Sale of Accounts Receivable (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Jul. 31, 2016
Receivables Sales Agreement | Other Income (Expense), Net
Transfer of Financial Assets Accounted for as Sales [Line Items]
Gain (Loss) on Sale of Accounts Receivable	$ (5)
Receivables Sales Agreement | Maximum
Transfer of Financial Assets Accounted for as Sales [Line Items]
Transfers Of Accounts Receivable Agreements	700	$ 550
Receivables Sales Agreement | Sold Since Inception
Transfer of Financial Assets Accounted for as Sales [Line Items]
Transfer of Accounts Receivable Agreements	1,500
Receivables Sales Agreement | Sold And Outstanding
Transfer of Financial Assets Accounted for as Sales [Line Items]
Transfer of Accounts Receivable Agreements	562
Kellogg Funding Company Program
Transfer of Financial Assets Accounted for as Sales [Line Items]
Cash Proceeds Received for Assets Derecognized	255
Deferred Purchase Price	37
Kellogg Funding Company Program | Maximum
Transfer of Financial Assets Accounted for as Sales [Line Items]
Transfers Of Accounts Receivable Agreements	600		$ 200
Kellogg Funding Company Program | Sold Since Inception
Transfer of Financial Assets Accounted for as Sales [Line Items]
Transfer of Accounts Receivable Agreements	839
Kellogg Funding Company Program | Sold And Outstanding
Transfer of Financial Assets Accounted for as Sales [Line Items]
Transfer of Accounts Receivable Agreements	292
Kellogg Foreign Subsidiaries Other Program | Sold Since Inception
Transfer of Financial Assets Accounted for as Sales [Line Items]
Transfer of Accounts Receivable Agreements	164
Kellogg Foreign Subsidiaries Other Program | Sold And Outstanding
Transfer of Financial Assets Accounted for as Sales [Line Items]
Transfer of Accounts Receivable Agreements	$ 124