INVESTMENTS (DETAILS 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010
Fixed Maturities [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	$ 167,614	$ 410,004
Unrealized Losses - 12 months or greater	(21,718)	(45,305)
Fair Value - Less than 12 months	3,785,593	3,701,428
Unrealized Losses - Less than 12 months	(106,137)	(68,590)
Total Fair Value of Securities in Unrealized Loss Position	3,953,207	4,111,432
Total Unrealized Losses	(127,855)	(113,895)
Number of Available For Sale Securities In Unrealized Loss Positions	1,017	1,150
Number of Available For Sale Securities in Unrealized Loss Positions for 12 Months or Greater	123	206
Fixed Maturities [Member] | Below Investment Grade or Not Rated [Member]
Schedule Of Available For Sale Securities [Line Items]
Total Unrealized Losses	(26,000)	(15,000)
Equities [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	3,022	4,347
Unrealized Losses - 12 months or greater	(990)	(601)
Fair Value - Less than 12 months	460,598	122,317
Unrealized Losses - Less than 12 months	(77,100)	(4,113)
Total Fair Value of Securities in Unrealized Loss Position	463,620	126,664
Total Unrealized Losses	(78,090)	(4,714)
Number of Available For Sale Securities In Unrealized Loss Positions	153	71
Number of Available For Sale Securities in Unrealized Loss Positions for 12 Months or Greater	9	12
US Government and Agency [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	0	0
Unrealized Losses - 12 months or greater	0	0
Fair Value - Less than 12 months	621,060	453,207
Unrealized Losses - Less than 12 months	(1,282)	(3,692)
Total Fair Value of Securities in Unrealized Loss Position	621,060	453,207
Total Unrealized Losses	(1,282)	(3,692)
Non-US Government [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	0	83,572
Unrealized Losses - 12 months or greater	0	(6,062)
Fair Value - Less than 12 months	669,817	302,431
Unrealized Losses - Less than 12 months	(22,278)	(7,697)
Total Fair Value of Securities in Unrealized Loss Position	669,817	386,003
Total Unrealized Losses	(22,278)	(13,759)
Corporate Debt [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	49,282	160,161
Unrealized Losses - 12 months or greater	(2,530)	(13,123)
Fair Value - Less than 12 months	1,759,460	1,087,683
Unrealized Losses - Less than 12 months	(72,298)	(22,973)
Total Fair Value of Securities in Unrealized Loss Position	1,808,742	1,247,844
Total Unrealized Losses	(74,828)	(36,096)
Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	0	735
Unrealized Losses - 12 months or greater	0	(42)
Fair Value - Less than 12 months	284,510	1,308,690
Unrealized Losses - Less than 12 months	(1,100)	(20,660)
Total Fair Value of Securities in Unrealized Loss Position	284,510	1,309,425
Total Unrealized Losses	(1,100)	(20,702)
CMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	20,237	1,164
Unrealized Losses - 12 months or greater	(585)	(59)
Fair Value - Less than 12 months	41,834	48,701
Unrealized Losses - Less than 12 months	(520)	(1,442)
Total Fair Value of Securities in Unrealized Loss Position	62,071	49,865
Total Unrealized Losses	(1,105)	(1,501)
Non-Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	43,727	100,074
Unrealized Losses - 12 months or greater	(7,382)	(10,030)
Fair Value - Less than 12 months	93,518	57,095
Unrealized Losses - Less than 12 months	(3,821)	(1,515)
Total Fair Value of Securities in Unrealized Loss Position	137,245	157,169
Total Unrealized Losses	(11,203)	(11,545)
ABS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	47,099	40,617
Unrealized Losses - 12 months or greater	(9,752)	(12,871)
Fair Value - Less than 12 months	206,310	155,491
Unrealized Losses - Less than 12 months	(4,084)	(2,179)
Total Fair Value of Securities in Unrealized Loss Position	253,409	196,108
Total Unrealized Losses	(13,836)	(15,050)
Municipals [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	7,269	23,681
Unrealized Losses - 12 months or greater	(1,469)	(3,118)
Fair Value - Less than 12 months	109,084	288,130
Unrealized Losses - Less than 12 months	(754)	(8,432)
Total Fair Value of Securities in Unrealized Loss Position	116,353	311,811
Total Unrealized Losses	$ (2,223)	$ (11,550)