Derivative Instruments (Detail) - Hedged Items - Amount of Gain/(Loss) Recognized in Income Attributable to Risk (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
GainLossRecognizedInIncomeOnDerivativeMember
Interest rate exposure	$ 20,514	$ (43,698)	$ 25,366	$ 48,339
Foreign exchange exposure	18,219	(33,124)	(3,084)	15,432
Total	38,733	(76,822)	22,282	63,771
DepositLiabilitiesMember
Total	(21,659)	53,417	(25,950)	(33,326)
FixedMaturityInvestmentsMember
Total	(18,116)	23,646	2,890	(22,688)
Notes Payable and Debt [Member]
Total				(15,940)
IneffectivePortionOfHedgingRelationshipGainLossMember
Total	$ (1,042)	$ 241	$ (778)	$ (8,183)

Amount of gain (loss) from the increase (decrease) in fair value of foreign currency derivatives and nonderivative instruments designated as fair value hedging instruments which were recognized in earnings, net of offsets by the gain (loss) on the hedged item to the extent that the fair value hedge was determined to be effective.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5618551-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959

Name:	us-gaap_GainLossOnForeignCurrencyFairValueHedgeDerivatives
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration