Weighted Average Actuarial Assumptions Used to Determine the Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.98%	6.58%	6.75%
Rate of compensation increase	4.50%	4.50%	4.50%
Expected return on assets	8.75%	8.75%	8.96%
U.S. Postretirement Medical Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.77%	6.43%	6.66%
Expected return on assets	8.75%	8.75%	9.00%
International Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.36%	5.84%	6.17%
Rate of compensation increase	3.57%	3.62%	3.65%
Expected return on assets	7.31%	7.25%	7.09%