Consolidated Statements of Income (Loss) and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net Operating Revenues and Other
Crude Oil and Condensate	$ 1,445,454	$ 1,059,690	$ 2,875,515	$ 1,813,401
Natural Gas Liquids	146,907	111,643	300,351	186,962
Natural Gas	224,008	155,983	454,610	321,486
Gains (Losses) on Mark-to-Market Commodity Derivative Contracts	9,446	(44,373)	71,466	(38,938)
Gathering, Processing and Marketing	778,797	485,256	1,505,334	819,209
Losses on Asset Dispositions, Net	(8,916)	(15,550)	(25,674)	(6,403)
Other, Net	16,776	23,091	41,435	34,372
Total	2,612,472	1,775,740	5,223,037	3,130,089
Operating Expenses
Lease and Well	255,186	218,393	510,963	459,258
Transportation Costs	186,356	179,471	365,070	369,925
Gathering and Processing Costs	34,746	29,226	72,890	57,750
Exploration Costs	34,711	30,559	91,605	60,388
Dry Hole Costs	27	(172)	27	74
Impairments	78,934	72,714	272,121	144,331
Marketing Costs	790,599	480,046	1,527,135	820,900
Depreciation, Depletion and Amortization	865,384	862,491	1,681,420	1,791,382
General and Administrative	108,507	97,705	205,745	198,236
Taxes Other Than Income	130,114	93,480	260,407	154,159
Total	2,484,564	2,063,913	4,987,383	4,056,403
Operating Income (Loss)	127,908	(288,173)	235,654	(926,314)
Other Income (Expense), Net	4,972	(20,996)	8,123	(25,433)
Income (Loss) Before Interest Expense and Income Taxes	132,880	(309,169)	243,777	(951,747)
Interest Expense
Interest Expense, Net	70,413	71,108	141,928	139,498
Income (Loss) Before Income Taxes	62,467	(380,277)	101,849	(1,091,245)
Income Tax Provision (Benefit)	39,414	(87,719)	50,279	(326,911)
Net Income (Loss)	$ 23,053	$ (292,558)	$ 51,570	$ (764,334)
Net Income (Loss) Per Share
Basic	$ 0.04	$ (0.53)	$ 0.09	$ (1.40)
Diluted	0.04	(0.53)	0.09	(1.40)
Dividends Declared per Common Share	$ 0.1675	$ 0.1675	$ 0.3350	$ 0.3350
Average Number of Common Shares
Basic	574,439	547,335	574,162	547,029
Diluted	578,483	547,335	578,573	547,029
Other Comprehensive Income
Foreign Currency Translation Adjustments	$ 1,260	$ 5,844	$ 1,569	$ 8,029
Other, Net of Tax	(86)	23	(49)	45
Other Comprehensive Income	1,174	5,867	1,520	8,074
Comprehensive Income (Loss)	$ 24,227	$ (286,691)	$ 53,090	$ (756,260)