Noncontrolling Interests (Details) In Millions, unless otherwise specified					9 Months Ended				9 Months Ended					1 Months Ended		3 Months Ended		9 Months Ended				9 Months Ended
	Sep. 30, 2012 USD ($)	Dec. 31, 2011 USD ($)	Sep. 30, 2011 USD ($)	Dec. 31, 2010 USD ($)	Sep. 30, 2012 TNCLP USD ($)	Sep. 30, 2011 TNCLP USD ($)	Dec. 31, 2011 TNCLP USD ($)	Dec. 31, 2010 TNCLP USD ($)	Sep. 30, 2012 TNCLP Minimum	Sep. 30, 2012 TNCLP Maximum	Sep. 30, 2012 Viterra Inc USD ($)	Sep. 30, 2012 Viterra Inc CAD	Dec. 31, 2011 Viterra Inc USD ($)	Oct. 31, 2012 La Coop Federee	Oct. 31, 2012 GROWMARK, Inc.	Sep. 30, 2012 CFL USD ($)	Sep. 30, 2011 CFL USD ($)	Sep. 30, 2012 CFL USD ($) item	Sep. 30, 2011 CFL USD ($)	Dec. 31, 2011 CFL USD ($)	Dec. 31, 2010 CFL USD ($)	Sep. 30, 2012 CFL CFI	Sep. 30, 2012 CFL CFI Common Stock	Sep. 30, 2012 CFL CFI Nonvoting preferred shares	Sep. 30, 2012 CFL Viterra Inc	Sep. 30, 2012 CFL Viterra Inc Common Stock	Sep. 30, 2012 CFL Viterra Inc Nonvoting preferred shares	Sep. 30, 2012 CFL Growmark and La Coop Federee Common Stock
Noncontrolling interest
Number of world-scale ammonia plants																		2
Reporting entity's ownership interest in VIE (as a percent)																							49.00%	66.00%
Third Party's ownership interest in VIE (as a percent)														8.00%	9.00%											34.00%	34.00%	17.00%
Minimum percentage of deficiency to be paid as advance under the product purchase agreement																						66.00%
Minimum percentage of purchases required which may result in increase in advance towards deficiency																						66.00%
Percentage of minimum economic risks and rewards received																						66.00%
Net sales																$ 172.0	$ 182.5	$ 560.1	$ 529.1
Assets																512.7		512.7		528.5
Liabilities																461.8		461.8		479.5
Percentage of ammonia and urea production purchased																						66.00%
Percentage of the facility's ammonia and urea production that the reporting entity is contingently required to purchase pursuant to a product purchase agreement											100.00%	100.00%										34.00%
Percentage of ammonia and urea production for which there is a right to purchase																									34.00%
Actual percentage purchased of the facility's ammonia and urea production each year, minimum																									34.00%
Percentage of interest in distributed and undistributed earnings																									34.00%
Notice period for termination of management agreement or product purchase agreement																						12 months
Percentage of aggregate ownership held by entity through general and limited partnership					75.30%
Percentage of ownership interest held by outside investors					24.70%
Accounts receivable - net	340.9	269.4									135.5		141.0
Noncontrolling interest	520.8	385.9	487.0	383.0	362.9	371.2	369.2	365.6			141.2		149.7			157.9	115.8	157.9	115.8	16.7	17.4
Total purchase price												915
Earnings attributable to general partnership interest in excess of the threshold levels					$ 172.3	$ 158.6
Percentage of ownership allowing majority owner to acquire outstanding units										25.00%
Notice period for making decision to purchase the outstanding units									30 days	60 days
Average trading days for which purchase price is greater					20 days
Number of days before announcing purchase price					5 days
Period within which highest price is paid for any unit preceding the date of purchase is announced					90 days