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Leases (Right-of-Use Assets and Liabilities) (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
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Lessee, Lease, Description [Line Items] |  |
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] | Net Property, Plant and Equipment | Net Property, Plant and Equipment
Finance Lease, Right-of-Use Asset | $ 184.3 | $ 153.4
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] | Deferred charges and other | Deferred charges and other
Operating Lease, Right-of-Use Asset | $ 32.9 | $ 35.7
Total leased assets | $ 217.2 | $ 189.1
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List] | Long-Term Debt and Lease Obligation, Current | Long-Term Debt and Lease Obligation, Current
Finance Lease, Liability, Current | $ 23.8 | $ 30.0
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] | Other Liabilities, Current | Other Liabilities, Current
Operating Lease, Liability, Current | $ 8.3 | $ 4.8
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] | Long-Term Debt and Lease Obligation | Long-Term Debt and Lease Obligation
Finance Lease, Liability, Noncurrent | $ 181.6 | $ 144.7
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] | Other noncurrent liabilities | Other noncurrent liabilities
Operating Lease, Liability, Noncurrent | $ 25.8 | $ 31.9
Total Lease Liability | $ 239.5 | $ 211.4

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- Definition Present value of lessee's discounted obligation for lease payments from finance lease, classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479041/842-20-45-1 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from finance lease, classified as noncurrent. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479041/842-20-45-1 + Details
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- Definition Amount, after accumulated amortization, of right-of-use asset from finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479041/842-20-45-1 + Details
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