Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance, Total	$ 3,980
Collections for Cases with Recoveries	(2,981)
Accretion of Recoveries	20
Changes in Discount Rates	(52)
Changes in Assumptions	144
Changes in LAE Recoveries	(31)
Other	(12)	[1]
Gross Reserve ending balance, Total	1,068
Insurance Loss Recoverable [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance, Insurance loss recoverable	3,648
Collections for Cases with Recoveries	(2,981)
Accretion of Recoveries	16
Changes in Discount Rates	(25)
Changes in Assumptions	129
Changes in LAE Recoveries	(33)
Other	(12)	[1]
Gross Reserve ending balance, Insurance loss recoverable	742
Recoveries On Unpaid Losses [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance,Recoveries on unpaid losses	332
Collections for Cases with Recoveries	0
Accretion of Recoveries	4
Changes in Discount Rates	(27)
Changes in Assumptions	15
Changes in LAE Recoveries	2
Other	0	[1]
Gross Reserve ending balance, Recoveries on unpaid losses	$ 326

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