Pensions and Postretirement Benefits Other Than Pensions (Schedule of Benefit Payments for Postretirement Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Multiemployer plan, period contributions	$ 10.4	$ 9.8	$ 9.0
Postretirement [Member]
2015	41.9
2016	41.5
2017	39.5
2018	37.1
2019	35.0
2020-2024	$ 142.7

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
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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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Amount of contributions made to multiemployer plan by employer.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 9
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