Pension Plans - Qualified and Non-Qualified Plans - Adjustments to Equity (Details) - Pension Plan [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Change in equity as a result of change in deferred net loss	$ 2.1	$ (1.3)	$ 4.5
Change in equity as result of change in deferred net loss taxes	$ 0.5	$ (0.4)	$ 1.5

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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