Asset Impairment, Exit, and Restructuring Costs (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) item	Dec. 31, 2015 USD ($)
Asset Impairment Charges And Exit Costs [Line Items]
Relocation and restructuring costs	$ 72	$ 21	$ 71
Number of securities impaired | item		2
Restructuring, Settlement and Impairment Provisions	173	$ 55	200
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	6	0
Goodwill, Impairment Loss			13
Goodwill and Intangible Asset Impairment	0	11	21
Other Asset Impairment Charges	101	$ 17	108
Corporate [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)			8
Other Asset Impairment Charges			1
Agricultural Services [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Other Asset Impairment Charges	11
Corn Processing [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Other Asset Impairment Charges	63		66
Oilseeds Processing
Asset Impairment Charges And Exit Costs [Line Items]
Other Asset Impairment Charges	7		40
Wild and Specialty Ingredients [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Other Asset Impairment Charges	20		1
Employee Severance [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Relocation and restructuring costs	54
Pension plan settlement [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Relocation and restructuring costs			29
Facility closing [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Relocation and restructuring costs			22
Other Restructuring [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Relocation and restructuring costs	$ 18		$ 20