CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Net loss	$ (1,257)	$ (2,003)	$ (3,097)
Net income (loss) attributable to noncontrolling interest	(2)	(7)	30
Net loss attributable to controlling interest	(1,255)	(1,996)	(3,127)
Components of net periodic benefit costs before reclassifications	(25)	6
Components of net periodic benefit costs reclassified to net loss	4	5	21
Other comprehensive income (loss) before income taxes	(21)	11	21
Income taxes related to other comprehensive income			(28)
Other comprehensive income (loss)	(21)	11	(7)
Other comprehensive income (loss) attributable to controlling interest	(21)	11	(7)
Total comprehensive loss	(1,278)	(1,992)	(3,104)
Total comprehensive income (loss) attributable to noncontrolling interest	(2)	(7)	30
Total comprehensive loss attributable to controlling interest	$ (1,276)	$ (1,985)	$ (3,134)