Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 254	$ (599)	$ 706	$ (5,695)
Postretirement and postemployment plans
Change in actuarial loss and other	20	5	37	17
Income tax provision (benefit)	0	19	0	19
Postretirement and postemployment plans, net of tax	20	24	37	36
Derivative hedges
Net unrecognized gain (loss)	0	0	0	(13)
Reclassification of gains on terminated derivative hedges	0	(46)	0	(47)
Income tax provision (benefit)	0	21	0	21
Derivative hedges, net of tax	0	(25)	0	(39)
Foreign currency hedges
Net recognized loss reclassified to discontinued operations	0	0	0	34
Income tax provision (benefit)	0	0	0	(4)
Foreign currency hedges, net of tax	0	0	0	30
Other, net of tax	0	1	4	2
Other comprehensive income (loss)	20	0	41	29
Comprehensive income (loss)	$ 274	$ (599)	$ 747	$ (5,666)