Retirement Benefits - Schedule of Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Mar. 31, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
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| Pension Benefits: | |||||
| Defined Benefit Plan Disclosure [Line Items] | |||||
| Service cost | $ 0.0 | $ 0.1 | $ 0.1 | $ 0.1 | |
| Interest cost | 0.1 | 2.8 | 0.3 | 8.5 | |
| Expected return on plan assets | 0.0 | (2.3) | (0.1) | (6.9) | |
| Amortization of: | |||||
| Prior service cost | 0.0 | 0.3 | 0.0 | 0.3 | |
| Settlement | 0.0 | (10.0) | 0.0 | (10.0) | |
| Curtailment | 0.0 | 0.0 | $ (0.7) | 0.0 | (0.7) |
| Net periodic benefit cost | 0.1 | (9.1) | 0.3 | (8.7) | |
| Other Postretirement Benefits: | |||||
| Defined Benefit Plan Disclosure [Line Items] | |||||
| Interest cost | 0.1 | 0.1 | 0.3 | 0.3 | |
| Amortization of: | |||||
| Net periodic benefit cost | $ 0.1 | $ 0.1 | $ 0.3 | $ 0.3 | |
| X | ||||||||||
- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit from event reducing expected years of future service of present employees or eliminating accrual of defined benefits for some or all future services of present employees. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Defined Benefit Plan, Amortization No definition available.
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- Details
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- Details
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