Derivative Financial Instruments (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 contract	Mar. 31, 2012	Dec. 31, 2012 contract
Derivative Financial Instruments
Cash flow hedge losses to be reclassified from AOCI during the next twelve months	$ 2
Hedge ineffectiveness in realized gains	0	0
Hedge ineffectiveness in realized losses	0	0
Effective portion
Gain (loss) recognized in OCI on derivatives during the period	3	(5)
Loss recognized in OCI on derivatives during the term of the hedging relationship	(19)	(21)
(Loss) gain reclassified from AOCI into income (realized capital gains and losses)		(1)
Derivative Instruments, Gain (Loss)
Total derivatives, Number of contracts	26,227		26,108
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(1)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	24	86
Total gain (loss) recognized in net income on derivatives	24	85
Fair value hedging | Derivatives designated as accounting hedging instruments
Derivative Instruments, Gain (Loss)
Total derivatives, Number of contracts	0
Net investment income
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(1)
Total gain (loss) recognized in net income on derivatives		(1)
Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(4)	22
Total gain (loss) recognized in net income on derivatives	(4)	22
Life and annuity contract benefits
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	26	31
Total gain (loss) recognized in net income on derivatives	26	31
Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(2)	17
Total gain (loss) recognized in net income on derivatives	(2)	17
Operating costs and expenses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	4	16
Total gain (loss) recognized in net income on derivatives	4	16
Interest rate contracts
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(1)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives		(1)
Interest rate contracts | Net investment income
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(1)
Interest rate contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives		(1)
Equity and index contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	40	63
Equity and index contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(9)	(3)
Equity and index contracts | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	38	53
Equity and index contracts | Operating costs and expenses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	11	13
Embedded derivative financial instruments
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(15)	8
Embedded derivative financial instruments | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(1)	15
Embedded derivative financial instruments | Life and annuity contract benefits
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	26	31
Embedded derivative financial instruments | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(40)	(38)
Foreign currency contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(6)	6
Foreign currency contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	1	3
Foreign currency contracts | Operating costs and expenses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(7)	3
Credit default swaps
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	5	8
Credit default swaps | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	5	8
Other contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives		2
Other contracts | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives		$ 2