FAIR VALUE MEASUREMENTS - Changes in Available-For-Sale Investments and Derivatives Classified as Level 3 (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 3,803		$ 560
Realized gains or losses included in earnings	95		(64)
Unrealized gains or losses included in other comprehensive income	(73)		(28)
Purchases	0		0
Issuances	0		0
Sales	(290)		0
Settlements	(28)		(3)
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	3,507		465
Change in unrealized gains (losses) still held	44	[1]	(64)	[2]
Fixed Maturities | Mortgage- and asset-backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	394		267
Realized gains or losses included in earnings	0		(6)
Unrealized gains or losses included in other comprehensive income	(23)		(10)
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	(4)		(3)
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	367		248
Change in unrealized gains (losses) still held	0	[1]	(6)	[2]
Fixed Maturities | Public Utilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	422		0
Realized gains or losses included in earnings	0		0
Unrealized gains or losses included in other comprehensive income	(13)		0
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	409		0
Change in unrealized gains (losses) still held	0	[1]	0	[2]
Fixed Maturities | Collateralized Debt Obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period			5
Realized gains or losses included in earnings			0
Unrealized gains or losses included in other comprehensive income			0
Purchases			0
Issuances			0
Sales			0
Settlements			0
Transfers into Level 3			0
Transfers out of Level 3			0
Balance, end of period			5
Change in unrealized gains (losses) still held			0	[2]
Fixed Maturities | Sovereign and Supranational
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	434		0
Realized gains or losses included in earnings	0		0
Unrealized gains or losses included in other comprehensive income	(16)		0
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	418		0
Change in unrealized gains (losses) still held	0	[1]	0	[2]
Fixed Maturities | Banks/financial Institutions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	1,074		386
Realized gains or losses included in earnings	0		1
Unrealized gains or losses included in other comprehensive income	23		33
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	1,097		420
Change in unrealized gains (losses) still held	0	[1]	1	[2]
Fixed Maturities | Other Corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	1,105		0
Realized gains or losses included in earnings	2		0
Unrealized gains or losses included in other comprehensive income	(38)		0
Purchases	0		0
Issuances	0		0
Sales	(34)		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	1,035		0
Change in unrealized gains (losses) still held	0	[1]	0	[2]
Perpetual Securities | Banks/financial Institutions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	526		0
Realized gains or losses included in earnings	49		0
Unrealized gains or losses included in other comprehensive income	6		0
Purchases	0		0
Issuances	0		0
Sales	(256)		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	325		0
Change in unrealized gains (losses) still held	0	[1]	0	[2]
Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	4		4
Realized gains or losses included in earnings	0		0
Unrealized gains or losses included in other comprehensive income	0		0
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	4		4
Change in unrealized gains (losses) still held	0	[1]	0	[2]
Derivatives | Interest rate swaps
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	30
Realized gains or losses included in earnings	(2)
Unrealized gains or losses included in other comprehensive income	0
Purchases	0
Issuances	0
Sales	0
Settlements	0
Transfers into Level 3	0
Transfers out of Level 3	0
Balance, end of period	28
Change in unrealized gains (losses) still held	(2)	[1]
Derivatives | Foreign currency swaps
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	(56)		241
Realized gains or losses included in earnings	13		(64)
Unrealized gains or losses included in other comprehensive income	(12)		(51)
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	(24)		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	(79)		126
Change in unrealized gains (losses) still held	13	[1]	(64)	[2]
Derivatives | Credit default swaps
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	(130)		(343)
Realized gains or losses included in earnings	33		5
Unrealized gains or losses included in other comprehensive income	0		0
Purchases	0		0
Issuances	0		0
Sales	0		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Balance, end of period	(97)		(338)
Change in unrealized gains (losses) still held	$ 33	[1]	$ 5	[2]

[1] Represents the amount of total gains or losses for the period, included in earnings, attributable to the change in unrealized gains (losses) relating to assets classified as Level 3 that were still held at March 31, 2012

[2] Represents the amount of total gains or losses for the period, included in earnings, attributable to the change in unrealized gains (losses) relating to assets classified as Level 3 that were still held at March 31, 2011