XML 43 R76.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Fair Value Of Financial Instruments (Changes In Fair Value Included In Company's Consolidated Statements Of Operations) (Detail) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010
Loan Repurchase Commitments [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Net Gains (Losses) on Financial Instruments at Fair Value and Foreign Exchange | $ 9 | $ 242 | $ 336
Fixed-Maturity Securities Held At Fair Value [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Net Gains (Losses) on Financial Instruments at Fair Value and Foreign Exchange | (55) | (484) | 374
Residential Mortgage Loans [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Net Gains (Losses) on Financial Instruments at Fair Value and Foreign Exchange | (107) | (143) | 295
Other Loans [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Net Gains (Losses) on Financial Instruments at Fair Value and Foreign Exchange | (56) | (19) | (26)
Other Assets [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Net Gains (Losses) on Financial Instruments at Fair Value and Foreign Exchange |  |  | 26
Long-Term Debt [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Net Gains (Losses) on Financial Instruments at Fair Value and Foreign Exchange | $ 107 | $ 594 | $ (661)

X
- Definition Change in the fair value of and realized gains and losses on 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
- Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration