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Derivatives Additional Collateral (Details) - White Mountains Life Re - USD ($) $ in Millions | Jun. 30, 2016 | Dec. 31, 2015 | Jun. 30, 2015
--- | --- | --- | ---
Credit risk on derivative instruments |  |  |
Collateral cash and investments | $ 0.0 | $ 5.8 | $ 25.3
Cash |  |  |
Credit risk on derivative instruments |  |  |
Derivative collateral right to reclaim | 0.0 | 5.8 | 20.9
Fixed maturity investments. |  |  |
Credit risk on derivative instruments |  |  |
Derivative collateral right to reclaim | $ 0.0 | $ 0.0 | $ 4.4

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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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