XML 108 R82.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Commitments and Contingencies (Details) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
300 properties designed and built in violation of accessibility requirements | 300 eqr_PropertiesDesignedAndBuiltInViolationOfAccessibilityRequirements |  |
Projects in various stages of development | 15 eqr_NumberOfProjectsInVariousStagesOfDevelopment |  |
Units in various stages of development | 4,917 eqr_NumberOfUnitsInVariousStagesOfDevelopment |  |
Consolidated Project Under Development Commitment Fund | $ 1,200,000,000 eqr_ConsolidatedProjectUnderDevelopmentCommitmentFund |  |
Various stages of development with estimated completion dates ranging through June 30, 2016 | Sep. 30, 2017 |  |
Number Of Unconsolidated Projects | 1 eqr_NumberOfUnconsolidatedProjects |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets | 498,640,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets | 108,000,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets |
Investment in Joint Venture | 336,900,000 eqr_InvestmentInJointVenture |  |
Noncontrolling Interests - Partially Owned Properties | 124,909,000 eqr_NoncontrollingInterestsPartiallyOwnedProperties | 126,583,000 eqr_NoncontrollingInterestsPartiallyOwnedProperties |
Number Of Operating Properties Under Long Term Ground Leases | 13 eqr_NumberOfOperatingPropertiesUnderLongTermGroundLeases |  |
Total operating lease payments | 14,700,000 us-gaap_OperatingLeasesRentExpenseNet | 13,200,000 us-gaap_OperatingLeasesRentExpenseNet | 8,100,000 us-gaap_OperatingLeasesRentExpenseNet
Compensation expense, Recognized | 500,000 us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense | 500,000 us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense | 1,000,000 us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense
Number Of Operating Properties and Land Parcels Under Long Term Ground Leases | 14 eqr_NumberOfOperatingPropertiesAndLandParcelsUnderLongTermGroundLeases |  |
Operating Leases: |  |  |
Minimum Rent Payments Due, Year 1 | (15,268,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent |  |
Minimum Rent Payments Due, Year 2 | (15,385,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears |  |
Minimum Rent Payments Due, Year 3 | (15,318,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears |  |
Minimum Rent Payments Due, Year 4 | (15,298,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears |  |
Minimum Rent Payments Due, Year 5 | (15,224,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears |  |
Minimum Rent Payments Due, Thereafter | (860,071,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter |  |
Minimum Rent Payments Due, Total | (936,564,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDue |  |
Other Long-Term Liabilities: |  |  |
Deferred Compensation Due, Year 1 | (1,382,000)us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths |  |
Deferred Compensation Due, Year 2 | (1,714,000)us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo |  |
Deferred Compensation Due, Year 3 | (1,714,000)us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree |  |
Deferred Compensation Due, Year 4 | (1,714,000)us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour |  |
Deferred Compensation Due, Year 5 | (1,120,000)us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive |  |
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter | (5,149,000)eqr_DefinedBenefitPlanExpectedFutureBenefitPaymentsThereafter |  |
Deferred Compensation Due, Total | (12,793,000)eqr_DefinedBenefitPlanExpectedFutureBenefitPayments |  |
Loss Contingency Accrual, Period Increase (Decrease) | 4,000,000 us-gaap_LossContingencyAccrualCarryingValuePeriodIncreaseDecrease |  |
Loss Contingency Accrual | 6,000,000 us-gaap_LossContingencyAccrualAtCarryingValue |  |
Company's Portion [Member] |  |  |
Land purchase price | 76,100,000 eqr_LandPurchasePrice / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = eqr_CompanysPortionMember |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets | 102,500,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = eqr_CompanysPortionMember |  |
Joint Venture Partner [Member] |  |  |
Land purchase price | 57,900,000 eqr_LandPurchasePrice / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = eqr_JointVenturePartnerMember |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets | 75,700,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = eqr_JointVenturePartnerMember |  |
Noncontrolling Interests - Partially Owned Properties | 117,400,000 eqr_NoncontrollingInterestsPartiallyOwnedProperties / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = eqr_JointVenturePartnerMember |  |
531190 Lessors of Other Real Estate Property [Member] |  |  |
Operating Leases: |  |  |
Minimum Rent Payments Due, Year 1 | (65,087,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent / us-gaap_TitleOfIndividualAxis = naics_ZZ531190 |  |
Minimum Rent Payments Due, Year 2 | (58,860,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears / us-gaap_TitleOfIndividualAxis = naics_ZZ531190 |  |
Minimum Rent Payments Due, Year 3 | (53,448,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears / us-gaap_TitleOfIndividualAxis = naics_ZZ531190 |  |
Minimum Rent Payments Due, Year 4 | (43,987,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears / us-gaap_TitleOfIndividualAxis = naics_ZZ531190 |  |
Minimum Rent Payments Due, Year 5 | (37,545,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears / us-gaap_TitleOfIndividualAxis = naics_ZZ531190 |  |
Minimum Rent Payments Due, Thereafter | (192,455,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter / us-gaap_TitleOfIndividualAxis = naics_ZZ531190 |  |
Minimum Rent Payments Due, Total | $ (451,382,000)us-gaap_OperatingLeasesFutureMinimumPaymentsDue / us-gaap_TitleOfIndividualAxis = naics_ZZ531190 |  |

X
- Definition Represents the company's remaining funding obligation (i.e. total project costs less book value) for consolidated projects that are under development. + References No definition available. + Details
Name: | eqr_ConsolidatedProjectUnderDevelopmentCommitmentFund
Namespace Prefix: | eqr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The total amount of benefits to be paid related to a defined benefit plan. + References No definition available. + Details
Name: | eqr_DefinedBenefitPlanExpectedFutureBenefitPayments
Namespace Prefix: | eqr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amounts of benefits expected to be paid six or more years subsequent to the balance sheet date. + References No definition available. + Details
Name: | eqr_DefinedBenefitPlanExpectedFutureBenefitPaymentsThereafter
Namespace Prefix: | eqr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The Company's and the Joint Venture partner's total combined investment in the project. + References No definition available. + Details
Name: | eqr_InvestmentInJointVenture
Namespace Prefix: | eqr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the purchase price of land acquired in a joint venture. + References No definition available. + Details
Name: | eqr_LandPurchasePrice
Namespace Prefix: | eqr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount of equity interests owned by noncontrolling partners in partially owned properties. + References No definition available. + Details
Name: | eqr_NoncontrollingInterestsPartiallyOwnedProperties
Namespace Prefix: | eqr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Total number of operating properties and land parcels for which the Company owns the building and improvements and leases the underlying land under long-term ground leases. + References No definition available. + Details
Name: | eqr_NumberOfOperatingPropertiesAndLandParcelsUnderLongTermGroundLeases
Namespace Prefix: | eqr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of operating properties for which the Company owns the building and improvements and leases the underlying land under long-term ground leases. + References No definition available. + Details
Name: | eqr_NumberOfOperatingPropertiesUnderLongTermGroundLeases
Namespace Prefix: | eqr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total number of open development projects. May include projects that are held for and/or under development, completed and not stabilized or completed and stabilized. These projects are consolidated. + References No definition available. + Details
Name: | eqr_NumberOfProjectsInVariousStagesOfDevelopment
Namespace Prefix: | eqr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total number of unconsolidated open development projects. May include projects that are held for and/or under development, completed and not stabilized or completed and stabilized. + References No definition available. + Details
Name: | eqr_NumberOfUnconsolidatedProjects
Namespace Prefix: | eqr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total number of units that are associated with open development projects. May include projects that are held for and/or under development, completed and not stabilized or completed and stabilized. These units are consolidated. + References No definition available. + Details
Name: | eqr_NumberOfUnitsInVariousStagesOfDevelopment
Namespace Prefix: | eqr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of properties that are party to a housing discrimination lawsuit. + References No definition available. + Details
Name: | eqr_PropertiesDesignedAndBuiltInViolationOfAccessibilityRequirements
Namespace Prefix: | eqr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the latest completion date for the current projects under development. + References No definition available. + Details
Name: | eqr_VariousStagesOfDevelopmentDateMaturity
Namespace Prefix: | eqr_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of assets acquired at the acquisition date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The compensation expense recognized during the period pertaining to the deferred compensation arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 30 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6409875&loc=d3e20015-108363 + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of benefits from a defined benefit plan expected to be paid in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of benefits from a defined benefit plan expected to be paid in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of benefits from a defined benefit plan expected to be paid in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of benefits from a defined benefit plan expected to be paid in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of benefits from a defined benefit plan expected to be paid in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of loss contingency liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase (decrease) in loss contingency liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyAccrualCarryingValuePeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717 + Details
Name: | us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_OtherLiabilitiesNoncurrentAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis=eqr_CompanysPortionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis=eqr_JointVenturePartnerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=naics_ZZ531190
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |