Income Taxes (Provision (Benefit) for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ (1)	$ (5)	$ (22)
State	(1)	6	0
Total Current	(2)	1	(22)
Deferred:
Federal	(431)	0	(71)
State	22	0	0
Total Deferred	(409)	0	(71)
Provision (benefit) for income taxes	$ (411)	$ 1	$ (93)