Statement of Consolidated Changes in Equity - USD ($) $ in Millions		Total		Common Stock [Member]	Paid-In Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive (Loss) [Member]	Parent [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2013	[1]	$ 30,756		$ 255	$ 12,403	$ 17,395	$ (1,027)	$ (115)	$ 28,911	$ 1,845
Net income (loss)	[1]	(8,019)	[2],[3],[4]			(8,360)			(8,360)	341
Postretirement benefit plans, net of tax	[2]	0
Distributions to noncontrolling interest	[1]	(140)								(140)
Commodity hedges, net of tax	[1]	(1)						(1)	(1)
Common dividends ($1.00 per share)	[1]	(380)				(380)			(380)
Common stock activity, net	[1]	(10)		1	(11)				(10)
Treasury stock activity, net	[1]	(1,864)			(1)		(1,863)		(1,864)
Compensation expense	[1]	202			202				202
Other	[1]	(3)			(3)				(3)
Ending Balance at Dec. 31, 2014	[1]	20,541		256	12,590	8,655	(2,890)	(116)	18,495	2,046
Net income (loss)	[1]	(10,667)	[2],[3],[4]			(10,352)			(10,352)	(315)
Postretirement benefit plans, net of tax	[1]	(3)	[2]					(3)	(3)
Distributions to noncontrolling interest	[1]	(129)								(129)
Common dividends ($1.00 per share)	[1]	(378)			(95)	(283)			(378)
Common stock activity, net	[1]	(14)		1	(15)				(14)
Treasury stock activity, net	[1]	0			(1)		1		0
Compensation expense	[1]	140			140				140
Ending Balance at Dec. 31, 2015	[1]	9,490	[5]	257	12,619	(1,980)	(2,889)	(119)	7,888	1,602
Net income (loss)		(1,273)				(1,405)			(1,405)	132
Postretirement benefit plans, net of tax		7						7	7
Distributions to noncontrolling interest		(293)								(293)
Common dividends ($1.00 per share)		(379)			(379)	0			(379)
Common stock activity, net		(38)		1	(39)				(38)
Treasury stock activity, net		1			(1)		2		1
Compensation expense		164			164				164
Ending Balance at Dec. 31, 2016		$ 7,679		$ 258	$ 12,364	$ (3,385)	$ (2,887)	$ (112)	$ 6,238	$ 1,441

[1] Financial information for 2015, 2014, and 2013 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[2] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[3] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[4] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[5] Financial information for 2015 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.