Reserves for Insurance Losses and Loss Adjustment Expenses 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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 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			215	186
Net insurance losses and loss adjustment expenses, prior years			1	0
Net insurance losses and loss adjustment expenses incurred	$ 142	$ 127	216	186
Net insurance losses and loss adjustment expenses paid or payable, current year			(178)	(134)
Net insurance losses and loss adjustment expenses paid or payable, prior years			(26)	(27)
Total net insurance losses and loss adjustment expenses paid or payable			(204)	(161)
Net reserves for insurance losses and loss adjustment expenses	46	63	46	63
Reinsurance recoverable	86	90	86	90
Gross reserves for insurance losses and loss adjustment expenses	$ 132	$ 153	$ 132	$ 153