Pension and Postretirement Benefit Plans - Narrative (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
U.S. Supplemental (Non-Qualified) Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions	$ 123
Expected contributions in next fiscal year	193
International Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions	156
Expected contributions in next fiscal year	336
Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions	115
Expected contributions in next fiscal year	$ 246