Pension and Postretirement Health and Life Benefits (Schedule of Net Benefit Costs) (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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| Pension Plan, Defined Benefit [Member] | ||||
| Service costs | $ 0.1 | $ 0.1 | $ 0.3 | $ 0.3 |
| Interest costs | 0.4 | 0.4 | 1.2 | 1.2 |
| Defined Benefit Plan, Amortization of Prior Service Cost (Credit) | 0.0 | 0.0 | (0.1) | (0.1) |
| Expected return on plan assets (gains) | (0.5) | (0.5) | (1.4) | (1.4) |
| Net periodic benefit cost (credit) | 0.0 | 0.0 | 0.0 | 0.0 |
| Postretirement Health and Life Benefits Plans [Member] | ||||
| Interest costs | 1.2 | 1.2 | 3.4 | 3.4 |
| Defined Benefit Plan, Amortization of Prior Service Cost (Credit) | 0.0 | (0.1) | (0.1) | (0.1) |
| Net periodic benefit cost (credit) | $ 1.2 | $ 1.1 | $ 3.3 | $ 3.3 |
| 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 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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