Financing Agreements (Details) (USD $)				1 Months Ended	9 Months Ended			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Credit Agreement	May 31, 2012 CFI Credit Agreement	Sep. 30, 2012 CFI Credit Agreement	May 01, 2012 CFI Credit Agreement	Sep. 30, 2012 CFI Revolving credit facility	Sep. 30, 2012 CFI Senior notes due 2018 and 2020	Sep. 30, 2012 CFI Unsecured senior notes 6.875% due 2018	Dec. 31, 2011 CFI Unsecured senior notes 6.875% due 2018	Apr. 23, 2010 CFI Unsecured senior notes 6.875% due 2018	Sep. 30, 2012 CFI Unsecured senior notes 7.125% due 2020	Dec. 31, 2011 CFI Unsecured senior notes 7.125% due 2020	Apr. 23, 2010 CFI Unsecured senior notes 7.125% due 2020	Dec. 31, 2011 CFI Unsecured senior notes 7.0% due 2017	Dec. 31, 2011 Terra Unsecured senior notes 7.0% due 2017
Financing agreements
Long-term debt	$ 1,600,000,000	$ 1,613,000,000						$ 1,600,000,000	$ 800,000,000	$ 800,000,000		$ 800,000,000	$ 800,000,000		$ 13,000,000	$ 13,000,000
Noncurrent	1,600,000,000	1,613,000,000
Debt Instruments
Maximum borrowing capacity						500,000,000	500,000,000
Maturity period (in years)				5 years
Guarantee for borrowed money			250,000,000
Interest rate (as a percent)									6.875%			7.125%			7.00%	7.00%
Principal amount											800,000,000			800,000,000
Variable interest base rate					Applicable margin over LIBOR or a base rate
Available credit					491,000,000
Carrying value of long term debt	1,600,000,000	1,613,000,000						1,600,000,000	800,000,000	800,000,000		800,000,000	800,000,000		13,000,000	13,000,000
Fair value of long-term debt								$ 2,000,000,000
Repurchase price of notes as a percentage of principal amount								101.00%