Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 13, 2020	Jun. 30, 2019
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	001-35971
Entity Central Index Key	0001579241
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
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	2
Entity Address, Country	IE
Country Region	353
City Area Code	1
Local Phone Number	2546200
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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 Public Float			$ 10.3
Entity Registrant Name	Allegion plc
Entity Common Stock, Shares Outstanding		92,600,522
Ordinary shares
Document Information [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
Document Information [Line Items]
Title of 12(b) Security	3.500% Senior Notes due 2029
Trading Symbol	ALLE 3 ½
Security Exchange Name	NYSE