Equity, Capital and Other Interests - Changes in Operating Partnership's Issued and Outstanding General Partner Units and Limited Partner Units (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
General and Limited Partner Units
Exercise of share options	217,935	1,059,674
Employee Share Purchase Plan (ESPP)	44,110	27,131
Restricted share grants, net	178,720	158,438
Restricted unit grants, net	245,999	140,055
Common Shares And Units Outstanding	386,088,963	384,694,494
Limited Partner Units
Total Units Outstanding	13,731,315	13,904,035
Restricted unit grants, net	245,999	140,055
Conversion of Limited Partner OP Units to EQR Common Shares	(97,363)	(188,406)
Total Units Outstanding	13,879,951	13,855,684
Units Ownership Interest in Operating Partnership	3.60%	3.60%
ERPOP [Member]
General and Limited Partner Units
Common Shares And Units Outstanding	385,402,199	383,309,196
Exercise of share options	217,935	1,059,674
Employee Share Purchase Plan (ESPP)	44,110	27,131
Restricted share grants, net	178,720	158,438
Restricted unit grants, net	245,999	140,055
Common Shares And Units Outstanding	386,088,963	384,694,494
Limited Partner Units
Total Units Outstanding	13,731,315	13,904,035
Restricted unit grants, net	245,999	140,055
Conversion of Limited Partner OP Units to EQR Common Shares	(97,363)	(188,406)
Total Units Outstanding	13,879,951	13,855,684
Units Ownership Interest in Operating Partnership	3.60%	3.60%