Consolidated Statement of Income Statement - USD ($) $ in Millions	12 Months Ended
	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Income Statement [Abstract]
Net sales	$ 13,770	$ 13,578	$ 13,547
Cost of goods sold	9,043	9,197	8,821
Selling, general and administrative expense	2,966	2,980	3,020
Operating profit	1,761	1,401	1,706
Interest expense	281	284	287
Other income (expense), net	121	188	(90)
Income before income taxes	1,601	1,305	1,329
Income taxes	323	321	181
Earnings (loss) from unconsolidated entities	(14)	(7)	196
Net income	1,264	977	1,344
Net income (loss) attributable to noncontrolling interests	13	17	8
Net income attributable to Kellogg Company	$ 1,251	$ 960	$ 1,336
Basic	$ 3.65	$ 2.81	$ 3.85
Diluted	$ 3.63	$ 2.80	$ 3.83