Reportable Segments (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jul. 01, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jul. 01, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments			10
Number of remaining reportable segments based on geographical locations			3
Net sales	$ 3,360	$ 3,175	$ 6,761	$ 6,423
Operating profit	474	385	984	665
Operating Segments
Segment Reporting Information [Line Items]
Operating profit	530	449	1,052	836
Operating Segments | U.S. Snacks
Segment Reporting Information [Line Items]
Net sales	745	815	1,507	1,610
Operating profit	111	29	213	(7)
Operating Segments | U.S. Morning Foods
Segment Reporting Information [Line Items]
Net sales	643	664	1,334	1,372
Operating profit	138	170	288	327
Operating Segments | U.S. Specialty Channels
Segment Reporting Information [Line Items]
Net sales	277	275	675	668
Operating profit	60	70	140	166
Operating Segments | North America Other
Segment Reporting Information [Line Items]
Net sales	462	390	941	782
Operating profit	76	59	143	108
Operating Segments | Europe
Segment Reporting Information [Line Items]
Net sales	621	567	1,208	1,080
Operating profit	97	77	171	143
Operating Segments | Latin America
Segment Reporting Information [Line Items]
Net sales	239	232	471	452
Operating profit	20	26	42	59
Operating Segments | Asia Pacific
Segment Reporting Information [Line Items]
Net sales	373	232	625	459
Operating profit	28	18	55	40
Corporate
Segment Reporting Information [Line Items]
Operating profit	$ (56)	$ (64)	$ (68)	$ (171)