XML 97 R58.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	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Loan Repurchase Commitments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	$ 19	$ 33	$ 62	$ 103
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	21	(286)	(36)	(338)
Residential Mortgage Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	(4)	(65)	(103)	65
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	(7)	(37)	(48)	(30)
Other Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange		(162)		(184)
Long-term Debt [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	$ 12	$ 481	$ 140	$ 367

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