Consolidated Statements Of Comprehensive Loss - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Consolidated Statements Of Comprehensive Loss [Abstract]
Net loss	$ (181)	$ (5,317)	$ (367)	$ (5,404)
Other comprehensive income (loss), net of tax	(423)	9	(337)	17
Comprehensive loss	$ (604)	$ (5,308)	$ (704)	$ (5,387)