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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 2,138								$ 10
Balance at Jan. 02, 2016			$ 105	$ 745	$ 6,597	$ (3,943)	$ (1,376)	$ 2,128
Balance (in shares) at Jan. 02, 2016			420			70
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchases (in shares)						6
Common stock repurchases	(426)					$ (426)		(426)
Net income	695				694			694	1
Noncontrolling Interest, Increase from Business Combination	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 (in shares)						(7)
Stock options exercised and other	366			(2)	(4)	$ 372		366
Balance (in shares) at Dec. 31, 2016			420			69
Balance at Dec. 31, 2016	1,910	[1]	$ 105	806	6,571	$ (3,997)	(1,575)	1,910
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,926	[1]							16
Common stock repurchases (in shares)	7					7
Common stock repurchases	$ (516)					$ (516)		(516)
Net income	841				841			841
Dividends	(550)				(550)			(550)
Other comprehensive income (loss)	109						109	109	0
Stock compensation	53			53				53
Stock options exercised and other (in shares)						(1)
Stock options exercised and other	80			(8)	0	$ 88		80
Balance (in shares) at Sep. 30, 2017			420			75
Balance at Sep. 30, 2017	1,927		$ 105	$ 851	$ 6,862	$ (4,425)	$ (1,466)	$ 1,927
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,943								$ 16

[1] Condensed from audited financial statements.