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Derivatives (Interest rate cap) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 6 Months Ended |  |  | 1 Months Ended | 6 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2014 Interest Rate Cap Rating | Jun. 30, 2014 Interest Rate Cap Rating | Mar. 31, 2014 Interest Rate Cap | Dec. 31, 2013 Interest Rate Cap | May 31, 2007 Sirius International Group Ltd Preferred Stock | Jun. 30, 2014 Sirius International Group Ltd Interest Rate Cap | Jun. 30, 2014 Standard & Poor's, A Rating Barclays Interest Rate Cap | Jun. 30, 2014 Standard & Poor's, AA- Rating Nordea Bank Finland Interest Rate Cap
Derivative [Line Items] |  |  |  |  |  |  |  |
Derivative collateral right to reclaim | $ 6.3 | $ 6.3 |  |  |  |  | $ 4.3 | $ 2.0
Preferred Stock, Dividend Rate, Percentage |  |  |  |  | 7.506% |  |  |
Term of LIBOR loan |  |  |  |  | 3 months |  |  |
Derivative, Cap Interest Rate |  |  |  |  |  | 8.30% |  |
Derivative, Cost of Hedge |  |  |  |  |  | 9.9 |  |
basis points |  |  |  |  | 3.20% | 3.95% |  |
Non-cumulative perpetual preference shares issued |  |  |  |  | 250.0 |  |  |
years of interest rate cap |  |  |  |  |  | 5 years |  |
Derivative, fair value, net | 6.2 | 6.2 | 8.2 | 11.1 |  |  |  |
Realized and unrealized gains (losses) | $ (2.0) | $ (4.9) |  |  |  |  |  |
S and P Credit Ratings | 21 | 21 |  |  |  |  |  |

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