v3.26.3
REGULATORY ASSETS AND LIABILITIES - REGULATORY ASSETS (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Regulatory assets    
Other current assets $ 46.2 $ 17.3
Regulatory assets 3,140.7 3,156.3
Total regulatory assets 3,186.9 3,173.6
Plant retirement related items    
Regulatory assets    
Total regulatory assets 722.1 768.6
Income tax related items    
Regulatory assets    
Total regulatory assets 549.8 493.4
Environmental remediation costs    
Regulatory assets    
Total regulatory assets 538.2 566.0
Pension and OPEB costs    
Regulatory assets    
Total regulatory assets 506.5 564.5
AROs    
Regulatory assets    
Total regulatory assets 215.0 185.1
Electric transmission costs    
Regulatory assets    
Total regulatory assets 100.0 30.7
System support resource    
Regulatory assets    
Total regulatory assets 85.0 92.6
Decoupling    
Regulatory assets    
Total regulatory assets 78.7 43.8
Derivatives    
Regulatory assets    
Total regulatory assets 66.2 57.7
Securitization    
Regulatory assets    
Total regulatory assets 60.9 67.5
Uncollectible expense    
Regulatory assets    
Total regulatory assets 49.3 123.9
Finance and operating leases    
Regulatory assets    
Total regulatory assets 48.6 36.0
Revenue requirements of generation facilities    
Regulatory assets    
Total regulatory assets 27.8 4.2
Bluewater    
Regulatory assets    
Total regulatory assets 22.2 37.7
Other, net    
Regulatory assets    
Total regulatory assets $ 116.6 $ 101.9