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 loss	$ (426)	$ (38)	$ (424)	$ (775)
Other comprehensive income (loss), net of tax	(34)	(20)	36	38
Comprehensive loss	$ (460)	$ (58)	$ (388)	$ (737)

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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