Quarterly Financial Results (Additional Information) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information [Line Items]
Full cost ceiling impairments								$ 164,800,000	$ 4,500,000,000	$ 164,800,000	$ 0
Asset impairment charges	$ 886,800,000	$ 1,100,000,000	$ 1,500,000,000	$ 1,100,000,000					4,534,689,000	192,768,000	26,280,000
(Gain) loss on derivative contracts	$ (14,000,000)	$ (42,200,000)	$ 33,000,000	$ (49,800,000)	$ (329,200,000)	$ (132,600,000)	$ 85,300,000	$ 42,500,000	(73,061,000)	(334,011,000)	47,123,000
Drilling Assets
Quarterly Financial Information [Line Items]
Asset impairment charges					$ 24,300,000		$ 3,100,000		37,600,000	3,100,000	11,100,000
Building and structures
Quarterly Financial Information [Line Items]
Asset impairment charges									15,400,000
Gas Treating Plants and other Midstream Assets
Quarterly Financial Information [Line Items]
Asset impairment charges									$ 7,100,000	$ 600,000	$ 12,200,000