Statement of Consolidated Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	[1]	Dec. 31, 2014	[1]
Statement of Comprehensive Income [Abstract]
NET LOSS INCLUDING NONCONTROLLING INTEREST	$ (1,273)	$ (10,667)	[2],[3],[4]	$ (8,019)	[2],[3],[4]
OTHER COMPREHENSIVE INCOME (LOSS):
Pension and postretirement benefit plan, net of tax	7	(3)	[4]	0
Commodity cash flow hedge activity, net of tax:
Change in fair value of derivative instruments	0	0		(1)
Commodity cash flow hedge activity, net of tax	7	(3)		(1)
COMPREHENSIVE LOSS INCLUDING NONCONTROLLING INTEREST	(1,266)	(10,670)		(8,020)
Comprehensive income (loss) attributable to noncontrolling interest	132	(315)		341
COMPREHENSIVE LOSS ATTRIBUTABLE TO COMMON STOCK	$ (1,398)	$ (10,355)		$ (8,361)

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