Financial Instruments and Fair Value Measurements Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Excluding Capital Leases and Note Issuance Costs, Net	$ 1,687.1	$ 1,149.2
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Excluding Capital Leases and Note Issuance Costs, Net	$ 1,687.5	$ 1,177.9

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.

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