Pensions and Other Post-Retirement Benefits - Weighted Average Asset Allocation by Asset Category (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	100.00%	100.00%
Equity securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	34.00%	36.00%
Fixed income securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	47.00%	50.00%
Other securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	19.00%	14.00%
The Netherlands
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	100.00%	100.00%
The Netherlands | Equity securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	25.00%	25.00%
The Netherlands | Fixed income securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	57.00%	59.00%
The Netherlands | Other securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	18.00%	16.00%
United States
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	100.00%	100.00%
United States | Equity securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	55.00%	54.00%
United States | Fixed income securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	44.00%	45.00%
United States | Other securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	1.00%	1.00%
Other
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	100.00%	100.00%
Other | Equity securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	34.00%	42.00%
Other | Fixed income securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	37.00%	41.00%
Other | Other securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Weighted average asset allocations	29.00%	17.00%