Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserves for insurance losses and loss adjustment expenses			$ 134	$ 140
Reinsurance recoverable			96	108
Net reserves for insurance losses and loss adjustment expenses			38	32
Net insurance losses and loss adjustment expenses, current year			186	159
Net insurance losses and loss adjustment expenses, prior years			0	5
Net insurance losses and loss adjustment expenses incurred	$ 127	$ 101	186	164
Net insurance losses and loss adjustment expenses paid or payable, current year			(134)	(121)
Net insurance losses and loss adjustment expenses paid or payable, prior years			(27)	(26)
Total net insurance losses and loss adjustment expenses paid or payable			(161)	(147)
Net reserves for insurance losses and loss adjustment expenses	63	49	63	49
Reinsurance recoverable	90	100	90	100
Gross reserves for insurance losses and loss adjustment expenses	$ 153	$ 149	$ 153	$ 149