Benefit Plans - Actual Overall Asset Allocation for U.S. And Non-U.S. Plans as Compared to Investment Policy Goals (Detail)	Dec. 31, 2017	Dec. 31, 2016
Foreign Plan [Member] | Equity securities
Plan Assets
Asset allocation	22.00%	23.00%
Target Allocation
Asset allocation	24.00%	23.00%
Foreign Plan [Member] | Fixed income
Plan Assets
Asset allocation	53.00%	46.00%
Target Allocation
Asset allocation	51.00%	48.00%
Foreign Plan [Member] | Other securities
Plan Assets
Asset allocation	22.00%	26.00%
Target Allocation
Asset allocation	23.00%	27.00%
Foreign Plan [Member] | Cash
Plan Assets
Asset allocation	3.00%	5.00%
Target Allocation
Asset allocation	2.00%	2.00%
U.S. | Fixed income
Plan Assets
Asset allocation	99.00%	99.00%
Target Allocation
Asset allocation	100.00%	100.00%
U.S. | Other securities
Plan Assets
Asset allocation	1.00%	1.00%
Target Allocation
Asset allocation	0.00%	0.00%