Changes in Available-For-Sale Investments and Derivatives Classified as Level 3 (Detail) (USD $) In Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	$ 465		$ 4,622		$ 560		$ 5,057
Effect of change in accounting principle							(575)	[1]
Revised balance, beginning of period							4,482
Realized gains or losses included in earnings	(19)		59		(83)		68
Unrealized gains or losses included in other comprehensive income	3		(122)		(25)		89
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		(534)		0		(763)
Settlements	125		0		122		0
Transfers into Level 3	0		549	[2]	0		698	[2]
Transfers out of Level 3	0		(4,210)	[3]	0		(4,210)	[3]
Balance, end of period	574		364		574		364
Change in unrealized gains (losses) still held	17	[4]	(66)	[5]	(60)	[4]	(45)	[5]
Mortgage- and asset-backed Securities | Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	248		63		267		62
Effect of change in accounting principle							0	[1]
Revised balance, beginning of period							62
Realized gains or losses included in earnings	0		0		(6)		0
Unrealized gains or losses included in other comprehensive income	12		1		2		2
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		(1)		0		(1)
Settlements	(3)		0		(6)		0
Transfers into Level 3	0		219	[2]	0		219	[2]
Transfers out of Level 3	0		0	[3]	0		0	[3]
Balance, end of period	257		282		257		282
Change in unrealized gains (losses) still held	0	[4]	0	[5]	(6)	[4]	0	[5]
Public Utilities | Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	0		488		0		497
Effect of change in accounting principle							0	[1]
Revised balance, beginning of period							497
Realized gains or losses included in earnings	0		0		0		0
Unrealized gains or losses included in other comprehensive income	0		0		0		(9)
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		(2)		0		(2)
Settlements	0		0		0		0
Transfers into Level 3	0		0	[2]	0		0	[2]
Transfers out of Level 3	0		(459)	[3]	0		(459)	[3]
Balance, end of period	0		27		0		27
Change in unrealized gains (losses) still held	0	[4]	0	[5]	0	[4]	0	[5]
Sovereign and Supranational | Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	0		298		0		293
Effect of change in accounting principle							0	[1]
Revised balance, beginning of period							293
Realized gains or losses included in earnings	0		0		0		0
Unrealized gains or losses included in other comprehensive income	0		0		0		5
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		0		0		0
Settlements	0		0		0		0
Transfers into Level 3	0		0	[2]	0		0	[2]
Transfers out of Level 3	0		(298)	[3]	0		(298)	[3]
Balance, end of period	0		0		0		0
Change in unrealized gains (losses) still held	0	[4]	0	[5]	0	[4]	0	[5]
Banks/financial Institutions | Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	420		1,103		386		1,240
Effect of change in accounting principle							0	[1]
Revised balance, beginning of period							1,240
Realized gains or losses included in earnings	0		0		1		5
Unrealized gains or losses included in other comprehensive income	(22)		1		11		34
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		0		0		(175)
Settlements	0		0		0		0
Transfers into Level 3	0		330	[2]	0		330	[2]
Transfers out of Level 3	0		(1,082)	[3]	0		(1,082)	[3]
Balance, end of period	398		352		398		352
Change in unrealized gains (losses) still held	0	[4]	0	[5]	1	[4]	0	[5]
Other Corporate | Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	0		1,253		0		1,248
Effect of change in accounting principle							0	[1]
Revised balance, beginning of period							1,248
Realized gains or losses included in earnings	0		0		0		0
Unrealized gains or losses included in other comprehensive income	0		1		0		6
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		0		0		0
Settlements	0		0		0		0
Transfers into Level 3	0		0	[2]	0		0	[2]
Transfers out of Level 3	0		(1,202)	[3]	0		(1,202)	[3]
Balance, end of period	0		52		0		52
Change in unrealized gains (losses) still held	0	[4]	0	[5]	0	[4]	0	[5]
Collateralized Debt Obligations | Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	5		4		5		267
Effect of change in accounting principle							(263)	[1]
Revised balance, beginning of period							4
Realized gains or losses included in earnings	(1)		0		(1)		0
Unrealized gains or losses included in other comprehensive income	0		0		0		0
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		0		0		0
Settlements	0		0		0		0
Transfers into Level 3	0		0	[2]	0		0	[2]
Transfers out of Level 3	0		0	[3]	0		0	[3]
Balance, end of period	4		4		4		4
Change in unrealized gains (losses) still held	(1)	[4]	0	[5]	(1)	[4]	0	[5]
Banks/financial Institutions | Perpetual Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	0		1,695		0		1,441
Effect of change in accounting principle							0	[1]
Revised balance, beginning of period							1,441
Realized gains or losses included in earnings	0		125		0		108
Unrealized gains or losses included in other comprehensive income	0		(125)		0		51
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		(531)		0		(585)
Settlements	0		0		0		0
Transfers into Level 3	0		0	[2]	0		149	[2]
Transfers out of Level 3	0		(1,164)	[3]	0		(1,164)	[3]
Balance, end of period	0		0		0		0
Change in unrealized gains (losses) still held	0	[4]	0	[5]	0	[4]	0	[5]
Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	4		9		4		9
Effect of change in accounting principle							0	[1]
Revised balance, beginning of period							9
Realized gains or losses included in earnings	0		0		0		0
Unrealized gains or losses included in other comprehensive income	0		0		0		0
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		0		0		0
Settlements	0		0		0		0
Transfers into Level 3	0		0	[2]	0		0	[2]
Transfers out of Level 3	0		(5)	[3]	0		(5)	[3]
Balance, end of period	4		4		4		4
Change in unrealized gains (losses) still held	0	[4]	0	[5]	0	[4]	0	[5]
Foreign currency swaps | Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	126				241
Realized gains or losses included in earnings	25				(39)
Unrealized gains or losses included in other comprehensive income	13				(38)
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	164				164
Change in unrealized gains (losses) still held	25	[4]			(39)	[4]
Credit default swaps | Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	(338)		(291)		(343)		0
Effect of change in accounting principle							(312)	[1]
Revised balance, beginning of period							(312)
Realized gains or losses included in earnings	(43)		(66)		(38)		(45)
Unrealized gains or losses included in other comprehensive income	0		0		0		0
Purchases	0		0		0		0
Issuances	0		0		0		0
Sales	0		0		0		0
Settlements	128		0		128		0
Transfers into Level 3	0		0	[2]	0		0	[2]
Transfers out of Level 3	0		0	[3]	0		0	[3]
Balance, end of period	(253)		(357)		(253)		(357)
Change in unrealized gains (losses) still held	$ (7)	[4]	$ (66)	[5]	$ (15)	[4]	$ (45)	[5]

[1] Change in accounting for VIEs effective January 1, 2010. See Notes 1, 3, and 4 for additional information.

[2] Due to a lack of visibility to observe significant inputs to price and credit downgrades of respective issuers of securities to below investment grade

[3] A result of changing our pricing methodology to using a pricing index for estimating fair value instead of obtaining pricing of the securities from brokers or arrangers

[4] 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 June 30, 2011

[5] 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 June 30, 2010