Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Contract with customer, asset, net	$ 301,500		$ 301,500		$ 783,000
Total revenues from contracts with customers	769,627	$ 1,049,594	2,941,767	$ 3,279,001
Gain (loss) on derivatives not designated as hedges	180,313	(3,075)	455,952	5,620
Total operating revenues	951,576	1,050,046	$ 3,405,001	3,312,730
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	726,076	931,976	$ 2,763,792	2,877,660
NGLs Sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	34,880	106,621	151,004	357,746
Oil Sales
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	8,671	8,392	26,971	29,322
Net Marketing Services and Other
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers	0	2,605	0	14,273
Net marketing services and other	$ 1,636	$ 3,527	$ 7,282	$ 28,109