| Cover Page | Oct. 28, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 28, 2020 |
| Entity Registrant Name | AVALONBAY COMMUNITIES, INC. |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 1-12672 |
| Entity Tax Identification Number | 77-0404318 |
| Entity Address, Address Line One | 4040 Wilson Blvd., Suite 1000 |
| Entity 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | AVB |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000915912 |
| Amendment Flag | false |
