Equity - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Apr. 02, 2016	Apr. 04, 2015
Equity [Abstract]
Net income attributable to Kellogg Company, Basic	$ 175	$ 227
Average shares outstanding, Basic (in shares)	351	355
Earnings per share, Basic (in dollars per share)	$ 0.50	$ 0.64
Average shares outstanding, Dilutive potential common shares (in shares)	4	2
Earnings per share, Dilutive potential common shares (in dollars per share)	$ (0.01)	$ 0.00
Net income attributable to Kellogg Company, Diluted	$ 175	$ 227
Average shares outstanding, Diluted (in shares)	355	357
Earnings per share, Diluted (in dollars per share)	$ 0.49	$ 0.64