XML 86 R71.htm IDEA: XBRL DOCUMENT v3.22.4
Retirement Benefits Plan Assumptions (Details 5)
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Benefit Obligation [Member]        
Defined Benefit Plan Disclosure (Table Amounts)        
Initial health care cost trend rate assumed for the next year   6.50% 5.30% 5.60%
Rate to which the health care cost trend rate is assumed to decline (the ultimate trend rate)   5.00% 5.00% 5.00%
Year that the health care cost trend rate reaches the ultimate trend rate   2028 2023 2023
Pension Benefits        
Assumptions Used to Determine Benefit Obligation        
Discount rate   5.54% 2.98% 2.68%
Initial cash balance crediting rate assumed for the next year   3.96% 2.25% 2.25%
Rate to which the cash balance crediting rate is assumed to increase/decrease (the ultimate rate)   3.88% 2.25% 2.25%
Year that the cash balance crediting rate reaches the ultimate rate   2028 2027 2026
Rate of compensation increase   3.00% 3.00% 3.00%
Assumptions Used to Determine Benefit Cost        
Discount rate   2.98% 2.68%  
Expected long-term return on plan assets   7.50% 7.50%  
Initial cash balance crediting rate assumed for the next year   2.25% 2.25%  
Rate to which the cash balance crediting rate is assumed to increase (the ultimate rate)   2.25% 2.25%  
Year that the cash balance crediting rate reaches the ultimate rate   2027 2026  
Rate of compensation increase   3.00% 3.00%  
Pension Benefits | Subsequent Event [Member]        
Assumptions Used to Determine Benefit Cost        
Discount rate 5.54%      
Expected long-term return on plan assets 7.50%      
Initial cash balance crediting rate assumed for the next year 3.96%      
Rate to which the cash balance crediting rate is assumed to increase (the ultimate rate) 3.88%      
Year that the cash balance crediting rate reaches the ultimate rate 2028      
Rate of compensation increase 3.00%      
Post-retirement Benefit Cost [Member]        
Defined Benefit Plan Disclosure (Table Amounts)        
Initial health care cost trend rate assumed for the next year   5.30% 5.60%  
Rate to which the health care cost trend rate is assumed to decline (the ultimate trend rate)   5.00% 5.00%  
Year that the health care cost trend rate reaches the ultimate trend rate   2023 2023  
Post-retirement Benefit Cost [Member] | Subsequent Event [Member]        
Defined Benefit Plan Disclosure (Table Amounts)        
Initial health care cost trend rate assumed for the next year 6.50%      
Rate to which the health care cost trend rate is assumed to decline (the ultimate trend rate) 5.00%      
Year that the health care cost trend rate reaches the ultimate trend rate 2028      
Medical and Life Benefits        
Assumptions Used to Determine Benefit Obligation        
Discount rate   5.57% 2.93% 2.58%
Assumptions Used to Determine Benefit Cost        
Discount rate   2.93% 2.58%  
Expected long-term return on plan assets   7.19% 7.22%  
Medical and Life Benefits | Subsequent Event [Member]        
Assumptions Used to Determine Benefit Cost        
Discount rate 5.57%      
Expected long-term return on plan assets 7.23%