Name:	eqr_DefinedContributionPlanVestingPeriod
Namespace Prefix:	eqr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the maximum amount of an employee's contribution to the defined contribution plan that is matched by the company.

No definition available.

Name:	eqr_MaximumEligibleCompensationPercentageForDefinedContributionPlanByEmployer
Namespace Prefix:	eqr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Represents the number of common shares available for purchase under the employee share purchase plan at the balance sheet date.

No definition available.

Name:	eqr_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForPurchaseUnderEmployeeSharePurchasePlan
Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Represents the maximum value of common shares an employee can acquire under the employee share purchase plan on an annual basis.

No definition available.

Name:	eqr_ShareBasedCompensationArrangementByShareBasedPaymentAwardValueOfCommonSharesThatCanBeAcquiredByEmployeeAndTrusteesUnderEmployeesSharePurchasePlan
Namespace Prefix:	eqr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents the number of shares authorized for purchase under the employee share purchase plan after the most recent amendment.

No definition available.

Name:	eqr_Sharebasedcompensationarrangementbysharebasedpaymentawardnumberofsharesauthorizedafteramendment
Namespace Prefix:	eqr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Amount of cost for defined contribution plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Discount rate from fair value on purchase date that participants pay for shares.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.