Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Consolidated Statements Of Comprehensive Income (Loss) [Abstract]
Net income (loss)	$ 20	$ (75)
Other comprehensive income (loss), net of tax	(1)	61
Comprehensive income (loss)	$ 19	$ (14)