INVESTMENTS - Additional Information (Detail) (USD $)	3 Months Ended						9 Months Ended			3 Months Ended		9 Months Ended					9 Months Ended			3 Months Ended										9 Months Ended				9 Months Ended								3 Months Ended			9 Months Ended																			3 Months Ended		3 Months Ended	12 Months Ended
	Sep. 30, 2011 Investment Year Entity	Jun. 30, 2011 Investment	Mar. 31, 2011 Investment	Sep. 30, 2010 Investment	Jun. 30, 2010 Investment	Mar. 31, 2010 Investment	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Sep. 30, 2011 Upper Limit Fair Value Option	Sep. 30, 2010 Upper Limit Fair Value Option	Sep. 30, 2010 Upper Limit Fair Value Option	Sep. 30, 2011 Fair Value Option	Dec. 31, 2010 Fair Value Option	Sep. 30, 2011 Variable Interest Entity, Not Consolidated	Dec. 31, 2010 Variable Interest Entity, Not Consolidated	Sep. 30, 2011 Variable Interest Entity, Not Consolidated A Entity	Oct. 31, 2011 Sovereign and Supranational Change in Investment Grading Spain Investment	Sep. 30, 2011 Parent Company	Mar. 31, 2011 Banks/financial Institutions Alpha Bank Investments Sold Greece Investment	Jun. 30, 2011 Banks/financial Institutions EFG Eurobank Ergasias Investments Sold Greece Investment	Jun. 30, 2011 Banks/financial Institutions National Bank of Greece (NBG) Investments Sold Greece	Jun. 30, 2011 Banks/financial Institutions Banco BPI, SA Investments Sold Portugal	Sep. 30, 2011 Banks/financial Institutions Caixa Geral de Depositos SA Investments Sold Portugal	Jun. 30, 2011 Banks/financial Institutions Caixa Geral de Depositos SA Impairments Portugal	Sep. 30, 2011 Banks/financial Institutions Banco Espirito Santo SA Investments Sold Portugal	Jun. 30, 2011 Banks/financial Institutions Banco Espirito Santo SA Impairments Portugal	Sep. 30, 2011 Perpetual Securities	Sep. 30, 2010 Perpetual Securities	Sep. 30, 2011 Perpetual Securities	Sep. 30, 2010 Perpetual Securities	Dec. 31, 2010 Perpetual Securities	Sep. 30, 2011 Perpetual Securities Lower Limit	Sep. 30, 2011 Perpetual Securities Below Investment Grade Entity	Sep. 30, 2011 Perpetual Securities Investment grade	Dec. 31, 2010 Perpetual Securities Investment grade	Sep. 30, 2011 Perpetual Securities Europe, excluding the United Kingdom	Sep. 30, 2011 Perpetual Securities United Kingdom	Sep. 30, 2011 Perpetual Securities Japan	Sep. 30, 2011 Perpetual Securities Other Countries	Sep. 30, 2011 Perpetual Securities Minimum Upper Limit	Jun. 30, 2011 Banks/financial Institutions Investments Sold Below Investment Grade Ireland	Mar. 31, 2011 Banks/financial Institutions Investments Sold Below Investment Grade Ireland	Sep. 30, 2011 Upper Limit Banks/financial Institutions Below Investment Grade	Sep. 30, 2011 Banks/financial Institutions Below Investment Grade Investment Entity	Sep. 30, 2011 Banks/financial Institutions Below Investment Grade Ireland	Sep. 30, 2011 Municipalities Investment grade	Dec. 31, 2010 Municipalities Investment grade	Sep. 30, 2011 Sovereign and Supranational Investment grade	Dec. 31, 2010 Sovereign and Supranational Investment grade	Sep. 30, 2011 Banks/financial Institutions Investment grade	Dec. 31, 2010 Banks/financial Institutions Investment grade	Sep. 30, 2011 Other Corporate Investment grade	Dec. 31, 2010 Other Corporate Investment grade	Sep. 30, 2011 Investment grade Public Utilities	Dec. 31, 2010 Investment grade Public Utilities	Sep. 30, 2011 Banks/financial Institutions	Dec. 31, 2010 Banks/financial Institutions	Sep. 30, 2011 Banks/financial Institutions Europe, excluding the United Kingdom	Sep. 30, 2011 Banks/financial Institutions United States	Sep. 30, 2011 Banks/financial Institutions United Kingdom	Sep. 30, 2011 Banks/financial Institutions Japan	Sep. 30, 2011 Banks/financial Institutions Other Countries	Mar. 31, 2011 Banks/financial Institutions Greece Investment	Mar. 31, 2011 Republic of Tunisia	Mar. 31, 2011 Portugal and Ireland Investment	Dec. 31, 2010 Greece Entity
Schedule of Investments [Line Items]
Available-for-sale fixed-maturity securities, amortized cost																			$ 120,000,000
Available-for-sale fixed maturity securities, fair value													514,000,000	619,000,000					139,000,000
Available-for-sale fixed maturity securities, recognized gains (losses)	(83,000,000)			9,000,000			(1,330,000,000)	(127,000,000)		(1,000,000)	(1,000,000)	(1,000,000)	12,000,000															(122,000,000)	0	(361,000,000)	92,000,000
Reclassified investments from the held-to-maturity portfolio to the available-for-sale portfolio, number of investments	0	0	8	2	4	0																																																												4
Reclassified investments from the held-to-maturity portfolio to the available-for-sale portfolio, amortized cost	0		1,600,000,000	267,000,000	1,200,000,000		0	267,000,000																																																									769,000,000	631,000,000
Reclassified investments from the held-to-maturity portfolio to the available-for-sale portfolio, aggregate unrealized gain (loss)	0		(270,000,000)	(165,000,000)	(665,000,000)
Perpetual securities, interest coupons that were fixed at issuance subsequently change to a floating short-term interest rate																														floating short-term interest rate of 125 to more than 300 basis points above an appropriate market index
Maturity date																														25 years
Perpetual securities, floating short-term interest rate basis point above market index																																	1.25%								3.00%
Geographic concentration of credit risk for issuer of investments owned																																					70.00%	10.00%	14.00%	6.00%																			42.00%	22.00%	8.00%	8.00%	20.00%
Amortized Cost															13,948,000,000	13,919,000,000		130,000,000																												261,000,000											27,770,000,000	29,540,000,000
Fair value															13,626,000,000	13,219,000,000		136,000,000																												100,000,000											25,333,000,000	27,910,000,000
Other-than-temporary impairment losses	166,000,000			13,000,000			1,100,000,000	55,000,000																	112,000,000		163,000,000	122,000,000	0	306,000,000	41,000,000															0																		397,000,000			0
Other-than-temporary impairment losses, after-tax																									73,000,000		106,000,000																																					258,000,000
Number of investments																				1	1																																											2
Realized pretax investment gains (losses) from sales and redemptions	307,000,000			8,000,000			49,000,000	0												(177,000,000)	2,000,000	(47,000,000)	(99,000,000)	52,000,000		54,000,000																(74,000,000)	2,000,000
Realized investment gains (losses) from sales and redemptions, after-tax																				(115,000,000)			(64,000,000)	34,000,000		35,000,000																(48,000,000)
Number of issuers																	161																	5																																	3
Investments down graded to below investment grade, number of Investments																		1
Valuation allowance related to deferred tax asset associated with realized investment losses	(17,000,000)	19,000,000
Valuation allowance related to deferred tax asset associated with realized investment losses, remaining valuation allowance	2,000,000						2,000,000
Percentage of unrealized losses attributable to securities that were investment grade																																			84.00%	83.00%											59.00%	82.00%	90.00%	100.00%	83.00%	53.00%	67.00%	51.00%	98.00%	100.00%
Fair value of investments in an unrealized loss position	35,395,000,000						35,395,000,000		30,654,000,000																			5,017,000,000		5,017,000,000		4,379,000,000													1,100,000,000												17,000,000,000
Total Unrealized Losses	5,039,000,000						5,039,000,000		3,363,000,000																			1,057,000,000		1,057,000,000		563,000,000													500,000,000												3,000,000,000
Number of investments																																													4
Percentage of unrealized losses attributable to a certain number of securities																																													99.00%
Number of issuers with average unrealized losses per investment																																													5
Issuers, average unrealized losses per investment																																												$ 1,000,000
Percentage that the lending policy requires that the fair value of the securities and/or unrestricted cash received as collateral be of the fair value of the loaned securities	102.00%						102.00%