v2.4.0.8

FAIR VALUE MEASUREMENTS (TABLES) | 6 Months Ended
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Jun. 30, 2013
Fair Value Disclosures [Abstract] |
FINANCIAL INSTRUMENTS MEASURED AT FAIR VALUE ON A RECURRING BASIS [Table Text Block] |
|  | Quoted Prices in Active Markets for Identical Assets (Level 1) |  | Significant Other Observable Inputs (Level 2) |  | Significant Unobservable Inputs (Level 3) |  | Total Fair Value |
| At June 30, 2013 |  |  |  |  |  |  |  |
| Assets |  |  |  |  |  |  |  |
| Fixed maturities |  |  |  |  |  |  |  |
| U.S. government and agency | $ | 1,168,380 |  |  | $ | 170,434 |  |  | $ | — |  |  | $ | 1,338,814 |  |
| Non-U.S. government | — |  |  | 1,176,949 |  |  | — |  |  | 1,176,949 |  |
| Corporate debt | — |  |  | 3,479,916 |  |  | — |  |  | 3,479,916 |  |
| Agency RMBS | — |  |  | 2,333,624 |  |  | — |  |  | 2,333,624 |  |
| CMBS | — |  |  | 762,865 |  |  | 11,785 |  |  | 774,650 |  |
| Non-Agency RMBS | — |  |  | 88,866 |  |  | — |  |  | 88,866 |  |
| ABS | — |  |  | 857,556 |  |  | 54,125 |  |  | 911,681 |  |
| Municipals | — |  |  | 1,540,412 |  |  | — |  |  | 1,540,412 |  |
|  | 1,168,380 |  |  | 10,410,622 |  |  | 65,910 |  |  | 11,644,912 |  |
| Equity securities |  |  |  |  |  |  |  |
| Common stocks | 390,180 |  |  | — |  |  | — |  |  | 390,180 |  |
| Exchange-traded funds | 119,236 |  |  | — |  |  | — |  |  | 119,236 |  |
| Non-U.S. bond mutual funds | — |  |  | 109,379 |  |  | — |  |  | 109,379 |  |
|  | 509,416 |  |  | 109,379 |  |  | — |  |  | 618,795 |  |
| Other investments |  |  |  |  |  |  |  |
| Hedge funds | — |  |  | 460,819 |  |  | 444,220 |  |  | 905,039 |  |
| Direct lending funds | — |  |  | — |  |  | 4,232 |  |  | 4,232 |  |
| CLO - Equities | — |  |  | — |  |  | 53,044 |  |  | 53,044 |  |
|  | — |  |  | 460,819 |  |  | 501,496 |  |  | 962,315 |  |
| Short-term investments | — |  |  | 45,904 |  |  | — |  |  | 45,904 |  |
| Derivative instruments (see Note 5) | — |  |  | 7,792 |  |  | — |  |  | 7,792 |  |
| Total | $ | 1,677,796 |  |  | $ | 11,034,516 |  |  | $ | 567,406 |  |  | $ | 13,279,718 |  |
| Liabilities |  |  |  |  |  |  |  |
| Derivative instruments (see Note 5) | $ | — |  |  | $ | 9,722 |  |  | $ | — |  |  | $ | 9,722 |  |
| Cash settled awards (see Note 7) | — |  |  | 4,106 |  |  | — |  |  | 4,106 |  |
| Total | $ | — |  |  | $ | 13,828 |  |  | $ | — |  |  | $ | 13,828 |  |
| At December 31, 2012 |  |  |  |  |  |  |  |
| Assets |  |  |  |  |  |  |  |
| Fixed maturities |  |  |  |  |  |  |  |
| U.S. government and agency | $ | 1,094,220 |  |  | $ | 328,665 |  |  | $ | — |  |  | $ | 1,422,885 |  |
| Non-U.S. government | — |  |  | 1,104,576 |  |  | — |  |  | 1,104,576 |  |
| Corporate debt | — |  |  | 3,874,832 |  |  | 1,550 |  |  | 3,876,382 |  |
| Agency RMBS | — |  |  | 2,659,908 |  |  | — |  |  | 2,659,908 |  |
| CMBS | — |  |  | 835,788 |  |  | 4,296 |  |  | 840,084 |  |
| Non-Agency RMBS | — |  |  | 94,089 |  |  | 1,110 |  |  | 95,199 |  |
| ABS | — |  |  | 579,231 |  |  | 63,975 |  |  | 643,206 |  |
| Municipals | — |  |  | 1,285,809 |  |  | — |  |  | 1,285,809 |  |
|  | 1,094,220 |  |  | 10,762,898 |  |  | 70,931 |  |  | 11,928,049 |  |
| Equity securities |  |  |  |  |  |  |  |
| Common stocks | 443,398 |  |  | — |  |  | — |  |  | 443,398 |  |
| Exchange-traded funds | 119,161 |  |  | — |  |  | — |  |  | 119,161 |  |
| Non-U.S. bond mutual funds | — |  |  | 103,989 |  |  | — |  |  | 103,989 |  |
|  | 562,559 |  |  | 103,989 |  |  | — |  |  | 666,548 |  |
| Other investments |  |  |  |  |  |  |  |
| Hedge funds | — |  |  | 421,006 |  |  | 359,996 |  |  | 781,002 |  |
| Direct lending funds | — |  |  | — |  |  | — |  |  | — |  |
| CLO - Equities | — |  |  | — |  |  | 62,435 |  |  | 62,435 |  |
|  | — |  |  | 421,006 |  |  | 422,431 |  |  | 843,437 |  |
| Short-term investments | — |  |  | 108,860 |  |  | — |  |  | 108,860 |  |
| Derivative instruments (see Note 5) | — |  |  | 5,838 |  |  | — |  |  | 5,838 |  |
| Total | $ | 1,656,779 |  |  | $ | 11,402,591 |  |  | $ | 493,362 |  |  | $ | 13,552,732 |  |
| Liabilities |  |  |  |  |  |  |  |
| Derivative instruments (see Note 5) | $ | — |  |  | $ | 3,737 |  |  | $ | — |  |  | $ | 3,737 |  |
| Cash settled awards (see Note 7) | — |  |  | — |  |  | — |  |  | — |  |
| Total | $ | — |  |  | $ | 3,737 |  |  | $ | — |  |  | $ | 3,737 |  |
LEVEL 3 FAIR VALUE MEASUREMENT INPUTS [Table Text Block] |
|  | Fair Value | Valuation Technique | Unobservable Input | Range | Weighted Average |
| ABS - CLO Debt | $ | 53,113 |  | Discounted cash flow | Credit spreads | 3.2% - 4.9% | 3.74% |
|  |  |  | Illiquidity discount (1) | 5.0% | 5% |
| Other investments - CLO - Equities | $ | 53,044 |  | Discounted cash flow | Default rates | 4.0% - 5.0% | 4.35% |
|  |  |  | Loss severity rate | 53.5% | 53.5% |
|  |  |  | Collateral spreads | 2.6% - 4.2% | 3.24% |
|  |  |  | Estimated maturity dates | 2.0 - 5.4 years | 4.2 years |
(1) Judgmentally determined based on limited trades of similar securities observed in the secondary markets.
CHANGES IN LEVEL 3 FINANCIAL INSTRUMENTS MEASURED AT FAIR VALUE ON A RECURRING BASIS [Table Text Block] |
|  | Opening Balance |  | Transfers into Level 3 |  | Transfers out of Level 3 |  | Included in earnings (1) |  | Included in OCI (2) |  | Purchases |  | Sales |  | Settlements/ Distributions |  | Closing Balance |  | Change in unrealized investment gain/loss (3) |
| Three months ended June 30, 2013 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Fixed maturities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Corporate debt | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |
| Non-Agency RMBS | 1,300 |  |  | — |  |  | (1,223 | ) |  | — |  |  | (77 | ) |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |
| CMBS | 12,600 |  |  | — |  |  | — |  |  | — |  |  | (69 | ) |  | — |  |  | — |  |  | (746 | ) |  | 11,785 |  |  | — |  |
| ABS | 266,749 |  |  | — |  |  | (213,212 | ) |  | — |  |  | 693 |  |  | — |  |  | — |  |  | (105 | ) |  | 54,125 |  |  | — |  |
|  | 280,649 |  |  | — |  |  | (214,435 | ) |  | — |  |  | 547 |  |  | — |  |  | — |  |  | (851 | ) |  | 65,910 |  |  | — |  |
| Other investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Hedge funds | 414,716 |  |  | 29,953 |  |  | — |  |  | 6,962 |  |  | — |  |  | — |  |  | — |  |  | (7,411 | ) |  | 444,220 |  |  | 6,962 |  |
| Direct lending funds | 2,436 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 1,796 |  |  | — |  |  | — |  |  | 4,232 |  |  | — |  |
| CLO - Equities | 64,255 |  |  | — |  |  | — |  |  | 5,072 |  |  | — |  |  | — |  |  | — |  |  | (16,283 | ) |  | 53,044 |  |  | 5,072 |  |
|  | 481,407 |  |  | 29,953 |  |  | — |  |  | 12,034 |  |  | — |  |  | 1,796 |  |  | — |  |  | (23,694 | ) |  | 501,496 |  |  | 12,034 |  |
| Total assets | $ | 762,056 |  |  | $ | 29,953 |  |  | $ | (214,435 | ) |  | $ | 12,034 |  |  | $ | 547 |  |  | $ | 1,796 |  |  | $ | — |  |  | $ | (24,545 | ) |  | $ | 567,406 |  |  | $ | 12,034 |  |
| Six months ended June 30, 2013 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Fixed maturities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Corporate debt | $ | 1,550 |  |  | $ | — |  |  | $ | — |  |  | $ | 1,550 |  |  | $ | — |  |  | $ | — |  |  | $ | (3,100 | ) |  | $ | — |  |  | $ | — |  |  | $ | — |  |
| Non-Agency RMBS | 1,110 |  |  | — |  |  | (1,223 | ) |  | — |  |  | 135 |  |  | — |  |  | — |  |  | (22 | ) |  | — |  |  | — |  |
| CMBS | 4,296 |  |  | 8,382 |  |  | — |  |  | — |  |  | (147 | ) |  | — |  |  | — |  |  | (746 | ) |  | 11,785 |  |  | — |  |
| ABS | 63,975 |  |  | — |  |  | (213,212 | ) |  | (112 | ) |  | 981 |  |  | 212,889 |  |  | (10,190 | ) |  | (206 | ) |  | 54,125 |  |  | — |  |
|  | 70,931 |  |  | 8,382 |  |  | (214,435 | ) |  | 1,438 |  |  | 969 |  |  | 212,889 |  |  | (13,290 | ) |  | (974 | ) |  | 65,910 |  |  | — |  |
| Other investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Hedge funds | 359,996 |  |  | 29,953 |  |  | — |  |  | 25,490 |  |  | — |  |  | 50,000 |  |  | — |  |  | (21,219 | ) |  | 444,220 |  |  | 25,490 |  |
| Direct lending funds | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 4,232 |  |  | — |  |  | — |  |  | 4,232 |  |  | — |  |
| CLO - Equities | 62,435 |  |  | — |  |  | — |  |  | 15,025 |  |  | — |  |  | — |  |  | — |  |  | (24,416 | ) |  | 53,044 |  |  | 15,025 |  |
|  | 422,431 |  |  | 29,953 |  |  | — |  |  | 40,515 |  |  | — |  |  | 54,232 |  |  | — |  |  | (45,635 | ) |  | 501,496 |  |  | 40,515 |  |
| Total assets | $ | 493,362 |  |  | $ | 38,335 |  |  | $ | (214,435 | ) |  | $ | 41,953 |  |  | $ | 969 |  |  | $ | 267,121 |  |  | $ | (13,290 | ) |  | $ | (46,609 | ) |  | $ | 567,406 |  |  | $ | 40,515 |  |
(1) | Gains and losses included in earnings on fixed maturities are included in net realized investment gains (losses). Gains and (losses) included in earnings on other investments are included in net investment income.
(2) | Gains and losses included in other comprehensive income (“OCI”) on fixed maturities are included in unrealized gains (losses) arising during the period.
(3) | Change in unrealized investment gain/(loss) relating to assets held at the reporting date.
|  | Opening Balance |  | Transfers into Level 3 |  | Transfers out of Level 3 |  | Included in earnings (1) |  | Included in OCI (2) |  | Purchases |  | Sales |  | Settlements/ Distributions |  | Closing Balance |  | Change in unrealized investment gain/loss (3) |
| Three months ended June 30, 2012 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Fixed maturities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Corporate debt | $ | 1,550 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 1,550 |  |  | $ | — |  |
| Non-Agency RMBS | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |
| CMBS | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |
| ABS | 50,415 |  |  | — |  |  | — |  |  | — |  |  | 164 |  |  | — |  |  | — |  |  | (635 | ) |  | 49,944 |  |  | — |  |
|  | 51,965 |  |  | — |  |  | — |  |  | — |  |  | 164 |  |  | — |  |  | — |  |  | (635 | ) |  | 51,494 |  |  | — |  |
| Other investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Hedge funds | 364,786 |  |  | — |  |  | — |  |  | (10,261 | ) |  | — |  |  | — |  |  | — |  |  | (3 | ) |  | 354,522 |  |  | (10,261 | ) |
| Direct lending funds | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |
| CLO - Equities | 60,908 |  |  | — |  |  | — |  |  | 9,634 |  |  | — |  |  | — |  |  | — |  |  | (8,976 | ) |  | 61,566 |  |  | 9,634 |  |
|  | 425,694 |  |  | — |  |  | — |  |  | (627 | ) |  | — |  |  | — |  |  | — |  |  | (8,979 | ) |  | 416,088 |  |  | (627 | ) |
| Total assets | $ | 477,659 |  |  | $ | — |  |  | $ | — |  |  | $ | (627 | ) |  | $ | 164 |  |  | $ | — |  |  | $ | — |  |  | $ | (9,614 | ) |  | $ | 467,582 |  |  | $ | (627 | ) |
| Six months ended June 30, 2012 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Fixed maturities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Corporate debt | $ | 1,550 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 1,550 |  |  | $ | — |  |
| Non-Agency RMBS | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |
| CMBS | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |
| ABS | 49,328 |  |  | — |  |  | — |  |  | — |  |  | 1,427 |  |  | — |  |  | — |  |  | (811 | ) |  | 49,944 |  |  | — |  |
|  | 50,878 |  |  | — |  |  | — |  |  | — |  |  | 1,427 |  |  | — |  |  | — |  |  | (811 | ) |  | 51,494 |  |  | — |  |
| Other investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| Hedge funds | 346,244 |  |  | — |  |  | — |  |  | 11,271 |  |  | — |  |  | — |  |  | — |  |  | (2,993 | ) |  | 354,522 |  |  | 11,271 |  |
| Direct lending funds | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |
| CLO - Equities | 66,560 |  |  | — |  |  | — |  |  | 13,024 |  |  | — |  |  | — |  |  | — |  |  | (18,018 | ) |  | 61,566 |  |  | 13,024 |  |
|  | 412,804 |  |  | — |  |  | — |  |  | 24,295 |  |  | — |  |  | — |  |  | — |  |  | (21,011 | ) |  | 416,088 |  |  | 24,295 |  |
| Total assets | $ | 463,682 |  |  | $ | — |  |  | $ | — |  |  | $ | 24,295 |  |  | $ | 1,427 |  |  | $ | — |  |  | $ | — |  |  | $ | (21,822 | ) |  | $ | 467,582 |  |  | $ | 24,295 |  |
(1) | Gains and losses included in earnings on fixed maturities are included in net realized investment gains (losses). Gains and (losses) included in earnings on other investments are included in net investment income.
(2) | Gains and losses included in other comprehensive income (“OCI”) on fixed maturities are included in unrealized gains (losses) arising during the period.
(3) | Change in unrealized investment gain/(loss) relating to assets held at the reporting date.

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- Definition Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19279-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
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- Definition Tabular disclosure of quantitative information about the inputs used in the fair value measurement of assets. This disclosure may include, but is not limited to, the fair value of the asset, valuation technique used to measure fair value, the inputs used to measure fair value, the ranges of the inputs, and the weighted averages of the inputs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
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- Definition Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19190-110258 + Details
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