Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 96	$ (139)	$ 452	$ (5,096)
Postretirement and postemployment plans
Change in actuarial loss and other	13	8	17	12
Postretirement and postemployment plans, net of tax	13	8	17	12
Derivative hedges
Net unrecognized gain (loss)	0	(14)	0	(13)
Derivative hedges, net of tax	0	(14)	0	(13)
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	4	0	4	0
Other comprehensive income (loss)	17	(6)	21	29
Comprehensive income (loss)	$ 113	$ (145)	$ 473	$ (5,067)