Reportable Segments (Narrative) (Details)	12 Months Ended
	Dec. 31, 2011	Jan. 01, 2011	Jan. 02, 2010
Reportable segments information	Beginning in the fourth quarter of 2011, the Company now 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.  Segment results of prior periods were recast to conform to the current presentation.  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.  The reportable segments are discussed in greater detail below:
Walmart Stores, Inc [Member]
Largest customer, percentage of consolidated net sales	20.00%	21.00%	21.00%
US Morning Foods and Kashi [Member]
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 business 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.
US Snacks [Member]
Reportable segments information	U.S. Snacks represents the U.S. snacks business which includes products such as cookies, crackers, cereal bars and fruit-flavored snacks.
US Specialty [Member]
Reportable segments information	U.S. Specialty primarily represents the food service and Girl Scouts business. The food service business is mostly non-commercial, and services schools, hospitals and prisons.
North America Other [Member]
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]
Reportable segments information	Europe which consists principally of European countries;
Latin America [Member]
Reportable segments information	Latin America which is comprised of Central and South America and includes Mexico;
Asia Pacific [Member]
Reportable segments information	Asia Pacific which is comprised of South Africa, Australia and other Asian and Pacific markets.