Income Taxes - Current and Deferred (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal	$ 31	$ 30	$ (10)
State	8	7	(1)
Current Income Tax Expense (Benefit)	39	37	(11)
Federal	(349)	2	(253)
State	(92)	10	1
Deferred income taxes	(441)	12	(252)
Total income tax expense (benefit)	$ (402)	$ 49	$ (263)