Restructuring and Cost Reduction Activities - Schedule of Restructuring and Cost Reduction Activities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 34	$ 1	$ 59	$ 239
Program costs to date	1,436		1,436
Employee related costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	17	31	22	166
Program costs to date	556		556
Pension curtailment (gain) loss, net
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(30)	(134)	(30)	(133)
Program costs to date	(167)		(167)
Asset related costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	10	38	0	68
Program costs to date	269		269
Asset impairment
Restructuring Cost and Reserve [Line Items]
Restructuring charges	14	0	14	0
Program costs to date	169		169
Other costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	23	66	53	138
Program costs to date	609		609
Operating Segments | U.S. Snacks
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4	106	13	305
Program costs to date	516		516
Operating Segments | U.S. Morning Foods
Restructuring Cost and Reserve [Line Items]
Restructuring charges	19	14	31	16
Program costs to date	282		282
Operating Segments | U.S. Specialty Channels
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1	0	1	1
Program costs to date	22		22
Operating Segments | North America Other
Restructuring Cost and Reserve [Line Items]
Restructuring charges	20	4	21	13
Program costs to date	161		161
Operating Segments | Europe
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(16)	13	(22)	21
Program costs to date	308		308
Operating Segments | Latin America
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3	2	7	6
Program costs to date	34		34
Operating Segments | Asia Pacific
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2	1	5	5
Program costs to date	92		92
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1	$ (139)	3	$ (128)
Program costs to date	$ 21		$ 21