Financial Instruments - Effect of Interest Rate and Cross Currency Swaps on Results of Operations (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Cross currency swap [Member] | Other operating expenses [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain Recognized in Operations on Derivatives	$ 3
Interest rate swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Loss Recognized in OCI on Derivatives, Net of Tax	96
Interest rate swaps [Member] | Interest expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Loss Reclassified from Accumulated OCI into Operations	$ 122