Income Tax - Components of Net Deferred Tax Assets (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Disclosure - Income Tax - Components of Net Deferred Tax Assets (Detail) [Line Items]
Postretirement benefits, net	$ 486	$ 543
Intangible assets	(1,464)	(1,490)
Investments in non-US subsidiaries	(317)	(317)
Other, net	94	114
Net deferred tax assets	$ (1,201)	$ (1,150)