Income Taxes (Details 6) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of unrecognized income tax benefits
Unrecognized tax benefits, beginning of year	$ 0	$ 4	$ 0
Additions for income tax positions related to current year	119	0	1
Additions for income tax positions related to prior year	0	0	3
Reductions for income tax positions related to settlements	0	(4)	0
Unrecognized tax benefits, end of year	119	0	4
Unrecognized tax benefits that, if recognized, would impact the effective tax rate	0	0	0
Recognized interest and penalties	(1)	2
Maximum
Reconciliation of unrecognized income tax benefits
Recognized interest and penalties			$ (1)
Accrued interest and penalties	$ 1	$ 1