Investments (Maturities of Fixed Maturity Securities) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, Due in one year or less	$ 13,648	$ 24,177
Amortized Cost, Due after one year through five years	72,766	66,973
Amortized Cost, Due after five years through ten years	77,195	82,376
Amortized Cost, Due after ten years	102,431	97,739
Amortized Cost, Subtotal	266,040	271,265
Amortized Cost, RMBS, CMBS and ABS	64,860	69,605
Amortized cost of fixed maturity securities available-for-sale	330,900	340,870
Estimated Fair Value, Due in one year or less	13,890	24,394
Estimated Fair Value, Due after one year through five years	76,296	70,759
Estimated Fair Value, Due after five years through ten years	82,484	91,975
Estimated Fair Value, Due after ten years	109,582	114,533
Estimated Fair Value, Subtotal	282,252	301,661
Estimated fair value, Mortgage-backed and asset-backed securities	66,535	72,605
Fixed maturity securities available-for-sale, at estimated fair value (amortized cost: $330,900 and $340,870, respectively; includes $3,940 and $3,378, respectively, relating to variable interest entities)	$ 348,787	$ 374,266