Pensions and Other Postretirement Benefit Plans (Narrative) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Canada [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued postretirement liability	$ 56.5
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued postretirement liability	$ 1.0
United States Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percent of consolidated pension plan assets	43.00%
Percent of consolidated pension plan obligations	44.00%