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
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net loss	$ 359	$ (825)	$ (529)	$ (1,202)
Net income attributable to noncontrolling interest			1	2
Net income (loss) attributable to controlling interest	359	(825)	(530)	(1,204)
Components of net periodic benefit income (costs) before reclassifications			(9)	7
Components of net periodic benefit costs reclassified to net income (loss)	2		6	1
Other comprehensive income (loss) before income taxes	2		(3)	8
Other comprehensive income (loss)	2		(3)	8
Other comprehensive income (loss) attributable to controlling interest	2		(3)	8
Total comprehensive income (loss)	361	(825)	(532)	(1,194)
Total comprehensive income attributable to noncontrolling interest			1	2
Total comprehensive income (loss) attributable to controlling interest	$ 361	$ (825)	$ (533)	$ (1,196)