Weighted Average Actuarial Assumptions Used to Determine the Benefit Obligations (Detail)	Dec. 31, 2011	Dec. 31, 2010
U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.64%	5.98%
Rate of compensation increase	4.50%	4.50%
U.S. Postretirement Medical Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.47%	5.77%
International Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.63%	5.36%
Rate of compensation increase	3.58%	3.57%