Annual report pursuant to Section 13 and 15(d)

Postretirement Benefits, Schedule of Assumptions Used (Details)

v3.6.0.2
Postretirement Benefits, Schedule of Assumptions Used (Details)
3 Months Ended 12 Months Ended
Mar. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation        
Discount rate   4.15% 4.45% 3.95%
Rate of compensation increase   2.20% 3.00% 2.50%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost        
Discount rate   4.45% 3.95% 4.75%
Expected return on plan assets   8.50% 8.50% 8.60%
Rate of compensation increase   3.00% 2.50% 3.00%
Scenario, Forecast        
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost        
Expected return on plan assets 7.60%