Equity, Capital and Other Interests - Changes in Operating Partnership's Issued and Outstanding General Partner Units and Limited Partner Units (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
General and Limited Partner Units
Common Shares And Units Outstanding	386,160,073	385,402,199
Exercise of share options	1,710,692	239,695	1,745,050
Employee Share Purchase Plan (ESPP)	70,702	90,196	48,131
Restricted share grants, net	89,593	178,720	158,602
Restricted unit grants, net	155,162	249,263	141,220
Common Shares And Units Outstanding	388,186,222	386,160,073	385,402,199
Limited Partner Units
Total Units Outstanding	13,858,073	13,731,315	13,904,035
Restricted unit grants, net	155,162	249,263	141,220
Conversion of Limited Partner OP Units to EQR Common Shares	(1,354,208)	(122,505)	(313,940)
Total Units Outstanding	12,659,027	13,858,073	13,731,315
Units Ownership Interest in Operating Partnership	3.30%	3.60%	3.60%
ERPOP [Member]
General and Limited Partner Units
Common Shares And Units Outstanding	386,160,073	385,402,199	383,309,196
Exercise of share options	1,710,692	239,695	1,745,050
Employee Share Purchase Plan (ESPP)	70,702	90,196	48,131
Restricted share grants, net	89,593	178,720	158,602
Restricted unit grants, net	155,162	249,263	141,220
Common Shares And Units Outstanding	388,186,222	386,160,073	385,402,199
Limited Partner Units
Total Units Outstanding	13,858,073	13,731,315	13,904,035
Restricted unit grants, net	155,162	249,263	141,220
Conversion of Limited Partner OP Units to EQR Common Shares	(1,354,208)	(122,505)	(313,940)
Total Units Outstanding	12,659,027	13,858,073	13,731,315
Units Ownership Interest in Operating Partnership	3.30%	3.60%	3.60%