Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 480	$ 1,096	$ (5,723)
Postretirement and postemployment plans
Change in actuarial loss and other	54	117	21
Income tax benefit (provision) on postretirement and postemployment plans	(38)	4	7
Postretirement and postemployment plans, net of tax	16	121	28
Derivative hedges
Net unrecognized gain (loss)	2	0	(13)
Reclassification of gains on terminated derivative hedges	0	0	(47)
Income tax provision on derivative hedges	0	0	21
Derivative hedges, net of tax	2	0	(39)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	30	0	0
Foreign currency translation adjustment related to sale of U.K. business	0	0	34
Income taxes related to sale of U.K. business (b)	(7)	0	(4)
Foreign currency translation, net of tax	23	0	30
Other, net of tax	1	4	2
Other comprehensive income (loss)	42	125	21
Comprehensive income (loss)	$ 522	$ 1,221	$ (5,702)