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Significant Transactions (Formation of HG and BAM) (Details) (USD $) In Millions, unless otherwise specified |  | 12 Months Ended | 3 Months Ended |  |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2012 | Dec. 31, 2012 White Mountains | Sep. 30, 2012 HG Global | Dec. 31, 2013 HG Global | Dec. 31, 2012 HG Global | Dec. 31, 2013 HG Global Total | Dec. 31, 2012 HG Global Total | Dec. 31, 2013 HG Global Redeemable preferred stocks | Dec. 31, 2012 HG Global Redeemable preferred stocks | Dec. 31, 2013 HG Re | Dec. 31, 2012 HG Re | Dec. 31, 2013 HG Global
Significant Transactions |  |  |  |  |  |  |  |  |  |  |  |
Capital contributions |  | $ 594.5 | $ 600.0 |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  | 97.30% |  | 88.70% | 88.70% | 97.30% | 97.30% |  |  |
Surplus notes |  |  |  | 503.0 | 503.0 |  |  |  |  |  |  |
Statutory capital and surplus |  |  |  |  |  |  |  |  |  | $ 436.9 | $ 412.0 |
Percentage of par value of policy reinsured | 15.00% |  |  | 15.00% |  |  |  |  |  |  |  | 15.00%

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