Consolidation and Basis of Presentation (UNITED DOMINION REALTY, L.P.) Consolidation and Basis of Presentation (UNITED DOMINION REALTY, L.P. - Phantoms) (Details) - shares	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Limited partnership units owned	183,278,698	183,278,698	183,278,698	184,281,254
United Dominion Reality L.P.
General Partners' Capital Account, Units Outstanding	110,883	110,883
Limited partnership units owned	183,167,815	183,167,815

The number of limited partner units outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB TOPIC 4.F)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section F

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Balance Type:	na
Period Type:	instant