Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018
Crude Oil and Condensate	$ 2,101,308	$ 1,430,061
Natural Gas Liquids	221,415	153,444
Natural Gas	299,766	230,602
Gathering, Processing and Marketing	1,101,822	726,537
Total	3,681,162	2,610,565
Gathering and Processing Costs	101,345
Marketing Costs	1,106,390	736,536
Total	2,806,574	2,502,819
Operating Income (Loss)	874,588	$ 107,746
Accounts Receivable From Contracts With Customers	1,428,000		$ 1,343,000
Amounts Without Adoption of ASU 2014-09 [Member]
Crude Oil and Condensate	2,101,308
Natural Gas Liquids	219,646
Natural Gas	256,620
Gathering, Processing and Marketing	1,096,236
Total	3,630,661
Gathering and Processing Costs	56,430
Marketing Costs	1,100,804
Total	2,756,073
Operating Income (Loss)	874,588
Effect of Change [Member]
Crude Oil and Condensate	0
Natural Gas Liquids	1,769
Natural Gas	43,146
Gathering, Processing and Marketing	5,586
Total	50,501
Gathering and Processing Costs	44,915
Marketing Costs	5,586
Total	50,501
Operating Income (Loss)	$ 0