CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Comprehensive income:
Net income	$ 391,717	$ 236,323	$ 1,789,483	$ 496,805
Other comprehensive income (loss) - derivative instruments:
Unrealized holding gains (losses) arising during the period	(3,600)	(3,695)	8,737	(12,337)
Losses reclassified into earnings from other comprehensive income	3,986	3,704	16,084	10,907
Other comprehensive income (loss) - other instruments:
Unrealized holding gains (losses) arising during the period	(374)	312	554	394
(Gain) Loss on Sale of Securities, Net	(830)	0	(830)	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(1,730)	0	(789)	0
Other comprehensive income (loss)	(2,548)	321	23,756	(1,036)
Comprehensive income	389,169	236,644	1,813,239	495,769
Comprehensive loss (income) attributable to Noncontrolling Interests	(14,525)	(10,184)	(69,846)	(22,103)
Comprehensive income attributable to controlling interests	374,644	226,460	1,743,393	473,666
OPERATING PARTNERSHIP
Comprehensive income:
Net income	391,717	236,323	1,789,483	496,805
Other comprehensive income (loss) - derivative instruments:
Unrealized holding gains (losses) arising during the period	(3,600)	(3,695)	8,737	(12,337)
Losses reclassified into earnings from other comprehensive income	3,986	3,704	16,084	10,907
Other comprehensive income (loss) - other instruments:
Unrealized holding gains (losses) arising during the period	(374)	312	554	394
(Gain) Loss on Sale of Securities, Net	(830)	0	(830)	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(1,730)	0	(789)	0
Other comprehensive income (loss)	(2,548)	321	23,756	(1,036)
Comprehensive income	389,169	236,644	1,813,239	495,769
Comprehensive loss (income) attributable to Noncontrolling Interests	311	312	1,101	(457)
Comprehensive income attributable to controlling interests	$ 389,480	$ 236,956	$ 1,814,340	$ 495,312