Oil and Natural Gas Property Transactions - VPP Volume Remaining to Be Delivered Table (Details) - VPP 9 Mid-Continent [Member] Mcf in Millions, MMBbls in Millions, MBbls in Millions, Mcfe in Billions	12 Months Ended
	Dec. 31, 2016 Mcfe MMBbls Mcf	May 31, 2011 Mcfe MBbls Mcf
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Energy) | Mcfe		177.0
Reserve Volume Remaining [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Term remaining (in months)	50 months
Proved Developed Reserves (Energy) | Mcfe	56.3
Oil [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | MBbls		1.7
Oil [Member] | Reserve Volume Remaining [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | MMBbls	0.5
Natural Gas [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | Mcf		138,000.0
Natural Gas [Member] | Reserve Volume Remaining [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | Mcf	45.9
Natural Gas Liquids [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | MBbls		4.8
Natural Gas Liquids [Member] | Reserve Volume Remaining [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | MMBbls	1.2