Total costs accrued as of the balance sheet date for environmental loss contingencies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346

Name:	us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Contingencies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Contingencies (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Loss Contingencies [Line Items]
Accrual for environmental investigation and remediation activities	$ 9.3	$ 9.1	$ 9.3
Minimum
Loss Contingencies [Line Items]
Estimate of possible loss	0.0
Maximum
Loss Contingencies [Line Items]
Estimate of possible loss	$ 5.4
Ohio Dormant Mineral Act, Mineral Abandonment Case
Loss Contingencies [Line Items]
Mineral interest abandonment statutory period	20 years
Estimate of possible loss	$ 4.5