Oil and Natural Gas Property Transactions - Narrative (Details) MMcf in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) a well MMcf	Mar. 31, 2016 USD ($)
Business Acquisition [Line Items]
Proceeds from divestitures of proved and unproved properties	$ 892,000,000	$ 62,000,000
Corporate VPP [Member]
Business Acquisition [Line Items]
Gain (Loss) on Disposition of Other Assets	0
Haynesville Shale [Member]
Business Acquisition [Line Items]
Proceeds from divestitures of proved and unproved properties	$ 915,000,000
Number Of Net Acres | a	119,500
Productive Gas Wells, Number of Wells, Net | well	576
Haynesville Shale [Member] | Natural Gas [Member]
Business Acquisition [Line Items]
Proved Developed Reserves (Volume) | MMcf	80
Other Properties [Member]
Business Acquisition [Line Items]
Proceeds from divestitures of proved and unproved properties	$ 20,000,000	140,000,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment		$ 78,000,000