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WUTC (Details 3) - Pending Rate Case [Member] - Gas Distribution [Member] - WUTC [Member] - Cascade Natural Gas [Member] - USD ($) $ in Millions | Mar. 24, 2022 | Mar. 22, 2022 | Sep. 30, 2021
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Public Utilities, General Disclosures [Line Items] |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount | $ 3.3 |  | $ 13.7
Public Utilities, Requested Rate Increase (Decrease), Percentage |  |  | 5.10%
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount |  | $ 10.7 |
Public Utilities, Requested Rate Increase (Decrease), Amended, Percentage |  | 4.00% |

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