Regulatory Matters - WUTC (Details) - Natural gas distribution - WUTC - Cascade Natural Gas - USD ($) $ in Millions	Dec. 11, 2024	Mar. 29, 2024
Pending Rate Case, Multi-Year, Year One
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount	$ 29.8	$ 43.8
Public utilities, requested rate increase (decrease), percentage	7.90%	11.60%
Pending Rate Case, Multi-Year, Year Two
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount	$ 10.8	$ 11.7
Public utilities, requested rate increase (decrease), percentage	2.60%	2.80%