CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)		$ (29)	$ 77	$ 230	$ 712
Change in value of pension and other postretirement liabilities:
Amortization of prior service cost and net gain included in net periodic pension cost	[1]	4	1	4	2
Comprehensive income		$ (25)	$ 78	$ 234	$ 714

[1] Net of $1 million in taxes for the three and nine months ended September 30, 2018. Net of less than $1 million in taxes for the three and nine months ended September 30, 2017. However, all deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.