Other Financial Data (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Income (Expense)
Equity earnings	$ 13	$ 7	$ 18
Realized gain (loss) on sale of investments	7	18	(2)
Gain (Loss) on disposal of businesses	1		(4)
Loss on extinguishment of debt		(19)	(8)
Foreign currency remeasurement (loss) gain	(19)	30	(7)
Hedging gain (loss)	3	(20)	(11)
Other	(2)	(1)	(4)
Other (Expense) Income	3	15	(18)
Fixed Assets, net
Fixed assets, gross	2,189	1,971
Less: Accumulated depreciation	1,369	1,188
Fixed assets, net	820	783
Depreciation expense including software amortization	232	220	151
Software
Fixed Assets, net
Fixed assets, gross	867	730
Leasehold improvements
Fixed Assets, net
Fixed assets, gross	426	407
Furniture, fixtures and equipment
Fixed Assets, net
Fixed assets, gross	331	326
Computer equipment
Fixed Assets, net
Fixed assets, gross	332	274
Land and buildings
Fixed Assets, net
Fixed assets, gross	100	108
Automobiles
Fixed Assets, net
Fixed assets, gross	24	39
Construction in progress
Fixed Assets, net
Fixed assets, gross	$ 109	$ 87