INVESTMENTS (Detail) - Analysis of net realized gains (losses) and the change in unrealized (losses) gains on investments (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Fixed maturities, short-term investments, cash and cash equivalents:
Net realized (losses) on investments	$ (188,359)	$ (270,803)	$ (921,437)
Net realized and unrealized (losses) on investment related derivative instruments	(22,981)	(16,321)	(29,709)
Net realized (losses) on investments and net realized and unrealized (losses) on investment related derivative instruments	(211,340)	(287,124)	(951,146)
Fixed maturities and short-term investments, available for sale	598,542	1,095,762	2,112,244
Fixed maturities, held to maturity	212,419	30,039	(15,748)
Equity securities	(40,518)	22,595	(18,619)
Affiliates and other investments	25,268	44,314	14,464
Net change in unrealized gains (losses) on investments	795,711	1,192,710	2,092,341
Total net realized (losses) on investments, net realized and unrealized (losses) on investment related derivative instruments, and net change in unrealized gains (losses) on investments	584,371	905,586	1,141,195
Reinsurance Segment [Member]
Fixed maturities, short-term investments, cash and cash equivalents:
Realized loss on sale of U.S. life reinsurance business	0	0	(10,923)
Fixed Maturities And Short Term Investments And Cash And Cash Equivalents [Member]
Fixed maturities, short-term investments, cash and cash equivalents:
Gross realized gains	185,530	133,521	349,629
Gross realized losses	(225,360)	(193,396)	(405,342)
OTTI on investments, net of amounts transferred to other comprehensive income	(159,435)	(197,377)	(811,572)
Net realized gains (losses)	(199,265)	(257,252)	(867,285)
Equity Securities [Member]
Fixed maturities, short-term investments, cash and cash equivalents:
Gross realized gains	2,194	11,605	65,289
Gross realized losses	(4,264)	(11,195)	(129,516)
OTTI on investments, net of amounts transferred to other comprehensive income	0	0	0
Net realized gains (losses)	(2,070)	410	(64,227)
Other Investments Securities [Member]
Fixed maturities, short-term investments, cash and cash equivalents:
Gross realized gains	18,505	4,889	27,647
Gross realized losses	(4,792)	(11,094)	(5,763)
OTTI on investments, net of amounts transferred to other comprehensive income	(737)	(7,756)	(886)
Net realized gains (losses)	$ 12,976	$ (13,961)	$ 20,998