Retirement Plans - Changes in Fair Value of Level Three Assets (Details) - Fair Value, Inputs, Level 3 - Private Equity $ in Millions	12 Months Ended
Dec. 31, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 47.3
Unrealized gains-net	11.9
Purchases, sales and settlements	(14.1)
Plan transfer	(45.1)
Fair value of plan assets at end of year	$ 0.0

Amount before tax, after reclassification adjustments, of actuarial gain (loss) that has not been recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=66004124&loc=SL7669646-108580

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
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-URI http://asc.fasb.org/extlink&oid=64937038&loc=d3e12355-114930

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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6749337

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Amount of increase (decrease) in plan assets from purchases, sales and settlement of plan obligations.

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Transfers in and out of Level 3. For example, transfers due to changes in the observability of significant inputs.

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