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	371			368			368	3
Dividends, Common Stock	(195)			(195)			(195)
Other comprehensive income (loss)	57					67	67	(10)
Stock compensation	20		20				20
Stock options exercised and other	6		(38)	7	$ 37		6
Stock options exercised and other (in shares)					0
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 at Apr. 03, 2021	$ 3,655
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 0.57
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	424			422			422	2
Dividends, Common Stock	(197)			(197)			(197)
Distributions to noncontrolling interest	(1)						0	(1)
Other comprehensive income (loss)	114					110	110	4
Stock compensation	16		16				16
Stock options exercised and other	24		(46)	1	$ 69		24
Stock options exercised and other (in shares)					(2)
Balance (in shares) at Apr. 02, 2022		421			83
Balance at Apr. 02, 2022	3,795	$ 105	$ 993	$ 9,254	$ (4,946)	$ (1,611)	$ 3,795	$ 500
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Apr. 02, 2022	$ 4,295
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared - per share	$ 0.58