Fair Value Option (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loans Held for Investment Not at Fair Value
Loans Held for Investment at Amortized Cost	$ 6,500,000,000	$ 3,760,000,000
Fair Value Option
Fair Value Option Gains/(Losses)	(4,063,000,000)	3,698,000,000	(2,908,000,000)
Fair Value Option Loans and Lending Commitments
Difference between aggregate contractual principal amount of performing loans and long-term receivable for which the fair value option was elected and related fair value	2,742,000,000	3,826,000,000
Fair value of loans on nonaccrual status for which the fair value option was elected	1,832,000,000	3,174,000,000
Difference between aggregate contractual principal amount of loans and long-term receivable for which the fair value option was elected and related fair value	25,352,000,000	26,860,000,000
Difference between aggregate contractual principal amount of loans on nonaccrual status for which the fair value option was elected and related fair value	22,610,000,000	23,034,000,000
Total contractual amount of unfunded commitments for which the fair value option was elected	59,290,000,000	66,120,000,000
Fair value of unfunded commitments for which the fair value option was elected	1,990,000,000	2,820,000,000
Fair Value, Option, Credit Risk, Gain (Loss) Quantitative Disclosures [Abstract]
Net Gains (Losses), Including Hedges, Attributable to the Impact of Changes in Own Credit Spreads on Borrowings For Which the Fair Value Option Was Elected	(714,000,000)	596,000,000	198,000,000
Net Gains (Losses), Excluding Hedges, Attributable to the Impact of Changes in Own Credit Spreads on Borrowings For Which the Fair Value Option Was Elected	(800,000,000)	714,000,000	199,000,000
Net Gains (Losses) Attributable to the Impact of Changes in Instrument-Specific Credit Spreads on Loans and Loan Commitments For Which the Fair Value Option Was Elected	3,070,000,000	(805,000,000)	1,850,000,000
Level 2 [Member]
Loans Held for Investment Not at Fair Value
Estimated Fair Value of Loans Held for Investment at Amortized Cost	2,410,000,000
Level 3 [Member]
Loans Held for Investment Not at Fair Value
Estimated Fair Value of Loans Held for Investment at Amortized Cost	4,060,000,000
Resale and Repurchase Agreements and Securities Borrowed and Loaned at Fair Value [Member] | Minimum [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	1.70%
Fair Value Unobservable Inputs, Duration	0.4
Resale and Repurchase Agreements and Securities Borrowed and Loaned at Fair Value [Member] | Maximum [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	5.40%
Fair Value Unobservable Inputs, Duration	4.5
Resale and Repurchase Agreements and Securities Borrowed and Loaned at Fair Value [Member] | Weighted Average [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	1.90%
Fair Value Unobservable Inputs, Duration	4.1
Insurance and Reinsurance Contracts at Fair Value [Member] | Minimum [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	4.40%
Fair Value Unobservable Inputs, Duration	5.3
Fair Value Unobservable Inputs, Funding Spreads	64 bps
Insurance and Reinsurance Contracts at Fair Value [Member] | Maximum [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	15.10%
Fair Value Unobservable Inputs, Duration	8.8
Fair Value Unobservable Inputs, Funding Spreads	105 bps
Insurance and Reinsurance Contracts at Fair Value [Member] | Weighted Average [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	6.20%
Fair Value Unobservable Inputs, Duration	7.6
Fair Value Unobservable Inputs, Funding Spreads	85 bps
Receivables from customers and counterparties at fair value [Member]
Fair Value Option
Fair Value Option Gains/(Losses)	190,000,000	97,000,000	(97,000,000)
Receivables from customers and counterparties at fair value [Member] | Minimum [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Funding Spreads	57 bps
Receivables from customers and counterparties at fair value [Member] | Maximum [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Funding Spreads	145 bps
Receivables from customers and counterparties at fair value [Member] | Weighted Average [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Funding Spreads	105 bps
Other Secured Financings At Fair Value [Member]
Fair Value Option
Fair Value Option Gains/(Losses)	(190,000,000)	(63,000,000)	(227,000,000)
Other Secured Financings At Fair Value [Member] | Minimum [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	0.30%
Fair Value Unobservable Inputs, Duration	0.3
Other Secured Financings At Fair Value [Member] | Maximum [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	20.00%
Fair Value Unobservable Inputs, Duration	10.8
Other Secured Financings At Fair Value [Member] | Weighted Average [Member]
Fair Value, Other Financial Assets And Liabilities, Unobservable Inputs [Abstract]
Fair Value Unobservable Inputs, Yield	4.20%
Fair Value Unobservable Inputs, Duration	2.4
Unsecured Short-Term Borrowings Including Current Portion Of Unsecured Long-Term Borrowings At Fair Value [Member]
Fair Value Option
Fair Value Option Gains/(Losses)	(973,000,000)	2,149,000,000	(1,455,000,000)
Gains/(Losses) on the Embedded Derivative Component Of Hybrid Financial Instruments	(814,000,000)	2,010,000,000	(1,490,000,000)
Unsecured Long-term Borrowings At Fair Value [Member]
Fair Value Option
Fair Value Option Gains/(Losses)	(1,523,000,000)	2,336,000,000	(1,169,000,000)
Gains/(Losses) on the Embedded Derivative Component Of Hybrid Financial Instruments	(887,000,000)	1,800,000,000	(1,320,000,000)
Fair Value Option Long Term Debt Instruments
Difference between aggregate contractual principal amount of long-term debt instruments for which the fair value option was elected and related fair value	379,000,000	693,000,000
Other Liabilities And Accrued Expenses At Fair Value [Member]
Fair Value Option
Fair Value Option Gains/(Losses)	(1,486,000,000)	(911,000,000)	50,000,000
Fair Value Option Other [Member]
Fair Value Option
Fair Value Option Gains/(Losses)	(81,000,000)	90,000,000	(10,000,000)
Long-term Other Secured Financings At Fair Value [Member]
Fair Value Option Long Term Debt Instruments
Difference between aggregate contractual principal amount of long-term debt instruments for which the fair value option was elected and related fair value	$ 115,000,000	$ 239,000,000