Business and Summary of Significant Accounting Principles (Asset Retirement Obligations Narrative) (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Accounting Policies [Abstract] | ||
| Additional capitalized costs | $ 4.7 | $ 4.9 |
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- References No definition available.
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- Definition The amount of asset retirement costs previously incurred and capitalized separately from the capitalized amount of the associated long-lived assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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