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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	$ 1,354	$ (783)	$ (806)	$ 1,627
Derivative Instruments, change in fair value	35,061	18,445	122,049	35,331
Gain (Loss) on Fair Value Hedges Recognized in Earnings	12,927	6,319	18,417	(20,971)
Cost of Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		(1,439)		1,692
Gain (Loss) on Fair Value Hedges Recognized in Earnings	61,124	1,930	90,441	(4,603)
Operating Expense [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	1,354	106	(806)	(259)
Gain (Loss) on Fair Value Hedges Recognized in Earnings	745	521	2,249	(1,052)
Sales and other revenues [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		550		194
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(48,942)	3,868	(74,273)	(15,316)
Commodity Contract [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Derivative Instruments, change in fair value	47,988	24,764	140,466	14,360
(Gain) Loss Reclassified to Earnings Due to Settlements	(13,197)	(6,589)	(18,957)	20,611
Amortization Of Discontinued Hedges Reclassified to Earnings	$ 270	$ 270	$ 540	$ 360