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Litigation (Details) - USD ($) $ in Millions | Mar. 31, 2022 | Dec. 31, 2021 | Mar. 31, 2021
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Loss Contingencies [Line Items] |  |  |
Potential liabilities related to litigation and environmental matters | $ 30.0 | $ 37.0 | $ 55.0
Insurance Receivable | 7.1 | 14.1 | 31.6
Regulatory Assets | $ 20.8 | $ 21.2 | $ 20.9

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