v3.26.3
Cover Page - shares
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2026
Nov. 02, 2026
Cover [Abstract]      
Document Type   10-Q  
Document Quarterly Report   true  
Document Period End Date   Sep. 30, 2026  
Document Transition Report   false  
Entity File Number   1-5924  
Entity Registrant Name   TUCSON ELECTRIC POWER CO  
Entity Incorporation, State or Country Code   AZ  
Entity Tax Identification Number   86-0062700  
Entity Address, Address Line One   88 East Broadway Boulevard  
Entity Address, City or Town   Tucson  
Entity Address, State or Province   AZ  
Entity Address, Postal Zip Code   85701  
City Area Code   520  
Local Phone Number   571-4000  
Entity Current Reporting Status   Yes  
Entity Interactive Data Current   Yes  
Entity Filer Category   Non-accelerated Filer  
Entity Small Business   false  
Entity Emerging Growth Company   false  
Entity Shell Company   false  
Entity Common Stock, Shares Outstanding     32,139,434
Amendment Flag   false  
Document Fiscal Year Focus   2026  
Document Fiscal Period Focus   Q3  
Entity Central Index Key   0000100122  
Current Fiscal Year End Date   --12-31  
No Insider Trading Flag true