Provision (Benefit) for Income Taxes Tax Provison (Benefit) Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current :
Federal	$ (29)	$ (41)	$ (83)
State	0	(5)	1
Foreign	0	2	0
Total	(29)	(44)	(82)
Deferred:
Federal	98	280	183
State	10	99	37
Total	108	379	220
Less: Provision (benefit) for income taxes	$ 79	$ 335	$ 138