Summary of Significant Accounting Policies Enviromental Costs (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accrued Environmental Loss Contingencies, Noncurrent	$ 25.0	$ 18.7

Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable after twelve months or beyond the next operating cycle if longer.

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-Name Accounting Standards Codification
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