Derivative Instruments (Detail) - Earnings relating to derivative instruments not formally designated as hedging instruments (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Total derivatives not designated as hedging instruments	$ (25,874)	$ 12,232	$ (33,521)	$ (19,720)
Amount of gain (loss) recognized in income from ineffective portion of fair value hedges	(1,042)	241	(778)	(8,183)
Net realized and unrealized gains (losses) on derivative instruments	(26,916)	12,473	(34,299)	(27,903)
Investment Related Derivatives [Member]
Interest rate exposure	2,559	(3,500)	(1,720)	1,406
Foreign exchange exposure	(23,214)	16,339	(5,763)	(11,672)
Credit exposure	5,207	(3,393)	(8,452)	(2,250)
Financial market exposure	(6,914)	58	(6,077)	193
Commodity exposure	(390)	-	(262)	-
Financial Operations Derivatives [Member]
Credit exposure	25	25	331	(7,317)
Other Non-Investment Derivatives [Member]
Contingent capital facility	(2,075)	(2,075)	(6,158)	(6,158)
Guaranteed minimum income benefit contract	(2,038)	173	(860)	(902)
Modified coinsurance funds withheld contract	$ 966	$ 4,605	$ (4,560)	$ 6,980

The amount of net gains and losses recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

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Net gain (loss) from the increase (decrease) in fair value of derivative instrument not designated as hedging instrument.

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Net gain (loss) recognized in earnings during the reporting period representing the amount of the fair value of the hedges' ineffectiveness.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of foreign currency derivatives not designated as hedging instruments.

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Amount of gain (loss) included in earnings for the period from the increase (decrease) in fair value of interest rate derivatives not designated as hedging instruments.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of price risk derivatives not designated as hedging instruments.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of contingent capital facility not designated as hedging instruments.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of credit risk derivatives not designated as hedging instruments.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of guaranteed minimum income benefit contract not designated as hedging instruments.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of modified coinsurance funds withheld contract not designated as hedging instruments.

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