WUTC (Details 6) - Natural gas rate proceeding [Member] - WUTC - USD ($) $ in Millions	Mar. 29, 2019	Mar. 28, 2019
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Amount		$ 48.0
Public utilities, requested rate increase (decrease), amount	$ 12.7
Public utilities, requested rate increase (decrease), percentage	5.50%

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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