Reinsurance - Effect of Reinsurance on Statement of Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Premiums Written:
Direct	$ 50	$ 62	$ 89	$ 135
Assumed	1	331	1	331
Ceded	(2)	24	13	13
Net	49	417	103	479
Premiums Earned:
Direct	99	130	204	273
Assumed	15	9	30	14
Ceded	(2)	(3)	(4)	(6)
Net	112	136	230	281
Loss and LAE:
Direct	0	49	54	35
Assumed	1	(5)	2	(8)
Ceded	(2)	0	(11)	(1)
Net	$ (1)	$ 44	$ 45	$ 26