CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Comprehensive income:
Net income	$ 205,456	$ 231,190	$ 694,298	$ 431,642
Other comprehensive income (loss) – derivative instruments:
Unrealized holding gains (losses) arising during the period	1,908	97	1,796	(21,784)
Losses reclassified into earnings from other comprehensive income	4,736	4,271	13,647	12,606
Other comprehensive (loss) income – foreign currency:
Currency translation adjustments arising during the period	191	(2,184)	(311)	(466)
Other comprehensive income (loss)	6,835	2,184	15,132	(9,644)
Comprehensive income	212,291	233,374	709,430	421,998
Comprehensive (income) attributable to Noncontrolling Interests – Partially Owned Properties	(9,025)	(9,530)	(29,244)	(17,705)
Comprehensive income attributable to controlling interests	203,266	223,844	680,186	404,293
ERPOP [Member]
Comprehensive income:
Net income	205,456	231,190	694,298	431,642
Other comprehensive income (loss) – derivative instruments:
Unrealized holding gains (losses) arising during the period	1,908	97	1,796	(21,784)
Losses reclassified into earnings from other comprehensive income	4,736	4,271	13,647	12,606
Other comprehensive (loss) income – foreign currency:
Currency translation adjustments arising during the period	191	(2,184)	(311)	(466)
Other comprehensive income (loss)	6,835	2,184	15,132	(9,644)
Comprehensive income	212,291	233,374	709,430	421,998
Comprehensive (income) attributable to Noncontrolling Interests – Partially Owned Properties	(986)	(708)	(2,473)	(1,800)
Comprehensive income attributable to controlling interests	$ 211,305	$ 232,666	$ 706,957	$ 420,198