Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses) (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($)
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance, Insurance loss recoverable	$ 533
Gross Reserve beginning balance, Total	680
Collections for Cases with Recoveries	(56)
Accretion of Recoveries	8
Changes in Discount Rates	7
Changes in Assumptions	47
Changes in LAE Recoveries	(1)
Other	(28)	[1]
Gross Reserve ending balance, Insurance loss recoverable	437
Gross Reserve ending balance, Total	657
Insurance Loss Recoverable [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Collections for Cases with Recoveries	(56)
Accretion of Recoveries	6
Changes in Discount Rates	6
Changes in Assumptions	(24)
Changes in LAE Recoveries	0
Other	(28)	[1]
Recoveries On Unpaid Losses [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance,Recoveries on unpaid losses	147
Collections for Cases with Recoveries	0
Accretion of Recoveries	2
Changes in Discount Rates	1
Changes in Assumptions	71
Changes in LAE Recoveries	(1)
Other	0	[1]
Gross Reserve ending balance, Recoveries on unpaid losses	$ 220

[1] Primarily changes in amount and timing of collections.