Statement of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common stock	Capital in excess of par value	Retained earnings	Treasury stock	Accumulated other comprehensive income (loss)	Total Kellogg Company equity	Non- controlling interests
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 29, 2018	$ 3,159							$ 558
Balance, in shares at Dec. 29, 2018		421			77
Balance at Dec. 29, 2018		$ 105	$ 895	$ 7,652	$ (4,551)	$ (1,500)	$ 2,601
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases	(220)				$ (220)		(220)
Common stock repurchases (in shares)					4
Net income (loss)	977			960			960	17
Sale of subsidiary shares to noncontrolling interest	1						0	1
Dividends declared	(769)			(769)			(769)
Distributions to noncontrolling interest	(9)						0	(9)
Other comprehensive income (loss)	74					74	74	0
Reclassification of tax effects relating to U.S. Tax Reform	0			22		(22)	0
Stock compensation	56		56				56
Stock options exercised and other	45		(30)	(6)	$ 81		45
Stock options exercised and other (in shares)		0			(2)
Balance, in shares at Dec. 28, 2019		421			79
Balance at Dec. 28, 2019		$ 105	921	7,859	$ (4,690)	(1,448)	2,747
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 28, 2019	3,314							567
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	1,264			1,251			1,251	13
Divestiture	(3)						0	(3)
Dividends declared	(782)			(782)			(782)
Distributions to noncontrolling interest	(1)						0	(1)
Other comprehensive income (loss)	(336)					(284)	(284)	(52)
Stock compensation	76		76				76
Stock options exercised and other	104		(25)	(2)	$ 131		104
Stock options exercised and other (in shares)		0			(2)
Balance, in shares at Jan. 02, 2021		421			77
Balance at Jan. 02, 2021	3,112	$ 105	972	8,326	$ (4,559)	(1,732)	3,112
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jan. 02, 2021	3,636							524
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases	(240)				$ (240)		(240)
Common stock repurchases (in shares)					4
Net income (loss)	1,495			1,488			1,488	7
Acquisition of noncontrolling interest and other	52		22				22	30
Dividends declared	(788)			(788)			(788)	0
Distributions to noncontrolling interest	(36)						0	(36)
Other comprehensive income (loss)	(19)					11	11	(30)
Stock compensation	68		68				68
Stock options exercised and other	47		(39)	2	$ 84		47
Stock options exercised and other (in shares)		0			(1)
Balance, in shares at Jan. 01, 2022		421			80
Balance at Jan. 01, 2022	3,720	$ 105	$ 1,023	$ 9,028	$ (4,715)	$ (1,721)	$ 3,720
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jan. 01, 2022	$ 4,215							$ 495