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Investments - Other Investments (Details) $ in Millions | 3 Months Ended
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Mar. 31, 2018 USD ($)
Equity Method Investment, Aggregate Cost [Roll Forward] |
Opening undistributed value of investment | $ 66.4
Unrealized/realized gain/(loss) | (0.3)
Closing value of investment | 66.1
MVI |
Equity Method Investment, Aggregate Cost [Roll Forward] |
Opening undistributed value of investment | 0.5
Unrealized/realized gain/(loss) | (0.1)
Closing value of investment | 0.4
Bene |
Equity Method Investment, Aggregate Cost [Roll Forward] |
Opening undistributed value of investment | 2.9
Unrealized/realized gain/(loss) | (0.2)
Closing value of investment | 2.7
Digital Re |
Equity Method Investment, Aggregate Cost [Roll Forward] |
Opening undistributed value of investment | 0.5
Unrealized/realized gain/(loss) | 0.0
Closing value of investment | 0.5
Crop Re |
Equity Method Investment, Aggregate Cost [Roll Forward] |
Opening undistributed value of investment | 62.5
Unrealized/realized gain/(loss) | 0.0
Closing value of investment | $ 62.5

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