Investments (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Available-for-sale Securities [Abstract]
Amortized Cost	$ 332,981	$ 329,811
Cost or Amortized Cost	3,063	3,208
Gross Unrealized OTTI Loss	668	724	724	601
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	354,451	350,271
Equity securities	3,043	3,023
Fixed maturity securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	332,981	329,811
Gross Unrealized Gain	25,203	25,973
Gross Unrealized Temporary Loss	3,065	4,789
Gross Unrealized OTTI Loss	668	724
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	354,451	350,271
% of Total	100.00%	100.00%
U.S. corporate securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	97,827	98,621
Gross Unrealized Gain	8,327	8,544
Gross Unrealized Temporary Loss	881	1,380
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	105,273	105,785
% of Total	29.70%	30.20%
Foreign corporate securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	61,857	61,568
Gross Unrealized Gain	4,149	3,789
Gross Unrealized Temporary Loss	651	1,338
Gross Unrealized OTTI Loss	1	1
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	65,354	64,018
% of Total	18.40%	18.30%
Foreign government debt securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	52,086	49,840
Gross Unrealized Gain	3,428	3,053
Gross Unrealized Temporary Loss	176	357
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	55,338	52,536
% of Total	15.60%	15.00%
RMBS [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	40,487	42,092
Gross Unrealized Gain	2,243	2,281
Gross Unrealized Temporary Loss	805	1,033
Gross Unrealized OTTI Loss	646	703
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	41,279	42,637
% of Total	11.70%	12.20%
U.S. Treasury and agency securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	37,187	34,132
Gross Unrealized Gain	4,316	5,882
Gross Unrealized Temporary Loss	87	2
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	41,416	40,012
% of Total	11.70%	11.40%
CMBS [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	17,980	18,565
Gross Unrealized Gain	863	730
Gross Unrealized Temporary Loss	108	218
Gross Unrealized OTTI Loss	3	8
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	18,732	19,069
% of Total	5.30%	5.40%
ABS [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	13,132	13,018
Gross Unrealized Gain	273	278
Gross Unrealized Temporary Loss	244	305
Gross Unrealized OTTI Loss	18	12
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	13,143	12,979
% of Total	3.70%	3.70%
State and political subdivision securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	12,425	11,975
Gross Unrealized Gain	1,604	1,416
Gross Unrealized Temporary Loss	113	156
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $ 332,981 and $329,811 respectively; includes $3,296 and $3,225, respectively, relating to variable interest entities)	13,916	13,235
% of Total	3.90%	3.80%
Equity Securities [Member]
Available-for-sale Securities [Abstract]
Cost or Amortized Cost	3,063	3,208
Gross Unrealized Gain	157	114
Gross Unrealized Temporary Loss	177	299
Gross Unrealized OTTI Loss	0	0
Equity securities	3,043	3,023
% of Total	100.00%	100.00%
Common Stock
Available-for-sale Securities [Abstract]
Cost or Amortized Cost	2,155	2,219
Gross Unrealized Gain	109	83
Gross Unrealized Temporary Loss	22	97
Gross Unrealized OTTI Loss	0	0
Equity securities	2,242	2,205
% of Total	73.70%	72.90%
Non-redeemable preferred stock [Member]
Available-for-sale Securities [Abstract]
Cost or Amortized Cost	908	989
Gross Unrealized Gain	48	31
Gross Unrealized Temporary Loss	155	202
Gross Unrealized OTTI Loss	0	0
Equity securities	$ 801	$ 818
% of Total	26.30%	27.10%