Schedule III - Real Estate and Accumulated Depreciation (Details) (USD $) In Billions, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Schedule III - Real Estate and Accumulated Depreciation (Details) [Line Items]
SEC Schedule III, Real Estate, Federal Income Tax Basis (in Dollars)	8.6us-gaap_RealEstateFederalIncomeTaxBasis
Minimum [Member]
Schedule III - Real Estate and Accumulated Depreciation (Details) [Line Items]
SEC Schedule III, Real Estate and Accumulated Depreciation, Life Used for Depreciation	15 years
Maximum [Member]
Schedule III - Real Estate and Accumulated Depreciation (Details) [Line Items]
SEC Schedule III, Real Estate and Accumulated Depreciation, Life Used for Depreciation	50 years

Useful life on which depreciation was computed for entities with a substantial portion of business acquiring and holding investment real estate, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 970

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-28)

-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule III)

-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 28

-Article 12

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph c

-Subparagraph Schedule III

-Article 5

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