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, 2022	Mar. 31, 2021
General and Limited Partner Units
Exercise of share options	269,665	506,342
Employee Share Purchase Plan (ESPP)	13,374	32,572
Restricted share grants, net	157,080	76,499
Restricted unit grants, net	220,333	184,301
Common Shares And Units Outstanding	388,846,674	386,959,787
Limited Partner Units
Total Units Outstanding	12,659,027	13,858,073
Restricted unit grants, net	220,333	184,301
Conversion of Limited Partner OP Units to EQR Common Shares	(6,756)
Total Units Outstanding	12,872,604	14,042,374
Units Ownership Interest in Operating Partnership	3.30%	3.60%
ERPOP [Member]
General and Limited Partner Units
Common Shares And Units Outstanding	388,186,222	386,160,073
Exercise of share options	269,665	506,342
Employee Share Purchase Plan (ESPP)	13,374	32,572
Restricted share grants, net	157,080	76,499
Restricted unit grants, net	220,333	184,301
Common Shares And Units Outstanding	388,846,674	386,959,787
Limited Partner Units
Total Units Outstanding	12,659,027	13,858,073
Restricted unit grants, net	220,333	184,301
Conversion of Limited Partner OP Units to EQR Common Shares	(6,756)
Total Units Outstanding	12,872,604	14,042,374
Units Ownership Interest in Operating Partnership	3.30%	3.60%