Investments in Real Estate - Gain on Sales of Real Estate (Details) $ in Millions	12 Months Ended
Dec. 31, 2023 USD ($) property	Dec. 31, 2022 USD ($) property	Dec. 31, 2021 USD ($) property
Properties sold during the period
Number of properties \| property	121	170	154
Net sales proceeds	$ 117.4	$ 436.1	$ 250.3
Gain on sales of real estate	$ 25.7	$ 103.0	$ 55.8

Gain (Loss) on Sale of Properties, Excluding Additional Proceeds Received

No definition available.

Name:	o_GainLossOnSaleOfPropertiesExcludingAdditionalProceedsReceived
Namespace Prefix:	o_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration