Intangible Assets - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 330	$ 331	$ 324
Weighted average amortization period for all intangible assets (years)	20 years
Estimated amortization charged to income, 2014	357
Estimated amortization charged to income, 2015	350
Estimated amortization charged to income, 2016	334
Estimated amortization charged to income, 2017	314
Estimated amortization charged to income, 2018	$ 307