v2.4.0.8
Commitments, Contingencies and Guarantees (Details) (USD $)
In Millions, unless otherwise specified
 9 Months Ended
Sep. 30, 2013
Dec. 31, 2012
Commitments and Contingencies Disclosure [Line Items]    
Financial guarantees obtained $ 18 $ 7
Margin deposits contributed to Cantor Fitzgerald 19  
Other guarantees   18
Voluntary accommodation program 62  
Clearinghouse Credit Facilities [Member]
    
Commitments and Contingencies Disclosure [Line Items]    
Credit facilities, total 313 310
Line of credit facility, available liquidity 220 217
Credit facility, regulatory requirements amount 93 93
Line of credit, outstanding amount 0 0
Escrow Agreement [Member]
    
Commitments and Contingencies Disclosure [Line Items]    
Contingency, accrual 12  
Property Lease Guarantee [Member]
    
Commitments and Contingencies Disclosure [Line Items]    
Other guarantees 15  
Performance guarantees [Member]
    
Commitments and Contingencies Disclosure [Line Items]    
Other guarantees 2 5
SEC Reserve Matter [Member]
    
Commitments and Contingencies Disclosure [Line Items]    
Contingency, accrual $ 10