Investments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Available-for-sale Securities [Abstract]
Amortized Cost	$ 340,870	$ 329,811
Cost or Amortized Cost	2,838	3,208
Gross Unrealized OTTI Loss	361	724	601
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	374,266	350,271
Equity securities	2,891	3,023
Fixed maturity securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	340,870	329,811
Gross Unrealized Gain	35,144	25,973
Gross Unrealized Temporary Loss	1,387	4,789
Gross Unrealized OTTI Loss	361	724
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	374,266	350,271
U.S. corporate securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	102,669	98,621
Gross Unrealized Gain	11,887	8,544
Gross Unrealized Temporary Loss	430	1,380
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	114,126	105,785
Foreign corporate securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	61,806	61,568
Gross Unrealized Gain	5,654	3,789
Gross Unrealized Temporary Loss	277	1,338
Gross Unrealized OTTI Loss	(1)	1
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	67,184	64,018
Foreign government debt securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	51,967	49,840
Gross Unrealized Gain	5,440	3,053
Gross Unrealized Temporary Loss	71	357
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	57,336	52,536
RMBS [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	35,666	42,092
Gross Unrealized Gain	2,477	2,281
Gross Unrealized Temporary Loss	315	1,033
Gross Unrealized OTTI Loss	349	703
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	37,479	42,637
U.S. Treasury and agency securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	41,874	34,132
Gross Unrealized Gain	6,104	5,882
Gross Unrealized Temporary Loss	11	2
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	47,967	40,012
CMBS [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	18,177	18,565
Gross Unrealized Gain	1,009	730
Gross Unrealized Temporary Loss	57	218
Gross Unrealized OTTI Loss	0	8
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	19,129	19,069
ABS [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	15,762	13,018
Gross Unrealized Gain	404	278
Gross Unrealized Temporary Loss	156	305
Gross Unrealized OTTI Loss	13	12
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	15,997	12,979
State and political subdivision securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	12,949	11,975
Gross Unrealized Gain	2,169	1,416
Gross Unrealized Temporary Loss	70	156
Gross Unrealized OTTI Loss	0	0
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $340,870 and $329,811, respectively; includes $3,378 and $3,225, respectively, relating to variable interest entities)	15,048	13,235
Equity Securities [Member]
Available-for-sale Securities [Abstract]
Cost or Amortized Cost	2,838	3,208
Gross Unrealized Gain	212	114
Gross Unrealized Temporary Loss	159	299
Gross Unrealized OTTI Loss	0	0
Equity securities	2,891	3,023
Common Stock
Available-for-sale Securities [Abstract]
Cost or Amortized Cost	2,034	2,219
Gross Unrealized Gain	147	83
Gross Unrealized Temporary Loss	19	97
Gross Unrealized OTTI Loss	0	0
Equity securities	2,162	2,205
Non-redeemable preferred stock [Member]
Available-for-sale Securities [Abstract]
Cost or Amortized Cost	804	989
Gross Unrealized Gain	65	31
Gross Unrealized Temporary Loss	140	202
Gross Unrealized OTTI Loss	0	0
Equity securities	$ 729	$ 818