Consolidated Statement of Income Statement - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Income Statement [Abstract]
Net sales	$ 13,578	$ 13,547	$ 12,854
Cost of goods sold	9,197	8,821	8,155
Selling, general and administrative expense	2,980	3,020	3,312
Operating profit	1,401	1,706	1,387
Interest expense	284	287	256
Other income (expense), net	188	(90)	526
Income before income taxes	1,305	1,329	1,657
Income taxes	321	181	410
Earnings (loss) from unconsolidated entities	(7)	196	7
Net income	977	1,344	1,254
Net income (loss) attributable to noncontrolling interests	17	8	0
Net income attributable to Kellogg Company	$ 960	$ 1,336	$ 1,254
Basic	$ 2.81	$ 3.85	$ 3.61
Diluted	$ 2.80	$ 3.83	$ 3.58