Deferred Revenue (Deferred Revenue) (Details) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010
Deferred Revenue Arrangement [Line Items]
Balance at January 1	$ 292		$ 265
Additions	262	[1]	278	[1]
Amortization	(242)	[1]	(221)	[1]
Translation adjustment	(2)		3
Balance at September 30	310		325
Initial Listing Revenues [Member]
Deferred Revenue Arrangement [Line Items]
Balance at January 1	42		46
Additions	10	[1]	10	[1]
Amortization	(12)	[1]	(14)	[1]
Balance at September 30	40		42
Listing Of Additional Shares Revenues [Member]
Deferred Revenue Arrangement [Line Items]
Balance at January 1	83		76
Additions	33	[1]	36	[1]
Amortization	(30)	[1]	(29)	[1]
Balance at September 30	86		83
Annual Renewal And Other Revenues [Member]
Deferred Revenue Arrangement [Line Items]
Balance at January 1	21		18
Additions	207	[1]	203	[1]
Amortization	(169)	[1]	(159)	[1]
Balance at September 30	59		62
Market Technology [Member]
Deferred Revenue Arrangement [Line Items]
Balance at January 1	146	[2]	125	[2]
Additions	12	[1],[2]	29	[1],[2]
Amortization	(31)	[1],[2]	(19)	[1],[2]
Translation adjustment	(2)	[2]	3	[2]
Balance at September 30	$ 125	[2]	$ 138	[2]

[1] The additions and amortization for initial listing revenues, listing of additional shares revenues and annual renewal and other revenues primarily reflects Issuer Services revenues from U.S. listing revenues.

[2] Market Technology deferred revenues include revenues from delivered client contracts in the support phase charged during the period. Under contract accounting, where customization and significant modifications to the software are made to meet the needs of our customers, total revenues, as well as costs incurred, are deferred until significant modifications are completed and delivered. Once delivered, deferred revenue and the related deferred costs are recognized over the post contract support period. We have included the deferral of costs in other current assets and other non-current assets in the Condensed Consolidated Balance Sheets. The amortization of Market Technology deferred revenue primarily includes revenues earned from client contracts recognized during the period.