Income Tax - Components of Net Deferred Tax Assets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Postretirement benefits, net	$ 522	$ 543
Intangible assets	(1,484)	(1,490)
Investments in non-US subsidiaries	(317)	(317)
Other, net	123	114
Net deferred tax assets	$ (1,156)	$ (1,150)