XML 37 R109.htm IDEA: XBRL DOCUMENT v2.4.1.9
Insurance In Force (Schedule Of Insurance In Force By Type Of Bond, Excluding Transactions Guaranteed By MBIA Corp. On Behalf Of Various Investment Management Services Affiliated Companies) (Detail) (USD $)
In Billions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Insurance in Force $ 437.8us-gaap_ParticipatingPoliciesAmountInForce $ 554.3us-gaap_ParticipatingPoliciesAmountInForce
% of Insurance in Force 100.00%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce 100.00%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
U S [Member]    
Insurance in Force 394.3us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_StatementGeographicalAxis
= country_US		 492.7us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_StatementGeographicalAxis
= country_US
% of Insurance in Force 90.10%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_StatementGeographicalAxis
= country_US		 88.90%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_StatementGeographicalAxis
= country_US
Non-United States [Member]    
Insurance in Force 43.5us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember		 61.6us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
% of Insurance in Force 9.90%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember		 11.10%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
Global Public Finance [Member]    
Insurance in Force 400.7us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember		 491.7us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
% of Insurance in Force 91.50%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember		 88.70%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
Global Public Finance [Member] | U S [Member]    
Insurance in Force 361.6us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US		 445.7us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
% of Insurance in Force 82.60%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US		 80.40%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
Global Public Finance [Member] | Non-United States [Member]    
Insurance in Force 39.1us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember		 46.0us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
% of Insurance in Force 8.90%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember		 8.30%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
Global Structured Finance [Member]    
Insurance in Force 37.1us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember		 62.6us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
% of Insurance in Force 8.50%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember		 11.30%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
General Obligation [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 122.8us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_GeneralObligationMember		 153.5us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_GeneralObligationMember
% of Insurance in Force 28.00%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_GeneralObligationMember		 27.70%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_GeneralObligationMember
General Obligation - Lease [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 27.9us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_GeneralObligationLeaseMember		 34.1us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_GeneralObligationLeaseMember
% of Insurance in Force 6.40%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_GeneralObligationLeaseMember		 6.20%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_GeneralObligationLeaseMember
Municipal Utilities [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 60.5us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MunicipalUtilitiesMember		 78.0us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MunicipalUtilitiesMember
% of Insurance in Force 13.80%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MunicipalUtilitiesMember		 14.10%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MunicipalUtilitiesMember
Tax-Backed [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 53.6us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TaxBackedMember		 66.1us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TaxBackedMember
% of Insurance in Force 12.20%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TaxBackedMember		 11.90%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TaxBackedMember
Tax-Backed [Member] | Global Public Finance [Member] | Non-United States [Member]    
Insurance in Force 0.2us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TaxBackedMember		 0.2us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TaxBackedMember
% of Insurance in Force 0.00%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TaxBackedMember		 0.00%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TaxBackedMember
Transportation [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 38.4us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TransportationMember		 46.2us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TransportationMember
% of Insurance in Force 8.80%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TransportationMember		 8.30%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TransportationMember
Transportation [Member] | Global Public Finance [Member] | Non-United States [Member]    
Insurance in Force 9.7us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TransportationMember		 12.2us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TransportationMember
% of Insurance in Force 2.20%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TransportationMember		 2.20%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_TransportationMember
Higher Education [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 19.5us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_HigherEducationMember		 24.1us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_HigherEducationMember
% of Insurance in Force 4.50%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_HigherEducationMember		 4.30%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_HigherEducationMember
Health Care [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 8.4us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_HealthCareMember		 9.5us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_HealthCareMember
% of Insurance in Force 1.90%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_HealthCareMember		 1.70%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_HealthCareMember
Military Housing [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 18.4us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MilitaryHousingMember		 19.2us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MilitaryHousingMember
% of Insurance in Force 4.20%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MilitaryHousingMember		 3.50%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MilitaryHousingMember
Investor-Owned Utilities [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 6.1us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_InvestorOwnedUtilitiesMember		 [1] 7.2us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_InvestorOwnedUtilitiesMember		 [1]
% of Insurance in Force 1.40%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_InvestorOwnedUtilitiesMember		 [1] 1.30%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_InvestorOwnedUtilitiesMember		 [1]
Municipal Housing [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 3.6us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MunicipalHousingMember		 4.8us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MunicipalHousingMember
% of Insurance in Force 0.80%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MunicipalHousingMember		 0.90%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_MunicipalHousingMember
Other Public Finance [Member] | Global Public Finance [Member] | U S [Member]    
Insurance in Force 2.4us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_OtherPublicFinanceMember		 [2] 3.0us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_OtherPublicFinanceMember		 [2]
% of Insurance in Force 0.60%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_OtherPublicFinanceMember		 [2] 0.50%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= country_US
/ us-gaap_UnderlyingAssetClassAxis
= mbi_OtherPublicFinanceMember		 [2]
International Utilities [Member] | Global Public Finance [Member] | Non-United States [Member]    
Insurance in Force 13.4us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_InternationalUtilitiesMember		 15.9us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_InternationalUtilitiesMember
% of Insurance in Force 3.10%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_InternationalUtilitiesMember		 2.90%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_InternationalUtilitiesMember
Sovereign Related And Sub-Sovereign [Member] | Global Public Finance [Member] | Non-United States [Member]    
Insurance in Force 15.5us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_SovereignRelatedAndSubSovereignMember		 [3] 17.3us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_SovereignRelatedAndSubSovereignMember		 [3]
% of Insurance in Force 3.50%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_SovereignRelatedAndSubSovereignMember		 [3] 3.10%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_SovereignRelatedAndSubSovereignMember		 [3]
Local Governments [Member] | Global Public Finance [Member] | Non-United States [Member]    
Insurance in Force 0.3us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_LocalGovernmentsMember		 [4] 0.4us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_LocalGovernmentsMember		 [4]
% of Insurance in Force 0.10%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_LocalGovernmentsMember		 [4] 0.10%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalPublicFinanceMember
/ us-gaap_StatementGeographicalAxis
= mbi_NonUnitedStatesMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_LocalGovernmentsMember		 [4]
Collateralized Debt Obligations [Member] | Global Structured Finance [Member]    
Insurance in Force 14.7us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_CollateralizedDebtObligationsMember		 [5] 31.7us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_CollateralizedDebtObligationsMember		 [5]
% of Insurance in Force 3.40%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_CollateralizedDebtObligationsMember		 [5] 5.70%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_CollateralizedDebtObligationsMember		 [5]
Residential Mortgage Backed Securities [Member] | Global Structured Finance [Member]    
Insurance in Force 9.9us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_ResidentialMortgageBackedSecuritiesMember		 12.4us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_ResidentialMortgageBackedSecuritiesMember
% of Insurance in Force 2.30%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_ResidentialMortgageBackedSecuritiesMember		 2.20%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_ResidentialMortgageBackedSecuritiesMember
Commercial Mortgage Backed Securities [Member] | Global Structured Finance [Member]    
Insurance in Force 1.1us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_CommercialMortgageBackedSecuritiesMember		 1.6us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_CommercialMortgageBackedSecuritiesMember
% of Insurance in Force 0.30%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_CommercialMortgageBackedSecuritiesMember		 0.30%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= us-gaap_CommercialMortgageBackedSecuritiesMember
Consumer Asset Backed [Member] | Global Structured Finance [Member]    
Insurance in Force 1.9us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_ConsumerAssetBackedMember		 2.8us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_ConsumerAssetBackedMember
% of Insurance in Force 0.40%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_ConsumerAssetBackedMember		 0.50%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_ConsumerAssetBackedMember
Corporate Asset Backed [Member] | Global Structured Finance [Member]    
Insurance in Force $ 9.5us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_CorporateAssetBackedMember		 [6] $ 14.1us-gaap_ParticipatingPoliciesAmountInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_CorporateAssetBackedMember		 [6]
% of Insurance in Force 2.10%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_CorporateAssetBackedMember		 2.60%us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
/ us-gaap_GuaranteeObligationsByNatureAxis
= mbi_GlobalStructuredFinanceMember
/ us-gaap_UnderlyingAssetClassAxis
= mbi_CorporateAssetBackedMember
[1]
Includes investor owned utilities, industrial development and pollution control revenue bonds.
[2]
Includes certain non-profit enterprises, stadium related financing and student loans.
[3]
Includes regions, departments or their equivalent in each jurisdiction as well as sovereign owned entities that are supported by a sovereign state, region or department.
[4]
Includes municipal owned entities backed by sponsoring local government.
[5]
Includes transactions (represented by structured pools of primarily investment grade corporate credit risks or CRE assets) that do not include typical CDO structuring characteristics, such as tranched credit risk, cash flow waterfalls, or interest and over-collateralization coverage tests.
[6]
Includes $5.3 billion and $5.5 billion of structured insurance securitizations as of December 31, 2014 and 2013, respectively.