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Summary of Significant Accounting Policies (Details) (OneBeacon Ltd.) In Millions, unless otherwise specified | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2006 | Dec. 31, 2011 | Dec. 31, 2010
OneBeacon Ltd. |  |  |
Basis of Presentation |  |  |
Ownership percentage in outstanding common shares |  | 75.50% | 76.00%
Number of common shares sold in an initial public offerings | 27.6 |  |
Percentage of common shares sold in an initial public offerings | 27.60% |  |

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
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- Details
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- Definition Represents the number of shares issued in the disposition of equity in securities of subsidiaries. + References No definition available. + Details
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- Definition Represents the shares issued in the disposition of equity in securities of subsidiaries as a percentage of total shares of the subsidiary. + References No definition available. + Details
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