Commitments and Contingencies (Piedmont) (Narrative) (Details) - Piedmont, Florida [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2015	Sep. 30, 2008
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 18.1	$ 24.0
Years to complete environmental remediation	until 2019 to complete source area remediation with groundwater recovery and treatment, continuing through 2029
Change in estimated exposure	$ 0.0
Segment Discontinued Operations Member
Loss Contingencies [Line Items]
Pretax environmental expense		$ 24.0

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
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The Increase or Decrease in the accrual for environmental loss in the period from revisions in estimates to existing obligations. The amount does not relate to changes in the environmental accrual related to business acquisitions or divestitures, or to currency movements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.Y.Q2)
-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

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The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13296-110859

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 30
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