Discontinued Operations (Major Categories of Assets and Liabilities Reflected as Held for Sale) (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable		$ 522,672	$ 873,277	[1]
Inventories		166,788	242,733	[1]
Total current assets held for sale		38,340	376,130	[1]
Property, plant and equipment, Net		9,818,365	13,331,047	[1]
Other		227,031	62,582	[1]
Total non-current assets held for sale	[1]		50,960
Other accrued taxes payable		38,498	52,457	[1]
Total current liabilities associated with assets held for sale		7,297	151,548	[1]
Deferred income taxes payable		239,811	1,193,864	[1]
Deferred credits and other liabilities		438,576	441,048	[1]
Total non-current liabilities associated with assets held for sale	[1]		8,310
UK Refining And Marketing Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash		7,927	200,512
Accounts receivable		12,037	97,568
Inventories			42,161
Other		18,376	35,889
Total current assets held for sale		38,340	376,130
Property, plant and equipment, Net			50,947
Other			13
Total non-current assets held for sale			50,960
Accounts payable		2,433	59,023
Other accrued taxes payable			40,653
Accrued compensation and severance		2,179	30,872
Refinery decommissioning cost		2,685	21,000
Total current liabilities associated with assets held for sale		$ 7,297	151,548
Deferred income taxes payable			3,873
Deferred credits and other liabilities			4,437
Total non-current liabilities associated with assets held for sale			$ 8,310

[1] Reclassified to conform to current presentation.