Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (74)	$ 1,035	$ 2	$ 1,852
Defined benefit plans:
Amortization of unrecognized amounts included in net periodic benefit costs	13	11	24	23
Foreign exchange losses	0	0	0	(1)
Other comprehensive income	13	11	24	22
Total comprehensive (loss) income	(61)	1,046	26	1,874
Total comprehensive loss (income) attributable to noncontrolling interests	1	(166)	(44)	(290)
Total comprehensive income (loss)	$ (60)	$ 880	$ (18)	$ 1,584