v3.26.1
Pension plans and other postretirement benefits (Tables)
 3 Months Ended
Mar. 31, 2026
Retirement Benefits [Abstract]  
Net Periodic Defined Benefit Cost for Defined Benefit Plans
The Company provides defined pension and other postretirement benefits (including health care and life insurance benefits) to eligible retired employees. Net periodic benefit for defined benefit plans consisted of the following.
Pension Benefits
Other Postretirement Benefits
(Dollars in millions)Three Months Ended March 31,
Net periodic pension (benefit)/cost2026202520262025
Service cost$2 $2 $— $— 
Interest cost on benefit obligation23 27 1 1 
Expected return on plan assets(43)(46)— — 
Amortization of prior service credit and actuarial gains— (1)(1)(1)
Net periodic benefit$(18)$(18)$— $—