Consolidated Statement of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Oct. 01, 2016	Oct. 03, 2015
Income Statement [Abstract]
Net sales	$ 3,254	$ 3,329	$ 9,917	$ 10,383
Cost of goods sold	1,990	2,096	6,138	6,664
Selling, general and administrative expense	854	899	2,482	2,589
Operating profit	410	334	1,297	1,130
Interest expense	58	56	343	168
Other income (expense), net	3	(6)	7	(78)
Income before income taxes	355	272	961	884
Income taxes	62	66	215	227
Earnings (loss) from unconsolidated entities	(1)	(1)	1	(3)
Net income	292	205	747	654
Net income (loss) attributable to noncontrolling interests	0	0	0	(1)
Net income attributable to Kellogg Company	$ 292	$ 205	$ 747	$ 655
Per share amounts:
Basic (in dollars per share)	$ 0.83	$ 0.58	$ 2.13	$ 1.85
Diluted (in dollars per share)	0.82	0.58	2.11	1.84
Dividends per share (in dollars per share)	$ 0.52	$ 0.50	$ 1.52	$ 1.48
Average shares outstanding:
Basic (in shares)	350	354	350	354
Diluted (in shares)	354	356	354	356
Actual shares outstanding at period end (in shares)	351	354	351	354