Goodwill and Other Intangible Assets - Carrying Amount of Goodwill (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
		Sep. 30, 2017	Sep. 30, 2017
Change in carrying amount of goodwill
Beginning Balance	[1]		$ 5,166
Purchase price allocation adjustment			(79)
Purchase price adjustment			(4)
Currency translation adjustment			52
Ending Balance		$ 5,135	5,135
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	131
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	3,568
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	82
North America Other
Change in carrying amount of goodwill
Beginning Balance			457
Purchase price allocation adjustment			0
Purchase price adjustment			0
Currency translation adjustment			4
Ending Balance		461	461
Europe
Change in carrying amount of goodwill
Beginning Balance			376
Purchase price allocation adjustment			0
Purchase price adjustment			0
Currency translation adjustment			35
Ending Balance		411	411
Latin America
Change in carrying amount of goodwill
Beginning Balance			328
Purchase price allocation adjustment			(79)
Purchase price adjustment			(4)
Currency translation adjustment			9
Ending Balance		254	254
Asia Pacific
Change in carrying amount of goodwill
Beginning Balance			224
Purchase price allocation adjustment			0
Purchase price adjustment			0
Currency translation adjustment			4
Ending Balance		228	228
Ritmo Investimentos
Change in carrying amount of goodwill
Purchase price adjustment		$ (3)	$ (7)

[1] Condensed from audited financial statements.