Commitments and Contingencies - Variable Interest Entities (Details) - MW	Mar. 31, 2021	Dec. 31, 2020
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Variable Interest Entity [Line Items]
Generating capacity under long term purchased power agreements	1,347	1,347

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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