v2.4.0.6
Goodwill and Purchased Intangible Assets (Finite-Lived and Indefinite-Lived Intangible Assets) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 12 Months Ended
Mar. 31, 2013
Dec. 31, 2012
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total finite-lived intangible assets, Gross Amount $ 894 $ 909
Accumulated Amortization (262) (251)
Total 632 658
Total indefinite-lived intangible assets, Net Amount 987 992
Total Intangible Assets, Gross Amount 1,881 1,901
Total Intangible Assets, Net Amount 1,619 1,650
Exchange and clearing registrations [Member]
    
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total indefinite-lived intangible assets, Net Amount 790 790
Trade Names [Member]
    
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total indefinite-lived intangible assets, Net Amount 183 185
Licenses [Member]
    
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total indefinite-lived intangible assets, Net Amount 51 51
Foreign currency translation adjustment [Member]
    
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total indefinite-lived intangible assets, Net Amount (37) (34)
Technology [Member]
    
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total finite-lived intangible assets, Gross Amount 25 26
Accumulated Amortization (10) (10)
Total 15 16
Total finite-lived intangible assets, Weighted-Average Useful Life (in Years) 6 years 5 years
Customer relationships [Member]
    
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total finite-lived intangible assets, Gross Amount 864 871
Accumulated Amortization (250) (238)
Total 614 633
Total finite-lived intangible assets, Weighted-Average Useful Life (in Years) 21 years 21 years
Other [Member]
    
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total finite-lived intangible assets, Gross Amount 6 6
Accumulated Amortization (2) (2)
Total 4 4
Total finite-lived intangible assets, Weighted-Average Useful Life (in Years) 8 years 8 years
Foreign currency translation adjustment [Member]
    
Finite Lived And Indefinite Lived Intangible Assets [Line Items]    
Total finite-lived intangible assets, Gross Amount (1) 6
Accumulated Amortization   (1)
Total $ (1) $ 5