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	3 Months Ended
	Mar. 31, 2015
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	(21)
Accretion of Recoveries	3
Changes in Discount Rates	8
Changes in Assumptions	(26)
Changes in LAE Recoveries	(1)
Other	(6)	[1]
Gross Reserve ending balance, Insurance loss recoverable	527
Gross Reserve ending balance, Total	637
Insurance Loss Recoverable [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Collections for Cases with Recoveries	(21)
Accretion of Recoveries	2
Changes in Discount Rates	5
Changes in Assumptions	14
Changes in LAE Recoveries	0
Other	(6)	[1]
Gross Reserve ending balance, Insurance loss recoverable	527
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	1
Changes in Discount Rates	3
Changes in Assumptions	(40)
Changes in LAE Recoveries	(1)
Other	0	[1]
Gross Reserve ending balance, Recoveries on unpaid losses	$ 110

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