Midcontinent Independent System Operator, Inc. (MISO) (Details 5) - USD ($) $ in Millions	Mar. 01, 2018	Jan. 01, 2018
MISO \| Electric transmission rate proceeding \| Tax Cuts and Jobs Act
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount	$ 12.0	$ 13.6

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.

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