Income Taxes - Current and Deferred (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal		$ 31	$ 30
State		8	7
Current Income Tax Expense (Benefit)		39	37
Federal		(349)	2
State		(92)	10
Deferred income taxes		(441)	12
Total income tax expense (benefit)	$ (3)	$ (402)	$ 49