Annual report pursuant to Section 13 and 15(d)

Benefit Plans - Weighted Average Assumptions for Net Periodic Cost (Details)

v3.8.0.1
Benefit Plans - Weighted Average Assumptions for Net Periodic Cost (Details)
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost      
Immediate trend rate 6.84% 7.28%  
Ultimate trend rate 4.50% 4.50%  
Year that the rate reaches ultimate trend rate 2035 2035  
Defined Benefit Pension Plans | U.S.      
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost      
Discount rate 4.24% 4.02% 4.09%
Rate of compensation increase 3.00% 3.10%  
Expected return on assets 6.37% 6.34%  
Defined Benefit Pension Plans | U.S. | Eco Services Hourly Pension Plan      
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost      
Rate of compensation increase     3.00%
Defined Benefit Pension Plans | Foreign      
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost      
Discount rate 2.99% 5.16% 0.00%
Rate of compensation increase 2.97% 3.95% 0.00%
Expected return on assets 3.58% 5.62% 0.00%
Supplemental Retirement Plans      
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost      
Discount rate 3.90% 3.40%  
Other Postretirement Benefits Plans      
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost      
Discount rate 3.74% 3.92% 4.36%