Derivative Instruments (Outstanding Derivative Instruments With Off-Balance-Sheet Risks) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	$ 68,490		$ 61,110
Asset Carrying or Fair Value	3,022		3,547
Liability Carrying or Fair Value	2,015		2,762
Cash Flow Hedges [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	3,626		3,634
Asset Carrying or Fair Value	533		501
Liability Carrying or Fair Value	219		250
Derivative investments [Member] | Cash Flow Hedges [Member] | Interest Rate Contract [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	3,094	[1]	3,214	[1]
Asset Carrying or Fair Value	487	[1]	462	[1]
Liability Carrying or Fair Value	197	[1]	224	[1]
Derivative investments [Member] | Cash Flow Hedges [Member] | Foreign Exchange Contract [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	532	[1]	420	[1]
Asset Carrying or Fair Value	46	[1]	39	[1]
Liability Carrying or Fair Value	22	[1]	26	[1]
Derivative investments [Member] | Fair Value Hedges [Member] | Interest Rate Contract [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	875	[1]	875	[1]
Asset Carrying or Fair Value	227	[1]	269	[1]
Derivative investments [Member] | Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member] | Interest Rate Contract [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	43,609	[1]	36,539	[1]
Asset Carrying or Fair Value	845	[1]	1,042	[1]
Liability Carrying or Fair Value	466	[1]	475	[1]
Derivative investments [Member] | Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member] | Foreign Exchange Contract [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	230	[1]	48	[1]
Derivative investments [Member] | Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member] | Equity Market Contract [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	19,993	[1]	19,857	[1]
Asset Carrying or Fair Value	1,417	[1]	1,734	[1]
Liability Carrying or Fair Value	69	[1]	170	[1]
Derivative investments [Member] | Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member] | Equity Collar [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	9	[1]	9	[1]
Asset Carrying or Fair Value			1	[1]
Other Liabilities [Member] | Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member] | Credit Risk Contract [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	148	[2]	148	[2]
Liability Carrying or Fair Value	10	[2]	11	[2]
Future contract benefits [Member] | Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member] | Indexed Annuity Contracts Embedded Derivatives [Member]
Outstanding derivative instruments with off-balance-sheet risks
Liability Carrying or Fair Value	853	[3]	732	[3]
Future contract benefits [Member] | Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member] | GLB Embedded Derivative Reserves [Member]
Outstanding derivative instruments with off-balance-sheet risks
Liability Carrying or Fair Value	199	[3]	909	[3]
Reinsurance Related Embedded Derivatives [Member] | Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member] | Reinsurance Related [Member]
Outstanding derivative instruments with off-balance-sheet risks
Liability Carrying or Fair Value	$ 199	[4]	$ 215	[4]

[1] Reported in derivative investments on our Consolidated Balance Sheets.

[2] Reported in other liabilities on our Consolidated Balance Sheets.

[3] Reported in future contract benefits on our Consolidated Balance Sheets.

[4] Reported in reinsurance related embedded derivatives on our Consolidated Balance Sheets.