Income Taxes (Provision (Benefit) for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ (5)	$ (22)	$ (6)
State	6		(1)
Total	1	(22)	(7)
Deferred:
Federal		(71)	(22)
Total		(71)	(22)
Provision (Benefit) for Income Taxes	$ 1	$ (93)	$ (29)