Loss And Loss Adjustment Expense Reserves (Schedule Of Total Estimated Recoveries From Ineligible Second-Lien Mortgage Loans) (Detail) (Ineligible Mortgage Loans [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Ineligible Mortgage Loans [Member]
Loss And Loss Adjustment Expense Reserves [Line Items]
Total Estimated Recoveries from Ineligible Loans as of December 31, 2011	$ 3,119
Accretion of Future Collections	24
Changes in Discount Rates	2
Recoveries (Collections)
Changes in Amount of Collections
Changes in Assumptions	39
Total Estimated Recoveries from Ineligible Loans Total Estimated as of June 30, 2012	$ 3,184