Employee Benefits - Funded Status of Pension and Other Postretirement Benefit Plans (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 2,717	$ 2,305
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, beginning of year	2,894	2,494
Service cost	95	88	79
Interest cost	125	124	120
Actuarial loss (gain)	(261)	256
Benefits paid	(75)	(74)
Foreign currency translation effect	(1)	6
Benefit obligation, end of year	2,777	2,894	2,494
Plan assets at fair value	2,717	2,305
Funded status at end of year, included in other liabilities	60	589
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation, beginning of year	470	454
Service cost	13	12	11
Interest cost	19	20	22
Actuarial loss (gain)	(97)	(4)
Benefits paid	(11)	(12)
Foreign currency translation effect
Benefit obligation, end of year	394	470	454
Plan assets at fair value	130	96
Funded status at end of year, included in other liabilities	$ 264	$ 374