Equity, Capital and Other Interests - Changes in Operating Partnership's Issued and Outstanding General Partner Units and Limited Partner Units (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
General and Limited Partner Units
Exercise of share options	214,521	709,071
Employee Share Purchase Plan (ESPP)	13,606	18,901
Restricted share grants, net	163,098	144,390
Restricted unit grants, net	243,063	133,214
Common Shares And Units Outstanding	386,036,487	384,314,772
Limited Partner Units
Total Units Outstanding	13,731,315	13,904,035
Restricted unit grants, net	243,063	133,214
Conversion of Limited Partner OP Units to EQR Common Shares	(41,945)	(184,878)
Total Units Outstanding	13,932,433	13,852,371
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	214,521	709,071
Employee Share Purchase Plan (ESPP)	13,606	18,901
Restricted share grants, net	163,098	144,390
Restricted unit grants, net	243,063	133,214
Common Shares And Units Outstanding	386,036,487	384,314,772
Limited Partner Units
Total Units Outstanding	13,731,315	13,904,035
Restricted unit grants, net	243,063	133,214
Conversion of Limited Partner OP Units to EQR Common Shares	(41,945)	(184,878)
Total Units Outstanding	13,932,433	13,852,371
Units Ownership Interest in Operating Partnership	3.60%	3.60%