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Investments (Investment Securities Whose Book Value Exceeded Market Value By More Than 5%) (Detail) (USD $) In Millions, unless otherwise specified | Jun. 30, 2012 Security
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5% To Less Than 16% [Member] |
Schedule of Investments [Line Items] |
Number of Securities | 39
Book Value | $ 1,784
Fair Value | 1,615
Percentage Book Value Exceeded Market Value, Minimum | 5.00%
Percentage Book Value Exceeded Market Value, Maximum | 16.00%
16% To Less Than 26% [Member] |
Schedule of Investments [Line Items] |
Number of Securities | 19
Book Value | 159
Fair Value | 124
Percentage Book Value Exceeded Market Value, Minimum | 16.00%
Percentage Book Value Exceeded Market Value, Maximum | 26.00%
26% To 50% [Member] |
Schedule of Investments [Line Items] |
Number of Securities | 39
Book Value | 170
Fair Value | 105
Percentage Book Value Exceeded Market Value, Minimum | 26.00%
Percentage Book Value Exceeded Market Value, Maximum | 50.00%
Greater Than 50% [Member] |
Schedule of Investments [Line Items] |
Number of Securities | 34
Book Value | 99
Fair Value | 22
Percentage Book Value Exceeded Market Value, Maximum | 50.00%
Greater Than 5% [Member] |
Schedule of Investments [Line Items] |
Number of Securities | 131
Book Value | 2,212
Fair Value | $ 1,866

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- Definition Disclosure regarding factors used to determine that the impairment of securities not categorized as trading securities (hence equal to available for sale and held to maturity securities) where cost exceeds fair value. This item contains disclosure of the number of investment positions in the investments determined to be temporarily impaired. + References No definition available. + Details
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- Definition Investments Securities In Unrealized Loss Position For Continuous Twelve Month Period or Longer At Fair Value + References No definition available. + Details
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- Definition Investments Securities In Unrealized Loss Position For Continuous Twelve Month Period or Longer Book Value + References No definition available. + Details
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- Definition Percentage Book Value Exceeded Market Value, Maximum + References No definition available. + Details
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- Definition Percentage Book Value Exceeded Market Value, Minimum + References No definition available. + Details
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Namespace Prefix: | mbi_
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Balance Type: | na
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- Details
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