Income Taxes - Reconciliation of Liabilities Associated with Uncertain Tax Provisions (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure Income Tax Reconciliation Of U S Statutory Federal Tax Rate Detail [Line Items]
Balance at beginning of year	$ 1,453	$ 1,353	$ 1,338
Additions based on tax positions related to the current year	146	156	153
Additions for tax positions of prior years	109	98	49
Additions related to acquisitions			48
Impact of changes in exchange rates	(47)	12	(18)
Settlements with tax authorities	(64)	(17)	(77)
Reductions for tax positions of prior years	(109)	(103)	(102)
Reductions due to the lapse of the applicable statute of limitations	(36)	(46)	(38)
Balance at end of year	$ 1,452	$ 1,453	$ 1,353