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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Commercial Paper Weighted average period outstanding.

No definition available.

Name:	eqr_CommercialPaperWeightedAveragePeriodOutstanding
Namespace Prefix:	eqr_
Data Type:	xbrli:durationItemType
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Period Type:	duration

Represents the gross amount of commercial paper outstanding, not adjusted for the discount.

No definition available.

Name:	eqr_Commercialpaperprincipaloutstanding
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Percentage points of line of credit facility commitment fee.

No definition available.

Name:	eqr_PercentagePointsOfLineOfCreditFacilityCommitmentFee
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Data Type:	num:percentItemType
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Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Period Type:	instant

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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Data Type:	num:percentItemType
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Period Type:	duration

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Amount, after accumulated amortization, of debt discount.

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Weighted average interest rate of debt outstanding.

No definition available.

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Data Type:	num:percentItemType
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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Name:	us-gaap_LineOfCredit
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Period Type:	instant

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Amount of increase (decrease), classified as other, of the credit facility.

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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.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.