Environmental and Legal Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Environmental-related capital investments	$ 6.8	$ 4.9	$ 7.1
Environmental compliance costs	$ 129.5	$ 123.9	$ 133.2

Amount of environmental remediation costs capitalized. These expenditures may relate to long-lived improvements in operating facilities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 25
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=39739230&loc=d3e11660-110855

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration