Summary Of Significant Accounting Policies (Property And Equipment) (Details) (USD $) In Millions, unless otherwise specified			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Data Processing Equipment [Member]	Dec. 31, 2011 Buildings And Leasehold Improvements [Member]	Dec. 31, 2011 Furniture And Equipment [Member]
Property and Equipment [Line Items]
Land	$ 23	$ 23
Data processing equipment	489	476
Buildings and leasehold improvements	190	184
Furniture and equipment	163	161
Property and equipment, gross	865	844
Less: accumulated depreciation	(607)	(577)
Total	$ 258	$ 267
Estimated Useful Lives, minimum, years			3	5	3
Estimated Useful Lives, maximum, years			7	40	10