Leases - Summary of Undiscounted Cash Flows for Contractual Obligations for Minimum Rent Payments/Receipts (Details) $ in Thousands	Sep. 30, 2019 USD ($)
Leases [Abstract]
Remaining 2019	$ (141)
2020	(567)
2021	(578)
2022	(590)
2023	(601)
2024	(614)
Thereafter	(33,850)
Total	(36,941)
Remaining 2019	(4,175)
2020	(16,840)
2021	(16,862)
2022	(16,602)
2023	(16,687)
2024	(17,014)
Thereafter	(977,238)
Total	(1,065,418)
Remaining 2019	16,194
2020	63,409
2021	60,140
2022	56,624
2023	49,150
2024	41,950
Thereafter	149,208
Total	$ 436,675

Finance lease liability payments due after year six.

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- Definition

Finance lease liability payments due year six.

+ References

No definition available.

+ Details

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- Definition

Lessee, operating lease, liability, payments, due after year six.

+ References

No definition available.

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- Definition

Lessee, operating lease, liability, payments, due year six.

+ References

No definition available.

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- Definition

Lessor, operating lease, payments to be received, six years.

+ References

No definition available.

+ Details

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Namespace Prefix:	eqr_
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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease, due in fifth fiscal year following latest fiscal year.

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease, due in fourth fiscal year following latest fiscal year.

+ References

+ Details

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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease, due in third fiscal year following latest fiscal year.

+ References

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- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease, due in second fiscal year following latest fiscal year.

+ References

+ Details

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Namespace Prefix:	us-gaap_
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Period Type:	instant

- Definition

Amount of lessee's undiscounted obligation for lease payments for finance lease, due in remainder of fiscal year following latest fiscal year ended.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980

+ Details

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- References

No definition available.

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- Definition

Amount of lessee's undiscounted obligation for lease payments for operating lease.

+ References

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- Definition

Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fifth fiscal year following latest fiscal year.

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Amount of lessee's undiscounted obligation for lease payments for operating lease, due in fourth fiscal year following latest fiscal year.

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Amount of lessee's undiscounted obligation for lease payments for operating lease, due in third fiscal year following latest fiscal year.

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- Definition

Amount of lessee's undiscounted obligation for lease payments for operating lease, due in second fiscal year following latest fiscal year.

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- Definition

Amount of lessee's undiscounted obligation for lease payments for operating lease having an initial or remaining lease term in excess of one year due in remainder of fiscal year following latest fiscal year.

+ References

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- Definition

Amount of lease payments to be received by lessor for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919396-209981

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- Definition

Amount of lease payments to be received by lessor in fifth fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.

+ References

+ Details

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- Definition

Amount of lease payments to be received by lessor in fourth year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

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- Definition

Amount of lease payments to be received by lessor in remainder of fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919396-209981

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- Definition

Amount of lease payments to be received by lessor after fifth fiscal year following latest statement of financial position date for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

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- Definition

Amount of lease payments to be received by lessor in third fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

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- Definition

Amount of lease payments to be received by lessor in second fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

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