Financial Instruments - Summary of Reconciliation of Net Carrying Amount of Derivative Financial Instruments (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Net derivative asset as of January 1	$ 10	$ 11
Total gain (loss) for the period included in net loss	2	(14)
Total loss for period accounted through other comprehensive income (loss)	(4)
Proceeds from settlement of foreign exchange derivative contracts	(3)	(2)
Settlement of interest rate derivative contracts		3
Termination of foreign exchange derivative contracts (settlement pending)		(2)
Net derivative asset (liability) as of June 30	$ 5	$ (4)