Marketable Securities, at Fair Value (Tables)

9 Months Ended

Sep. 30, 2011

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-sale Securities

	Amortized Cost	Gross Unrealized Gain	Gross Unrealized Loss	Fair Value
	(In $ millions)
Mutual funds	64	—	—	64
As of September 30, 2011	64	—	—	64
US corporate debt securities	1	—	—	1
Mutual funds	77	—	—	77
As of December 31, 2010	78	—	—	78