Divestiures, West Africa Investments and Acquisitions Multipro Schedule of Pro Forma Results (Details) - Multipro - USD ($) $ in Millions	12 Months Ended
Dec. 29, 2018	Dec. 30, 2017
Business Acquisition [Line Items]
Pro forma net sales	$ 13,829	$ 13,511
Pro forma net income attributable to Kellogg Company	$ 1,336	$ 1,255

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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