Significant Weighted Average Assumptions Used in Measurement of OPEB Obligation (Detail) (Foreign Postretirement Benefit Plans, Defined Benefit)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Foreign Postretirement Benefit Plans, Defined Benefit
OPEB benefit obligations:
Discount rate	3.90%	4.18%	5.11%
Net periodic benefit cost:
Discount rate	4.18%	5.11%	5.79%
Initial health care costs trend rate	6.40%	6.70%	7.00%
Ultimate health care costs trend rate	5.02%	5.02%	5.02%
Year ultimate reached	2018	2018	2015