Reportable Segments (Reportable Segment Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Segment Reporting Information [Line Items]
Net sales	$ 3,474	$ 3,386	$ 6,914	$ 6,871
Operating profit	485	543	1,020	1,115
Reportable segments information			The Company currently manages its operations through nine 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 fourth quarter of 2011, the Company has the following reportable segments: U.S. Morning Foods and Kashi; U.S. Snacks; U.S. Specialty; North America Other; Europe; Latin America; and Asia Pacific.  In addition, subsequent to the filing of the Company’s Annual Report on Form 10-K, the Company reclassified certain customers between reportable segments within North America. Segment results of prior periods were recast to conform to the current presentation.  The reportable segments are discussed in greater detail below.
U.S. Morning Foods and Kashi [Member]
Segment Reporting Information [Line Items]
Net sales	939	927	1,880	1,885
Operating profit	183	176	342	357
Reportable segments information			U.S. Morning Foods and Kashi aggregates the U.S. Morning Foods and U.S. Kashi operating segments.  The U.S. Morning Foods operating segment includes cereal, toaster pastries, and health and wellness products generally marketed under the Kellogg’s name.  The U.S. Kashi operating segment represents Kashi-branded cereal, cereal bars, crackers, cookies and Stretch Island fruit snacks.
U.S. Snacks [Member]
Segment Reporting Information [Line Items]
Net sales	803	729	1,545	1,454
Operating profit	117	111	235	235
Reportable segments information			U.S. Snacks represents the U.S. snacks business which 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	252	232	600	555
Operating profit	55	56	126	121
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	369	343	737	701
Operating profit	70	63	140	133
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	613	634	1,151	1,255
Operating profit	72	102	150	203
Reportable segments information			Europe which consists principally of European countries;
Latin America [Member]
Segment Reporting Information [Line Items]
Net sales	274	281	544	542
Operating profit	48	61	99	109
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	224	240	457	479
Operating profit	16	25	50	56
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	561	594	1,142	1,214
Corporate [Member]
Segment Reporting Information [Line Items]
Operating profit	$ (76)	$ (51)	$ (122)	$ (99)