Annual report pursuant to Section 13 and 15(d)

Securitizations and Other Variable Interest Entities - Municipal Bond Trusts (Details)

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Securitizations and Other Variable Interest Entities - Municipal Bond Trusts (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Variable Interest Entity [Line Items]    
Weighted average remaining life of bonds held in trusts 10 years 7 months 6 days  
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Total Assets $ 602,928 $ 565,516
Short-term borrowings 3,376 6,051
Payables to affiliates 8,752 31,731
Total Liabilities 538,528 506,476
Municipal Bond Trusts [Member]
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Maximum Loss Exposure 1,454 4,633
Municipal Bond Trusts [Member] | Consolidated VIE
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Maximum Loss Exposure 1,348 3,713
Municipal Bond Trusts [Member] | Unconsolidated VIEs
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Maximum Loss Exposure 106 920
New transfers between transferor and transferee 338 645
Principal balance outstanding for unconsolidated municipal bond securitization trusts 133 1,200
Liquidity commitments to unconsolidated trusts 106 742
Municipal Bond Trusts [Member]
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Short-term borrowings 2,859 4,939
Payables to affiliates 1,157 0
Total Liabilities 4,016 4,939
Municipal Bond Trusts [Member] | Consolidated VIE
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Short-term borrowings 2,859 4,939
Payables to affiliates 1,157 0
Total Liabilities 4,016 4,939
Municipal Bond Trusts [Member] | Unconsolidated VIEs
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Short-term borrowings 0 0
Payables to affiliates 0 0
Total Liabilities 0 0
Municipal Bond Trusts [Member]
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Trading assets 2,505 3,891
Total Assets 2,505 3,891
Total assets of VIEs 2,638 4,867
Municipal Bond Trusts [Member] | Consolidated VIE
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Trading assets 2,505 3,713
Total Assets 2,505 3,713
Total assets of VIEs, consolidated 2,505 3,713
Municipal Bond Trusts [Member] | Unconsolidated VIEs
   
Summary Of Information Related To Municipal Bond Trusts [Abstract]    
Trading assets 0 178
Total Assets 0 178
Total assets of VIEs, unconsolidated $ 133 $ 1,154