Consolidated Statement of Income (unaudited) - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jul. 01, 2023	Jul. 02, 2022	Jul. 01, 2023	Jul. 02, 2022
Income Statement [Abstract]
Net sales	$ 4,041	$ 3,864	$ 8,094	$ 7,536
Cost of goods sold	2,708	2,721	5,551	5,234
Selling, general and administrative expense	824	728	1,594	1,370
Operating profit	509	415	949	932
Interest expense	82	54	162	110
Other income (expense), net	36	60	62	134
Income before income taxes	463	421	849	956
Income tax expense (benefit)	104	97	190	209
Earnings (loss) from unconsolidated entities	3	2	5	3
Net income	362	326	664	750
Net income attributable to noncontrolling interests	5	0	9	2
Net income attributable to Kellogg Company	$ 357	$ 326	$ 655	$ 748
Per share amounts:
Basic earnings (in dollars per share)	$ 1.04	$ 0.96	$ 1.91	$ 2.20
Diluted earnings (in dollars per share)	$ 1.03	$ 0.95	$ 1.90	$ 2.19
Average shares outstanding:
Basic (in shares)	343,000	339,000	342,000	340,000
Diluted (in shares)	345,000	342,000	345,000	342,000
Actual shares outstanding at period end (in shares)	342,000	340,000	342,000	340,000