Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Contract with customer, asset, net	$ 360,800		$ 360,800		$ 783,000
Total revenues from contracts with customers	900,527	$ 1,000,756	2,172,140	$ 2,229,407
Gain (loss) on derivatives not designated as hedges	407,635	(53,897)	275,639	8,695
Total operating revenues	1,310,252	950,648	$ 2,453,425	2,262,684
Natural Gas, Oil, and NGLs Sales
Disaggregation of Revenue [Line Items]
Number of days in which payment is required			25 days
Natural Gas Sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	843,867	855,924	$ 2,037,716	1,945,684
NGLs Sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	46,520	125,657	116,124	251,125
Oil Sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	10,140	9,784	18,300	20,930
Net Marketing Services and Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	9,391	0	11,668
Net marketing services and other	$ 2,090	$ 3,789	$ 5,646	$ 24,582