Derivative Financial Instruments (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 contract	Dec. 31, 2012 contract
Derivative Financial Instruments
Assumed recoveries under sale of credit protection	$ 0
Securities pledged in the form of margin deposits	4
Derivatives, Fair Value
Total asset derivatives, Notional amount	1,013	6,362
Total liability derivatives, Notional amount	6,666	7,697
Total derivatives, Notional amount	7,679	14,059
Total asset derivatives, Number of contracts	10,570	12,651
Total liability derivatives, Number of contracts	10,866	12,619
Total derivatives, Number of contracts	21,436	25,270
Total asset derivatives, Fair value, net	202	147
Asset derivatives, Gross asset	215	169
Asset derivatives, Gross liability	(13)	(22)
Derivative liabilities net amount on balance sheet	(680)	(645)
Total derivatives, Fair value, net	(478)	(498)
Liability derivatives, Gross asset	12	19
Liability derivatives, Gross liability	(692)	(664)
Number of stock warrants held by the company related to derivative contracts (in shares)	837,100	837,100
Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	997	6,346
Total liability derivatives, Notional amount	6,534	7,562
Total asset derivatives, Number of contracts	10,570	12,651
Total liability derivatives, Number of contracts	10,866	12,619
Total asset derivatives, Fair value, net	200	145
Asset derivatives, Gross asset	213	167
Asset derivatives, Gross liability	(13)	(22)
Derivative liabilities net amount on balance sheet	(664)	(626)
Liability derivatives, Gross asset	12	19
Liability derivatives, Gross liability	(676)	(645)
Interest rate swap agreements | Derivatives not designated as accounting hedging instruments | Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	700	5,541
Total asset derivatives, Fair value, net	3	19
Asset derivatives, Gross asset	4	28
Asset derivatives, Gross liability	(1)	(9)
Interest rate swap agreements | Derivatives not designated as accounting hedging instruments | Other liabilities and accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	685	1,185
Derivative liabilities net amount on balance sheet	8	16
Liability derivatives, Gross asset	8	18
Liability derivatives, Gross liability		(2)
Other contracts | Derivatives not designated as accounting hedging instruments | Other assets
Derivatives, Fair Value
Total asset derivatives, Notional amount	3	4
Total asset derivatives, Fair value, net	1	1
Asset derivatives, Gross asset	1	1
Foreign currency swap agreements | Derivatives designated as accounting hedging instruments | Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	16	16
Total asset derivatives, Fair value, net	2	2
Asset derivatives, Gross asset	2	2
Foreign currency swap agreements | Derivatives designated as accounting hedging instruments | Other liabilities and accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	132	135
Derivative liabilities net amount on balance sheet	(16)	(19)
Liability derivatives, Gross liability	(16)	(19)
Interest rate swaption agreements | Derivatives not designated as accounting hedging instruments | Other liabilities and accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount		250
Interest rate cap agreements | Derivatives not designated as accounting hedging instruments | Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	122	372
Total asset derivatives, Fair value, net	2	1
Asset derivatives, Gross asset	2	1
Interest rate cap agreements | Derivatives not designated as accounting hedging instruments | Other liabilities and accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	234	429
Derivative liabilities net amount on balance sheet	3	1
Liability derivatives, Gross asset	3	1
Financial futures contracts - Interest rate contracts | Derivatives not designated as accounting hedging instruments | Other assets
Derivatives, Fair Value
Total asset derivatives, Number of contracts		2
Financial futures contracts - Interest rate contracts | Derivatives not designated as accounting hedging instruments | Other liabilities and accrued expenses
Derivatives, Fair Value
Total asset derivatives, Number of contracts		357
Financial futures contracts - Equity and index contracts | Derivatives not designated as accounting hedging instruments | Other assets
Derivatives, Fair Value
Total asset derivatives, Number of contracts		249
Total asset derivatives, Fair value, net		2
Asset derivatives, Gross asset		2
Options and warrants | Derivatives not designated as accounting hedging instruments | Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	3	146
Total asset derivatives, Number of contracts	10,570	12,400
Total asset derivatives, Fair value, net	205	125
Asset derivatives, Gross asset	205	125
Options and futures | Derivatives not designated as accounting hedging instruments | Other liabilities and accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	81
Total liability derivatives, Number of contracts	10,866	12,262
Derivative liabilities net amount on balance sheet	(125)	(58)
Liability derivatives, Gross asset	1
Liability derivatives, Gross liability	(126)	(58)
Foreign currency forwards | Derivatives not designated as accounting hedging instruments | Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	46	44
Conversion options | Derivatives not designated as accounting hedging instruments | Fixed income securities
Derivatives, Fair Value
Total asset derivatives, Notional amount	5	5
Equity-indexed call options | Derivatives not designated as accounting hedging instruments | Fixed income securities
Derivatives, Fair Value
Total asset derivatives, Notional amount		90
Total asset derivatives, Fair value, net		9
Asset derivatives, Gross asset		9
Credit default swaps | Derivatives not designated as accounting hedging instruments | Fixed income securities
Derivatives, Fair Value
Total asset derivatives, Notional amount	12	12
Total asset derivatives, Fair value, net	(12)	(12)
Asset derivatives, Gross liability	(12)	(12)
Guaranteed accumulation benefits | Derivatives not designated as accounting hedging instruments | Contractholder funds
Derivatives, Fair Value
Total liability derivatives, Notional amount	734	820
Derivative liabilities net amount on balance sheet	(54)	(86)
Liability derivatives, Gross liability	(54)	(86)
Guaranteed withdrawal benefits | Derivatives not designated as accounting hedging instruments | Contractholder funds
Derivatives, Fair Value
Total liability derivatives, Notional amount	505	554
Derivative liabilities net amount on balance sheet	(19)	(39)
Liability derivatives, Gross liability	(19)	(39)
Equity-indexed and forward starting options in life and annuity product contracts | Derivatives not designated as accounting hedging instruments | Contractholder funds
Derivatives, Fair Value
Total liability derivatives, Notional amount	1,463	3,916
Derivative liabilities net amount on balance sheet	(205)	(419)
Liability derivatives, Gross liability	(205)	(419)
Equity-indexed and forward starting options in life and annuity product contracts | Derivatives not designated as accounting hedging instruments | Liabilities held for sale
Derivatives, Fair Value
Total liability derivatives, Notional amount	2,493
Derivative liabilities net amount on balance sheet	(249)
Liability derivatives, Gross liability	(249)
Other embedded derivative financial instruments | Derivatives not designated as accounting hedging instruments | Contractholder funds
Derivatives, Fair Value
Total liability derivatives, Notional amount	85	85
Derivative liabilities net amount on balance sheet	(5)	(9)
Liability derivatives, Gross liability	(5)	(9)
Credit default swaps - buying protection | Derivatives not designated as accounting hedging instruments | Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	21	32
Total asset derivatives, Fair value, net		(1)
Asset derivatives, Gross liability		(1)
Credit default swaps - buying protection | Derivatives not designated as accounting hedging instruments | Other liabilities and accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	154	193
Derivative liabilities net amount on balance sheet	(2)	(2)
Liability derivatives, Gross liability	(2)	(2)
Credit default swaps - selling protection | Derivatives not designated as accounting hedging instruments | Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	85	100
Total asset derivatives, Fair value, net	1	1
Asset derivatives, Gross asset	1	1
Credit default swaps - selling protection | Derivatives not designated as accounting hedging instruments | Other liabilities and accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	100	130
Derivative liabilities net amount on balance sheet	(16)	(30)
Liability derivatives, Gross liability	$ (16)	$ (30)