Derivative Instruments - Credit Derivatives (Details 4a) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Total credit derivatives and credit-related notes
Protection sold	$ (3,108,408)	$ (2,919,945)
Protection purchased with identical underlyings	3,023,235	2,803,161
Net protection (sold)/purchased	(85,173)	(116,784)
Other protection purchased	69,114	55,375
Credit Derivatives - supplemental information
Stockholders' equity	199,693		182,287
Total credit derivatives
Total credit derivatives and credit-related notes
Protection sold	(3,108,121)	(2,919,203)
Protection purchased with identical underlyings	3,023,235	2,803,161
Net protection (sold)/purchased	(84,886)	(116,042)
Other protection purchased	66,353	51,431
Credit default swaps
Total credit derivatives and credit-related notes
Protection sold	(3,031,683)	(2,839,492)
Protection purchased with identical underlyings	3,011,250	2,798,207
Net protection (sold)/purchased	(20,433)	(41,285)
Other protection purchased	35,903	29,139
Other credit derivatives
Total credit derivatives and credit-related notes
Protection sold	(76,438)	(79,711)
Protection purchased with identical underlyings	11,985	4,954
Net protection (sold)/purchased	(64,453)	(74,757)
Other protection purchased	30,450	22,292
Credit-related notes
Total credit derivatives and credit-related notes
Protection sold	(287)	(742)
Protection purchased with identical underlyings	0	0
Net protection (sold)/purchased	(287)	(742)
Other protection purchased	$ 2,761	$ 3,944