Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 30, 2020
Cover [Abstract]
Document Type	10-Q
Document Period End Date	Sep. 30, 2020
Entity File Number	1-12672
Entity Registrant Name	AVALONBAY COMMUNITIES, INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	77-0404318
Entity Address, Address Line One	4040 Wilson Blvd., Suite 1000
Entity Address, Address City or Town	Arlington
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	22203
City Area Code	703
Local Phone Number	329-6300
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	AVB
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		139,608,983
Entity Central Index Key	0000915912
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false