Commitments and Contingencies Coal Ash Regulation (Details)	Sep. 30, 2019
Federal Coal Ash Regulation [Domain]
Site Contingency [Line Items]
Number of sites where regulated ash units will still be in operation at a specified date	6

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.

No definition available.

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