v3.26.1
Pension and Postretirement Benefit Costs (Tables)
3 Months Ended
Mar. 31, 2026
Retirement Benefits [Abstract]  
Schedule of Net Benefit Costs
Net periodic postretirement benefit credit included the following components:
Three Months Ended March 31,
20262025
 (Dollars in millions)
Service cost for benefits earned$— $0.1 
Interest cost on accumulated postretirement benefit obligation1.6 2.0 
Expected return on plan assets— (0.1)
Amortization of prior service credit(2.8)(10.2)
Net periodic postretirement benefit credit$(1.2)$(8.2)