Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserves for insurance losses and loss adjustment expenses			$ 140	$ 149
Reinsurance recoverable			108	108
Net reserves for insurance losses and loss adjustment expenses			32	41
Net insurance losses and loss adjustment expenses, current year			235	276
Net insurance losses and loss adjustment expenses, prior years			6	2
Net insurance losses and loss adjustment expenses incurred	$ 77	$ 65	241	278
Net insurance losses and loss adjustment expenses paid or payable, current year			205	248
Net insurance losses and loss adjustment expenses paid or payable, prior years			27	31
Total net insurance losses and loss adjustment expenses paid or payable			232	279
Foreign exchange and other			0	1
Net reserves for insurance losses and loss adjustment expenses	41	41	41	41
Reinsurance recoverable	98	132	98	132
Gross reserves for insurance losses and loss adjustment expenses	$ 139	$ 173	$ 139	$ 173