Reserves for Insurance Losses and Loss Adjustment Expenses (Rollforward of Reserves for Insurance Losses and Loss Adjustment Expenses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserves for insurance losses and loss adjustment expenses			$ 122	$ 134
Reinsurance recoverable			88	96
Net reserves for insurance losses and loss adjustment expenses			34	38
Net insurance losses and loss adjustment expenses, current year			298	259
Net insurance losses and loss adjustment expenses, prior years			3	1
Net insurance losses and loss adjustment expenses incurred	$ 85	$ 74	301	260
Net insurance losses and loss adjustment expenses paid or payable, current year			(271)	(227)
Net insurance losses and loss adjustment expenses paid or payable, prior years			(27)	(29)
Total net insurance losses and loss adjustment expenses paid or payable			(298)	(256)
Net reserves for insurance losses and loss adjustment expenses	37	42	37	42
Reinsurance recoverable	88	93	88	93
Gross reserves for insurance losses and loss adjustment expenses	$ 125	$ 135	$ 125	$ 135