INVESTMENTS (DETAILS) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 10,641,187	$ 10,346,243
Cost	634,268	327,207
Fair Value (fixed maturities)	10,736,729	10,482,897
Fair Value (equities)	567,881	349,254
US Government and Agency [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,103,869	856,711
Gross Unrealized Gains	6,856	7,101
Gross Unrealized Losses	(1,282)	(3,692)
Fair Value (fixed maturities)	1,109,443	860,120
Non-credit OTTI in AOCI	0	0
Non-US Government [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,015,795	777,236
Gross Unrealized Gains	7,061	9,321
Gross Unrealized Losses	(22,278)	(13,759)
Fair Value (fixed maturities)	1,000,578	772,798
Non-credit OTTI in AOCI	0	0
Corporate Debt [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,716,760	4,054,048
Gross Unrealized Gains	78,168	144,956
Gross Unrealized Losses	(74,828)	(36,096)
Fair Value (fixed maturities)	3,720,100	4,162,908
Non-credit OTTI in AOCI	0	0
Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	2,538,293	2,571,124
Gross Unrealized Gains	73,876	43,160
Gross Unrealized Losses	(1,100)	(20,702)
Fair Value (fixed maturities)	2,611,069	2,593,582
Non-credit OTTI in AOCI	0	0
CMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	273,278	454,288
Gross Unrealized Gains	10,987	21,998
Gross Unrealized Losses	(1,105)	(1,501)
Fair Value (fixed maturities)	283,160	474,785
Non-credit OTTI in AOCI	0	0
Non-Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	186,480	252,460
Gross Unrealized Gains	1,509	3,287
Gross Unrealized Losses	(11,203)	(11,545)
Fair Value (fixed maturities)	176,786	244,202
Non-credit OTTI in AOCI	(874)	(7,443)
ABS [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	643,332	668,037
Gross Unrealized Gains	9,046	8,856
Gross Unrealized Losses	(13,836)	(15,050)
Fair Value (fixed maturities)	638,542	661,843
Non-credit OTTI in AOCI	0	(1,275)
Municipals [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	1,163,380	712,339
Gross Unrealized Gains	35,894	11,870
Gross Unrealized Losses	(2,223)	(11,550)
Fair Value (fixed maturities)	1,197,051	712,659
Non-credit OTTI in AOCI	0	(350)
Fixed Maturities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	10,641,187	10,346,243
Gross Unrealized Gains	223,397	250,549
Gross Unrealized Losses	(127,855)	(113,895)
Fair Value (fixed maturities)	10,736,729	10,482,897
Non-credit OTTI in AOCI	(874)	(9,068)
Equities [Member]
Schedule Of Available For Sale Securities [Line Items]
Cost	634,268	327,207
Gross Unrealized Gains	11,703	26,761
Gross Unrealized Losses	(78,090)	(4,714)
Fair Value (equities)	$ 567,881	$ 349,254

Total of accumulated other comprehensive loss related to that portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized either as available-for-sale or held-to-maturity that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

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

- Definition

For an unclassified balance sheet, this item represents equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 3

-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 Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 19

-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 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

Reference 4: 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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 320

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803

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 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558

Reference 8: 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 9: 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 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 86-40

-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