Pensions and Postretirement Benefits (Summary Company's Expected Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Pension Benefits
Other postretirement benefit plans defined benefit net including medicare subsidy
Pension Benefits 2018	$ 5.1
Pension Benefits 2019	4.4
Pension Benefits 2020	4.5
Pension Benefits 2021	4.6
Pension Benefits 2022	4.4
Pension Benefits 2023 to 2027	22.8
Postretirement Benefits
Other postretirement benefit plans defined benefit net including medicare subsidy
Pension Benefits 2018	0.1
Pension Benefits 2019	0.1
Pension Benefits 2020	0.1
Pension Benefits 2021	0.1
Pension Benefits 2022	0.1
Pension Benefits 2023 to 2027	0.4
Postretirement Benefits \| Gross
Other postretirement benefit plans defined benefit net including medicare subsidy
Pension Benefits 2018	1.2
Pension Benefits 2019	1.1
Pension Benefits 2020	1.0
Pension Benefits 2021	0.9
Pension Benefits 2022	0.9
Pension Benefits 2023 to 2027	3.6
Postretirement Benefits \| Expected Medicare Subsidy
Other postretirement benefit plans defined benefit net including medicare subsidy
Pension Benefits 2018	1.1
Pension Benefits 2019	1.0
Pension Benefits 2020	0.9
Pension Benefits 2021	0.8
Pension Benefits 2022	0.8
Pension Benefits 2023 to 2027	$ 3.2

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- Definition

Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

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