Notes Payable (Details) (USD $)	9 Months Ended
Sep. 30, 2011	Dec. 31, 2010
Debt instrument [Abstract]
Notes payable	$ 1,750,000,000	$ 1,600,000,000
Notes Payable Due March 2013 [Member]
Debt instrument [Abstract]
Notes payable	100,000,000	100,000,000
Issuance date	March 2003
Maturity date	March 2013
Interest rate (in hundredths)	5.375%
Notes Payable Due November 2015 [Member]
Debt instrument [Abstract]
Notes payable	150,000,000	150,000,000
Issuance date	November 2003
Maturity date	November 2015
Interest rate (in hundredths)	5.50%
Notes Payable Due September 2016 [Member]
Debt instrument [Abstract]
Notes payable	275,000,000	275,000,000
Issuance date	September 2006
Maturity date	September 2016
Interest rate (in hundredths)	5.95%
Notes Payable Due September 2017 [Member]
Debt instrument [Abstract]
Notes payable	175,000,000	175,000,000
Issuance date	September 2005
Maturity date	September 2017
Interest rate (in hundredths)	5.375%
Notes Payable Due August 2019 [Member]
Debt instrument [Abstract]
Notes payable	550,000,000	550,000,000
Issuance date	September 2007
Maturity date	August 2019
Interest rate (in hundredths)	6.75%
Notes Payable Due January 2021 [Member]
Debt instrument [Abstract]
Notes payable	250,000,000	250,000,000
Issuance date	June 2010
Maturity date	January 2021
Interest rate (in hundredths)	5.75%
Percentage price to the investor (in hundredths)	99.404%
Effective yield (in hundredths)	5.826%
Net proceeds from the issuance of debt	246,100,000
Bonds [Member]
Debt instrument [Abstract]
Notes payable	250,000,000	100,000,000
Bonds Payable 150M issued Due March 2035 [Member]
Debt instrument [Abstract]
Notes payable	150,000,000
Issuance date	June 2011
Maturity date	March 2035
Interest rate (in hundredths)	5.875%
Percentage price to the investor (in hundredths)	94.578%
Effective yield (in hundredths)	6.318%
Net proceeds from the issuance of debt	140,100,000
Bonds Payable 100M issued Due March 2035 [Member]
Debt instrument [Abstract]
Notes payable	$ 100,000,000
Issuance date	March 2005
Maturity date	March 2035
Interest rate (in hundredths)	5.875%

Date, as Month and Year, when the debt instrument is scheduled to be fully repaid.

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Namespace Prefix:	o
Data Type:	invest:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective yield of the investment

+ Details

Name:	o_EffectiveYield
Namespace Prefix:	o
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage price to the investor on a basis of investment.

+ Details

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Namespace Prefix:	o
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Interest rate stated in the contractual debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Date when the debt instrument was issued, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap
Data Type:	us-types:dateStringItemType
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- Details

Name:	us-gaap_DebtInstrumentsAbstract
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- Definition

Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13, 16

-Article 9

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
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Period Type:	duration