New Accounting Pronouncements (Narrative) (Details) - ASU No. 2016-09 [Member] $ in Millions	6 Months Ended
Jun. 30, 2017 USD ($)
Reclassification from Operating Activities to Financing Activities [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Shares withheld from employee awards for tax withholding purposes	$ 38.1
Incentive Stock Award Plans [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Provision for income tax expense (benefit)	$ (17.1)

Amount of cash outflow to satisfy an employee's income tax withholding obligation as part of a net-share settlement of a share-based award.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 25
-Paragraph 19A
-URI http://asc.fasb.org/extlink&oid=96949009&loc=SL79513924-113897

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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