Pension and Other Postretirement Benefits, Weighted Average Assumptions Used to Determine Benefit Obligations (Details)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Pension Plans [Member]
Benefit obligations [Abstract]
Discount rate	[1]	3.78%	4.40%
Rate of compensation increase	[2]	3.50%	3.50%
Pension Plans [Member] | U.S. [Member]
Benefit obligations [Abstract]
Rate of compensation increase		3.50%	3.50%
Assumptions used to determine net periodic benefit cost, weighted average discount rate		3.81%	4.45%
Pension Plans [Member] | Canada [Member]
Benefit obligations [Abstract]
Rate of compensation increase		3.50%	3.50%
Assumptions used to determine net periodic benefit cost, weighted average discount rate		3.39%	3.79%
Postretirement Benefit Plans [Member]
Benefit obligations [Abstract]
Discount rate	[3]	3.59%	4.05%
Postretirement Benefit Plans [Member] | U.S. [Member]
Benefit obligations [Abstract]
Assumptions used to determine net periodic benefit cost, weighted average discount rate		3.63%	4.11%
Postretirement Benefit Plans [Member] | Canada [Member]
Benefit obligations [Abstract]
Assumptions used to determine net periodic benefit cost, weighted average discount rate		3.33%	3.64%

[1] The weighted average discount rate assumptions used at December 31, 2017 and 2016 were comprised of separate assumptions determined by country of 3.81% and 4.45% for the U.S. based plans, respectively, and 3.39% and 3.79% for the Canadian based plans, respectively.

[2] The weighted average rate of compensation increase assumptions were comprised of separate assumptions determined by country of 3.5% for both the U.S. based plans and Canadian based plans at December 31, 2017 and 2016.

[3] The weighted average discount rate assumptions used at December 31, 2017 and 2016 were comprised of separate assumptions determined by country of 3.63% and 4.11% for the U.S. based plans, respectively, and 3.33% and 3.64% for the Canadian based plans, respectively.