Other Comprehensive Income (Loss) Other Comprehensive Income (Loss) Amounts Reclassified to Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Income tax expense (benefit)									$ 347,243	$ (12,379)	$ 19,411
Net of tax									1,177,224	881,242	(190,945)
Sales and other revenues	$ (4,344,204)	$ (4,770,799)	$ (4,471,236)	$ (4,128,427)	$ (3,992,705)	$ (3,719,247)	$ (3,458,864)	$ (3,080,483)	(17,714,666)	(14,251,299)	(10,535,700)
Cost of products sold									13,940,782	11,467,873	8,766,027
Operating expenses									(1,285,838)	(1,296,669)	(1,021,152)
Interest Expense									(131,363)	(117,597)	(72,192)
Noncontrolling interest									(79,264)	(75,847)	(69,508)
Selling, general and Administrative Expense									290,424	265,721	125,930
Net Income (Loss) Attributable to Parent	$ 141,896	$ 342,466	$ 345,507	$ 268,091	$ 521,082	$ 272,014	$ 57,767	$ (45,468)	1,097,960	805,395	(260,453)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Reclassifications for the period									(1,938)	(4,988)	(23,847)
Commodity price swaps | Reclassification out of Accumulated Other Comprehensive Income [Member]
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Sales and other revenues									5,093	(7,836)	20,293
Cost of products sold									0	(299)	0
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Interest Income									0	0	(23)
Income tax expense (benefit)									0	0	(9)
Net of tax											(14)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Income tax expense (benefit)									(1,544)	(4,490)	(16,387)
Net of tax									(4,511)	(7,038)	(26,278)
Before tax									(6,055)	(11,528)	(42,665)
Noncontrolling interest									0	(74)	320
Net Income (Loss) Attributable to Parent									(4,511)	(7,112)	(25,958)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Commodity price swaps | Reclassification out of Accumulated Other Comprehensive Income [Member]
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Sales and other revenues									(5,093)	7,836	(20,293)
Cost of products sold									0	299	0
Operating expenses									(962)	(19,244)	(21,864)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | Interest Rate Contract | Reclassification out of Accumulated Other Comprehensive Income [Member]
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Interest Expense									0	179	(508)
Accumulated Defined Benefit Plans Adjustment [Member] | Other Pension, Postretirement and Supplemental Plans [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Income tax expense (benefit)									888	1,347	1,348
Net of tax									2,593	2,134	2,134
Other Expenses									3,481	3,481	3,482
Accumulated Defined Benefit Plans Adjustment [Member] | Other Pension Plan [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Other Comprehensive Income (Loss) Reclassified to Income Statement [Line Items]
Income tax expense (benefit)									(7)	(7)	(6)
Net of tax									(20)	(10)	(9)
Selling, general and Administrative Expense									$ (27)	$ (17)	$ (15)