Name:	mbi_FinancialGuaranteeCeded
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Represents the Company's balance sheet carrying amount of the financial guarantee insurance contract obligations with third parties. The gross balance sheet carrying amount comprises the unearned premium revenue and the loss and loss adjustment expense reserves balances

No definition available.

Name:	mbi_FinancialGuaranteeGross
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Guaranteed Investment Agreements Fair Value

No definition available.

Name:	mbi_GuaranteedInvestmentAgreementsFairValue
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Payable for investments purchased fair value disclosure

No definition available.

Name:	mbi_PayableForInvestmentsPurchasedFairValueDisclosure
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Receivable for investments sold.

No definition available.

Name:	mbi_ReceivableForInvestmentsSold
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Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

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This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

No definition available.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Fair value of investments in debt securities classified as held-to-maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Aggregation of the liabilities reported on the balance sheet measured at fair value on a nonrecurring basis by the entity.

No definition available.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

No definition available.

Name:	us-gaap_LongTermDebtFairValue
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Including the current and noncurrent portions, carrying value at the balance sheet date of a financial instrument used to receive debt funding on a regular basis with original maturities ranging from 5-10 years.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02.22)
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Section 02
-Paragraph 20, 22
-Article 5

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Other investments not otherwise specified in the taxonomy.

Name:	us-gaap_OtherInvestments
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