Fair Value of Financial Instruments (Fair Value Asets Liabilities Measured on Recurring Basis Level 3) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Future contract benefits:
GLB embedded derivative reserves	$ (909)	$ (2,217)
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	849	653
Sales	(58)	(339)
Maturities	(256)	(293)
Settlements	(179)	14
Calls	(7)	(91)
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	349	(56)
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3	83	274	(55)
Transfers Out of Level 3	(971)	(162)	(923)
Transfers In or Out of Level 3, Net	(888)	112	(978)
Corporate bonds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	364	237
Sales	(30)	(216)
Maturities	(6)	(16)
Settlements	(55)	(54)
Calls	(7)	(89)
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	266	(138)
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3	35	249	147
Transfers Out of Level 3	(691)	(83)	(197)
Transfers In or Out of Level 3, Net	(656)	166	(50)
U.S. government bonds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances		0
Sales		0
Maturities		0
Settlements		(1)
Calls		0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net		(1)
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3			3
Transfers Out of Level 3			0
Transfers In or Out of Level 3, Net	0	0	3
Foreign government bonds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	0	0
Sales	0	(2)
Maturities	(5)	0
Settlements	0	0
Calls	0	(1)
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	(5)	(3)
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3	0	0	17
Transfers Out of Level 3	(46)	(17)	0
Transfers In or Out of Level 3, Net	(46)	(17)	17
CMBS [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	0	0
Sales	0	(53)
Maturities	0	0
Settlements	(12)	(24)
Calls	0	(1)
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	(12)	(78)
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3	5	4	3
Transfers Out of Level 3	(7)	(1)	(121)
Transfers In or Out of Level 3, Net	(2)	3	(118)
RMBS [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	0	51
Sales	0	(1)
Maturities	(7)	0
Settlements	(1)	(15)
Calls	0	0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	(8)	35
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3	0		0
Transfers Out of Level 3	(147)		(4)
Transfers In or Out of Level 3, Net	(147)	0	(4)
CDOs [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	72	0
Sales	0	(33)
Maturities	0	0
Settlements	(11)	(39)
Calls	0	0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	61	(72)
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3	6
Transfers Out of Level 3	(21)
Transfers In or Out of Level 3, Net	(15)	0	0
CLNs [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3			0
Transfers Out of Level 3			(600)
Transfers In or Out of Level 3, Net			(600)
State and municipal bonds [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	32
Sales	0
Maturities	0
Settlements	0
Calls	0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	32
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In or Out of Level 3, Net	0
Hybrid and redeemable preferred securities [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances		9
Sales		(18)
Maturities		0
Settlements		0
Calls		0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net		(9)
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3	35	18
Transfers Out of Level 3	(40)	(21)
Transfers In or Out of Level 3, Net	(5)	(3)	0
Equity securities [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	26	19
Sales	0	(18)
Maturities	0	0
Settlements	0	0
Calls	0	0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	26	1
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3		2
Transfers Out of Level 3		(35)
Transfers In or Out of Level 3, Net	0	(33)	0
Trading securities [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	0	0
Sales	0	(3)
Maturities	0	0
Settlements	(2)	(5)
Calls	0	0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	(2)	(8)
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3	2	1	0
Transfers Out of Level 3	(19)	(5)	(1)
Transfers In or Out of Level 3, Net	(17)	(4)	(1)
Derivative investments [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	454	396
Sales	(28)	(2)
Maturities	(238)	(277)
Settlements	0	0
Calls	0	0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	188	117
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In or Out of Level 3, Net	0	0
Variable Interest Entities Liabilities - Derivative Instruments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In to Level 3			(225)
Transfers Out of Level 3			0
Transfers In or Out of Level 3, Net	0	0	(225)
Credit default swaps [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances		0
Sales		7
Maturities		0
Settlements		0
Calls		0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net		7
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In or Out of Level 3, Net	0	0	0
U.S. pension plan assets [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances		0
Sales		(22)
Maturities		(17)
Settlements		0
Calls		0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net		(39)
Indexed Annuity Contracts [Member]
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements [Abstract]
Issuances	(99)	(59)
Sales	0	0
Maturities	0	0
Settlements	(98)	152
Calls	0	0
Fair Value Investments Entities That Calculate Net Asset Value Per Share Unobservable Input Investment Holdings Movements Net	(197)	93
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In or Out of Level 3, Net	0	0	0
Guaranteed Living Benefits Embedded Derivative Reserves [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In or Out of Level 3, Net	0	0	0
Pension and Postretirement Benefit Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Transfers Into And Out Of Level 3 [Abstract]
Transfers In or Out of Level 3, Net		$ 0	$ 0