v3.25.4
COVER
 12 Months Ended
Dec. 31, 2025
shares
Document Information [Line Items]  
Document Type 40-F
Document Registration Statement false
Document Annual Report true
Document Period End Date Dec. 31, 2025
Current Fiscal Year End Date --12-31
Entity File Number 333-225519-01
Entity Registrant Name Hydro One Limited
Entity Incorporation, State or Country Code A6
Entity Primary SIC Number 4911
Entity Address, Address Line One 483 Bay Street
Entity Address, Address Line Two South Tower, 8th Floor
Entity Address, City or Town Toronto
Entity Address, State or Province ON
Entity Address, Postal Zip Code M5G 2P5
Entity Address, Country CA
City Area Code 416
Local Phone Number 345-5000
Security Reporting Obligation 15(d)
Annual Information Form true
Audited Annual Financial Statements true
Entity Common Stock, Shares Outstanding 599,781,811
Entity Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Emerging Growth Company false
ICFR Auditor Attestation Flag false
Document Financial Statement Error Correction [Flag] false
Entity Central Index Key 0001712356
Document Fiscal Year Focus 2025
Document Fiscal Period Focus FY
Amendment Flag false
Business Contact  
Document Information [Line Items]  
Entity Address, Address Line One 28 Liberty St.
Entity Address, City or Town New York
Entity Address, State or Province NY
Entity Address, Postal Zip Code 10005
City Area Code 212
Local Phone Number 894-8940
Contact Personnel Name C T Corporation System