Financial Instruments (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Summary of reconciliation of the carrying amount of derivative financial instruments, net liability position
Net derivative liability as of January 1, 2012	$ (37)
Total losses for the period included in net loss	(4)
Net payment on settlement of foreign currency derivative contracts	42
Settlement of interest rate derivative contracts	3
Termination of foreign currency derivative contracts (settlement pending)	7
Net derivative asset as of December 31, 2012	$ 11