CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net income	$ 194,190		$ 127,515
Change in derivatives:
Settlements	25,186	[1]	(47,173)	[1]
Ineffectiveness	1,164	[2]	(781)	[2]
Change in fair value of derivative instruments	(54,200)	[3]	(45,481)	[3]
Total change in derivatives	(27,850)		(93,435)
Change in value of pension and other postretirement liabilities:
Amortization of prior service cost included in net periodic pension cost	81	[4]	267	[4]
Change in currency translation adjustment	(2,856)		(1,029)
Comprehensive income	$ 163,565		$ 33,318

[1] Net of $16.8 and ($31.4) million in taxes for the three months ended March 31, 2014 and 2013, respectively.

[2] Net of $0.8 and ($0.5) million in taxes for the three months ended March 31, 2014 and 2013, respectively.

[3] Net of ($36.1) and ($30.3) million in taxes for the three months ended March 31, 2014 and 2013, respectively.

[4] Net of $0.1 and $0.2 million in taxes for the three months ended March 31, 2014 and 2013, respectively.