Pension and Postretirement Benefit Costs - Schedule of Net Periodic Benefit (Benefit) Cost (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
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| Defined Benefit Plan Disclosure [Line Items] | ||||
| Net periodic postretirement benefit credit | $ (12.1) | $ (7.5) | $ (12.8) | $ (22.3) |
| Postretirement benefit plans | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Service cost for benefits earned | 0.0 | 0.1 | 0.1 | 0.3 |
| Interest cost on accumulated postretirement benefit obligation | 1.3 | 1.9 | 4.6 | 5.8 |
| Expected return on plan assets | 0.0 | (0.1) | (0.1) | (0.3) |
| Amortization of prior service credit | (14.3) | (10.2) | (20.0) | (30.6) |
| Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) | (3.3) | 0.0 | (3.3) | 0.0 |
| Net periodic postretirement benefit credit | $ (16.3) | $ (8.3) | $ (18.7) | $ (24.8) |
| X | ||||||||||
- Definition Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- 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 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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- Details
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