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. 03, 2015	$ 2,851							$ 62
Balance, in shares at Jan. 03, 2015		420			64
Balance at Jan. 03, 2015		$ 105	$ 678	$ 6,689	$ (3,470)	$ (1,213)	$ 2,789
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases	$ (731)				$ (731)		(731)
Common stock repurchases (in shares)	11				11
Net income (loss)	$ 614			614			614	0
Acquisition of noncontrolling interest	7						0	7
VIE deconsolidation	(58)						0	(58)
Dividends	(700)			(700)			(700)
Other comprehensive income (loss)	(164)					(163)	(163)	(1)
Stock compensation	51		51				51
Stock options exercised and other	268		16	(6)	$ 258		268
Stock options exercised and other (in shares)					(5)
Balance, in shares at Jan. 02, 2016		420			70
Balance at Jan. 02, 2016		$ 105	745	6,597	$ (3,943)	(1,376)	2,128
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jan. 02, 2016	2,138							10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases	$ (426)				$ (426)		(426)
Common stock repurchases (in shares)	6				6
Net income (loss)	$ 695			694			694	1
Acquisition of noncontrolling interest	5						0	5
Dividends	(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	1,910	$ 105	806	6,571	$ (3,997)	(1,575)	1,910
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2016	1,926							16
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases	$ (516)				$ (516)		(516)
Common stock repurchases (in shares)	7				7
Net income (loss)	$ 1,269			1,269			1,269	0
Acquisition of noncontrolling interest	0						0	0
Dividends	(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	2,212	$ 105	$ 878	$ 7,103	$ (4,417)	$ (1,457)	$ 2,212
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 30, 2017	$ 2,228							$ 16