Discontinued Operations (Major Categories of Assets and Liabilities Reflected as Held for Sale) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable	$ 873,277	$ 999,872
Inventory	242,733	294,195
Total current assets held for sale	376,130	943,732
Property, plant and equipment, net	13,331,047	13,481,055
Other	81,151	98,123
Total non-current assets held for sale	50,960	381,404
Other accrued taxes payable	52,457	33,969
Total current liabilities associated with assets held for sale	151,548	639,140
Deferred income taxes payable	1,193,864	1,466,100
Deferred credits and other liabilities	441,048	339,028
Total non-current liabilities associated with assets held for sale	8,310	95,544
UK Refining And Marketing Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	200,512	301,302
Accounts receivable	97,568	302,059
Inventory	42,161	254,240
Other	35,889	86,131
Total current assets held for sale	376,130	943,732
Property, plant and equipment, net	50,947	360,347
Other	13	21,057
Total non-current assets held for sale	50,960	381,404
Accounts payable	59,023	484,082
Other accrued taxes payable	40,653	130,028
Accrued compensation and severance	30,872	17,020
Refinery decommissioning cost	21,000
Other		8,010
Total current liabilities associated with assets held for sale	151,548	639,140
Deferred income taxes payable	3,873	68,096
Deferred credits and other liabilities	4,437	27,448
Total non-current liabilities associated with assets held for sale	$ 8,310	$ 95,544