CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	[1]	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)		$ 1,046		$ (2,643)	$ (4,556)
Change in derivatives:
Settlements	[2]				(128)
Ineffectiveness					1
Change in fair value of derivative instruments	[3]				29
Total change in derivatives					(98)
Change in value of pension and other postretirement liabilities:
Amortization of prior service cost and net loss included in net periodic pension cost	[4]	2		13	2
Net loss incurred in period	[5]	(13)		(7)	(3)
Total change in value of pension and postretirement liabilities		(11)		6	(1)
Change in currency translation adjustment		6		3	(11)
Comprehensive income (loss)		$ 1,041		$ (2,634)	$ (4,666)

[1] In 2017, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.

[2] Net of ($81) million in taxes for the year ended December 31, 2015.

[3] Net of $16 million in taxes for the year ended December 31, 2015.

[4] Net of $8 million in taxes for the year ended December 31, 2016.

[5] Net of ($4) million in taxes for the year ended December 31, 2016.