Financial Instruments and Risk Management (Derivatives Designated as Hedging Instruments Fair Values of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Fair value of financial instruments	$ 88.9	$ 62.2
Liability derivatives, fair value	31.1	15.3
Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Fair value of financial instruments	79.6	48.1
Designated as hedging instrument \| Prepaid expenses and other current assets \| Interest rate swaps
Derivatives, Fair Value [Line Items]
Fair value of financial instruments	16.2	26.2
Designated as hedging instrument \| Prepaid expenses and other current assets \| Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Fair value of financial instruments	$ 63.4	$ 21.9

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=64830801&loc=SL51823488-111719

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624163-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226000-175313

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant