Segment Information - Table (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total Revenues	$ 2,893,000,000	$ 5,703,000,000	$ 8,686,000,000	$ 15,901,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(5,576,000,000)	1,129,000,000	(16,264,000,000)	2,246,000,000
TOTAL ASSETS	21,286,000,000		21,286,000,000		$ 40,751,000,000
Oil And Gas Exploration And Production [Member]
Segment Reporting Information [Line Items]
Total Revenues	880,000,000	2,341,000,000	2,693,000,000	5,812,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(5,625,000,000)	987,000,000
Marketing, Gathering And Compression [Member]
Segment Reporting Information [Line Items]
Total Revenues	2,013,000,000	3,362,000,000	5,993,000,000	9,543,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	70,000,000	113,000,000
Oilfield Services [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	516,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	0	0
Other Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	30,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(37,000,000)	(63,000,000)
Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Total Revenues	2,893,000,000	5,703,000,000	8,686,000,000	15,901,000,000
Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	0
Operating Segments [Member] | Reportable Subsegments [Member] | Oil And Gas Exploration And Production [Member]
Segment Reporting Information [Line Items]
Total Revenues	853,000,000	2,341,000,000	2,614,000,000	5,812,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest			(16,759,000,000)	2,089,000,000
TOTAL ASSETS	15,646,000,000		15,646,000,000		35,381,000,000
Operating Segments [Member] | Reportable Subsegments [Member] | Marketing, Gathering And Compression [Member]
Segment Reporting Information [Line Items]
Total Revenues	3,059,000,000	5,512,000,000	9,476,000,000	16,289,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest			208,000,000	325,000,000
TOTAL ASSETS	1,711,000,000		1,711,000,000		1,978,000,000
Operating Segments [Member] | Reportable Subsegments [Member] | Oilfield Services [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	1,060,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest			0	(16,000,000)
TOTAL ASSETS	0		0		0
Operating Segments [Member] | Reportable Subsegments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	30,000,000
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest			(82,000,000)	(24,000,000)
TOTAL ASSETS	4,342,000,000		4,342,000,000		4,283,000,000
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	16,000,000	92,000,000	369,000,000	(128,000,000)
Intersegment Eliminations [Member] | Oil And Gas Exploration And Production [Member]
Segment Reporting Information [Line Items]
Total Revenues	27,000,000	0	79,000,000	0
Intersegment Eliminations [Member] | Marketing, Gathering And Compression [Member]
Segment Reporting Information [Line Items]
Total Revenues	(1,046,000,000)	(2,150,000,000)	(3,483,000,000)	(6,746,000,000)
Intersegment Eliminations [Member] | Oilfield Services [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	(544,000,000)
Intersegment Eliminations [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	0
Intersegment Eliminations [Member] | Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Total Revenues	(1,019,000,000)	(2,150,000,000)	(3,404,000,000)	(7,290,000,000)
TOTAL ASSETS	(413,000,000)		(413,000,000)		$ (891,000,000)
Intersegment Eliminations [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total Revenues	$ 1,019,000,000	$ 2,150,000,000	$ 3,404,000,000	$ 7,290,000,000