v3.26.1
Cover Page - shares
 6 Months Ended
Jun. 30, 2026
Jul. 20, 2026
Class of Stock [Line Items]    
Entity Address, City or Town Dublin 7  
Entity Address, Address Line One Unit No. 233  
Entity Address, Postal Zip Code D07 X324  
NumberofAuthorizedSharesNotDisclosed true  
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2026  
Document Transition Report false  
Entity File Number 001-35971  
Entity Central Index Key 0001579241  
Entity Registrant Name Allegion plc  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Entity Incorporation, State or Country Code L2  
Entity Tax Identification Number 98-1108930  
Entity Address, Address Line One Unit No. 233  
Entity Address, Address Line Two The Capel Building  
Entity Address, Address Line Three Mary’s Abbey  
Entity Address, City or Town Dublin 7  
Entity Address, Postal Zip Code D07 X324  
Entity Address, Country IE  
Country Region 353  
City Area Code 1  
Local Phone Number 6833399  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   85,036,786
Ordinary shares    
Class of Stock [Line Items]    
Title of 12(b) Security Ordinary shares, par value $0.01 per share  
Trading Symbol ALLE  
Security Exchange Name NYSE  
3.500% Senior Notes Due 2029    
Class of Stock [Line Items]    
Title of 12(b) Security 3.500% Senior Notes due 2029  
Trading Symbol ALLE 3 ½  
Security Exchange Name NYSE