Derivative Financial Instruments (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013 MMBTU	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012 MMBTU	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013 MMBTU	Dec. 31, 2012 MMBTU	Dec. 31, 2011
Fair values of derivatives on consolidated balance sheets
Maximum period covering risk of changes in supply of gas prices									18 months
Open derivative contracts for natural gas (in MMBtus)	76,300,000				58,900,000				76,300,000	58,900,000
Percentage of natural gas consumption covered by derivatives									90.00%
Aggregate fair value of the derivative instruments with credit risk related contingent features in a net liability position	$ 200,000				$ 900,000				$ 200,000	$ 900,000
Authorized expenditure for construction of new ammonia and urea/UAN production units					3,800,000,000					3,800,000,000
Unrealized gains (losses)
Derivatives not designated as hedges									67,700,000	72,800,000	(77,300,000)
Cash flow hedge ineffectiveness									(1,800,000)	1,800,000
Total unrealized gains (losses)	55,800,000	15,700,000	(14,400,000)	8,800,000	13,100,000	39,800,000	77,600,000	(55,900,000)	65,900,000	74,600,000	(77,300,000)
Realized gains (losses)									1,800,000	(144,400,000)	(54,500,000)
Net derivative gains (losses)									67,700,000	(69,800,000)	(131,800,000)
Cash collateral on deposit with derivative counterparties	0				0				0	0
Foreign exchange contracts
Fair values of derivatives on consolidated balance sheets
Notional amount of derivative	636,300,000								636,300,000
Derivatives not designated as cash flow hedges
Unrealized gains (losses)
Derivatives not designated as hedges									67,700,000	72,800,000	(77,300,000)
Derivatives not designated as cash flow hedges | Natural gas derivatives
Unrealized gains (losses)
Derivatives not designated as hedges									52,900,000	66,500,000	(77,300,000)
Derivatives not designated as cash flow hedges | Foreign exchange contracts
Unrealized gains (losses)
Derivatives not designated as hedges									14,800,000	6,300,000
Derivatives designated as cash flow hedges | Foreign exchange contracts
Fair values of derivatives on consolidated balance sheets
Notional amount of derivative	0								0
Net gain (loss) expected to be reclassified into earnings from AOCI									0	0	0
Gain (loss) recognized in OCI									3,000,000	7,200,000
Unrealized gains (losses)
Net derivative gains (losses)									$ (1,800,000)	$ 1,800,000