XML 46 R32.htm IDEA: XBRL DOCUMENT
v3.25.3

Pension and Postretirement Benefit Costs (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2025
Retirement Benefits [Abstract] |
Schedule of Net Benefit Costs | Net periodic postretirement benefit credit included the following components:
| Three Months Ended September 30, |  | Nine Months Ended September 30,
| 2025 |  | 2024 |  | 2025 |  | 2024
| (Dollars in millions)
Service cost for benefits earned | $ | 0.1 |  |  | $ | 0.1 |  |  | $ | 0.3 |  |  | $ | 0.3 |
Interest cost on accumulated postretirement benefit obligation | 1.9 |  |  | 2.3 |  |  | 5.8 |  |  | 6.9 |
Expected return on plan assets | (0.1) |  |  | (0.1) |  |  | (0.3) |  |  | (0.3) |
Amortization of prior service credit | (10.2) |  |  | (13.3) |  |  | (30.6) |  |  | (39.8) |
Net periodic postretirement benefit credit | $ | (8.3) |  |  | $ | (11.0) |  |  | $ | (24.8) |  |  | $ | (32.9) |

X
- References No definition available. + Details
Name: | us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (q) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 715 -SubTopic 20 -Subparagraph (h) -Name Accounting Standards Codification -Paragraph 1 -Section 50 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration