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Loss And Loss Adjustment Expense Reserves (Schedule Of Losses And Loss Adjustment Expenses) (Detail) (USD $) In Millions, unless otherwise specified | 9 Months Ended
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Sep. 30, 2012
Loss And Loss Adjustment Expense Reserves [Line Items] |  |
Losses and LAE related to actual and expected payments | $ 453 |
Recoveries of actual and expected payments | (123) |
Gross losses incurred | 330 |
Reinsurance |  |
Losses and LAE | 330 |
Second-Lien RMBS Reserves [Member] |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |
Losses and LAE related to actual and expected payments | 180 |
Recoveries of actual and expected payments | (74) |
Gross losses incurred | 106 |
Reinsurance |  |
Losses and LAE | 106 |
Other [Member] |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |
Losses and LAE related to actual and expected payments | 273 | [1]
Recoveries of actual and expected payments | (49) | [1]
Gross losses incurred | 224 | [1]
Reinsurance |  | [1]
Losses and LAE | $ 224 | [1]
[1] | Primarily first-lien RMBS and financial guarantee CMBS.

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- Definition Provision for benefits, claims and claims settlement expenses incurred during the period net of the effects of contracts assumed and ceded. + 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 + Details
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- Definition The net amount in the period for future policy benefits and costs incurred under policies assumed and estimated recoupments under policies ceded. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 94-5 -Paragraph 11 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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