Derivative Instruments And Hedging Activities Derivatives and Hedging Instruments Gains Losses due to Settlements Hedge Ineffectiveness (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Trading Activity, Gains and Losses, Net [Line Items]
Sales and other revenues	$ 4,128,427	$ 3,080,483
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	(5,570)	4,044
Reclassification out of Accumulated Other Comprehensive Income [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Other Cost and Expense, Operating	1,191	(631)
Forward Contracts [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Sales and other revenues	1,647	3,950
Commodity [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Operating Expenses	(456)	(4,295)
Commodity Contract [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	(5,570)	3,981
Commodity Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Cost of Goods and Services Sold	0	(299)
Interest Rate Swap [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	0	63
Interest Rate Swap [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Interest Expense, Other	0	13
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Commodity Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Sales and other revenues	$ 1,647	$ 3,950