Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 432	$ (234)	$ 7	$ (232)
Defined benefit plans:
Actuarial losses arising during the period	(89)	0	(89)	0
Amortization or curtailment of unrecognized amounts included in net periodic benefit costs	14	11	38	35
Foreign exchange losses	(1)	0	(2)	0
Other comprehensive (loss) income	(76)	11	(53)	35
Total comprehensive income (loss)	356	(223)	(46)	(197)
Total comprehensive (income) loss attributable to noncontrolling interests	(103)	28	(115)	(16)
Total comprehensive income (loss)	$ 253	$ (195)	$ (161)	$ (213)