v3.25.4
REGULATORY ASSETS AND LIABILITIES (Tables)
 12 Months Ended
Dec. 31, 2025
Regulated Operations [Abstract]  
Summary of Regulatory Assets and Liabilities
Regulatory assets and liabilities arise as a result of the rate-setting process. Hydro One has recorded the following regulatory assets and liabilities:
As at December 31 (millions of dollars)
20252024
Regulatory assets:
    Deferred income tax regulatory asset3,549 3,263 
    Broadband deferral73 48 
    Post-retirement and post-employment benefits - non-service cost49 72 
    Environmental43 44 
    Getting Ontario Connected Act variance39 24 
    Distribution rate riders26 — 
    Incremental cloud computing implementation costs deferral20 10 
    Stock-based compensation18 24 
    Rural and remote rate protection (RRRP) variance— 18 
    Other50 42 
Total regulatory assets3,867 3,545 
Less: current portion(10)(42)
3,857 3,503 
Regulatory liabilities:
    Pension benefit regulatory liability610 647 
    Post-retirement and post-employment benefits336 376 
    Earnings sharing mechanism (ESM) deferral310 150 
    Retail settlement variance account (RSVA)242 157 
    External revenue variance75 31 
    Capitalized overhead tax variance50 38 
    Other post-employment benefits (OPEB) asymmetrical carrying charge variance49 33 
    Asset removal costs cumulative variance48 26 
    Tax rule changes variance36 34 
    Pension cost differential variance30 21 
    Advanced Metering Infrastructure (AMI) 2.0 variance29 7 
    Deferred income tax regulatory liability9 4 
    Distribution rate riders— 45 
    Other27 29 
Total regulatory liabilities1,851 1,598 
Less: current portion(230)(122)
1,621 1,476