Cover Page - shares	3 Months Ended
	Nov. 30, 2021	Jan. 03, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Nov. 30, 2021
Document Transition Report	false
Entity File Number	001-16583
Entity Registrant Name	ACUITY BRANDS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	58-2632672
Entity Address, Address Line One	1170 Peachtree Street, N.E.
Entity Address, Address Line Two	Suite 2300
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30309-7676
City Area Code	404
Local Phone Number	853-1400
Title of 12(b) Security	Common stock, $0.01 par value per share
Trading Symbol	AYI
Security Exchange Name	NYSE
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		35,018,213
Entity Central Index Key	0001144215
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--08-31