Derivative Instruments & Hedging Activities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2010
Gains on interest rate swaps	$ (55)		$ (24)
Not Designated As Hedging Instrument [Member]
After-tax gains deferred in AOCI on discontinuation of hedge accounting treatment on interest rate swaps				21
Amortization period for gains on de-designated hedges in AOCI (in years)		30
Gains on interest rate swaps	55		24
Designated As Hedging Instrument [Member]
After-tax gains (losses) in AOCI from commodity cash flow hedge transactions		7
Number of months cash flow hedge gains (losses) will be recognized in earnings (in months)		12
After-tax losses in AOCI related to foreign exchange contracts designated as cash flow hedging instruments		2
Cash flow hedge losses that will be recognized in earnings		2
Total after-tax gains deferred in AOCI related to treasury-lock agreements and interest rate swaps that will be recognized in earnings		22
Number of years in which after-tax gains (losses) in AOCI related to treasury-lock agreements and interest rate swaps will be recognized in earnings, low end of range (in years)		10
Number of years in which after-tax gains (losses) in AOCI related to treasury-lock agreements and interest rate swaps will be recognized in earnings, high end of range (in years)		30
After-tax gains deferred in AOCI on discontinuation of hedge accounting treatment on interest rate swaps, net of amortization		20
Corn | Designated As Hedging Instrument [Member]
Corn processed per month (in bushels)		77,000,000
Historical time period of hedge percentages (in months)		12
Percentage of anticipated commodity purchases or production hedged during historical hedging period, low end of range (as a percent)		1.00%
Percentage of anticipated commodity purchases or production hedged during historical hedging period, high end of range (as a percent)		100.00%
Percentage of anticipated commodity purchases or production hedged over future hedging period, low end of range (as a percent)		13.00%
Percentage of anticipated commodity purchases or production hedged over future hedging period, high end of range (as a percent)		21.00%
Number of months for which hedges for future monthly commodity purchases, sales or production have been made (in months)		12
Natural Gas | Designated As Hedging Instrument [Member]
Natural gas used by production facilities per month (in MMbtus)		3,750,000
Historical time period of hedge percentages (in months)		12
Percentage of anticipated commodity purchases or production hedged during historical hedging period, low end of range (as a percent)		21.00%
Percentage of anticipated commodity purchases or production hedged during historical hedging period, high end of range (as a percent)		50.00%
Percentage of anticipated commodity purchases or production hedged over future hedging period, low end of range (as a percent)		8.00%
Percentage of anticipated commodity purchases or production hedged over future hedging period, high end of range (as a percent)		30.00%
Number of months for which hedges for future monthly commodity purchases, sales or production have been made (in months)		9
Ethanol | Designated As Hedging Instrument [Member]
Historical time period of hedge volumes (in months)		12
Commodity sales volume hedged during historical hedging period, low end of range (in gallons)		10,000,000
Commodity sales volume hedged during historical hedging period, high end of range (in gallons)		19,000,000
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)		14,000,000
Number of months for which hedges for future monthly commodity purchases, sales or production have been made (in months)		6