Consolidated Statement of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Apr. 03, 2021	Mar. 28, 2020
Income Statement [Abstract]
Net sales	$ 3,584	$ 3,412
Cost of goods sold	2,418	2,268
Selling, general and administrative expense	694	685
Operating profit	472	459
Interest expense	59	64
Other income (expense), net	69	51
Income before income taxes	482	446
Income taxes	109	94
Earnings (loss) from unconsolidated entities	(2)	(2)
Net income	371	350
Net income attributable to noncontrolling interests	3	3
Net income attributable to Kellogg Company	$ 368	$ 347
Per share amounts:
Basic earnings (in dollars per share)	$ 1.07	$ 1.01
Diluted earnings (in dollars per share)	$ 1.07	$ 1.01
Average shares outstanding:
Basic (in shares)	342	342
Diluted (in shares)	344	344
Actual shares outstanding at period end (in shares)	340	343