Derivative Instruments (Details) - Gross amounts of derivative fair values contained in the consolidated balance sheet (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Designated as Hedging Instrument [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	$ 532,583		$ 2,189,699
Asset derivative fair value	8,173	[1]	135,148	[1]
Liability derivative notional amount	2,237,428		457,892
Liability derivative fair value	(78,246)	[1]	(4,518)	[1]
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	0	[2]	156,271	[2]
Asset derivative fair value	0	[1],[2]	109,761	[1],[2]
Liability derivative notional amount	0	[2]	0	[2]
Liability derivative fair value	0	[1],[2]	0	[1],[2]
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	532,583		2,033,428
Asset derivative fair value	8,173	[1]	25,387	[1]
Liability derivative notional amount	2,237,428		457,892
Liability derivative fair value	(78,246)	[1]	(4,518)	[1]
Not Designated as Hedging Instrument [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	372,361		576,974
Asset derivative fair value	4,579	[1]	11,591	[1]
Liability derivative notional amount	587,559		1,063,914
Liability derivative fair value	(40,965)	[1]	(58,544)	[1]
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Investment Related Derivatives [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	83,265		70,978
Asset derivative fair value	2,402	[1]	1,946	[1]
Liability derivative notional amount	26,878		55,033
Liability derivative fair value	(292)	[1]	(43)	[1]
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Investment Related Derivatives [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	77,366		232,422
Asset derivative fair value	484	[1]	3,759	[1]
Liability derivative notional amount	19,902		384,592
Liability derivative fair value	(710)	[1]	(11,737)	[1]
Not Designated as Hedging Instrument [Member] | Credit Exposure [Member] | Investment Related Derivatives [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	62,000		172,500
Asset derivative fair value	906	[1]	5,271	[1]
Liability derivative notional amount	397,574		449,513
Liability derivative fair value	(15,627)	[1]	(13,986)	[1]
Not Designated as Hedging Instrument [Member] | Credit Exposure [Member] | Financial Operations Derivatives [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	0	[2],[3]	0	[2],[3]
Asset derivative fair value	0	[1],[2],[3]	0	[1],[2],[3]
Liability derivative notional amount	58,149	[2],[3]	81,678	[2],[3]
Liability derivative fair value	(3,626)	[1],[2],[3]	(10,288)	[1],[2],[3]
Not Designated as Hedging Instrument [Member] | Financial Market Exposure [Member] | Investment Related Derivatives [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	72,707		23,874
Asset derivative fair value	787	[1]	615	[1]
Liability derivative notional amount	17,528		14,321
Liability derivative fair value	(191)	[1]	0	[1]
Not Designated as Hedging Instrument [Member] | Guaranteed Minimum Income Benefit Contract [Member] | Other Non Investment Derivatives [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	0		0
Asset derivative fair value	0	[1]	0	[1]
Liability derivative notional amount	67,528		78,777
Liability derivative fair value	(20,519)	[1]	(22,490)	[1]
Not Designated as Hedging Instrument [Member] | Modified Coinsurance Funds Withheld Contract [Member] | Other Non Investment Derivatives [Member]
Derivatives Fair Value [Line Items]
Asset derivative notional amount	77,023		77,200
Asset derivative fair value	0	[1]	0	[1]
Liability derivative notional amount	0		0
Liability derivative fair value	$ 0	[1]	$ 0	[1]

[1] Derivative instruments in an asset or liability position are included within Other assets or Other liabilities, respectively, in the balance sheet.

[2] The Company held net cash collateral related to these derivative positions that is included within Cash and cash equivalents and the corresponding liability to return the collateral has been offset against the derivative asset within the balance sheet as appropriate under the netting agreement.

[3] Financial operations derivatives represent interests in variable interest entities as described in Note 10, "Variable Interest Entities".