Oil and Natural Gas Property Transactions - VPP Volumes Produced During Period Table (Details) Mcfe in Billions, Mcf in Billions	3 Months Ended
	Mar. 31, 2017 Mcfe MBbls Mcf	Mar. 31, 2016 Mcfe MBbls Mcf
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserve, Production (Energy) | Mcfe		15.3
Oil [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		115,500
Natural Gas [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production | Mcf		12.8
NGL [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		312,000
VPP 10 Anadarko Basin Granite Wash [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserve, Production (Energy) | Mcfe		3.5
VPP 10 Anadarko Basin Granite Wash [Member] | Oil [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		66,000
VPP 10 Anadarko Basin Granite Wash [Member] | Natural Gas [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production | Mcf		1.8
VPP 10 Anadarko Basin Granite Wash [Member] | NGL [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		222,700
VPP 9 Mid-Continent [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserve, Production (Energy) | Mcfe	3.8	4.1
VPP 9 Mid-Continent [Member] | Oil [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production	35,900	39,400
VPP 9 Mid-Continent [Member] | Natural Gas [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production | Mcf	3.1	3.4
VPP 9 Mid-Continent [Member] | NGL [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production	82,800	89,300
VPP 4 Anadarko and Arkoma Basins [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserve, Production (Energy) | Mcfe		2.0
VPP 4 Anadarko and Arkoma Basins [Member] | Oil [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		10,100
VPP 4 Anadarko and Arkoma Basins [Member] | Natural Gas [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production | Mcf		1.9
VPP 4 Anadarko and Arkoma Basins [Member] | NGL [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		0
VPP 3 Anadarko Basin [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserve, Production (Energy) | Mcfe		1.5
VPP 3 Anadarko Basin [Member] | Oil [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		0
VPP 3 Anadarko Basin [Member] | Natural Gas [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production | Mcf		1.5
VPP 3 Anadarko Basin [Member] | NGL [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		0
VPP 2 Texas, Oklahoma and Kansas [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserve, Production (Energy) | Mcfe		0.9
VPP 2 Texas, Oklahoma and Kansas [Member] | Oil [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		0
VPP 2 Texas, Oklahoma and Kansas [Member] | Natural Gas [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production | Mcf		0.9
VPP 2 Texas, Oklahoma and Kansas [Member] | NGL [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		0
VPP 1 Kentucky and West Virginia [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserve, Production (Energy) | Mcfe		3.3
VPP 1 Kentucky and West Virginia [Member] | Oil [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		0
VPP 1 Kentucky and West Virginia [Member] | Natural Gas [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production | Mcf		3.3
VPP 1 Kentucky and West Virginia [Member] | NGL [Member]
VPP Volumes Produced During Period [Line Items]
Proved Developed and Undeveloped Reserves, Production		0