Commitments and Contingencies Personal Injury Liability Activity (Details) - Personal Injury [Member] - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Personal Injury Liability Activity [Roll Forward]
Balance at beginning of year	$ 23.8	$ 23.9
Accruals	2.4	2.4
Change in estimate	(2.0)	(0.6)
Payments	(2.8)	(2.0)
Balance at end of period	$ 21.4	$ 23.7

Amount of increase decrease in loss contingency liability for change in estimate

No definition available.

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- Definition

Amount of loss contingency liability.

+ References

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

+ Details

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- Definition

Amount of cash outflow reducing loss contingency liability.

+ References

+ Details

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- Definition

Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges.

+ References

+ Details

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Details

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