Income Taxes AFMC and CBPC (Details) (USD $)	12 Months Ended
	Dec. 31, 2009 Alternative Fuel Mixture Credit [Member]	Dec. 31, 2010 Cellulosic Biofuel Producer Credit	Dec. 31, 2009 Cellulosic Biofuel Producer Credit	Dec. 31, 2012 Exchange of Alternative Fuel Tax Benefit [Member]	Dec. 31, 2011 Exchange of Alternative Fuel Tax Benefit [Member]
Tax Credit Amount per Gallon	$ 0.50		$ 1.01
Income Tax Credits and Adjustments	$ 205,200,000	$ 24,300,000		$ 12,200,000	$ 5,800,000