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Loss And Loss Adjustment Expense Reserves (Schedule Of Losses And Loss Adjustment Expenses) (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2013 | Sep. 30, 2012
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |  |  |
Losses and LAE related to actual and expected payments |  |  | $ 205 |  |
Recoveries of actual and expected payments |  |  | (112) |  |
Gross losses incurred |  |  | 93 |  |
Reinsurance |  |  | (1) |  |
Losses and LAE | 98 | 171 | 92 |  | 330
Second-Lien RMBS [Member] |  |  |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |  |  |
Losses and LAE related to actual and expected payments |  |  | 85 |  |
Recoveries of actual and expected payments |  |  | (177) |  |
Gross losses incurred |  |  | (92) |  |
Reinsurance |  |  | 0 |  |
Losses and LAE |  |  | (92) |  |
First-Lien RMBS [Member] |  |  |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |  |  |
Losses and LAE related to actual and expected payments |  |  | 12 |  |
Recoveries of actual and expected payments |  |  | (11) |  |
Gross losses incurred |  |  | 1 |  |
Reinsurance |  |  | 0 |  |
Losses and LAE |  |  | 1 |  |
Other [Member] |  |  |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |  |  |
Losses and LAE related to actual and expected payments |  |  | 108 | [1] |
Recoveries of actual and expected payments |  |  | 76 | [1] |
Gross losses incurred |  |  | 184 | [1] |
Reinsurance |  |  | (1) | [1] |
Losses and LAE |  |  | $ 183 | [1] |
[1] | Includes ABS CDOs, CMBS, U.S. public finance and other issues.

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- Definition Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.5) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 5 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6811-158387 + Details
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