Goodwill And Purchased Intangible Assets (Schedule Of Changes In Goodwill) (Details) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011
Goodwill [Line Items]
Balance at December 31, 2010	$ 5,127
Foreign currency translation adjustment	(81)
Balance at September 30, 2011	5,046
Market Services [Member]
Goodwill [Line Items]
Balance at December 31, 2010	4,679
Foreign currency translation adjustment	(70)
Balance at September 30, 2011	4,609
Issuer Services [Member]
Goodwill [Line Items]
Balance at December 31, 2010	292
Foreign currency translation adjustment	(5)
Balance at September 30, 2011	287
Market Technology [Member]
Goodwill [Line Items]
Balance at December 31, 2010	156
Foreign currency translation adjustment	(6)
Balance at September 30, 2011	$ 150