Loss And Loss Adjustment Expense Reserves (Schedule Of Losses And Loss Adjustment Expenses) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Loss And Loss Adjustment Expense Reserves [Line Items]
Losses and LAE	$ 133		$ 117		$ 50
Second-Lien RMBS [Member]
Loss And Loss Adjustment Expense Reserves [Line Items]
Losses and LAE	70		(2)		(151)
First-Lien RMBS [Member]
Loss And Loss Adjustment Expense Reserves [Line Items]
Losses and LAE	65		(70)		147
Other [Member]
Loss And Loss Adjustment Expense Reserves [Line Items]
Losses and LAE	$ (2)	[1]	$ 189	[1]	$ 54	[1]

[1] Includes ABS CDOs, CMBS, U.S. public finance and other issues.