Loss And Loss Adjustment Expense Reserves (Schedule Of Present Value Of The Probability-Weighted Future Claim Payments And Recoveries) (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Loss And Loss Adjustment Expense Reserves [Line Items]
LAE insurance loss recoverable	$ (6)	$ 0
Insurance loss recoverable	(577)	(533)	$ (694)
Reinsurance recoverable on unpaid losses	6	6
Reinsurance recoverable on unpaid LAE	0	1
Reinsurance recoverable on paid and unpaid losses	6	7
Loss Reserves Claim Liability [Member] | Classified [Member]
Loss And Loss Adjustment Expense Reserves [Line Items]
Loss and loss adjustment expense reserves	470	464
Lae Reserves [Member] | Classified [Member]
Loss And Loss Adjustment Expense Reserves [Line Items]
Loss and loss adjustment expense reserves	46	42
Loss And Lae Reserves [Member]
Loss And Loss Adjustment Expense Reserves [Line Items]
Loss and loss adjustment expense reserves	$ 516	$ 506	$ 641