Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Current:
Federal	$ 0	$ (10)	$ (28)	$ (25)
State	0	0	0	0
Foreign	0	1	0	1
Total	0	(9)	(28)	(24)
Deferred:
Federal	97	73	56	225
State	14	13	(4)	43
Total	111	86	52	268
Provision (benefit) for income taxes	$ 111	$ 77	$ 24	$ 244