Income Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Taxes [Abstract]
Benefit (provision) for income taxes	$ (22)	$ (124)	$ (10)	$ (200)
Effective tax rate	(44.90%)	57.40%	(6.40%)	25.30%