Derivative Instruments - Credit Derivatives, Protection Sold, Notional and Fair Value (Details 4b) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
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	$ (564,648)	$ (624,697)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from one to five years	(2,426,002)	(2,105,759)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than five years	(165,268)	(290,726)
Total notional amount	(3,155,918)	(3,021,182)
Fair value	(5,035)	(20,163)
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	(370,635)	(409,748)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from one to five years	(1,753,481)	(1,383,644)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than five years	(132,951)	(224,001)
Total notional amount	(2,257,067)	(2,017,393)
Fair value	910	(5,703)
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	(194,013)	(214,949)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from one to five years	(672,521)	(722,115)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than five years	(32,317)	(66,725)
Total notional amount	(898,851)	(1,003,789)
Fair value	(5,945)	(14,460)
Trading assets
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	42,277	39,045
Trading assets | Investment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	20,698	16,690
Trading assets | Noninvestment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	21,579	22,355
Trading Liabilities
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	(47,312)	(59,208)
Trading Liabilities | Investment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	(19,788)	(22,393)
Trading Liabilities | Noninvestment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Fair value	$ (27,524)	$ (36,815)