Derivative Instruments and Hedging Activities (Narrative) (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Designated As Hedging Instrument [Member]	Mar. 31, 2013 Corn [Member] Designated As Hedging Instrument [Member] bu	Mar. 31, 2013 Natural gas [Member] Designated As Hedging Instrument [Member] MMBTU	Mar. 31, 2013 Ethanol [Member] Designated As Hedging Instrument [Member] gal	Mar. 31, 2013 Corn Gluten Meal [Member] Designated As Hedging Instrument [Member] T	Mar. 31, 2013 Foreign Currency Exchange [Member] Designated As Hedging Instrument [Member]
Derivative [Line Items]
Long-term marketable securities	$ 683	$ 717
After-tax losses in AOCI from commodity cash flow hedge transactions			8
After-tax losses in AOCI from commodity cash flow hedge transactions expected to be recognized in earnings.			8
Number of months cash flow hedge losses will be recognized in earnings			12 months
Corn processed per month (in bushels)				76,000,000
Natural gas used by production facilities per month (in MMbtus)					3,800,000
Historical time period of hedge percentages				12 months	12 months
Percentage of anticipated commodity purchases or production hedged during historical hedging period, low end of range (as a percent)				15.00%	11.00%
Percentage of anticipated commodity purchases or production hedged during historical hedging period, high end of range (as a percent)				26.00%	66.00%
Percentage of anticipated commodity purchases or production hedged over future hedging period, low end of range (as a percent)				0.10%	13.00%
Percentage of anticipated commodity purchases or production hedged over future hedging period, high end of range (as a percent)				19.00%	49.00%
Historical time period of hedge volumes						12 months
Commodity sales volume hedged during historical hedging period, low end of range (in gallons)						1,000,000
Commodity sales volume hedged during historical hedging period, high end of range (in gallons)						21,000,000
Contracted commodity sales volume hedged over future hedging period, low end of range (in gallons)						2,000,000
Contracted commodity sales volume hedged over future hedging period, high end of range (in gallons)						12,000,000
Contracted commodity sales weight hedged over future hedging period, high end of range (in tons)							23,000
Number of months for which hedges for future monthly commodity purchases, sales or production have been made				15 months	9 months	9 months	12 months
Historical time period of hedged amounts								12 months
Foreign currency expenditures hedged during historical hedging period, low end of range								13
Foreign currency expenditures hedged during historical hedging period, high end of range								25
Foreign currency expenditures hedged								13
After-tax losses in AOCI related to foreign exchange contracts designated as cash flow hedging instruments								1
Cash flow hedge losses that will be recognized in earnings								1
Total after-tax gains deferred in AOCI related to treasury-lock agreements and interest rate swaps			21
Total after-tax gains deferred in AOCI related to treasury-lock agreements and interest rate swaps that will be recognized in earnings			$ 21
Number of years in which after-tax gains in AOCI related to treasury-lock agreements and interest rate swaps will be recognized in earnings, low end of range			10 years
Number of years in which after-tax gains in AOCI related to treasury-lock agreements and interest rate swaps will be recognized in earnings, high end of range			30 years