Derivative Instruments - Credit Derivatives, Protection Sold, Notional and Fair Value (Details 4b) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Protection sold credit derivatives and credit related notes ratings/maturity profile
Protection sold credit derivatives and credit related notes ratings/maturity profile - less than one year	$ (624,697)	$ (594,038)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from one to five years	(2,105,759)	(1,852,097)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than five years	(290,726)	(473,810)
Total notional amount	(3,021,182)	(2,919,945)
Fair value	(20,163)	(121,980)
Investment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Protection sold credit derivatives and credit related notes ratings/maturity profile - less than one year	(409,748)	(352,215)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from one to five years	(1,383,644)	(1,262,143)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than five years	(224,001)	(345,996)
Total notional amount	(2,017,393)	(1,960,354)
Fair value	(5,703)	(49,888)
Noninvestment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Protection sold credit derivatives and credit related notes ratings/maturity profile - less than one year	(214,949)	(241,823)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from one to five years	(722,115)	(589,954)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than five years	(66,725)	(127,814)
Total notional amount	(1,003,789)	(959,591)
Fair value	(14,460)	(72,092)
Trading assets
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	39,045	21,021
Trading assets | Investment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	16,690	7,809
Trading assets | Noninvestment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	22,355	13,212
Trading Liabilities [Member]
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	(59,208)	(143,001)
Trading Liabilities [Member] | Investment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	(22,393)	(57,697)
Trading Liabilities [Member] | Noninvestment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	(36,815)	(85,304)
Credit Default Swap [Member]
Protection sold credit derivatives and credit related notes ratings/maturity profile
Total notional amount	(2,954,705)	(2,839,492)
Other Credit Derivatives [Member]
Protection sold credit derivatives and credit related notes ratings/maturity profile
Total notional amount	(66,244)	(79,711)
Total Credit Derivatives [Member]
Protection sold credit derivatives and credit related notes ratings/maturity profile
Total notional amount	(3,020,949)	(2,919,203)
Hybrid Instrument [Member]
Protection sold credit derivatives and credit related notes ratings/maturity profile
Total notional amount	$ (233)	$ (742)