XML 70 R60.htm IDEA: XBRL DOCUMENT
v3.22.1

Derivative Instruments (Total Fair Value Of Company's Derivative Assets And Liabilities By Instrument And Balance Sheet Location, Before Counterparty Netting) (Detail) - Not Designated as Hedging Instrument [Member] - Derivative Instrument [Member] - USD ($) $ in Millions | Mar. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Derivative [Line Items] |  |  |
Derivative notional amount |  | $ 2,109 | $ 2,144
Derivative Assets, Not designated, Fair Value | [1] | 9 | 10
Derivative Liabilities, Not designated, Fair Value | [1] | (105) | (140)
Insured swaps [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative notional amount |  | 1,473 | 1,489
Insured swaps [Member] | Other assets [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative Assets, Not designated, Fair Value | [1] | 0 | 0
Insured swaps [Member] | Derivative liabilities [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative Liabilities, Not designated, Fair Value | [1] | (1) | (1)
Interest rate swaps [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative notional amount |  | 384 | 399
Interest rate swaps [Member] | Other assets [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative Assets, Not designated, Fair Value | [1] | 0 | 1
Interest rate swaps [Member] | Derivative liabilities [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative Liabilities, Not designated, Fair Value | [1] | (98) | (130)
Interest rate swaps-embedded [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative notional amount |  | 203 | 206
Interest rate swaps-embedded [Member] | Medium-term notes [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative Assets, Not designated, Fair Value | [1] | 0 | 0
Derivative Liabilities, Not designated, Fair Value | [1] | (6) | (9)
Currency swaps-VIE [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative notional amount |  | 49 | 50
Currency swaps-VIE [Member] | Other assets-VIE [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative Assets, Not designated, Fair Value | [1] | 9 | 9
Currency swaps-VIE [Member] | Derivative liabilities-VIE [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative Liabilities, Not designated, Fair Value | [1] | $ 0 | $ 0
[1] | In accordance with the accounting guidance for derivative instruments and hedging activities, the balance sheet location of the Company’s embedded derivative instruments is determined by the location of the related host contract.

X
- Definition Fair value of derivative Asset Not Designated As Hedging Instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. + References No definition available. + Details
Name: | mbi_DerivativeAssetsNotDesignatedAsHedgingInstrumentFairValue
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of derivative liability Not Designated As Hedging Instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. + References No definition available. + Details
Name: | mbi_DerivativeLiabilitiesNotDesignatedAsHedgingInstrumentFairValue
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | mbi_DerivativeInstrumentDetailsAxis=mbi_DerivativeInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=mbi_InsuredSwapsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=mbi_DerivativeLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=mbi_InterestRateSwapsEmbeddedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_MediumTermNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=mbi_CurrencySwapsVieMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=mbi_OtherAssetsVieMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=mbi_DerivativeLiabilitiesVIEMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |