Fair Value Measurement - Level 3 Analysis (Details 4) (USD $)		3 Months Ended																						3 Months Ended		3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Asset Backed Securities Trading Account [Member]	Mar. 31, 2012 Asset Backed Securities Trading Account [Member]	Mar. 31, 2013 Interest rate contract	Mar. 31, 2012 Interest rate contract	Mar. 31, 2013 Equity Contract	Mar. 31, 2012 Equity Contract	Mar. 31, 2013 Assets [Member]	Mar. 31, 2013 Available-for-sale Securities	Mar. 31, 2012 Available-for-sale Securities	Mar. 31, 2013 Servicing Contracts [Member]	Mar. 31, 2012 Servicing Contracts [Member]	Mar. 31, 2013 Derivative Receivables Net Of Payables [ Member]	Mar. 31, 2013 Debt and Equity Instruments [Member]	Mar. 31, 2012 Debt and Equity Instruments [Member]	Mar. 31, 2013 Asset backed Security Available for Sale [Member]	Mar. 31, 2012 Asset backed Security Available for Sale [Member]	Mar. 31, 2013 Credit derivatives	Mar. 31, 2012 Credit derivatives	Mar. 31, 2013 Private Equity Funds [Member]	Mar. 31, 2012 Private Equity Funds [Member]	Mar. 31, 2013 Fair Value, Measurements, Recurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member]	Mar. 31, 2013 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Fair Value, Inputs, Level 3 [Member]	Mar. 31, 2013 Fair Value, Measurements, Recurring [Member] Asset Backed Securities Trading Account [Member]	Mar. 31, 2013 Fair Value, Measurements, Recurring [Member] Equity Contract	Mar. 31, 2013 Fair Value, Measurements, Recurring [Member] Available-for-sale Securities	Mar. 31, 2013 Fair Value, Measurements, Recurring [Member] Derivative Receivables Net Of Payables [ Member]	Mar. 31, 2012 Fair Value, Measurements, Recurring [Member] Derivative Receivables Net Of Payables [ Member]	Mar. 31, 2013 Fair Value, Measurements, Recurring [Member] Credit derivatives	Mar. 31, 2013 Fair Value, Measurements, Recurring [Member] Interest Rate, Foreign Exchange, Commodity Contract [Member]	Mar. 31, 2013 Liabilities, Total [Member]
Level 3 Analysis
Percentage of Level 3 Assets To Total Assets	2.90%
Assets, Fair Value Disclosure, Recurring																						$ 854,018,000,000	$ 882,235,000,000	$ 67,356,000,000	$ 99,148,000,000
Increase (Decrease) In Level 3 Assets																								31,800,000,000		2,100,000,000	1,200,000,000	26,900,000,000	(1,400,000,000)		(1,200,000,000)	(1,400,000,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings																																	(537,000,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(64,000,000)	(230,000,000)	(306,000,000)	(1,328,000,000)	(863,000,000)	720,000,000	(851,000,000)	18,000,000	(96,000,000)	(309,000,000)	(596,000,000)	(922,000,000)	46,000,000	(734,000,000)	(5,000,000)	(3,000,000)	489,000,000	2,354,000,000	269,000,000	(252,000,000)									(1,600,000,000)
Gains (losses) on level 3 assets									$ (4,000,000)	$ 11,000,000