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Reserves for Unpaid Losses and Loss Adjustment Expenses (Details 2) (USD $) | 12 Months Ended | 127 Months Ended
--- | --- | ---
Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009 | Dec. 31, 2011
OneBeacon |  |  |  |
Asbestos and Environmental Loss and Loss Adjustment Expense Reserve Activity |  |  |  |
Net losses paid by NICO during the period |  |  |  | $ 1,400,000,000
Gross |  |  |  |
Beginning balance | 1,023,000,000 | 1,336,300,000 | 1,568,700,000 |
Incurred losses and LAE | 488,600,000 | 6,200,000 | 5,900,000 |
Paid losses and LAE | (157,500,000) | (319,500,000) | (238,300,000) |
Ending balance | 1,354,100,000 | 1,023,000,000 | 1,336,300,000 | 1,354,100,000
Pre-NICO Net |  |  |  |
Beginning balance | 741,100,000 | 907,400,000 | 1,002,700,000 |
Incurred losses and LAE | 94,400,000 | 6,000,000 | 5,000,000 |
Paid losses and LAE | (2,700,000) | (172,300,000) | (100,300,000) |
Ending balance | 832,800,000 | 741,100,000 | 907,400,000 | 832,800,000
Net |  |  |  |
Beginning balance | 15,600,000 | 14,100,000 | 12,000,000 |
Incurred losses and LAE | 6,000,000 | 6,000,000 | 5,000,000 |
Paid losses and LAE | (10,400,000) | (4,500,000) | (2,900,000) |
Ending balance | 11,200,000 | 15,600,000 | 14,100,000 | 11,200,000
OneBeacon | NICO Cover |  |  |  |
Asbestos and Environmental Loss and Loss Adjustment Expense Reserve Activity |  |  |  |
Period during which asbestos and environmental losses have been recovered under the historical third-party reinsurance (in years) | 11 |  |  |
Asbestos and environmental losses recovered under the historical third-party reinsurance (as a percent) | 47.00% |  |  | 47.00%
Utilized asbestos and environmental coverage |  |  |  | 2,300,000,000
Percentage of utilized coverage from NICO that relates to uncollectible Third-Party Recoverables |  |  |  | 8.00%
Net |  |  |  |
Beginning balance | 2,200,000,000 |  |  |
Increase in A&E reserves ceded to NICO | 122,000,000 |  |  |
Ending balance | 2,300,000,000 |  |  | 2,300,000,000
OneBeacon | Asbestos |  |  |  |
Gross |  |  |  |
Beginning balance | 904,000,000 | 985,600,000 | 1,098,400,000 |
Incurred losses and LAE | 256,800,000 |  | 1,000,000 |
Paid losses and LAE | (86,500,000) | (81,600,000) | (113,800,000) |
Ending balance | 1,074,300,000 | 904,000,000 | 985,600,000 | 1,074,300,000
Pre-NICO Net |  |  |  |
Beginning balance | 647,300,000 | 688,800,000 | 741,500,000 |
Incurred losses and LAE | 32,200,000 |  |  |
Paid losses and LAE | 1,700,000 | (41,500,000) | (52,700,000) |
Ending balance | 681,200,000 | 647,300,000 | 688,800,000 | 681,200,000
Net |  |  |  |
Beginning balance | 6,400,000 | 6,500,000 | 6,500,000 |
Incurred losses and LAE | (4,000,000) |  |  |
Paid losses and LAE | (200,000) | (100,000) |  |
Ending balance | 2,200,000 | 6,400,000 | 6,500,000 | 2,200,000
OneBeacon | Environmental |  |  |  |
Gross |  |  |  |
Beginning balance | 119,000,000 | 350,700,000 | 470,300,000 |
Incurred losses and LAE | 231,800,000 | 6,200,000 | 4,900,000 |
Paid losses and LAE | (71,000,000) | (237,900,000) | (124,500,000) |
Ending balance | 279,800,000 | 119,000,000 | 350,700,000 | 279,800,000
Pre-NICO Net |  |  |  |
Beginning balance | 93,800,000 | 218,600,000 | 261,200,000 |
Incurred losses and LAE | 62,200,000 | 6,000,000 | 5,000,000 |
Paid losses and LAE | (4,400,000) | (130,800,000) | (47,600,000) |
Ending balance | 151,600,000 | 93,800,000 | 218,600,000 | 151,600,000
Net |  |  |  |
Beginning balance | 9,200,000 | 7,600,000 | 5,500,000 |
Incurred losses and LAE | 10,000,000 | 6,000,000 | 5,000,000 |
Paid losses and LAE | (10,200,000) | (4,400,000) | (2,900,000) |
Ending balance | 9,000,000 | 9,200,000 | 7,600,000 | 9,000,000
Sirius |  |  |  |
Asbestos and Environmental Loss and Loss Adjustment Expense Reserve Activity |  |  |  |
A&E three year survival ratio (in years) | 11.1 | 12.5 |  |
Gross |  |  |  |
Beginning balance | 214,300,000 | 209,200,000 | 198,200,000 |
Losses and LAE acquired Central National |  | 13,900,000 |  |
Incurred losses and LAE | 16,500,000 | 6,500,000 | 23,900,000 |
Paid losses and LAE | (23,600,000) | (15,300,000) | (12,900,000) |
Ending balance | 207,200,000 | 214,300,000 | 209,200,000 | 207,200,000
Net |  |  |  |
Beginning balance | 169,600,000 | 164,500,000 | 158,600,000 |
Losses and LAE acquired Central National |  | 12,100,000 |  |
Incurred losses and LAE | 12,300,000 | 6,000,000 | 17,700,000 |
Paid losses and LAE | (19,200,000) | (13,000,000) | (11,800,000) |
Ending balance | 162,800,000 | 169,600,000 | 164,500,000 | 162,800,000
Sirius | Asbestos |  |  |  |
Asbestos and Environmental Loss and Loss Adjustment Expense Reserve Activity |  |  |  |
Increase (decrease) in reserves | 10,300,000 |  |  |
Gross |  |  |  |
Beginning balance | 191,900,000 | 187,000,000 | 173,700,000 |
Losses and LAE acquired Central National |  | 10,400,000 |  |
Incurred losses and LAE | 13,600,000 | 9,000,000 | 24,700,000 |
Paid losses and LAE | (20,400,000) | (14,500,000) | (11,400,000) |
Ending balance | 185,100,000 | 191,900,000 | 187,000,000 | 185,100,000
Net |  |  |  |
Beginning balance | 151,500,000 | 146,600,000 | 138,500,000 |
Losses and LAE acquired Central National |  | 9,700,000 |  |
Incurred losses and LAE | 10,300,000 | 7,300,000 | 18,400,000 |
Paid losses and LAE | (15,600,000) | (12,100,000) | (10,300,000) |
Ending balance | 146,200,000 | 151,500,000 | 146,600,000 | 146,200,000
Sirius | Environmental |  |  |  |
Asbestos and Environmental Loss and Loss Adjustment Expense Reserve Activity |  |  |  |
Increase (decrease) in reserves | 2,000,000 |  |  |
Gross |  |  |  |
Beginning balance | 22,400,000 | 22,200,000 | 24,500,000 |
Losses and LAE acquired Central National |  | 3,500,000 |  |
Incurred losses and LAE | 2,900,000 | (2,500,000) | (800,000) |
Paid losses and LAE | (3,200,000) | (800,000) | (1,500,000) |
Ending balance | 22,100,000 | 22,400,000 | 22,200,000 | 22,100,000
Net |  |  |  |
Beginning balance | 18,100,000 | 17,900,000 | 20,100,000 |
Losses and LAE acquired Central National |  | 2,400,000 |  |
Incurred losses and LAE | 2,000,000 | (1,300,000) | (700,000) |
Paid losses and LAE | (3,600,000) | (900,000) | (1,500,000) |
Ending balance | $ 16,500,000 | $ 18,100,000 | $ 17,900,000 | $ 16,500,000

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- Definition Carrying amount as of the balance sheet date of reserves for the costs of settling insured claims and costs incurred in the claims settlement process attributable to asbestos and environmental claims, before estimated recoveries from reinsurers. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-PLI -Chapter 4 -Paragraph 132, 133, 135, 136, 137 -IssueDate 2006-09-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 94-5 -Paragraph 11, 12 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437 + Details
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- Definition Amount of asbestos claims paid in the current period, before estimated recoveries from reinsurers. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14784-158437 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-PLI -Chapter 4 -Paragraph 132, 133, 135, 136, 137 -IssueDate 2006-09-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 94-5 -Paragraph 11, 12 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437 + Details
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- Definition Increase in asbestos and environmental reserve based on known and estimated costs of settling insured claims and costs incurred in the claims settlement process, before estimated recoveries from reinsurers. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-PLI -Chapter 4 -Paragraph 132, 133, 135, 136, 137 -IssueDate 2006-09-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 94-5 -Paragraph 11, 12 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437 + Details
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- Definition Carrying amount as of the balance sheet date of reserves for the costs of settling insured claims and costs incurred in the claims settlement process attributable to asbestos and environmental claims, net of estimated reinsurance recoveries. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-PLI -Chapter 4 -Paragraph 132, 133, 135, 136, 137 -IssueDate 2006-09-01 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 94-5 -Paragraph 11, 12 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437 + Details
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