Derivative Instruments And Hedging Activities Schedule of Realized Gain (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	$ 1,521	$ 1,232	$ (4,049)	$ 5,276
Refining and Marketing Revenue	4,471,236	3,458,864	8,599,663	6,539,347
Gain (Loss) on Price Risk Hedge Ineffectiveness	1,898	5,442	13,228	32,817
Foreign Currency Gain (Loss) [Member] | Other Nonoperating Income (Expense) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Hedge Ineffectiveness	9,359	0	25,556	0
Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Hedge Ineffectiveness			(12,328)	14,035
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	1,521	1,323	(4,049)	5,304
Commodity Contract [Member] | Operating Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Hedge Ineffectiveness	0	(1,541)
Commodity Contract [Member] | Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Hedge Ineffectiveness	(7,461)	6,983
Other Nonoperating Income (Expense) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Hedge Ineffectiveness			0	(5,763)
Foreign Exchange Contract [Member] | Other Nonoperating Income (Expense) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Price Risk Hedge Ineffectiveness	0	0	0	24,545	[1]
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	0	(91)	0	(28)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Cost and Expense, Operating	(5,598)	157	(4,407)	(474)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Refining and Marketing Revenue	(5,317)	4,476	(3,671)	8,426
Reclassification out of Accumulated Other Comprehensive Income [Member] | Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cost of Goods and Services Sold			0	(299)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Commodity [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Operating Expenses	(281)	(4,421)	(736)	(8,716)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest Expense, Other	$ 0	$ 102	$ 0	$ 115

[1] (1) Relates to Canadian currency swap contracts that settled on February 1, 2017 and effectively fixed the conversion rate on our PCLI purchase price.