Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 12, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-13374
Entity Registrant Name	REALTY INCOME CORPORATION
Entity Central Index Key	0000726728
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	33-0580106
Entity Address, Address Line One	11995 El Camino Real
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92130
City Area Code	858
Local Phone Number	284-5000
Title of 12(b) Security	Common Stock, $0.01 Par Value
Trading Symbol	O
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 21.9
Entity Common Stock, Shares Outstanding		333,627,261
Documents Incorporated by Reference	Part III, Items 10, 11, 12, 13, and 14 incorporate by reference certain specific portions of the definitive Proxy Statement for Realty Income Corporation’s Annual Meeting to be held on May 12, 2020, to be filed pursuant to Regulation 14A. Only those portions of the proxy statement which are specifically incorporated by reference herein shall constitute a part of this annual report.