XML 140 R49.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Business Developments And Risks And Uncertainties (Narrative) (Detail) (USD $) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2012 | Dec. 31, 2011
Business Acquisition [Line Items] |  |
Number of business segments | 3 |
Amount released from escrow account, subsequent fiscal period | $ 115,000,000 |
Repurchase of senior notes | 172,000,000 |
Aggregate claim amount on CDS contracts | 7,000,000,000 |
CMBS Pools [Member] |  |
Business Acquisition [Line Items] |  |
Insurance par exposure | 15,600,000,000 |
ABS CDO [Member] |  |
Business Acquisition [Line Items] |  |
Insurance par exposure | 4,300,000,000 |
MBIA Inc. [Member] |  |
Business Acquisition [Line Items] |  |
Liquid assets | 239,000,000 | 386,000,000
MBIA Corp. [Member] |  |
Business Acquisition [Line Items] |  |
Liquid assets | 345,000,000 | 534,000,000
Claims payments | 1,200,000,000 |
Commuted gross insured exposure | $ 13,400,000,000 |

X
- Definition Aggregate Claim Amount + References No definition available. + Details
Name: | mbi_AggregateClaimAmount
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount Released From Escrow In Subsequent Fiscal Period + References No definition available. + Details
Name: | mbi_AmountReleasedFromEscrowInSubsequentFiscalPeriod
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Claim Payments + References No definition available. + Details
Name: | mbi_ClaimPayments
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Commuted gross insured exposure + References No definition available. + Details
Name: | mbi_CommutedGrossInsuredExposure
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Liquid Assets + References No definition available. + Details
Name: | mbi_LiquidAssets
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_BusinessAcquisitionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value amount of debt instrument that was repurchased. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentRepurchaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Interpretation (FIN) -Number 45 -Paragraph 13 -Subparagraph b -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 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248 + Details
Name: | us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues. + References No definition available. + Details
Name: | us-gaap_NumberOfOperatingSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration