Investments in Real Estate - Properties with Existing Leases Narrative (Details) $ in Millions	6 Months Ended
Jun. 30, 2022 USD ($) property	Jun. 30, 2021 USD ($) property
Real Estate Properties [Line Items]
Value of properties acquired during the period	$ 3,231.1	$ 2,161.9
Number of properties acquired during the period \| property	423	254
Real Estate Investment
Real Estate Properties [Line Items]
Value of properties acquired during the period	$ 3,230.0	$ 2,160.0
Properties under development
Real Estate Properties [Line Items]
Value of properties acquired during the period	267.9	114.8
Properties under development \| Real Estate Investment
Real Estate Properties [Line Items]
Value of properties acquired during the period	267.9	114.8
New properties
Real Estate Properties [Line Items]
Value of properties acquired during the period	2,963.2	2,047.1
New properties \| Real Estate Investment
Real Estate Properties [Line Items]
Value of properties acquired during the period	2,960.0	2,050.0
Properties with existing leases \| Real Estate Investment
Real Estate Properties [Line Items]
Value of properties acquired during the period	$ 2,210.0	$ 1,810.0
Number of properties acquired during the period \| property	168	143
In-place leases
Real Estate Properties [Line Items]
Depreciation and amortization expense	$ 318.3	$ 77.5
Above and below market leases
Real Estate Properties [Line Items]
Amortization of above and below market Leases	$ 48.6	$ 19.7

The number of new properties and properties under development in which the entity invested during the period.

No definition available.

Name:	o_RealEstatePropertyInvestmentsNumberOfNewPropertiesAndPropertiesUnderDevelopment
Namespace Prefix:	o_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the net assets recorded as part of the real estate acquisition.

+ References

No definition available.

+ Details

Name:	o_RealEstatePropertyInvestmentsValueOfPropertiesAcquired
Namespace Prefix:	o_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of non-cash amortization of intangible asset (liability) for above and below market leases.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

+ Details

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

- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI https://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_RealEstateInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=o_PropertiesUnderDevelopmentOrExpansionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=o_PropertiesNewMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=o_PropertiesWithExistingLeasesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_LeasesAcquiredInPlaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=o_LeasesAboveAndBelowMarketMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: