Derivative Financial Instruments and Off-balance sheet Financial Instruments (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014 item	Dec. 31, 2013 item
Derivative Financial Instruments and Off-balance sheet Financial Instruments
Assumed recoveries under sale of credit protection	$ 0
Securities pledged in the form of margin deposits	30us-gaap_MarginDepositAssets
Derivatives, Fair Value
Total asset derivatives, Notional amount	407us-gaap_DerivativeAssetNotionalAmount	1,649us-gaap_DerivativeAssetNotionalAmount
Total liability derivatives, Notional amount	3,242	10,760
Total derivatives, Notional amount	3,649invest_DerivativeNotionalAmount	12,409invest_DerivativeNotionalAmount
Total asset derivatives, Number of contracts	3,929	10,662
Total liability derivatives, Number of contracts	3,331	10,035
Total derivatives, Number of contracts	7,260	20,697
Total asset derivatives, Fair value, net	92us-gaap_DerivativeAssets	254us-gaap_DerivativeAssets
Asset derivatives, Gross asset	92	266
Asset derivatives, Gross liability	0	(12)
Derivative liabilities net amount on balance sheet	(354)us-gaap_DerivativeLiabilities	(741)us-gaap_DerivativeLiabilities
Total derivatives, Fair value, net	(262)	(487)
Liability derivatives, Gross asset	2	11
Liability derivatives, Gross liability	(356)	(752)
Number of stock warrants held by the company related to derivative contracts (in shares)		837,100all_DerivativesWarrantsOutstanding
Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	322	1,633
Total liability derivatives, Notional amount	3,192	10,628
Total asset derivatives, Number of contracts	3,929	10,662
Total liability derivatives, Number of contracts	3,331	10,035
Total asset derivatives, Fair value, net	89	253
Asset derivatives, Gross asset	89	265
Asset derivatives, Gross liability	0	(12)
Derivative liabilities net amount on balance sheet	(353)	(726)
Liability derivatives, Gross asset	2	11
Liability derivatives, Gross liability	(355)	(737)
Foreign currency swap agreements \| Derivatives designated as accounting hedging instruments \| Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	85	16
Total asset derivatives, Fair value, net	3	1
Asset derivatives, Gross asset	3	1
Asset derivatives, Gross liability	0	0
Foreign currency swap agreements \| Derivatives designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	50	132
Derivative liabilities net amount on balance sheet	(1)	(15)
Liability derivatives, Gross asset	0	0
Liability derivatives, Gross liability	(1)	(15)
Interest rate swaption agreements \| Derivatives not designated as accounting hedging instruments \| Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount		1,420
Total asset derivatives, Fair value, net		0
Asset derivatives, Gross asset		0
Asset derivatives, Gross liability		0
Interest rate swaption agreements \| Derivatives not designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount		4,570
Derivative liabilities net amount on balance sheet		1
Liability derivatives, Gross asset		1
Liability derivatives, Gross liability		0
Interest rate cap agreements \| Derivatives not designated as accounting hedging instruments \| Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	163	61
Total asset derivatives, Fair value, net	2	2
Asset derivatives, Gross asset	2	2
Asset derivatives, Gross liability	0	0
Interest rate cap agreements \| Derivatives not designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	11	262
Derivative liabilities net amount on balance sheet	0	4
Liability derivatives, Gross asset	0	4
Liability derivatives, Gross liability	0	0
Interest rate swap agreements \| Derivatives not designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	85	85
Derivative liabilities net amount on balance sheet	1	4
Liability derivatives, Gross asset	1	4
Liability derivatives, Gross liability	0	0
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	0
Asset derivatives, Gross asset	1	0
Asset derivatives, Gross liability	0	0
Options and warrants \| Derivatives not designated as accounting hedging instruments \| Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	0	3
Total asset derivatives, Number of contracts	3,225	10,035
Total asset derivatives, Fair value, net	83	261
Asset derivatives, Gross asset	83	261
Asset derivatives, Gross liability	0	0
Financial futures contracts - Equity and index contracts \| Derivatives not designated as accounting hedging instruments \| Other assets
Derivatives, Fair Value
Total asset derivatives, Notional amount	0
Total asset derivatives, Number of contracts	704	627
Total asset derivatives, Fair value, net	1	0
Asset derivatives, Gross asset	1	0
Asset derivatives, Gross liability	0	0
Financial futures contracts - Equity and index contracts \| Derivatives not designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Number of contracts	200
Foreign currency forwards \| Derivatives not designated as accounting hedging instruments \| Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	57	47
Total asset derivatives, Fair value, net	0	0
Asset derivatives, Gross asset	0	0
Asset derivatives, Gross liability	0	0
Foreign currency forwards \| Derivatives not designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	36
Derivative liabilities net amount on balance sheet	1
Liability derivatives, Gross asset	1
Liability derivatives, Gross liability	0
Options and futures \| Derivatives not designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	0	55
Total liability derivatives, Number of contracts	3,131	10,035
Derivative liabilities net amount on balance sheet	(22)	(165)
Liability derivatives, Gross asset	0	2
Liability derivatives, Gross liability	(22)	(167)
Credit default swaps \| Derivatives not designated as accounting hedging instruments \| Fixed income securities
Derivatives, Fair Value
Total asset derivatives, Notional amount		12
Total asset derivatives, Fair value, net		(12)
Asset derivatives, Gross asset		0
Asset derivatives, Gross liability		(12)
Guaranteed accumulation benefits \| Derivatives not designated as accounting hedging instruments \| Contractholder funds
Derivatives, Fair Value
Total liability derivatives, Notional amount	615	738
Derivative liabilities net amount on balance sheet	(32)	(43)
Liability derivatives, Gross asset	0	0
Liability derivatives, Gross liability	(32)	(43)
Guaranteed withdrawal benefits \| Derivatives not designated as accounting hedging instruments \| Contractholder funds
Derivatives, Fair Value
Total liability derivatives, Notional amount	425	506
Derivative liabilities net amount on balance sheet	(13)	(13)
Liability derivatives, Gross asset	0	0
Liability derivatives, Gross liability	(13)	(13)
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	1,786	1,693
Derivative liabilities net amount on balance sheet	(278)	(247)
Liability derivatives, Gross asset	0	0
Liability derivatives, Gross liability	(278)	(247)
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		2,363
Derivative liabilities net amount on balance sheet		(246)
Liability derivatives, Gross asset		0
Liability derivatives, Gross liability		(246)
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	0	(4)
Liability derivatives, Gross asset	0	0
Liability derivatives, Gross liability	0	(4)
Credit default swaps - buying protection \| Derivatives not designated as accounting hedging instruments \| Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	19	1
Total asset derivatives, Fair value, net	0	0
Asset derivatives, Gross asset	0	0
Asset derivatives, Gross liability	0	0
Credit default swaps - buying protection \| Derivatives not designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	49	171
Derivative liabilities net amount on balance sheet	(1)	(2)
Liability derivatives, Gross asset	0	0
Liability derivatives, Gross liability	(1)	(2)
Credit default swaps – selling protection \| Derivatives not designated as accounting hedging instruments \| Other investments
Derivatives, Fair Value
Total asset derivatives, Notional amount	80	85
Total asset derivatives, Fair value, net	2	2
Asset derivatives, Gross asset	2	2
Asset derivatives, Gross liability	0	0
Credit default swaps – selling protection \| Derivatives not designated as accounting hedging instruments \| Other liabilities & accrued expenses
Derivatives, Fair Value
Total liability derivatives, Notional amount	100	100
Derivative liabilities net amount on balance sheet	(9)	(15)
Liability derivatives, Gross asset	0	0
Liability derivatives, Gross liability	$ (9)	$ (15)

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The number of stock warrants held by the company as of the balance sheet date which are related to derivative contracts.

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Represents the potential amount of recoveries under sale of credit protection.

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Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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Nominal or face amount used to calculate payments on the derivative asset.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Nominal or face amount used to calculate payments on the derivative liability.

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The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.

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