Reportable Segments (Reportable Segment Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 3,861	$ 3,440
Operating profit	503	527
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.
U.S. Morning Foods [Member]
Segment Reporting Information [Line Items]
Net sales	911	897
Operating profit	163	153
Reportable segments information	The U.S. Morning Foods operating segment 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	901	786
Operating profit	106	123
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	379	348
Operating profit	78	71
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	403	368
Operating profit	75	70
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	692	538
Operating profit	71	70
Reportable segments information	Europe which consists principally of European countries;
Latin America [Member]
Segment Reporting Information [Line Items]
Net sales	308	270
Operating profit	48	51
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	267	233
Operating profit	21	33
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	562	571
Corporate [Member]
Segment Reporting Information [Line Items]
Operating profit	$ (59)	$ (44)