Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Significant Unobservable Inputs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Corporate And Other Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	$ 624	$ 609
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(11)	9
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	(1)	56
Purchases, Assets	484
Sales, Assets	(204)
Settlements, Assets	(149)
Purchases, Sales, Issuances and Settlements, Assets		45
Transfers into Level 3, Assets	79	60
Transfers out of Level 3, Assets	(340)	(155)
Balance, December 31	482	624
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(12)	(4)
States, Municipalities And Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	266	756
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	(1)	15
Purchases, Assets	3
Settlements, Assets	(92)
Purchases, Sales, Issuances and Settlements, Assets		(507)
Transfers into Level 3, Assets		2
Transfers out of Level 3, Assets	(5)
Balance, December 31	171	266
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31
Residential Mortgage-Backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	767	629
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(16)	(10)
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	(11)	15
Purchases, Assets	225
Sales, Assets	(290)
Settlements, Assets	(60)
Purchases, Sales, Issuances and Settlements, Assets		181
Transfers into Level 3, Assets
Transfers out of Level 3, Assets	(163)	(48)
Balance, December 31	452	767
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(6)	(13)
Commercial Mortgage-Backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	73	123
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	20	10
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	(7)	13
Purchases, Assets	81
Sales, Assets	(27)
Settlements, Assets
Purchases, Sales, Issuances and Settlements, Assets		(8)
Transfers into Level 3, Assets		7
Transfers out of Level 3, Assets	(81)	(72)
Balance, December 31	59	73
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31		(2)
Other Asset-Backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	359	348
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(9)	6
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	5	30
Purchases, Assets	537
Sales, Assets	(341)
Settlements, Assets	(99)
Purchases, Sales, Issuances and Settlements, Assets		30
Transfers into Level 3, Assets	2
Transfers out of Level 3, Assets	(111)	(55)
Balance, December 31	343	359
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(5)	(1)
Asset-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	1,199	1,100
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(5)	6
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	(13)	58
Purchases, Assets	843
Sales, Assets	(658)
Settlements, Assets	(159)
Purchases, Sales, Issuances and Settlements, Assets		203
Transfers into Level 3, Assets	2	7
Transfers out of Level 3, Assets	(355)	(175)
Balance, December 31	854	1,199
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(11)	(16)
Redeemable Preferred Stock [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	3	2
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	3	6
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	(3)	2
Purchases, Assets
Sales, Assets	(3)
Settlements, Assets
Purchases, Sales, Issuances and Settlements, Assets		(7)
Transfers into Level 3, Assets
Transfers out of Level 3, Assets
Balance, December 31		3
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31
Fixed Maturities Available For Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	2,092	2,467
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(13)	21
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	(18)	131
Purchases, Assets	1,330
Sales, Assets	(865)
Settlements, Assets	(400)
Purchases, Sales, Issuances and Settlements, Assets		(266)
Transfers into Level 3, Assets	81	69
Transfers out of Level 3, Assets	(700)	(330)
Balance, December 31	1,507	2,092
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(23)	(20)
Fixed Maturities Trading [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	184	197
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(11)	9
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets
Purchases, Assets
Sales, Assets	(72)
Settlements, Assets
Purchases, Sales, Issuances and Settlements, Assets		(22)
Transfers into Level 3, Assets
Transfers out of Level 3, Assets
Balance, December 31	101	184
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(4)	5
Fixed Maturity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	2,276	2,664
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(24)	30
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	(18)	131
Purchases, Assets	1,330
Sales, Assets	(937)
Settlements, Assets	(400)
Purchases, Sales, Issuances and Settlements, Assets		(288)
Transfers into Level 3, Assets	81	69
Transfers out of Level 3, Assets	(700)	(330)
Balance, December 31	1,608	2,276
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(27)	(15)
Equity Securities Available For Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	26	11
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(2)	(4)
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	2	1
Purchases, Assets	66
Sales, Assets	(27)
Settlements, Assets
Purchases, Sales, Issuances and Settlements, Assets		17
Transfers into Level 3, Assets	5	8
Transfers out of Level 3, Assets	(3)	(7)
Balance, December 31	67	26
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(3)	(5)
Equity Securities Trading [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	6
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(7)	2
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets
Purchases, Assets	1
Settlements, Assets
Purchases, Sales, Issuances and Settlements, Assets		4
Transfers into Level 3, Assets	14
Transfers out of Level 3, Assets
Balance, December 31	14	6
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(7)	2
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	32	11
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	(9)	(2)
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets	2	1
Purchases, Assets	67
Sales, Assets	(27)
Settlements, Assets
Purchases, Sales, Issuances and Settlements, Assets		21
Transfers into Level 3, Assets	19	8
Transfers out of Level 3, Assets	(3)	(7)
Balance, December 31	81	32
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(10)	(3)
Short Term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	27
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets
Purchases, Assets	39
Settlements, Assets	(29)
Purchases, Sales, Issuances and Settlements, Assets		37
Transfers into Level 3, Assets		1
Transfers out of Level 3, Assets	(10)	(11)
Balance, December 31	27	27
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31
Other Invested Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	26
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	4
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets
Purchases, Assets
Sales, Assets	(19)
Settlements, Assets
Purchases, Sales, Issuances and Settlements, Assets		26
Transfers into Level 3, Assets
Transfers out of Level 3, Assets
Balance, December 31	11	26
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	1	(1)
Life Settlement Contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	129	130
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets	33	29
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets
Purchases, Assets
Settlements, Assets	(45)
Purchases, Sales, Issuances and Settlements, Assets		(30)
Transfers into Level 3, Assets
Transfers out of Level 3, Assets
Balance, December 31	117	129
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	5	10
Separate Account Business [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1	41	38
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets
Purchases, Assets
Sales, Assets	(6)
Settlements, Assets
Purchases, Sales, Issuances and Settlements, Assets		3
Transfers into Level 3, Assets
Transfers out of Level 3, Assets	(12)
Balance, December 31	23	41
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31
Discontinued Operations Investments, Included In Other Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, January 1		16
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Assets
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Assets		1
Purchases, Sales, Issuances and Settlements, Assets		(2)
Transfers into Level 3, Assets
Transfers out of Level 3, Assets		(15)
Balance, December 31
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31
Derivative Financial Instruments Net [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Purchases, Assets	9
Transfers into Level 3, Assets
Transfers out of Level 3, Assets
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	1
Balance, January 1, Liabilities	(21)	(48)
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in Net Income, Liabilities	(42)	(27)
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses) Included in OCI, Liabilities	(1)	16
Settlements, Liabilities	40
Purchases, Sales, Issuances and Settlements, Liabilities		38
Balance, December 31, Liabilities	$ (15)	$ (21)