| Document and Entity Information | Apr. 22, 2022 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | Allegion plc |
| Amendment Flag | false |
| Entity Central Index Key | 0001579241 |
| Document Type | 8-K |
| Document Period End Date | Apr. 22, 2022 |
| Entity Incorporation State Country Code | L2 |
| Entity Address, Country | IE |
| Entity File Number | 001-35971 |
| 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 2 |
| Entity Address, Postal Zip Code | D02 VH94 |
| City Area Code | (353)(1) |
| Local Phone Number | 2546200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Fair Value Measured at Net Asset Value Per Share [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Ordinary shares, par value $0.01 per share |
| Trading Symbol | ALLE |
| Security Exchange Name | NYSE |
| Senior Notes [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 3.500% Senior Notes due 2029 |
| Trading Symbol | ALLE 3 1⁄2 |
| Security Exchange Name | NYSE |
