Restructuring and Cost Reduction Activities Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	$ 1,520
Restructuring and Related Cost, Incurred Cost	143	$ 263	$ 325
Exit cost reserve	104	160	131
Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	99	115	172
SGA
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	74	296	152
Other (income) expense
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	$ (30)	(148)	1
Minimum
Restructuring Cost and Reserve [Line Items]
Restructuring and related activities cash implementation costs recovery time frame	3 years
Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring and related activities cash implementation costs recovery time frame	5 years
U.S. Snacks
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	$ 531
Restructuring and Related Cost, Incurred Cost	28	309	76
U.S. Morning Foods
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	301
Restructuring and Related Cost, Incurred Cost	50	18	23
U.S. Specialty
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	25
Restructuring and Related Cost, Incurred Cost	4	2	8
North America Other
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	165
Restructuring and Related Cost, Incurred Cost	25	16	38
Europe
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	333
Restructuring and Related Cost, Incurred Cost	3	40	126
Latin America
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	42
Restructuring and Related Cost, Incurred Cost	15	9	8
Asia Pacific
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	98
Restructuring and Related Cost, Incurred Cost	11	11	7
Asset related costs
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	285
Restructuring and Related Cost, Incurred Cost	16	77	46
Exit cost reserve	1	0	0
Employee related cost
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	597
Restructuring and Related Cost, Incurred Cost	63	177	108
Exit cost reserve	93	97	102
Pension curtailment (gain) loss, net
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	(167)
Restructuring and Related Cost, Incurred Cost	(30)	(148)	1
Exit cost reserve	0	0	0
Other cost
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	636
Restructuring and Related Cost, Incurred Cost	80	157	120
Exit cost reserve	10	63	29
Asset impairment
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	169
Restructuring and Related Cost, Incurred Cost	14	0	50
Exit cost reserve	0	0	0
Project K
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	1,520
Project K | Revenue
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	6
Project K | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	893
Project K | SGA
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	788
Project K | Other (income) expense
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	(167)
Project K | Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	1,600
Estimated after-tax cash costs for program, including incremental capital investments	$ 1,200
Project K | U.S. Snacks
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost expected cost allocation	31.00%
Project K | U.S. Morning Foods
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost expected cost allocation	17.00%
Project K | U.S. Specialty
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost expected cost allocation	1.00%
Project K | North America Other
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost expected cost allocation	16.00%
Project K | Europe
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost expected cost allocation	22.00%
Project K | Latin America
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost expected cost allocation	3.00%
Project K | Asia Pacific
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost expected cost allocation	6.00%
Project K | Asset related costs | Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	$ 500
Project K | Employee related cost | Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	400
Project K | Other cost | Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost	700
ZBB
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	40
Restructuring and Related Cost, Incurred Cost		3	25
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs since inception of program	25
Restructuring and Related Cost, Incurred Cost	$ 7	$ (142)	$ 39
Corporate | Project K
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost expected cost allocation	4.00%