Derivative Instruments (Detail) - Hedged Items - Amount of Gain/(Loss) Recognized in Income Attributable to Risk (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Gain Loss Recognized InIncome OnDerivative [Member]
Interest rate exposure	$ 5,726	$ 85,900	$ 4,852	$ 92,036
Foreign exchange exposure	(877)	13,312	(21,303)	48,556
Total	4,849	99,212	(16,451)	140,592
Deposit Liabilities [Member]
Total	(6,672)	(85,918)	(4,291)	(86,742)
Fixed Maturity Investments [Member]
Total	866	(11,668)	21,006	(46,334)
Notes Payable And Debt [Member]
Total		(6,209)		(15,940)
Ineffective Portion OfHedging Relationship Gain Loss [Member]
Total	$ (957)	$ (4,583)	$ 264	$ (8,424)