Fair Value Measurement - Level 3 Analysis (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Level 3 Analysis - Supplemental Data [Abstract]
Percentage of level 3 assets in total Firm assets	4.40%
Increase (decrease) in level 3 assets	$ (14,300,000,000)
Fair Value, Measurements, Recurring [Member]
Level 3 Analysis - Supplemental Data [Abstract]
Assets, Fair Value Disclosure, Recurring	882,235,000,000	872,062,000,000
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Level 3 Analysis - Supplemental Data [Abstract]
Assets, Fair Value Disclosure, Recurring	99,148,000,000	113,489,000,000
Asset backed Security Available for Sale [Member]
Level 3 Analysis - Supplemental Data [Abstract]
Increase (decrease) in level 3 assets	(3,100,000,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	135,000,000	(95,000,000)	(146,000,000)
Derivative Receivables Net Of Payables [ Member]
Level 3 Analysis - Supplemental Data [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	1,138,000,000	6,068,000,000	(507,000,000)
Gains (losses) on level 3 assets		6,100,000,000
Derivative Receivables Net Of Payables [ Member] | Level 3 [Member]
Level 3 Analysis - Supplemental Data [Abstract]
Increase (decrease) in level 3 assets	(11,800,000,000)
Debt and Equity Instruments [Member]
Level 3 Analysis - Supplemental Data [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	1,251,000,000	980,000,000	614,000,000
Debt and Equity Instruments [Member] | Level 3 [Member]
Level 3 Analysis - Supplemental Data [Abstract]
Increase (decrease) in level 3 assets	(7,300,000,000)
Servicing Contracts [Member]
Level 3 Analysis - Supplemental Data [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(635,000,000)	(7,119,000,000)	(2,268,000,000)
Gains (losses) on level 3 assets		7,100,000,000	2,300,000,000
Private Equity Funds [Member]
Level 3 Analysis - Supplemental Data [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	420,000,000	943,000,000	1,038,000,000
Gains (losses) on level 3 assets			$ 1,000,000,000