Fair Value Measurements (Financial Instruments Measured At Fair Value Using Significant Unobservable Inputs) (Details) (USD $) In Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Dec. 31, 2010	Jun. 30, 2010	Dec. 31, 2009
Available-For-Sale Debt Securities [Member] | Foreign [Member]
Fair Value Measurements [Line Items]
Balance-Beginning of Period, Assets	$ 27		$ 28		$ 26		$ 59
Transfers into Level 3, Assets					9
Transfers into (out of) Level 3			1				(30)
Transfers out of Level 3, Assets	(11)				(18)
Changes in Net Unrealized Gains (Losses) included in OCI, Assets			(1)		(1)
Net Realized Gains/Losses, Assets	(1)		1
Purchases, Sales, Issuances, and Settlements, Net, Assets			2				2
Sales, Assets					(3)
Purchases, Assets	1				6
Issuances, Assets
Settlements, Assets					(3)
Balance-End of Period, Assets	16		31		16		31
Available-For-Sale Debt Securities [Member] | Corporate Securities [Member]
Fair Value Measurements [Line Items]
Balance-Beginning of Period, Assets	142		121		115		168
Transfers into Level 3, Assets					34
Transfers into (out of) Level 3							(35)
Transfers out of Level 3, Assets					(4)
Changes in Net Unrealized Gains (Losses) included in OCI, Assets	(6)		3		(5)		9
Net Realized Gains/Losses, Assets			1		(2)
Purchases, Sales, Issuances, and Settlements, Net, Assets			34				17
Sales, Assets	(3)				(23)
Purchases, Assets	1				23
Issuances, Assets
Settlements, Assets	(9)				(13)
Balance-End of Period, Assets	125		159		125		159
Available-For-Sale Debt Securities [Member] | Mortgage-Backed Securities [Member]
Fair Value Measurements [Line Items]
Balance-Beginning of Period, Assets	34				39		21			12
Transfers into Level 3, Assets					4
Transfers out of Level 3, Assets	(13)				(48)
Changes in Net Unrealized Gains (Losses) included in OCI, Assets
Purchases, Sales, Issuances, and Settlements, Net, Assets							(9)
Sales, Assets	(2)				(17)
Purchases, Assets					46
Issuances, Assets
Settlements, Assets	(1)				(6)
Balance-End of Period, Assets	18		12		18		12			12
Available-For-Sale Debt Securities [Member] | States, Municipalities, And Political Subdivisions [Member]
Fair Value Measurements [Line Items]
Balance-Beginning of Period, Assets	1		3		2		3
Transfers into Level 3, Assets
Changes in Net Unrealized Gains (Losses) included in OCI, Assets
Purchases, Sales, Issuances, and Settlements, Net, Assets			(1)				(1)
Issuances, Assets
Settlements, Assets					(1)
Balance-End of Period, Assets	1		2		1		2
Guaranteed Minimum Death Benefits [Member]
Fair Value Measurements [Line Items]
Reported liabilities	179				179				185
Guaranteed Minimum Income Benefit [Member]
Fair Value Measurements [Line Items]
Reported liabilities	1,635		758		1,635		758		648	776	559
Guaranteed Minimum Benefits Fair Value Derivative Adjustment In Liability	1,476		623		1,476		623		507	648	443
Balance-Beginning of Period, Liabilities	524	[1]	648	[1]	507	[1]	443	[1]
Transfers into Level 3, Liabilities		[1]
Changes in Net Unrealized Gains (Losses) included in OCI, Liabilities		[1]
Net realized gains/losses, Liabilities	952	[1]	(25)	[1]	969	[1]	180	[1]
Issuances, Liabilities		[1]
Balance-End of Period, Liabilities	1,476	[1]	623	[1]	1,476	[1]	623	[1]
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Liabilities	952	[1]	(25)	[1]	969	[1]	180	[1]
Equity Securities [Member]
Fair Value Measurements [Line Items]
Balance-Beginning of Period, Assets	10		16		13		12
Transfers into Level 3, Assets
Changes in Net Unrealized Gains (Losses) included in OCI, Assets			3		(1)		3
Net Realized Gains/Losses, Assets					4		1
Purchases, Sales, Issuances, and Settlements, Net, Assets			(4)				(1)
Sales, Assets					(8)
Purchases, Assets					2
Issuances, Assets
Balance-End of Period, Assets	10		15		10		15
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets			(1)
Other Investments [Member]
Fair Value Measurements [Line Items]
Balance-Beginning of Period, Assets	1,680		1,227		1,432		1,149
Transfers into Level 3, Assets
Changes in Net Unrealized Gains (Losses) included in OCI, Assets	59		14		110		47
Net Realized Gains/Losses, Assets	(1)		6		(4)		(7)
Purchases, Sales, Issuances, and Settlements, Net, Assets			133				191
Sales, Assets					(55)
Purchases, Assets	85				418
Issuances, Assets
Settlements, Assets	(58)				(136)
Balance-End of Period, Assets	1,765		1,380		1,765		1,380
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	(1)				(4)
Other Derivative Instruments [Member]
Fair Value Measurements [Line Items]
Balance-Beginning of Period, Assets	4		14		4		14
Transfers into Level 3, Assets
Changes in Net Unrealized Gains (Losses) included in OCI, Assets
Net Realized Gains/Losses, Assets	5		(8)		6		4
Purchases, Sales, Issuances, and Settlements, Net, Assets							(12)
Issuances, Assets
Settlements, Assets	(1)				(2)
Balance-End of Period, Assets	8		6		8		6
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	$ 4		$ (8)		$ 4		$ 4

[1] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as future policy benefits in the consolidated balance sheets. Refer to Note 6 for additional information.