Financial Instruments - Summary of Reconciliation of Net Carrying Amount of Derivative Financial Instruments (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Net derivative asset as of January 1	$ 11
Loss for the period included in net loss	(7)
Loss for the period included in other comprehensive income (loss)	(2)
Premium paid for interest rate cap derivative contracts	12
Proceeds from settlement of foreign exchange derivative contracts hedging debt instruments, net	(2)
Settlement of foreign exchange derivative contracts and interest rate swaps, net	7
Termination of foreign currency derivative contracts (settlement pending)	(4)
Net derivative asset as of September 30	$ 15