XML 50 R53.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Fair Value Of Financial Instruments (Realized And Unrealized Gains And Losses Included In Earnings Pertaining To Level 3 Assets And Liabilities) (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Unrealized gains (losses) on insured derivatives |  |  | $ 863 | $ 1,562
Net gains (losses) on financial instruments at fair value and foreign exchange | 57 | 5 | 63 | 62
Net investment losses related to other-than-temporary impairments | (14) |  | (14) |
Fair Value Inputs Level 3 [Member] | Total Gains Losses Included In Earnings [Member] |  |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Unrealized gains (losses) on insured derivatives | 48 | 285 | 863 | 1,562
Realized gains and other settlements on insured derivatives | (24) | (28) | (418) | (1,548)
Net gains (losses) on financial instruments at fair value and foreign exchange | 9 | (24) | (1) | (39)
Total revenues | 47 | 222 | 432 | 168
Fair Value Inputs Level 3 [Member] | Change In Unrealized Gains Losses For Period Included In Earnings For Assets And Liabilities Still Held [Member] |  |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Unrealized gains (losses) on insured derivatives | 14 | 285 | (20) | (301)
Net gains (losses) on financial instruments at fair value and foreign exchange | 10 | (1) | (3) | (11)
Total revenues | 38 | 278 | (1) | (19)
Fair Value Inputs Level 3 [Member] | Variable Interest Entity Primary Beneficiary [Member] | Total Gains Losses Included In Earnings [Member] |  |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange | 14 | (11) | (12) | 193
Fair Value Inputs Level 3 [Member] | Variable Interest Entity Primary Beneficiary [Member] | Change In Unrealized Gains Losses For Period Included In Earnings For Assets And Liabilities Still Held [Member] |  |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Net gains (losses) on financial instruments at fair value and foreign exchange | $ 14 | $ (6) | $ 22 | $ 293

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 Realized gains and losses and recognized premiums and fees related to insurance policies on derivatives included in earnings. + References No definition available. + Details
Name: | mbi_RealizedGainsLossesAndOtherSettlementsOnInsuredDerivatives
Namespace Prefix: | mbi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of realized and unrealized gain (loss) included in earnings, which have arisen from the use of significant unobservable inputs (level 3) to measure fair value of assets, liabilities, and financial instruments classified in shareholders' equity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasuredOnRecurringBasisGainLossIncludedInEarnings
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -URI http://asc.fasb.org/extlink&oid=27724398&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
Name: | us-gaap_UnrealizedGainLossOnDerivatives
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration