Reserves for Insurance Losses and Loss Adjustment Expenses Reserves for Insurance Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 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	59	60
Net insurance losses and loss adjustment expenses, prior years	0	3
Net insurance losses and loss adjustment expenses incurred	59	63
Net insurance losses and loss adjustment expenses paid or payable, current year	33	31
Net insurance losses and loss adjustment expenses paid or payable, prior years	23	19
Total net insurance losses and loss adjustment expenses paid or payable	56	50
Net reserves for insurance losses and loss adjustment expenses	41	45
Reinsurance recoverable	94	112
Gross reserves for insurance losses and loss adjustment expenses	$ 135	$ 157