Derivative Financial Instruments (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014 contract	Dec. 31, 2013 contract
Derivative Financial Instruments
Assumed recoveries under sale of credit protection	$ 0
Cash and securities pledged in the form of margin deposits	43
Derivatives, Fair Value
Total asset derivatives, Notional amount	1,344	2,784
Total liability derivatives, Notional amount	4,553	11,219
Total derivatives, Notional amount	5,897	14,003
Total asset derivatives, Number of contracts	4,761	12,017
Total liability derivatives, Number of contracts	4,136	10,035
Total derivatives, Number of contracts	8,897	22,052
Derivative assets net amount on balance sheet	76	267
Asset derivatives, Gross asset	76	279
Asset derivatives, Gross liability		(12)
Total liability derivatives, Fair value, net	(373)	(746)
Total derivatives, Fair value, net	(297)	(479)
Liability derivatives, Gross asset	10	15
Liability derivatives, Gross liability	(383)	(761)
Number of stock rights and warrants held by the company related to derivative contracts (in shares)	220	1,238,580
Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	1,328	2,768
Total liability derivatives, Notional amount	4,434	11,087
Total asset derivatives, Number of contracts	4,761	12,017
Total liability derivatives, Number of contracts	4,136	10,035
Derivative assets net amount on balance sheet	74	266
Asset derivatives, Gross asset	74	278
Asset derivatives, Gross liability		(12)
Total liability derivatives, Fair value, net	(367)	(731)
Liability derivatives, Gross asset	10	15
Liability derivatives, Gross liability	(377)	(746)
Interest rate swap agreements | Other liabilities and accrued expenses | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	85	85
Total liability derivatives, Fair value, net	3	4
Liability derivatives, Gross asset	3	4
Foreign currency swap agreements | Other investments | Derivatives designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	16	16
Derivative assets net amount on balance sheet	2	1
Asset derivatives, Gross asset	2	1
Foreign currency swap agreements | Other liabilities and accrued expenses | Derivatives designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	119	132
Total liability derivatives, Fair value, net	(6)	(15)
Liability derivatives, Gross liability	(6)	(15)
Interest rate swaption agreements | Other investments | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount		1,420
Interest rate swaption agreements | Other liabilities and accrued expenses | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount		4,570
Total liability derivatives, Fair value, net		1
Liability derivatives, Gross asset		1
Interest rate cap agreements | Other investments | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	95	61
Derivative assets net amount on balance sheet		2
Asset derivatives, Gross asset		2
Interest rate cap agreements | Other liabilities and accrued expenses | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	90	262
Total liability derivatives, Fair value, net	2	4
Liability derivatives, Gross asset	2	4
Financial futures contracts - Interest rate contracts | Other assets | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Number of contracts	50	550
Options | Other liabilities and accrued expenses | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount		55
Total liability derivatives, Number of contracts		10,035
Total liability derivatives, Fair value, net		(165)
Liability derivatives, Gross asset		2
Liability derivatives, Gross liability		(167)
Options and futures | Other liabilities and accrued expenses | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Number of contracts	4,136
Total liability derivatives, Fair value, net	(21)
Liability derivatives, Gross liability	(21)
Options and warrants | Other investments | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount		3
Total asset derivatives, Number of contracts	2,932	10,035
Derivative assets net amount on balance sheet	65	263
Asset derivatives, Gross asset	65	263
Financial futures contracts - Equity and index contracts | Other assets | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Number of contracts	1,779	1,432
Derivative assets net amount on balance sheet		1
Asset derivatives, Gross asset		1
Foreign currency forwards | Other investments | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	82	161
Derivative assets net amount on balance sheet	6	10
Asset derivatives, Gross asset	6	10
Foreign currency forwards | Other liabilities and accrued expenses | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	608	148
Total liability derivatives, Fair value, net	(13)	(3)
Liability derivatives, Gross asset	3	2
Liability derivatives, Gross liability	(16)	(5)
Credit default swaps | Fixed income securities | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount		12
Derivative assets net amount on balance sheet		(12)
Asset derivatives, Gross liability		(12)
Guaranteed accumulation benefits | Contractholder funds | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	650	738
Total liability derivatives, Fair value, net	(36)	(43)
Liability derivatives, Gross liability	(36)	(43)
Guaranteed withdrawal benefits | Contractholder funds | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	453	506
Total liability derivatives, Fair value, net	(13)	(13)
Liability derivatives, Gross liability	(13)	(13)
Equity-indexed and forward starting options in life and annuity product contracts | Contractholder funds | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	1,773	1,693
Total liability derivatives, Fair value, net	(269)	(247)
Liability derivatives, Gross liability	(269)	(247)
Equity-indexed and forward starting options in life and annuity product contracts | Liabilities held for sale | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount		2,363
Total liability derivatives, Fair value, net		(246)
Liability derivatives, Gross liability		(246)
Other embedded derivative financial instruments | Other investments | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	1,000	1,000
Other embedded derivative financial instruments | Contractholder funds | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	85	85
Total liability derivatives, Fair value, net	(3)	(4)
Liability derivatives, Gross liability	(3)	(4)
Credit Default Swaps - Buying Protection | Other investments | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	33	2
Credit Default Swaps - Buying Protection | Other liabilities and accrued expenses | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	500	397
Total liability derivatives, Fair value, net	(9)	(6)
Liability derivatives, Gross asset	1
Liability derivatives, Gross liability	(10)	(6)
Credit Default Swaps - Selling Protection | Other investments | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	115	105
Derivative assets net amount on balance sheet	2	2
Asset derivatives, Gross asset	2	2
Credit Default Swaps - Selling Protection | Other liabilities and accrued expenses | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total liability derivatives, Notional amount	190	185
Total liability derivatives, Fair value, net	(8)	(13)
Liability derivatives, Gross asset	1	2
Liability derivatives, Gross liability	(9)	(15)
Other contracts | Other assets | Derivatives not designated as accounting hedging instruments
Derivatives, Fair Value
Total asset derivatives, Notional amount	3	4
Derivative assets net amount on balance sheet	1
Asset derivatives, Gross asset	$ 1