Investments (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, Due in one year or less	$ 24,177	$ 16,747
Amortized Cost, Due after one year through five years	66,973	62,819
Amortized Cost, Due after five years through ten years	82,376	82,694
Amortized Cost, Due after ten years	97,739	93,876
Amortized Cost, Subtotal	271,265	256,136
Amortized Cost, RMBS, CMBS and ABS	69,605	73,675
Amortized cost of fixed maturity securities available-for-sale	340,870	329,811
Estimated Fair Value, Due in one year or less	24,394	16,862
Estimated Fair Value, Due after one year through five years	70,759	64,414
Estimated Fair Value, Due after five years through ten years	91,975	88,036
Estimated Fair Value, Due after ten years	114,533	106,274
Estimated Fair Value, Subtotal	301,661	275,586
Estimated fair value, Mortgage-backed and asset-backed securities	72,605	74,685
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