XML 61 R50.htm IDEA: XBRL DOCUMENT
v3.19.2

Fair Value Of Financial Instruments (Gains And Losses On Fair Value Option Included In The Company's Consolidated Statements Of Operations) (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | $ (26) |  | $ 22 | $ (4) |  | $ 13 |
Non Variable Interest Entity [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | (26) |  | 22 | (4) |  | 13 |
Variable Interest Entity [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | 18 |  | 13 | 36 |  | 17 |
Investments Carried At Fair Value [Member] | Non Variable Interest Entity [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange | [1] | 4 |  | (3) | 11 |  | (5) |
Fixed Maturity Securities Held At Fair Value - VIE [Member] | Variable Interest Entity [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange | [2] | 26 |  | (6) | 56 |  | (12) |
Loans Receivable and Other Instruments at Fair Value [Member] | Variable Interest Entity [Member] | Residential Mortgage Loans [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange | [2] | 1 |  | (54) | 43 |  | (76) |
Loans Receivable and Other Instruments at Fair Value [Member] | Variable Interest Entity [Member] | Corporate Loans [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | 0 |  | 0 | 0 |  | 11 | [2]
Loan Repurchase Commitments [Member] | Variable Interest Entity [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange | [2] | 9 |  | 9 | 10 |  | 9 |
Medium Term Notes [Member] | Non Variable Interest Entity [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange | [1] | 3 |  | 12 | (5) |  | 6 |
Other Liabilities [Member] | Non Variable Interest Entity [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange |  | (1) | [3] | 0 | (1) | [3] | (2) | [3]
Variable Interest Entity Notes [Member] | Variable Interest Entity [Member] |  |  |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange | [2] | $ (24) |  | $ 56 | $ (80) |  | $ 83 |
[1] | Reported within “Net gains (losses) on financial instruments at fair value and foreign exchange” on MBIA’s consolidated statements of operations.
[2] | Reported within “Net gains (losses) on financial instruments at fair value and foreign exchange-VIE” on MBIA’s consolidated statements of operations.
[3] | Reported within “Other net realized gains (losses)” on MBIA’s consolidated statements of operations.

X
- Definition Change in the fair value of and realized gains and losses on sale of financial instruments and foreign exchange included in earnings. + References No definition available. + Details
Name: | mbi_NetGainsLossesOnFinancialInstrumentsAtFairValueAndForeignExchange
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=srt_ConsolidatedEntityExcludingVariableInterestEntitiesVIEMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=mbi_InvestmentsCarriedAtFairValueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=mbi_FixedMaturitySecuritiesHeldAtFairValueVieMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_LoansReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=mbi_ResidentialMortgageLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=mbi_LoanRepurchaseCommitmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_OtherLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=mbi_VariableInterestEntityNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |