	140
Reportable segments information			North America Other represents the U.S. Frozen and Canada operating segments.  As these operating segments are not considered economically similar enough to aggregate with other operating segments and are immaterial for separate disclosure, they have been grouped together as a single reportable segment.
Europe [Member]
Segment Reporting Information [Line Items]
Net sales	723	613	1,415	1,151
Operating profit	75	64	146	134
Reportable segments information			Europe which consists principally of European countries;
Latin America [Member]
Segment Reporting Information [Line Items]
Net sales	304	274	612	544
Operating profit	42	48	90	99
Reportable segments information			Latin America which is comprised of Central and South America and includes Mexico;
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales	247	224	514	457
Operating profit	17	17	38	50
Reportable segments information			Asia Pacific which is comprised of South Africa, Australia and other Asian and Pacific markets.
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating profit	584	554	1,146	1,125
Corporate [Member]
Segment Reporting Information [Line Items]
Operating profit	$ (14)	$ (35)	$ (73)	$ (79)