Goodwill and Other Intangible Assets - Intangible Assets Not Subject to Amortization (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets not subject to amortization, beginning balance	$ 2,505
Purchase price allocation adjustment	0
Currency translation adjustment	11
Intangible assets not subject to amortization, ending balance	2,516
U.S. Snacks
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets not subject to amortization, beginning balance	1,625
Purchase price allocation adjustment	0
Currency translation adjustment	0
Intangible assets not subject to amortization, ending balance	1,625
U.S. Morning Foods
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets not subject to amortization, beginning balance	0
Purchase price allocation adjustment	0
Currency translation adjustment	0
Intangible assets not subject to amortization, ending balance	0
U.S. Specialty
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets not subject to amortization, beginning balance	0
Purchase price allocation adjustment	0
Currency translation adjustment	0
Intangible assets not subject to amortization, ending balance	0
North America Other
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets not subject to amortization, beginning balance	360
Purchase price allocation adjustment	0
Currency translation adjustment	0
Intangible assets not subject to amortization, ending balance	360
Europe
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets not subject to amortization, beginning balance	434
Purchase price allocation adjustment	0
Currency translation adjustment	11
Intangible assets not subject to amortization, ending balance	445
Latin America
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets not subject to amortization, beginning balance	86
Purchase price allocation adjustment	0
Currency translation adjustment	0
Intangible assets not subject to amortization, ending balance	86
Asia Pacific
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets not subject to amortization, beginning balance	0
Purchase price allocation adjustment	0
Currency translation adjustment	0
Intangible assets not subject to amortization, ending balance	$ 0