Derivative Instruments And Hedging Activities Derivatives and Hedging Instruments Gains Losses due to Settlements Hedge Ineffectiveness (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	$ (2,160)	$ 2,410
Derivative Instruments, change in fair value	86,988	16,886
Gain (Loss) on Fair Value Hedges Recognized in Earnings	5,490	(27,290)
Cost of Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		3,131
Gain (Loss) on Fair Value Hedges Recognized in Earnings	29,317	(6,532)
Operating Expense [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	(2,160)	(365)
Gain (Loss) on Fair Value Hedges Recognized in Earnings	1,504	(1,573)
Sales and other revenues [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		(356)
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(25,331)	(19,185)
Commodity Contract [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative Instruments, change in fair value	92,478	(10,404)
(Gain) Loss Reclassified to Earnings Due to Settlements	(5,760)	27,200
Amortization Of Discontinued Hedges Reclassified to Earnings	$ 270	$ 90