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 Jan. 02, 2016	$ 2,114							$ 10
Balance, in shares at Jan. 02, 2016		420			70
Balance at Jan. 02, 2016		$ 105	$ 745	$ 6,573	$ (3,943)	$ (1,376)	$ 2,104
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases	$ (426)				$ (426)		(426)
Common stock repurchases (in shares)	6				6
Net income (loss)	$ 700			699			699	1
Acquisition of noncontrolling interest	5						0	5
Dividends declared ($2.20, $2.12, $2.04 per share for 2018, 2017 and 2016 respectively)	(716)			(716)			(716)
Other comprehensive income (loss)	(199)					(199)	(199)	0
Stock compensation	63		63				63
Stock options exercised and other	366		(2)	(4)	$ 372		366
Stock options exercised and other (in shares)					(7)
Balance, in shares at Dec. 31, 2016		420			69
Balance at Dec. 31, 2016		$ 105	806	6,552	$ (3,997)	(1,575)	1,891
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2016	1,907							16
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases	$ (516)				$ (516)		(516)
Common stock repurchases (in shares)	7				7
Net income (loss)	$ 1,254			1,254			1,254	0
Acquisition of noncontrolling interest	0						0	0
Dividends declared ($2.20, $2.12, $2.04 per share for 2018, 2017 and 2016 respectively)	(736)			(736)			(736)
Other comprehensive income (loss)	118					118	118	0
Stock compensation	66		66				66
Stock options exercised and other	101		6	(1)	$ 96		101
Stock options exercised and other (in shares)		1			(1)
Balance, in shares at Dec. 30, 2017		421			75
Balance at Dec. 30, 2017	2,178	$ 105	878	7,069	$ (4,417)	(1,457)	2,178
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 30, 2017	2,194							16
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases	$ (320)				$ (320)		(320)
Common stock repurchases (in shares)	5				5
Net income (loss)	$ 1,344			1,336			1,336	8
Acquisition of noncontrolling interest	552						0	552
Dividends declared ($2.20, $2.12, $2.04 per share for 2018, 2017 and 2016 respectively)	(773)			(762)			(762)	(11)
Other comprehensive income (loss)	(50)					(43)	(43)	(7)
Stock compensation	59		59				59
Stock options exercised and other	153		(42)	9	$ 186		153
Stock options exercised and other (in shares)		0			(3)
Balance, in shares at Dec. 29, 2018		421			77
Balance at Dec. 29, 2018	2,601	$ 105	$ 895	$ 7,652	$ (4,551)	$ (1,500)	$ 2,601
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 29, 2018	$ 3,159							$ 558