Derivative Financial Instruments (Details) (USD $) In Millions, except Share data, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
Derivatives, Fair Value
Notional amount of asset derivatives designated as accounting hedging instruments	$ 257	$ 220
Notional amount of asset derivatives not designated as accounting hedging instruments	10,897	9,035
Total asset derivatives, notional amount	11,154	9,255
Notional amount of liability derivatives designated as accounting hedging instruments	191	3,918
Notional amount of liability derivatives not designated as accounting hedging instruments	13,379	20,733
Total liability derivatives, notional amount	13,570	24,651
Total derivatives, notional amount	24,724	33,906
Number of contracts of asset derivatives not designated as accounting hedging instruments	25,954	48,163
Total asset derivatives, number of contracts	25,954	48,163
Number of contracts of liability derivatives not designated as accounting hedging instruments	15,586	36,735
Total liability derivatives, number of contracts	15,586	36,735
Total derivatives, number of contracts	41,540	84,898
Fair value, net of asset derivatives designated as accounting hedging instruments	(20)	(16)
Fair value, net of asset derivatives not designated as accounting hedging instruments	311	670
Total asset derivatives, fair value, net	291	654
Fair value, net of liability derivatives designated as accounting hedging instruments	(29)	(137)
Fair value, net of liability derivatives not designated as accounting hedging instruments	(798)	(875)
Total liability derivatives, fair value, net	(827)	(1,012)
Total derivatives, fair value, net	(536)	(358)
Gross asset of asset derivatives designated as accounting hedging instruments	2	3
Gross asset of asset derivatives not designated as accounting hedging instruments	421	797
Total asset derivatives, gross asset	423	800
Gross asset of liability derivatives designated as accounting hedging instruments		84
Gross asset of liability derivatives not designated as accounting hedging instruments	43	127
Total liability derivatives, gross asset	43	211
Gross liability of asset derivatives designated as accounting hedging instruments	(22)	(19)
Gross liability of asset derivatives not designated as accounting hedging instruments	(110)	(127)
Total asset derivatives, gross liability	(132)	(146)
Gross liability of liability derivatives designated as accounting hedging instruments	(29)	(221)
Gross liability of liability derivatives not designated as accounting hedging instruments	(841)	(1,002)
Total liability derivatives, gross liability	(870)	(1,223)
Securities pledged in the form of margin deposits	12
Foreign currency and interest rate swap agreements | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives designated as accounting hedging instruments		435
Fair value, net of liability derivatives designated as accounting hedging instruments		34
Gross asset of liability derivatives designated as accounting hedging instruments		34
Foreign currency and interest rate swap agreements | Contractholder funds.
Derivatives, Fair Value
Fair value, net of liability derivatives designated as accounting hedging instruments		28
Gross asset of liability derivatives designated as accounting hedging instruments		28
Interest rate swap agreements | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives designated as accounting hedging instruments	207	156
Notional amount of asset derivatives not designated as accounting hedging instruments	5,585	1,469
Fair value, net of asset derivatives designated as accounting hedging instruments	(15)	(18)
Fair value, net of asset derivatives not designated as accounting hedging instruments	138	65
Gross asset of asset derivatives not designated as accounting hedging instruments	161	81
Gross liability of asset derivatives designated as accounting hedging instruments	(15)	(18)
Gross liability of asset derivatives not designated as accounting hedging instruments	(23)	(16)
Interest rate swap agreements | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives designated as accounting hedging instruments	39	3,345
Notional amount of liability derivatives not designated as accounting hedging instruments	2,479	4,543
Fair value, net of liability derivatives designated as accounting hedging instruments	(2)	(181)
Fair value, net of liability derivatives not designated as accounting hedging instruments	15	29
Gross asset of liability derivatives designated as accounting hedging instruments		20
Gross asset of liability derivatives not designated as accounting hedging instruments	28	97
Gross liability of liability derivatives designated as accounting hedging instruments	(2)	(201)
Gross liability of liability derivatives not designated as accounting hedging instruments	(13)	(68)
Interest rate swap agreements | Contractholder funds.
Derivatives, Fair Value
Fair value, net of liability derivatives designated as accounting hedging instruments		2
Gross asset of liability derivatives designated as accounting hedging instruments		2
Foreign currency swap agreements | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives designated as accounting hedging instruments	50	64
Notional amount of asset derivatives not designated as accounting hedging instruments		90
Fair value, net of asset derivatives designated as accounting hedging instruments	(5)	2
Fair value, net of asset derivatives not designated as accounting hedging instruments		6
Gross asset of asset derivatives designated as accounting hedging instruments	2	3
Gross asset of asset derivatives not designated as accounting hedging instruments		6
Gross liability of asset derivatives designated as accounting hedging instruments	(7)	(1)
Foreign currency swap agreements | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives designated as accounting hedging instruments	152	138
Notional amount of liability derivatives not designated as accounting hedging instruments	50
Fair value, net of liability derivatives designated as accounting hedging instruments	(27)	(20)
Gross liability of liability derivatives designated as accounting hedging instruments	(27)	(20)
Interest rate swaption agreements | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	2,250	4,161
Fair value, net of asset derivatives not designated as accounting hedging instruments	13	50
Gross asset of asset derivatives not designated as accounting hedging instruments	13	50
Interest rate swaption agreements | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	940	4,400
Fair value, net of liability derivatives not designated as accounting hedging instruments	5	18
Gross asset of liability derivatives not designated as accounting hedging instruments	5	18
Interest rate cap and floor agreements | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	1,383	226
Fair value, net of asset derivatives not designated as accounting hedging instruments	(5)	(2)
Gross asset of asset derivatives not designated as accounting hedging instruments		1
Gross liability of asset derivatives not designated as accounting hedging instruments	(5)	(3)
Interest rate cap and floor agreements | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	1,669	3,216
Fair value, net of liability derivatives not designated as accounting hedging instruments	(19)	(22)
Gross asset of liability derivatives not designated as accounting hedging instruments	1	1
Gross liability of liability derivatives not designated as accounting hedging instruments	(20)	(23)
Financial futures contracts and options | Other investments.
Derivatives, Fair Value
Number of contracts of asset derivatives not designated as accounting hedging instruments	9,000	8,000
Fair value, net of asset derivatives not designated as accounting hedging instruments	5	3
Gross asset of asset derivatives not designated as accounting hedging instruments	5	3
Financial futures contracts and options | Other assets.
Derivatives, Fair Value
Number of contracts of asset derivatives not designated as accounting hedging instruments	840	1,420
Financial futures contracts and options | Other liabilities and accrued expenses
Derivatives, Fair Value
Number of contracts of liability derivatives not designated as accounting hedging instruments	270	15,150
Fair value, net of liability derivatives not designated as accounting hedging instruments		(1)
Gross liability of liability derivatives not designated as accounting hedging instruments		(1)
Options and futures
Derivatives, Fair Value
Stock rights held by the Company related to derivative contracts (number of rights)	308,430	2,768
Stock warrants held by the Company related to derivative contracts (number of warrants)	4,389,707	1,379,932
Options and futures | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	160	64
Number of contracts of asset derivatives not designated as accounting hedging instruments	14,931	38,451
Fair value, net of asset derivatives not designated as accounting hedging instruments	221	359
Gross asset of asset derivatives not designated as accounting hedging instruments	221	359
Options and futures | Other assets.
Derivatives, Fair Value
Number of contracts of asset derivatives not designated as accounting hedging instruments	1,183	292
Fair value, net of asset derivatives not designated as accounting hedging instruments	2
Gross asset of asset derivatives not designated as accounting hedging instruments	2
Options and futures | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments		64
Number of contracts of liability derivatives not designated as accounting hedging instruments	15,316	21,585
Fair value, net of liability derivatives not designated as accounting hedging instruments	(104)	(168)
Gross asset of liability derivatives not designated as accounting hedging instruments		2
Gross liability of liability derivatives not designated as accounting hedging instruments	(104)	(170)
Foreign currency forwards and options | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments		257
Fair value, net of asset derivatives not designated as accounting hedging instruments		6
Gross asset of asset derivatives not designated as accounting hedging instruments		7
Gross liability of asset derivatives not designated as accounting hedging instruments		(1)
Foreign currency forwards and options | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	277	316
Fair value, net of liability derivatives not designated as accounting hedging instruments	(2)	1
Gross asset of liability derivatives not designated as accounting hedging instruments	2	2
Gross liability of liability derivatives not designated as accounting hedging instruments	(4)	(1)
Conversion options | Fixed income securities
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	5	820
Fair value, net of asset derivatives not designated as accounting hedging instruments		236
Gross asset of asset derivatives not designated as accounting hedging instruments		238
Gross liability of asset derivatives not designated as accounting hedging instruments		(2)
Equity-indexed call options | Fixed income securities
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	150	300
Fair value, net of asset derivatives not designated as accounting hedging instruments	16	47
Gross asset of asset derivatives not designated as accounting hedging instruments	16	47
Credit default swaps | Fixed income securities
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	172	181
Fair value, net of asset derivatives not designated as accounting hedging instruments	(78)	(88)
Gross liability of asset derivatives not designated as accounting hedging instruments	(78)	(88)
Other embedded derivative financial instruments | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	1,000	1,000
Other embedded derivative financial instruments | Contractholder funds.
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	85	85
Fair value, net of liability derivatives not designated as accounting hedging instruments	(8)	(3)
Gross liability of liability derivatives not designated as accounting hedging instruments	(8)	(3)
Guaranteed accumulation benefits | Contractholder funds.
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	1,085	1,067
Fair value, net of liability derivatives not designated as accounting hedging instruments	(62)	(88)
Gross liability of liability derivatives not designated as accounting hedging instruments	(62)	(88)
Guaranteed withdrawal benefits | Contractholder funds.
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	737	739
Fair value, net of liability derivatives not designated as accounting hedging instruments	(31)	(47)
Gross liability of liability derivatives not designated as accounting hedging instruments	(31)	(47)
Equity-indexed and forward starting options in life and annuity product contracts | Contractholder funds.
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	4,432	4,694
Fair value, net of liability derivatives not designated as accounting hedging instruments	(528)	(515)
Gross liability of liability derivatives not designated as accounting hedging instruments	(528)	(515)
Credit Default Swaps - Buying Protection | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	121	299
Fair value, net of asset derivatives not designated as accounting hedging instruments	(1)	(5)
Gross asset of asset derivatives not designated as accounting hedging instruments	1	2
Gross liability of asset derivatives not designated as accounting hedging instruments	(2)	(7)
Credit Default Swaps - Buying Protection | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	1,020	1,127
Fair value, net of liability derivatives not designated as accounting hedging instruments	(10)	(13)
Gross asset of liability derivatives not designated as accounting hedging instruments	5	6
Gross liability of liability derivatives not designated as accounting hedging instruments	(15)	(19)
Credit Default Swaps - Selling Protection | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	60	150
Fair value, net of asset derivatives not designated as accounting hedging instruments	(1)	(8)
Gross asset of asset derivatives not designated as accounting hedging instruments	1	2
Gross liability of asset derivatives not designated as accounting hedging instruments	(2)	(10)
Credit Default Swaps - Selling Protection | Other liabilities and accrued expenses
Derivatives, Fair Value
Notional amount of liability derivatives not designated as accounting hedging instruments	605	482
Fair value, net of liability derivatives not designated as accounting hedging instruments	(54)	(66)
Gross asset of liability derivatives not designated as accounting hedging instruments	2	1
Gross liability of liability derivatives not designated as accounting hedging instruments	(56)	(67)
Other contracts | Other investments.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	6	13
Other contracts | Other assets.
Derivatives, Fair Value
Notional amount of asset derivatives not designated as accounting hedging instruments	5	5
Fair value, net of asset derivatives not designated as accounting hedging instruments	1	1
Gross asset of asset derivatives not designated as accounting hedging instruments	$ 1	$ 1