Consolidated Statement of Equity (Unaudited) - 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
Balance (in shares) at Jan. 02, 2021		421			77
Balance at Jan. 02, 2021		$ 105	$ 972	$ 8,326	$ (4,559)	$ (1,732)	$ 3,112	$ 524
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Jan. 02, 2021	$ 3,636
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased	(240)				$ (240)		(240)
Common stock repurchased (in shares)					4
Net income	1,061			1,055			1,055	6
Acquisition of noncontrolling interest and other	52		22				22	30
Dividends, Common Stock	(590)			(590)			(590)
Distributions to noncontrolling interest	(18)						0	(18)
Other comprehensive income (loss)	22					39	39	(17)
Stock compensation	50		50				50
Stock options exercised and other	36		(39)	5	$ 70		36
Stock options exercised and other (in shares)					(1)
Balance (in shares) at Oct. 02, 2021		421			80
Balance at Oct. 02, 2021		$ 105	1,005	8,796	$ (4,729)	(1,693)	3,484	525
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Oct. 02, 2021	$ 4,009
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 1.73
Balance (in shares) at Jul. 03, 2021		421			80
Balance at Jul. 03, 2021		$ 105	973	8,688	$ (4,741)	(1,663)	3,362	518
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Jul. 03, 2021	$ 3,880
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	305			307			307	(2)
Acquisition of noncontrolling interest and other	52		22				22	30
Dividends, Common Stock	(198)			(198)			(198)
Distributions to noncontrolling interest	(17)						0	(17)
Other comprehensive income (loss)	(34)					(30)	(30)	(4)
Stock compensation	11		11				11
Stock options exercised and other	10		(1)	(1)	$ 12		10
Stock options exercised and other (in shares)					0
Balance (in shares) at Oct. 02, 2021		421			80
Balance at Oct. 02, 2021		$ 105	1,005	8,796	$ (4,729)	(1,693)	3,484	525
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Oct. 02, 2021	$ 4,009
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 0.58
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	495
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Jan. 01, 2022	4,215
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased	(300)				$ (300)		(300)
Common stock repurchased (in shares)					5
Net income	1,062			1,058			1,058	4
Dividends, Common Stock	(596)			(596)			(596)
Distributions to noncontrolling interest	(18)						0	(18)
Other comprehensive income (loss)	97					123	123	(26)
Stock compensation	56		56				56
Stock options exercised and other	222		(52)	9	$ 265		222
Stock options exercised and other (in shares)					(5)
Balance (in shares) at Oct. 01, 2022		421			80
Balance at Oct. 01, 2022	4,283	$ 105	1,027	9,499	$ (4,750)	(1,598)	4,283	455
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Oct. 01, 2022	$ 4,738
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 1.75
Balance (in shares) at Jul. 02, 2022		421			81
Balance at Jul. 02, 2022		$ 105	1,008	9,387	$ (4,817)	(1,601)	4,082	476
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Jul. 02, 2022	$ 4,558
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	312			310			310	2
Dividends, Common Stock	(202)			(202)			(202)
Distributions to noncontrolling interest	(1)						0	(1)
Other comprehensive income (loss)	(19)					3	3	(22)
Stock compensation	21		21				21
Stock options exercised and other	69		(2)	4	$ 67		69
Stock options exercised and other (in shares)					(1)
Balance (in shares) at Oct. 01, 2022		421			80
Balance at Oct. 01, 2022	4,283	$ 105	$ 1,027	$ 9,499	$ (4,750)	$ (1,598)	$ 4,283	$ 455
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Oct. 01, 2022	$ 4,738
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 0.59