Weighted Average Actuarial Assumptions to Determine Net Period Cost (Detail) (Domestic Pension and Other Postretirement Benefit Plans)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Domestic Pension and Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.40%	5.90%	6.30%
Expected return on plan assets	8.50%	8.50%	8.50%
Rate of compensation increase	3.20%	3.40%	3.40%
Health care cost trend rate	8.00%	8.00%	7.90%