Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses) (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance, Insurance loss recoverable	$ 577
Gross Reserve beginning balance, Total	677
Collections for Cases with Recoveries	(17)
Accretion of Recoveries	3
Changes in Discount Rates	13
Changes in Assumptions	(134)
Changes in LAE Recoveries	1
Other	(33)	[1]
Gross Reserve ending balance, Insurance loss recoverable	409
Gross Reserve ending balance, Total	510
Insurance Loss Recoverable [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance, Insurance loss recoverable	577
Collections for Cases with Recoveries	(17)
Accretion of Recoveries	2
Changes in Discount Rates	7
Changes in Assumptions	(123)
Changes in LAE Recoveries	(4)
Other	(33)	[1]
Gross Reserve ending balance, Insurance loss recoverable	409
Recoveries On Unpaid Losses [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance,Recoveries on unpaid losses	100
Collections for Cases with Recoveries	0
Accretion of Recoveries	1
Changes in Discount Rates	6
Changes in Assumptions	(11)
Changes in LAE Recoveries	5
Other	0	[1]
Gross Reserve ending balance, Recoveries on unpaid losses	$ 101

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