Equity, Capital and Other Interests - Changes in Operating Partnership's Issued and Outstanding Units (Details) - shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
General and Limited Partner Units
Exercise of share options	1,059,674	80,875
Employee Share Purchase Plan (ESPP)	27,131	44,858
Restricted share grants, net	158,438	123,027
Restricted unit grants, net	140,055	267,074
Common Shares And Units Outstanding	384,694,494	382,302,354
LIMITED PARTNERS
Total Units Outstanding	13,904,035	13,768,438
Restricted unit grants, net	140,055	267,074
Conversion of Limited Partner OP Units to EQR Common Shares	(188,406)	(11,494)
Total Units Outstanding	13,855,684	14,024,018
Units Ownership Interest in Operating Partnership	3.60%	3.70%
ERPOP [Member]
General and Limited Partner Units
Common Shares And Units Outstanding	383,309,196	381,786,520
Exercise of share options	1,059,674	80,875
Employee Share Purchase Plan (ESPP)	27,131	44,858
Restricted share grants, net	158,438	123,027
Restricted unit grants, net	140,055	267,074
Common Shares And Units Outstanding	384,694,494	382,302,354
LIMITED PARTNERS
Total Units Outstanding	13,904,035	13,768,438
Restricted unit grants, net	140,055	267,074
Conversion of Limited Partner OP Units to EQR Common Shares	(188,406)	(11,494)
Total Units Outstanding	13,855,684	14,024,018
Units Ownership Interest in Operating Partnership	3.60%	3.70%