Pensions and Postretirement Benefits Other Than Pensions - Weighted Average Asset Allocations for Domestic and U.K. Pension Plans' Assets (Detail)	Dec. 31, 2016	Dec. 31, 2015
Domestic
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	100.00%	100.00%
Domestic | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	63.00%	62.00%
Domestic | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	36.00%	38.00%
Domestic | Other investments
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	0.00%	0.00%
Domestic | Cash
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	1.00%	0.00%
United Kingdom plan
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	100.00%	100.00%
United Kingdom plan | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	18.00%	21.00%
United Kingdom plan | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	68.00%	70.00%
United Kingdom plan | Other investments
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	14.00%	9.00%
United Kingdom plan | Cash
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations (as a percent)	0.00%	0.00%