Asset Impairment, Exit, and Restructuring Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Asset Impairment Charges And Exit Costs [Line Items]
Asset impairment, exit, and restructuring costs	$ 16	$ 10
Asset Impairment Charges	12
Restructuring Charges	$ 4
Restructuring Costs and Asset Impairment Charges		4
Agricultural Services [Member]
Asset Impairment Charges And Exit Costs [Line Items]
Restructuring Charges		$ 6