Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable And Changes In Recoveries On Unpaid Losses) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance, Insurance loss recoverable		$ 533	$ 694
Gross Reserve beginning balance, Total		680	900
Collections for Cases with Recoveries		(74)	(108)
Accretion of Recoveries		10	17
Changes in Discount Rates		(1)	33
Changes in Assumptions		94	(156)
Changes in LAE Recoveries		5	1
Other	[1]	(37)	(7)
Gross Reserve ending balance, Insurance loss recoverable		577	533
Gross Reserve ending balance, Total		677	680
Insurance Loss Recoverable [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance, Insurance loss recoverable		533	694
Collections for Cases with Recoveries		(74)	(108)
Accretion of Recoveries		8	13
Changes in Discount Rates		1	18
Changes in Assumptions		140	(77)
Changes in LAE Recoveries		6	0
Other	[1]	(37)	(7)
Gross Reserve ending balance, Insurance loss recoverable		577	533
Recoveries On Unpaid Losses [Member]
Loss And Loss Adjustment Expense Recoveries [Line Items]
Gross Reserve beginning balance,Recoveries on unpaid losses		147	206
Collections for Cases with Recoveries		0	0
Accretion of Recoveries		2	4
Changes in Discount Rates		(2)	15
Changes in Assumptions		(46)	(79)
Changes in LAE Recoveries		(1)	1
Other	[1]	0	0
Gross Reserve ending balance, Recoveries on unpaid losses		$ 100	$ 147

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