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	756			748			748	8
Dividends, Common Stock	(392)			(392)			(392)
Distributions to noncontrolling interest	(1)						0	(1)
Other comprehensive income (loss)	56					69	69	(13)
Stock compensation	39		39				39
Stock options exercised and other	26		(38)	6	$ 58		26
Stock options exercised and other (in shares)					(1)
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 at Jul. 03, 2021	$ 3,880
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 1.15
Balance (in shares) at Apr. 03, 2021		421			81
Balance at Apr. 03, 2021		$ 105	954	8,506	$ (4,762)	(1,665)	3,138	517
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Apr. 03, 2021	$ 3,655
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	385			380			380	5
Dividends, Common Stock	(197)			(197)			(197)
Distributions to noncontrolling interest	(1)						0	(1)
Other comprehensive income (loss)	(1)					2	2	(3)
Stock compensation	19		19				19
Stock options exercised and other	20		0	(1)	$ 21		20
Stock options exercised and other (in shares)					(1)
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 at Jul. 03, 2021	$ 3,880
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	750			748			748	2
Dividends, Common Stock	(394)			(394)			(394)
Distributions to noncontrolling interest	(17)						0	(17)
Other comprehensive income (loss)	116					120	120	(4)
Stock compensation	35		35				35
Stock options exercised and other	153		(50)	5	$ 198		153
Stock options exercised and other (in shares)					(4)
Balance (in shares) at Jul. 02, 2022		421			81
Balance at Jul. 02, 2022	4,082	$ 105	1,008	9,387	$ (4,817)	(1,601)	4,082	476
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jul. 02, 2022	$ 4,558
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 1.16
Balance (in shares) at Apr. 02, 2022		421			83
Balance at Apr. 02, 2022		$ 105	993	9,254	$ (4,946)	(1,611)	3,795	500
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Apr. 02, 2022	$ 4,295
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	326			326			326	0
Dividends, Common Stock	(197)			(197)			(197)
Distributions to noncontrolling interest	(16)						0	(16)
Other comprehensive income (loss)	2					10	10	(8)
Stock compensation	19		19				19
Stock options exercised and other	129		(4)	4	$ 129		129
Stock options exercised and other (in shares)					(2)
Balance (in shares) at Jul. 02, 2022		421			81
Balance at Jul. 02, 2022	4,082	$ 105	$ 1,008	$ 9,387	$ (4,817)	$ (1,601)	$ 4,082	$ 476
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jul. 02, 2022	$ 4,558
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 0.58