Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses) (Detail) - Segment [Domain] $ in Millions		6 Months Ended
		Jun. 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		(39)
Accretion of Recoveries		5
Changes in Discount Rates		(3)
Changes in Assumptions		76
Changes in LAE Recoveries		(1)
Other	[1]	(16)
Gross Reserve ending balance, Insurance loss recoverable		483
Gross Reserve ending balance, Total		702
Insurance Loss Recoverable [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Collections for Cases with Recoveries		(39)
Accretion of Recoveries		4
Changes in Discount Rates		(1)
Changes in Assumptions		2
Changes in LAE Recoveries		0
Other	[1]	(16)
Gross Reserve ending balance, Insurance loss recoverable		483
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		(2)
Changes in Assumptions		74
Changes in LAE Recoveries		(1)
Other	[1]	0
Gross Reserve ending balance, Recoveries on unpaid losses		$ 219

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