Segment Information - Table (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total Revenues	$ 3,033	$ 5,152	$ 5,793	$ 10,198
Income (Loss) Before Income Taxes	(5,596)	371	(10,688)	1,117
TOTAL ASSETS	28,598		28,598		$ 40,751
Oil And Gas Exploration And Production [Member]
Segment Reporting Information [Line Items]
Total Revenues	728	1,704	1,813	3,471
Income (Loss) Before Income Taxes	(5,785)	410
Marketing, Gathering And Compression [Member]
Segment Reporting Information [Line Items]
Total Revenues	2,305	3,167	3,980	6,181
Income (Loss) Before Income Taxes	134	109
Oilfield Services [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	278	0	516
Income (Loss) Before Income Taxes	0	19
Other Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	3	0	30
Income (Loss) Before Income Taxes	(31)	(20)
Reportable Subsegments [Member]
Segment Reporting Information [Line Items]
Total Revenues	3,033	5,152	5,793	10,198
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	699	1,704	1,761	3,471
Income (Loss) Before Income Taxes			(11,134)	1,098
TOTAL ASSETS	22,815		22,815		35,381
Operating Segments [Member] | Reportable Subsegments [Member] | Marketing, Gathering And Compression [Member]
Segment Reporting Information [Line Items]
Total Revenues	3,509	5,355	6,417	10,777
Income (Loss) Before Income Taxes			138	213
TOTAL ASSETS	1,946		1,946		1,978
Operating Segments [Member] | Reportable Subsegments [Member] | Oilfield Services [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	552	0	1,060
Income (Loss) Before Income Taxes			0	(16)
TOTAL ASSETS	0		0		0
Operating Segments [Member] | Reportable Subsegments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	3	0	30
Income (Loss) Before Income Taxes			(45)	39
TOTAL ASSETS	4,364		4,364		4,283
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	0
Income (Loss) Before Income Taxes	86	(147)	353	(217)
Intersegment Eliminations [Member] | Oil And Gas Exploration And Production [Member]
Segment Reporting Information [Line Items]
Total Revenues	29	0	52	0
Intersegment Eliminations [Member] | Marketing, Gathering And Compression [Member]
Segment Reporting Information [Line Items]
Total Revenues	(1,204)	(2,188)	(2,437)	(4,596)
Intersegment Eliminations [Member] | Oilfield Services [Member]
Segment Reporting Information [Line Items]
Total Revenues	0	(274)	0	(544)
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	(1,175)	(2,462)	(2,385)	(5,140)
TOTAL ASSETS	(527)		(527)		$ (891)
Intersegment Eliminations [Member] | Intersubsegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total Revenues	$ 1,175	$ 2,462	$ 2,385	$ 5,140