Annual report pursuant to Section 13 and 15(d)

Pension And Other Postretirement Benefit Programs - Asset Allocation (Details)

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Pension And Other Postretirement Benefit Programs - Asset Allocation (Details) - Pension Plan
Dec. 31, 2019
Dec. 31, 2018
United States | Fixed income securities    
Defined Benefit Plan Disclosure [Line Items]    
Target Weight End of Period 56.00%  
Position at End of Period 55.00% 59.00%
United States | Equities    
Defined Benefit Plan Disclosure [Line Items]    
Target Weight End of Period 44.00%  
Position at End of Period 45.00% 41.00%
Canadian Pension Plan | Fixed income securities    
Defined Benefit Plan Disclosure [Line Items]    
Target Weight End of Period 50.00%  
Position at End of Period 50.00% 50.00%
Canadian Pension Plan | Equities    
Defined Benefit Plan Disclosure [Line Items]    
Target Weight End of Period 48.00%  
Position at End of Period 48.00% 48.00%
Canadian Pension Plan | Other    
Defined Benefit Plan Disclosure [Line Items]    
Target Weight End of Period 2.00%  
Position at End of Period 2.00% 2.00%