Insurance Premiums and Service Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Written
Direct Premiums, Written	$ 397	$ 438	$ 491
Assumed Premiums, Written	15	3	0
Premiums Written, Gross	412	441	491
Earned
Direct Premiums, Earned	389	429	464
Assumed Premiums, Earned	8	3	2
Premiums Earned, Gross	397	432	466
Written
Ceded Premiums, Written	(200)	(211)	(232)
Premiums Written, Net	212	230	259
Earned
Ceded Premiums, Earned	(205)	(208)	(209)
Premiums Earned, Net	192	224	257
Service Revenue, Written	985	999	1,051
Service Revenue, Earned	925	879	830
Insurance Premiums and Service Revenue, Written	1,197	1,229	1,310
Insurance Premiums and Service Revenue, Earned	$ 1,117	$ 1,103	$ 1,087