v3.25.4
Postretirement Benefits Other Than Pensions (Tables)
 12 Months Ended
Dec. 31, 2025
Defined Benefit Plan Disclosure [Line Items]  
Schedule of Changes in Fair Value of Plan Assets
Changes in Fair Value of Plan Assets and Changes in Projected Benefit Obligation for the Pension Plan for the years ended December 31, 2025 and 2024 is presented below.
DOLLARS IN MILLIONS20252024
Fair Value of Plan Assets at Beginning of Year$— $16.3 
Actual Return on Plan Assets— (1.1)
Benefits Paid— — 
Settlement Benefits— 2.6 
Assets contributed to 401(k) Plan
— (4.7)
Assets reverted to the Company
— (13.1)
Fair Value of Plan Assets at End of Year— — 
Projected Benefit Obligation at Beginning of Year— — 
Interest Cost— — 
Benefits Paid— — 
Settlement Benefits— — 
Actuarial Gains— — 
Projected Benefit Obligation at End of Year— — 
Funded Status—Plan Assets in Excess of Projected Benefit Obligation$— $— 
Unamortized Amount Reported in AOCI at End of Year$— $— 
Accumulated Benefit Obligation at End of Year$— $— 
Schedule of Assumptions Used
The weighted-average discount rate, service cost discount rate, interest cost discount rate, rate of increase in future compensation levels and expected long-term rate of return on plan assets used to develop the components of Pension Expense for the Pension Plan for the years ended December 31, 2025, 2024 and 2023 were:
202520242023
Weighted-average Discount Rate— %— %5.05 %
Interest Cost Discount Rate— — 4.92 
Rate of Increase in Future Compensation LevelsN/AN/AN/A
Expected Long Term Rate of Return on Plan Assets— — 3.79 
Other Postretirement Benefit Plan, Defined Benefit  
Defined Benefit Plan Disclosure [Line Items]  
Schedule of Changes in Fair Value of Plan Assets
Changes in Fair Value of Plans’ Assets and Changes in Accumulated Postretirement Benefit Obligation for the years ended December 31, 2025 and 2024 were:
DOLLARS IN MILLIONS
20252024
Fair Value of Plans’ Assets at Beginning of Year$— $— 
Employer Contributions0.5 0.4 
Plan Participants’ Contributions0.1 0.1 
Benefits Paid(0.6)(0.5)
Fair Value of Plan Assets at End of Year— — 
Accumulated Postretirement Benefit Obligation at Beginning of Year6.5 7.5 
Service Cost0.1 0.1 
Interest Cost0.3 0.3 
Plan Participants’ Contributions0.1 0.1 
Benefits Paid(0.6)(0.5)
Actuarial Gain(0.2)(1.0)
Accumulated Postretirement Benefit Obligation at End of Year6.2 6.5 
Funded Status—Accumulated Postretirement Benefit Obligation in Excess of Plans’ Assets$(6.2)$(6.5)
Unamortized Actuarial Gain Reported in AOCI at End of Year
$10.1 $12.0 
Schedule of Assumptions Used
The weighted-average discount rate and rate of increase in future compensation levels used to develop the components of the Accumulated Postretirement Benefit Obligation at December 31, 2025 and 2024 were:
20252024
Discount Rate5.22 %5.55 %
Rate of Increase in Future Compensation Levels2.20 2.20 
The weighted-average discount rate and rate of increase in future compensation levels used to develop OPEB Expense for the years ended December 31, 2025, 2024 and 2023 were:
202520242023
Weighted-average Discount Rate5.54 %4.92 %5.11 %
Service Cost Discount Rate5.61 4.94 5.12 
Interest Cost Discount Rate5.21 4.85 5.03 
Effective Rate for Interest on Service Cost5.50 4.85 5.04 
Rate of Increase in Future Compensation Levels2.20 2.20 2.20 
Schedule of Comprehensive Other Postretirement Employee Benefit Expense
The components of Comprehensive OPEB (Income) Expense for the years ended December 31, 2025, 2024 and 2023 were:
DOLLARS IN MILLIONS202520242023
Service Cost Earned During the Year$0.1 $0.1 $0.1 
Interest Cost on Accumulated Postretirement Benefit Obligation0.3 0.3 0.4 
Amortization of Prior Service Credit(0.5)(1.3)(1.3)
Amortization of Accumulated Unrecognized OPEB Gain(1.6)(1.5)(1.8)
OPEB Income Recognized in Consolidated Statements of Income (Loss)
(1.7)(2.4)(2.6)
Unrecognized OPEB Gain Arising During the Year
(0.2)(1.0)(0.1)
Amortization of Prior Service Credit0.5 1.3 1.3 
Amortization of Accumulated Unrecognized OPEB Gain1.6 1.5 1.8 
Comprehensive OPEB Expense (Income)
$0.2 $(0.6)$0.4 
Schedule of Expected Benefit Payments
The following benefit payments (net of participant contributions), which consider expected future service, as appropriate, are expected to be paid:
DOLLARS IN MILLIONSYears Ending December 31,
202620272028202920302031-2034
Estimated Benefit Payments:
Excluding Medicare Part D Subsidy$0.8 $0.8 $0.7 $0.6 $0.6 $2.5 
Expected Medicare Part D Subsidy— — — — — — 
Net Estimated Benefit Payments$0.8 $0.8 $0.7 $0.6 $0.6 $2.5