Derivative Financial Instruments and Off-balance sheet Financial Instruments (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Effective portion
(Loss) gain recognized in OCI on derivatives during the period	$ (6)	$ 4	$ 3
Loss recognized in OCI on derivatives during the term of the hedging relationship	(22)	(17)	(22)
(Loss) gain reclassified from AOCI into income (realized capital gains and losses)	(1)	(1)	2
Cash flow hedge losses to be reclassified from AOCI during the next twelve months	1
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives	(1)	(47)	(139)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	277	(454)	(471)
Total gain (loss) recognized in net income on derivatives	276	(501)	(610)
Net investment income
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives	(1)	(2)	(139)
Total gain (loss) recognized in net income on derivatives	(1)	(2)	(139)
Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(8)	7
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	24	(388)	(608)
Total gain (loss) recognized in net income on derivatives	24	(396)	(601)
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	36	(32)	(28)
Total gain (loss) recognized in net income on derivatives	36	(32)	(28)
Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(37)	(7)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	193	(33)	150
Total gain (loss) recognized in net income on derivatives	193	(70)	143
Operating costs and expenses
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	24	(1)	15
Total gain (loss) recognized in net income on derivatives	24	(1)	15
Interest rate contracts
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives	(1)	(15)	(119)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(1)	(304)	(496)
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)	(2)	(139)
Interest rate contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(8)	9
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	(1)	(304)	(496)
Interest rate contracts | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(5)	11
Equity and index contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	69	(48)	40
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	(4)	(43)	(91)
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	56	(2)	113
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	17	(3)	18
Embedded derivative financial instruments
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	191	(107)	3
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	21	(37)	(3)
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	36	(32)	(28)
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	134	(38)	34
Foreign currency contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	6	(10)	(13)
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)	(12)	(10)
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	2	(3)
Credit default swaps
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	9	8	(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	9	8	(8)
Other contracts
Derivative Instruments, Gain (Loss)
Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives	3	7	3
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	3	7	3
Foreign currency and interest rate contracts
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		(32)	(20)
Foreign currency and interest rate contracts | Realized capital gains and losses
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives			(2)
Foreign currency and interest rate contracts | Interest credited to contractholder funds
Derivative Instruments, Gain (Loss)
Derivatives in fair value accounting hedging relationships, total gain (loss) recognized in net income on derivatives		$ (32)	$ (18)