Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 16	$ (750)	$ 113	$ (796)
Other comprehensive income (loss), net of tax
Change in actuarial gain (loss) and other for postretirement and postemployment plans	16	(42)	13	(42)
Change in derivative hedges unrecognized gain (loss)	(21)	(4)	19	(26)
Reclassification of de-designated forward interest rate swaps	(30)	0	(28)	0
Other comprehensive income (loss)	(35)	(46)	4	(68)
Comprehensive income (loss)	$ (19)	$ (796)	$ 117	$ (864)