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Derivatives Additional Collateral (Details) - White Mountains Life Re - USD ($) $ in Millions | Dec. 31, 2015 | Sep. 30, 2015
--- | --- | ---
Credit risk on derivative instruments |  |
Collateral cash and investments | $ 5.8 | $ 16.8
Cash |  |
Credit risk on derivative instruments |  |
Derivative collateral right to reclaim | 5.8 | 16.8
Fixed maturity investments. |  |
Credit risk on derivative instruments |  |
Derivative collateral right to reclaim | $ 0.0 | $ 0.0

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- References No definition available. + Details
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- Definition Represents cash and short-term investments held and posted as collateral to reinsurance counterparties. + References No definition available. + Details
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- Definition The amount of collateral held against amounts due to counterparties for over the counter derivative instruments against net derivative instrument positions. + References No definition available. + Details
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- Details
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