Goodwill and Other Intangible Assets - Carrying Amount of Goodwill (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Change in carrying amount of goodwill
Beginning Balance	$ 5,504
Purchase price allocation adjustment	(1)
Purchase price adjustment	(1)
Currency translation adjustment	12
Ending Balance	5,514
U.S. Snacks
Change in carrying amount of goodwill
Beginning Balance	3,568
Purchase price allocation adjustment	0
Purchase price adjustment	0
Currency translation adjustment	0
Ending Balance	3,568
U.S. Morning Foods
Change in carrying amount of goodwill
Beginning Balance	131
Purchase price allocation adjustment	0
Purchase price adjustment	0
Currency translation adjustment	0
Ending Balance	131
U.S. Specialty
Change in carrying amount of goodwill
Beginning Balance	82
Purchase price allocation adjustment	0
Purchase price adjustment	0
Currency translation adjustment	0
Ending Balance	82
North America Other
Change in carrying amount of goodwill
Beginning Balance	836
Purchase price allocation adjustment	(1)
Purchase price adjustment	(1)
Currency translation adjustment	(1)
Ending Balance	833
Europe
Change in carrying amount of goodwill
Beginning Balance	414
Purchase price allocation adjustment	0
Purchase price adjustment	0
Currency translation adjustment	10
Ending Balance	424
Latin America
Change in carrying amount of goodwill
Beginning Balance	244
Purchase price allocation adjustment	0
Purchase price adjustment	0
Currency translation adjustment	3
Ending Balance	247
Asia Pacific
Change in carrying amount of goodwill
Beginning Balance	229
Purchase price allocation adjustment	0
Purchase price adjustment	0
Currency translation adjustment	0
Ending Balance	$ 229