v3.25.2
Cover Page - shares
 6 Months Ended
Jun. 30, 2025
Jul. 22, 2025
Class of Stock [Line Items]    
Entity Address, City or Town Dublin  
Entity Address, Address Line One Block D  
Entity Address, Postal Zip Code D02 VH94  
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2025  
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 2025  
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 Block D  
Entity Address, Address Line Two Iveagh Court  
Entity Address, Address Line Three Harcourt Road  
Entity Address, City or Town Dublin  
Entity Address, Postal Zip Code D02 VH94  
Entity Address, Country IE  
Country Region 353  
City Area Code 1  
Local Phone Number 2546200  
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   85,846,520
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