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Regulatory matters - IPUC (Details) - Natural gas distribution - IPUC - Intermountain Gas Company - USD ($) $ in Millions | Oct. 20, 2025 | May 30, 2025
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Public Utilities, General Disclosures [Line Items] |  |
Public utilities, requested rate increase (decrease), amount |  | $ 26.5
Public utilities, requested rate increase (decrease), percentage |  | 8.60%
Subsequent Event |  |
Public Utilities, General Disclosures [Line Items] |  |
Public utilities, requested rate increase (decrease), percentage | 4.20% |
Public utilities, annual revenue increase (decrease) | $ 13.0 |

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