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INVESTMENTS (DETAILS 9) (USD $) In Thousands, unless otherwise specified | 12 Months Ended
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Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009
Schedule Of Available For Sale Securities [Line Items] |  |  |
Decrease in credit loss impairments due to sale of previously impaired securities | $ 55,784 | $ 107,244 |
Realized gains on maturity | 260,288 | 326,930 | 181,075
Fair Value (Fixed Maturities) | 10,940,100 | 10,482,897 |
Non-US Government [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Fair Value (Fixed Maturities) | 1,212,451 | 772,798 |
Non-US Government [Member] | eurozone [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Fair Value (Fixed Maturities) | 634,000 | 451,000 |
MTNs [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Decrease in credit loss impairments due to sale of previously impaired securities | 52,000 | 85,000 |
Realized gains on maturity | 15,000 | 29,000 |
Corporate Debt [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Fair Value (Fixed Maturities) | 3,609,591 | 4,162,908 |
Corporate Debt [Member] | Weighted Average [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Default rate input for determining credit loss |  | 35.00% |
Loss severity rate input for determining credit loss |  | 100.00% |
CMBS [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Fair Value (Fixed Maturities) | 312,691 | 474,785 |
CMBS [Member] | Weighted Average [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Estimated subordination percentage input for determining credit loss | 25.00% | 27.00% |
Non-Agency RMBS [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Fair Value (Fixed Maturities) | 165,713 | 244,202 |
Non-Agency RMBS [Member] | Prime [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Fair Value (Fixed Maturities) | 128,000 | 174,000 |
Non-Agency RMBS [Member] | Alt A [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Fair Value (Fixed Maturities) | 23,000 | 52,000 |
CLO - Debt Tranched Securities [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Default rate input for determining credit loss | 4.00% | 3.80% |
Loss severity rate input for determining credit loss | 53.50% | 65.00% |
Fair Value (Fixed Maturities) | $ 48,000 | $ 43,000 |
CLO - Debt Tranched Securities [Member] | Minimum [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Collateral spread input for determining credit loss | 2.60% | 2.90% |
CLO - Debt Tranched Securities [Member] | Maximum [Member] |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Collateral spread input for determining credit loss | 3.80% | 3.70% |

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- Definition Collateral spreads are used in assessing potential OTTI on a CLO debt by forecasting anticipated income to be generated by the CLO structure and assessing whether these estimated cash flows are sufficient to meet the interest and principal repayment obligations for a particular tranche. + References No definition available. + Details
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- Definition This item represents the current level of subordination of the entity's receipt of consideration should the assets underlying the security be liquidated when the level of subordination was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are other than temporarily impaired and the amount of such impairment determined to be related to credit loss recognized in earnings. + References No definition available. + Details
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- Definition This item represents the loss severity rate (loss, principal only, incurred on a defaulted security, stated as a percentage of the original principal balance) that was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are other than temporarily impaired and the amount of such impairment determined to be related to credit loss recognized in earnings. + References No definition available. + Details
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- Definition For an unclassified balance sheet, total of debt securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 12 -Subparagraph b -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 FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 15D -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 Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 22 -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 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 15C -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 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 -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 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 2 -Subparagraph (b)-(g) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 137 -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 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 16 -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 10: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558 + Details
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- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 21 -Subparagraph a -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 FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27357-111563 + Details
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- Definition This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security because of the sale of impaired securities during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 18B -Subparagraph c -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 FASB -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c) -SubTopic 10 -Topic 320 -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27340-111563 + Details
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- Definition This item represents the default rate of the underlying assets in the security that was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are other than temporarily impaired and the amount of such impairment determined to be related to credit loss recognized in earnings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 18A -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. + Details
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