Regulatory Matters - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Regulated Asset Liability [Line Items]
Threshold limit of deadband and sharing bands for future surcharge or rebate to customer	$ 4
Threshold to return washington energy recovery mechanism dollars to customers	$ 30
Proposed cumulative rebate refund period	2 years
Deferred natural gas costs, asset		$ 52
Deferred natural gas costs, liability	$ 25
WASHINGTON
Regulated Asset Liability [Line Items]
Decoupling maximum rate increase request	3.00%
WASHINGTON | Power Deferrals Regulatory Asset [Member]
Regulated Asset Liability [Line Items]
Regulatory assets	$ 36	38
IDAHO | Power Deferrals Regulatory Asset [Member]
Regulated Asset Liability [Line Items]
Regulatory assets		8
Regulatory liabilities	15
Revenue Subject to Refund [Member] | IDAHO
Regulated Asset Liability [Line Items]
Regulatory liabilities	$ 0	$ 1