v3.26.1
REGULATORY ASSETS AND LIABILITIES - REGULATORY ASSETS (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Regulatory assets    
Other current assets $ 38.7 $ 17.3
Regulatory assets 3,130.4 3,156.3
Total regulatory assets 3,169.1 3,173.6
Plant retirement related items    
Regulatory assets    
Total regulatory assets 736.6 768.6
Environmental remediation costs    
Regulatory assets    
Total regulatory assets 545.6 566.0
Income tax related items    
Regulatory assets    
Total regulatory assets 531.4 493.4
Pension and OPEB costs    
Regulatory assets    
Total regulatory assets 524.9 564.5
AROs    
Regulatory assets    
Total regulatory assets 205.5 185.1
System support resource    
Regulatory assets    
Total regulatory assets 87.5 92.6
Decoupling    
Regulatory assets    
Total regulatory assets 81.0 43.8
Electric transmission costs    
Regulatory assets    
Total regulatory assets 73.8 30.7
Uncollectible expense    
Regulatory assets    
Total regulatory assets 71.1 123.9
Securitization    
Regulatory assets    
Total regulatory assets 63.6 67.5
Derivatives    
Regulatory assets    
Total regulatory assets 48.7 57.7
Finance and operating leases    
Regulatory assets    
Total regulatory assets 44.5 36.0
Bluewater    
Regulatory assets    
Total regulatory assets 28.6 37.7
Energy costs recoverable through rate adjustments    
Regulatory assets    
Total regulatory assets 24.3 6.7
Other, net    
Regulatory assets    
Total regulatory assets $ 102.0 $ 99.4