Reportable Segments Supplemental product information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jan. 02, 2016	Oct. 03, 2015	Jul. 04, 2015	Apr. 04, 2015	Jan. 03, 2015	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Jan. 02, 2016	Jan. 03, 2015	Dec. 28, 2013
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net	$ 3,142	$ 3,329	$ 3,498	$ 3,556	$ 3,514	$ 3,639	$ 3,685	$ 3,742	$ 13,525	$ 14,580	$ 14,792
Cereal [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net									5,871	6,570	6,753
Snacks [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net									6,698	7,002	7,011
Frozen [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net									$ 956	$ 1,008	$ 1,028