XML 63 R62.htm IDEA: XBRL DOCUMENT
v2.4.0.6

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, 2012
Loss And Loss Adjustment Expense Reserves [Line Items] |  |
Losses and LAE related to actual and expected payments | $ 479 |
Recoveries of actual and expected payments | (428) |
Gross losses incurred | 51 |
Reinsurance | (1) |
Losses and LAE | 50 |
Second-Lien RMBS Reserves [Member] |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |
Losses and LAE related to actual and expected payments | 220 |
Recoveries of actual and expected payments | (371) |
Gross losses incurred | (151) |
Reinsurance |  |
Losses and LAE | (151) |
First-Lien RMBS Reserves [Member] |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |
Losses and LAE related to actual and expected payments | 147 |
Recoveries of actual and expected payments | 1 |
Gross losses incurred | 148 |
Reinsurance | (1) |
Losses and LAE | 147 |
Other [Member] |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |
Losses and LAE related to actual and expected payments | 112 | [1]
Recoveries of actual and expected payments | (58) | [1]
Gross losses incurred | 54 | [1]
Reinsurance |  | [1]
Losses and LAE | $ 54 | [1]
[1] | Primarily financial guarantee CMBS.

X
- Details
Name: | mbi_LossAndLossAdjustmentExpenseReservesLineItems
Namespace Prefix: | mbi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Losses And Loss Adjustment Expenses Related To Actual And Expected Payments + References No definition available. + Details
Name: | mbi_LossesAndLossAdjustmentExpensesRelatedToActualAndExpectedPayments
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Recoveries of actual and expected payments. + References No definition available. + Details
Name: | mbi_RecoveriesOfActualAndExpectedPayments
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Reinsurance Gains Of Third Party + References No definition available. + Details
Name: | mbi_ReinsuranceGainsOfThirdParty
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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
Name: | us-gaap_PolicyholderBenefitsAndClaimsIncurredNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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
Name: | us-gaap_ReinsuranceCostsAndRecoveriesNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration