Recent Accounting Pronouncements Adoption of ASU 2016-02 Leases - Impact of Adoption (Details) - Adjustments for New Accounting Pronouncement [Member] - USD ($) $ in Millions	Jan. 01, 2019	Dec. 31, 2018
Other Noncurrent Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Balance as of December 31, 2018 - Prior to Adoption of ASU 2016-02		$ (196.8)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 80.0
Balance as of January 1, 2019 - Subsequent to Adoption of ASU 2016-02	(276.8)
Accrued Liabilities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Balance as of December 31, 2018 - Prior to Adoption of ASU 2016-02		416.7
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(18.7)
Balance as of January 1, 2019 - Subsequent to Adoption of ASU 2016-02	435.4
Other Noncurrent Liabilities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Balance as of December 31, 2018 - Prior to Adoption of ASU 2016-02		$ 166.5
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(61.3)
Balance as of January 1, 2019 - Subsequent to Adoption of ASU 2016-02	$ 227.8