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Retirement Benefits (Details 3)
Dec. 31, 2020
Dec. 31, 2019
Pension Benefits [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Discount rate 2.60% 3.40%
Rate of increase in future compensation levels 1.00%  
Pension Benefits [Member] | Minimum    
Defined Benefit Plan Disclosure [Line Items]    
Rate of increase in future compensation levels   0.50%
Pension Benefits [Member] | Maximum    
Defined Benefit Plan Disclosure [Line Items]    
Rate of increase in future compensation levels   1.00%
Other Postretirement Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Discount rate 2.45% 3.25%
Rate of increase in future compensation levels 0.00% 0.00%