XML 30 R38.htm IDEA: XBRL DOCUMENT
v2.3.0.15

Loss And Loss Adjustment Expense Reserves (Summary Of Credit Impairments Related To Derivatives) (Narrative) (Details) (USD $) | 9 Months Ended
--- | ---
Sep. 30, 2011
Loss And Loss Adjustment Expense Reserves [Line Items] |
Discount rate of credit impairments | 5.93%
Additional estimated credit impairment on CMBS derivatives | $ 858,000,000
Aggregate ITD credit impairment on CMBS derivatives | 2,000,000,000
Number of structured CMBS commutations | 22
Gross exposure commuted on CMBS insured derivatives | 10,300,000,000
Life of loans, minimum | 5Y
Life of loans, maximum | 6Y
Maximum loans with debt service coverage ratio | 75,000,000
Debt service coverage ratio | 1.0
Percentage of financial statements received from properties held in pools | 80.00%
Probability-weighted loss estimate | $ 2,000,000,000
Maximum Range [Member] |
Loss And Loss Adjustment Expense Reserves [Line Items] |
Percentage of loss on liquidation | 2.00%
Minimum Range [Member] |
Loss And Loss Adjustment Expense Reserves [Line Items] |
Percentage of loss on liquidation | 1.00%

X
- Definition Additional Estimated Credit Impairment On CMBS Derivatives + Details
Name: | mbi_AdditionalEstimatedCreditImpairmentOnCMBSDerivatives
Namespace Prefix: | mbi
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate ITD Credit Impairment On CMBS Derivatives + Details
Name: | mbi_AggregateITDCreditImpairmentOnCMBSDerivatives
Namespace Prefix: | mbi
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Discount Rate Of Credit Impairments + Details
Name: | mbi_DiscountRateOfCreditImpairments
Namespace Prefix: | mbi
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Gross exposure commuted on CMBS insured derivatives + Details
Name: | mbi_GrossExposureCommutedOnCMBSInsuredDerivatives
Namespace Prefix: | mbi
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Loss And Loss Adjustment Expense Reserves [Line Items] + Details
Name: | mbi_LossAndLossAdjustmentExpenseReservesLineItems
Namespace Prefix: | mbi
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum Loans With Debt Service Coverage Ratio + Details
Name: | mbi_MaximumLoansWithDebtServiceCoverageRatio
Namespace Prefix: | mbi
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Number Of Structured CMBS Commutations + Details
Name: | mbi_NumberOfStructuredCMBSCommutations
Namespace Prefix: | mbi
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of financial statements received from properties held in pools. + Details
Name: | mbi_PercentageOfFinancialStatementsReceivedFromPropertiesHeldInPools
Namespace Prefix: | mbi
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Loss On Liquidation + Details
Name: | mbi_PercentageOfLossOnLiquidation
Namespace Prefix: | mbi
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Probability-weighted loss estimate + Details
Name: | mbi_ProbabilityWeightedLossEstimate
Namespace Prefix: | mbi
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The ratio applied to the debt for purposes of determining the number of shares of the equity security into which the debt will be converted. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -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. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(5)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Conversion Rate -URI http://asc.fasb.org/extlink&oid=6509012 + Details
Name: | us-gaap_DebtInstrumentConvertibleConversionRatio
Namespace Prefix: | us-gaap
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition When presenting a range of maturity dates, the latest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -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. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2 -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_DebtInstrumentMaturityDateRangeEnd
Namespace Prefix: | us-gaap
Data Type: | us-types:dateStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition When presenting a range of maturity dates, the earliest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -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. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2 -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_DebtInstrumentMaturityDateRangeStart
Namespace Prefix: | us-gaap
Data Type: | us-types:dateStringItemType
Balance Type: | na
Period Type: | duration