Investments (Details 16) (USD $) In Millions, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Total number of securities in an unrealized loss position less than 12 months	4,834	5,609
Total number of securities in an unrealized loss position equal to or greater than 12 months	1,351	1,704
Gross Unrealized Loss	$ 115	$ 241
Fixed maturity securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	77,453	104,579
Less than 12 Months Gross Unrealized Loss	2,291	2,501
Equal to or Greater than 12 Months Estimated Fair Value	19,065	24,679
Equal to or Greater than 12 Months Gross Unrealized Loss	3,046	4,079
Total Estimated Fair Value	96,518	129,258
Total Gross Unrealized Loss	5,337	6,580
U.S. corporate securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	15,021	22,954
Less than 12 Months Gross Unrealized Loss	289	447
Equal to or Greater than 12 Months Estimated Fair Value	6,662	8,319
Equal to or Greater than 12 Months Gross Unrealized Loss	835	1,155
Total Estimated Fair Value	21,683	31,273
Total Gross Unrealized Loss	1,124	1,602
RMBS [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	5,742	7,588
Less than 12 Months Gross Unrealized Loss	159	212
Equal to or Greater than 12 Months Estimated Fair Value	5,540	6,700
Equal to or Greater than 12 Months Gross Unrealized Loss	1,006	1,175
Total Estimated Fair Value	11,282	14,288
Total Gross Unrealized Loss	1,165	1,387
U.S. Treasury, agency and government guaranteed securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	11,586	13,401
Less than 12 Months Gross Unrealized Loss	562	530
Equal to or Greater than 12 Months Estimated Fair Value	108	118
Equal to or Greater than 12 Months Gross Unrealized Loss	26	29
Total Estimated Fair Value	11,694	13,519
Total Gross Unrealized Loss	588	559
ABS [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	2,212	2,713
Less than 12 Months Gross Unrealized Loss	22	42
Equal to or Greater than 12 Months Estimated Fair Value	2,723	3,026
Equal to or Greater than 12 Months Gross Unrealized Loss	533	667
Total Estimated Fair Value	4,935	5,739
Total Gross Unrealized Loss	555	709
Other fixed maturity securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	2	1
Less than 12 Months Gross Unrealized Loss	0	0
Equal to or Greater than 12 Months Estimated Fair Value	0	0
Equal to or Greater than 12 Months Gross Unrealized Loss	0	0
Total Estimated Fair Value	2	1
Total Gross Unrealized Loss	0	0
State and political subdivision securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	2,684	5,061
Less than 12 Months Gross Unrealized Loss	96	246
Equal to or Greater than 12 Months Estimated Fair Value	1,000	988
Equal to or Greater than 12 Months Gross Unrealized Loss	232	272
Total Estimated Fair Value	3,684	6,049
Total Gross Unrealized Loss	328	518
CMBS [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	1,606	3,787
Less than 12 Months Gross Unrealized Loss	32	29
Equal to or Greater than 12 Months Estimated Fair Value	926	1,363
Equal to or Greater than 12 Months Gross Unrealized Loss	138	249
Total Estimated Fair Value	2,532	5,150
Total Gross Unrealized Loss	170	278
Equity Securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	270	280
Less than 12 Months Gross Unrealized Loss	17	21
Equal to or Greater than 12 Months Estimated Fair Value	485	825
Equal to or Greater than 12 Months Gross Unrealized Loss	98	220
Total Estimated Fair Value	755	1,105
Gross Unrealized Loss	(115)	(241)
Common stock [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	96	89
Less than 12 Months Gross Unrealized Loss	11	12
Equal to or Greater than 12 Months Estimated Fair Value	23	1
Equal to or Greater than 12 Months Gross Unrealized Loss	0	0
Total Estimated Fair Value	119	90
Total Gross Unrealized Loss	11	12
Gross Unrealized Loss	(11)	(12)
Foreign corporate securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	17,137	22,415
Less than 12 Months Gross Unrealized Loss	592	410
Equal to or Greater than 12 Months Estimated Fair Value	1,953	3,976
Equal to or Greater than 12 Months Gross Unrealized Loss	265	515
Total Estimated Fair Value	19,090	26,391
Total Gross Unrealized Loss	857	925
Foreign government debt securities [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	21,463	26,659
Less than 12 Months Gross Unrealized Loss	539	585
Equal to or Greater than 12 Months Estimated Fair Value	153	189
Equal to or Greater than 12 Months Gross Unrealized Loss	11	17
Total Estimated Fair Value	21,616	26,848
Total Gross Unrealized Loss	550	602
Non-redeemable preferred stock [Member]
Continuous Gross Unrealized Loss and OTTI Loss for Fixed Maturity and Equity Securities Available-for-Sale
Less than 12 months Estimated Fair Value	174	191
Less than 12 Months Gross Unrealized Loss	6	9
Equal to or Greater than 12 Months Estimated Fair Value	462	824
Equal to or Greater than 12 Months Gross Unrealized Loss	98	220
Total Estimated Fair Value	636	1,015
Total Gross Unrealized Loss	104	229
Gross Unrealized Loss	$ (104)	$ (229)