Postretirement Benefit Plans

6 Months Ended

Jun. 30, 2025

Retirement Benefits [Abstract]

Postretirement Benefit Plans

Postretirement Benefit Plans

Pension Plan

As of June 30, 2025, we had one qualified noncontributory defined benefit pension plan, the Union Plan, which was frozen and ceased accruing benefits in 2013. The measurement date is December 31st for each respective plan year. We were not required to make any contributions to the Union Plan in 2024 and will not be required to make any contributions in 2025.

Deferred Compensation Plan

We sponsor a non-qualified deferred compensation plan, which provides specified deferred compensation benefits to a certain group of select employees. The deferred compensation plan is funded through a rabbi trust, which is ultimately invested in accordance with each plan participants’ selections from pre-approved funds. As of June 30, 2025 and December 31, 2024, our deferred compensation plan primarily consisted of marketable securities, which includes mutual funds and fixed income funds. Marketable securities are recorded at fair value. The balances are reflected in the “Other long-term assets” line item in the condensed consolidated statements of financial position. The following table summarizes, by major security type, our marketable securities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy:

	Fair Value of Deferred Compensation Plan as of June 30, 2025
(Dollars in millions)	Adjusted Cost		Unrealized Gains		Unrealized Losses		Fair Value
Level 1 Securities:
Mutual funds	$	4.0	$	0.7	$	(0.1)	$	4.6
Level 2 Securities:
Fixed income funds	$	0.1	$	—	$	—	$	0.1
Total	$	4.1	$	0.7	$	(0.1)	$	4.7

	Fair Value of Deferred Compensation Plan as of December 31, 2024
(Dollars in millions)	Adjusted Cost		Unrealized Gains		Unrealized Losses		Fair Value
Level 1 Securities:
Mutual funds	$	4.6	$	0.5	$	—	$	5.1
Level 2 Securities:
Fixed income funds	$	0.2	$	—	$	—	$	0.2
Total	$	4.8	$	0.5	$	—	$	5.3