v3.25.4
Pending Merger with NorthWestern Energy - Additional Information (Details)
Dec. 31, 2025
$ / shares
Aug. 18, 2025
$ / shares
Dec. 31, 2024
$ / shares
Business Combination [Line Items]      
Common stock, par value (usd per share) $ 1   $ 1
NorthWestern      
Business Combination [Line Items]      
Common stock, par value (usd per share)   $ 0.01  
Business acquisition exchange ratio on common stock   0.98  
Business acquisition exchange of common stock par value per share   $ 1