Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (386)	$ 540	$ (662)	$ 1,689
Postretirement and postemployment plans
Change in actuarial loss and other	86	(13)	162	(43)
Income tax benefit (provision) on postretirement and postemployment plans	(30)	5	(57)	15
Postretirement and postemployment plans, net of tax	56	(8)	105	(28)
Comprehensive income (loss)	$ (330)	$ 532	$ (557)	$ 1,661