Pension Plans and Postretirement Benefits - Target Allocation by Asset Class (Detail) - Foreign Plans	12 Months Ended
	Dec. 31, 2015
Fixed Income | Canada
Defined Benefit Plan Disclosure [Line Items]
Target allocation by asset class	50.00%
Fixed Income | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Target allocation by asset class	74.00%
U. S. Equity | Canada
Defined Benefit Plan Disclosure [Line Items]
Target allocation by asset class	20.00%
U. S. Equity | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Target allocation by asset class	12.00%
Global Equity | Canada
Defined Benefit Plan Disclosure [Line Items]
Target allocation by asset class	30.00%
Global Equity | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Target allocation by asset class	14.00%