Financial Instruments (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Summary of reconciliation of the net carrying amount of derivative financial instruments
Net derivative asset (liability) as of January 1	$ 11
Total loss (gain) for the period included in net loss	(15)
Proceeds from settlement of foreign exchange derivative contracts	(2)
Settlement of interest rate derivative contracts	1
Net derivative liability as of March 31	$ (5)