Investments (Amortized Cost And Fair Values Of Securities) (Details) (USD $) In Millions	9 Months Ended	12 Months Ended
Sep. 30, 2011	Dec. 31, 2010
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	$ 38,079	$ 37,656
Gross Unrealized Gains	3,174	2,095
Gross Unrealized Losses	649	851
Estimated Fair Value	40,604	38,900
Unrealized OTTI Losses (Gains)	74	112
Available-For-Sale [Member] \| Fixed Maturity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	36,904	36,433
Gross Unrealized Gains	3,089	1,945
Gross Unrealized Losses	546	795
Estimated Fair Value	39,447	37,583
Unrealized OTTI Losses (Gains)	74	112
Available-For-Sale [Member] \| Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	316	422
Gross Unrealized Gains	21	27
Gross Unrealized Losses	10	9
Estimated Fair Value	327	440
Trading Securities [Member] \| Fixed Maturity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	240	244
Gross Unrealized Losses	7	13
Estimated Fair Value	233	231
Trading Securities [Member] \| Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost, Trading securities	619	557
Gross Unrealized Gains, Trading securities	64	123
Gross Unrealized Losses, Trading securities	86	34
Estimated Fair Value, Trading Securities	597	646
Residential Mortgage-Backed [Member] \| Fixed Maturity Securities [Member] \| Asset-Backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	5,812	6,255
Gross Unrealized Gains	199	101
Gross Unrealized Losses	161	265
Estimated Fair Value	5,850	6,091
Unrealized OTTI Losses (Gains)	82	114
Commercial Mortgage-Backed [Member] \| Fixed Maturity Securities [Member] \| Asset-Backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	1,255	994
Gross Unrealized Gains	55	40
Gross Unrealized Losses	61	41
Estimated Fair Value	1,249	993
Unrealized OTTI Losses (Gains)	(8)	(2)
Other Asset-Backed [Member] \| Fixed Maturity Securities [Member] \| Asset-Backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	1,035	753
Gross Unrealized Gains	15	18
Gross Unrealized Losses	14	8
Estimated Fair Value	1,036	763
Fixed Maturity Securities [Member] \| Asset-Backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	8,102	8,002
Gross Unrealized Gains	269	159
Gross Unrealized Losses	236	314
Estimated Fair Value	8,135	7,847
Unrealized OTTI Losses (Gains)	74	112
Asset-Backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	3,110
Gross Unrealized Losses	236
Estimated Fair Value	2,874
Fixed Maturity Securities [Member] \| U.S. Treasury And Obligations Of Government-Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	221	122
Gross Unrealized Gains	16	16
Gross Unrealized Losses		1
Estimated Fair Value	237	137
Common Stock [Member] \| Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	103	90
Gross Unrealized Gains	19	25
Gross Unrealized Losses	2
Estimated Fair Value	120	115
Preferred Stock [Member] \| Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	213	332
Gross Unrealized Gains	2	2
Gross Unrealized Losses	8	9
Estimated Fair Value	207	325
Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	935	979
Gross Unrealized Gains	85	150
Gross Unrealized Losses	96	43
Estimated Fair Value	924	1,086
States, Municipalities And Political Subdivisions [Member] \| Fixed Maturity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	8,834	8,157
Gross Unrealized Gains	853	142
Gross Unrealized Losses	150	410
Estimated Fair Value	9,537	7,889
Corporate And Other Bonds [Member] \| Fixed Maturity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	19,141	19,503
Gross Unrealized Gains	1,918	1,603
Gross Unrealized Losses	160	70
Estimated Fair Value	20,899	21,036
Fixed Maturity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	37,144	36,677
Gross Unrealized Gains	3,089	1,945
Gross Unrealized Losses	553	808
Estimated Fair Value	39,680	37,814
Unrealized OTTI Losses (Gains)	74	112
Fixed Maturity Securities [Member] \| Foreign Government [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	557	602
Gross Unrealized Gains	25	18
Estimated Fair Value	582	620
Fixed Maturity Securities [Member] \| Redeemable Preferred Stock [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	49	47
Gross Unrealized Gains	8	7
Estimated Fair Value	57	54
Corporate And Other Bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	$ 1,793

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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