Commitments and Contingencies Commitments and Contingencies (Narrative) (Details)	6 Months Ended
Jun. 30, 2019
System Energy [Member]
Loss Contingencies [Line Items]
Minimum Rate Of Equity Capital	35.00%

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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration