Commitments and Contingencies Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Loss Contingencies [Line Items]
Litigation proceeds for reimbursement of spent nuclear fuel storage costs	$ 62,162	$ 0

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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