XML 79 R61.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Loss And Loss Adjustment Expense Reserves (Schedule Of Insurance Loss Recoverable) (Detail) - Insurance Loss Recoverable [Member] - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Roll forward of Insurance Loss Recoverable [Line Items] |  |  |  |  |
Gross Reserve beginning balance, Insurance loss recoverable |  | $ 1,595 |  | $ 545 |
Collections for Cases |  | (148) |  | (56) |
Accretion of Recoveries |  | 35 |  | 25 |
Changes in Discount Rates |  | 70 |  | (13) |
Changes in Assumptions |  | 105 | [1] | 1,096 | [2]
Other | [3] | 37 |  | (2) |
Gross Reserve ending balance, Insurance loss recoverable |  | $ 1,694 |  | $ 1,595 |
[1] | Includes amounts related to paid claims and LAE that are expected to be recovered in the future.
[2] | Includes amounts which have been paid and are expected to be recovered in the future.
[3] | Primarily changes in amount and timing of collections.

X
- Definition Cash receipts related to recoveries of previously paid claims + References No definition available. + Details
Name: | mbi_CollectionsForCases
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of paid insurance policy claims and LAE expense expected to be recovered. + References No definition available. + Details
Name: | mbi_InsuranceLossRecoverable
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Insurance Loss Recoverable And Changes In Recoveries Of Unpaid Losses Accretion Of Recoveries + References No definition available. + Details
Name: | mbi_InsuranceLossRecoverableAndChangesInRecoveriesOfUnpaidLossesAccretionOfRecoveries
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Insurance Loss Recoverable And Changes In Recoveries Of Unpaid Losses Change In Assumptions + References No definition available. + Details
Name: | mbi_InsuranceLossRecoverableAndChangesInRecoveriesOfUnpaidLossesChangeInAssumptions
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Insurance Loss Recoverable And Changes In Recoveries Of Unpaid Losses Change In Discount Rate + References No definition available. + Details
Name: | mbi_InsuranceLossRecoverableAndChangesInRecoveriesOfUnpaidLossesChangeInDiscountRate
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Changes in the timing and amount of net collections on financial guarantee contracts. + References No definition available. + Details
Name: | mbi_InsuranceLossRecoverableAndChangesInRecoveriesOfUnpaidLossesOther
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Roll forward of Insurance Loss Recoverable [Line Items] + References No definition available. + Details
Name: | mbi_RollForwardOfInsuranceLossRecoverableLineItems
Namespace Prefix: | mbi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | mbi_ClaimLiabilityAxis=mbi_InsuranceLossRecoverableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |