WUTC (Details 4) - Pending Rate Case [Member] - Gas Distribution [Member] - WUTC [Member] - Cascade Natural Gas [Member] $ in Millions	Sep. 30, 2021 USD ($)
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 13.7
Public Utilities, Requested Rate Increase (Decrease), Percentage	5.10%

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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