Consolidated Statement of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Income Statement [Abstract]
Net sales	$ 3,412	$ 3,522
Cost of goods sold	2,268	2,415
Selling, general and administrative expense	685	726
Operating profit	459	381
Interest expense	64	74
Other income (expense), net	51	52
Income before income taxes	446	359
Income taxes	94	72
Earnings (loss) from unconsolidated entities	(2)	(2)
Net income	350	285
Net income attributable to noncontrolling interests	3	3
Net income attributable to Kellogg Company	$ 347	$ 282
Per share amounts:
Basic earnings (in dollars per share)	$ 1.01	$ 0.82
Diluted earnings (in dollars per share)	$ 1.01	$ 0.82
Average shares outstanding:
Basic (in shares)	342	342
Diluted (in shares)	344	343
Actual shares outstanding at period end (in shares)	343	340