CONSOLIDATED STATEMENTS OF OPERATIONS OF ERP OPERATING LIMITED PARTNERSHIP (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
REVENUES
Rental income	$ 2,378,004,000	$ 1,737,929,000	$ 1,516,194,000
Fee and asset management	9,698,000	9,573,000	9,026,000
Total revenues	2,387,702,000	1,747,502,000	1,525,220,000
EXPENSES
Property and maintenance	449,461,000	332,190,000	304,380,000
Real estate taxes and insurance	293,999,000	206,723,000	178,406,000
Property management	84,342,000	81,902,000	81,867,000
Fee and asset management	6,460,000	4,663,000	4,279,000
Depreciation	978,973,000	560,669,000	506,175,000
General and administrative	62,179,000	47,233,000	43,604,000
Total expenses	1,875,414,000	1,233,380,000	1,118,711,000
Operating income	512,288,000	514,122,000	406,509,000
Interest and other income	4,656,000	150,546,000	7,963,000
Other expenses	(9,105,000)	(21,692,000)	(12,400,000)
Merger Expenses	(19,864,000)	(5,619,000)	(1,736,000)
Interest:
Expense incurred, net	(586,854,000)	(455,236,000)	(460,172,000)
Amortization of deferred financing costs	(22,197,000)	(21,295,000)	(16,616,000)
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of unconsolidated entities and land parcels and discontinued operations	(121,076,000)	160,826,000	(76,452,000)
Income and other tax (expense) benefit	(1,169,000)	(514,000)	(706,000)
(Loss) from investments in unconsolidated entities due to operations	(4,159,000)	(14,000)	0
(Loss) from investments in unconsolidated entities due to merger expenses	(54,004,000)	0	0
Net gain on sales of unconsolidated entities	7,000	0	0
Net gain on sales of land parcels	12,227,000	0	4,217,000
(Loss) income from continuing operations	(168,174,000)	160,298,000	(72,941,000)
Discontinued operations, net	2,073,527,000	720,906,000	1,008,138,000
Net income	1,905,353,000	881,204,000	935,197,000
Net loss (income) attributable to Noncontrolling Interests - Partially Owned Properties	538,000	(844,000)	(832,000)
Net income attributable to controlling interests	1,830,613,000	841,719,000	893,585,000
ALLOCATION OF NET INCOME:
Redemption Premium	0	5,152,000	0
Earnings per Unit - basic:
(Loss) income from continuing operations available to Common Shares	$ (0.466)	$ 0.454	$ (0.284)
Net income available to Units	$ 5.155	$ 2.729	$ 2.984
Earnings per Unit - diluted:
(Loss) income from Continuing Operations, Per Diluted Share	$ (0.466)	$ 0.450	$ (0.284)
Net income available to Units	$ 5.155	$ 2.705	$ 2.984
OPERATING PARTNERSHIP
REVENUES
Rental income	2,378,004,000	1,737,929,000	1,516,194,000
Fee and asset management	9,698,000	9,573,000	9,026,000
Total revenues	2,387,702,000	1,747,502,000	1,525,220,000
EXPENSES
Property and maintenance	449,461,000	332,190,000	304,380,000
Real estate taxes and insurance	293,999,000	206,723,000	178,406,000
Property management	84,342,000	81,902,000	81,867,000
Fee and asset management	6,460,000	4,663,000	4,279,000
Depreciation	978,973,000	560,669,000	506,175,000
General and administrative	62,179,000	47,233,000	43,604,000
Total expenses	1,875,414,000	1,233,380,000	1,118,711,000
Operating income	512,288,000	514,122,000	406,509,000
Interest and other income	4,656,000	150,546,000	7,963,000
Other expenses	(9,105,000)	(21,692,000)	(12,400,000)
Merger Expenses	(19,864,000)	(5,619,000)	(1,736,000)
Interest:
Expense incurred, net	(586,854,000)	(455,236,000)	(460,172,000)
Amortization of deferred financing costs	(22,197,000)	(21,295,000)	(16,616,000)
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of unconsolidated entities and land parcels and discontinued operations	(121,076,000)	160,826,000	(76,452,000)
Income and other tax (expense) benefit	(1,169,000)	(514,000)	(706,000)
(Loss) from investments in unconsolidated entities due to operations	(4,159,000)	(14,000)	0
(Loss) from investments in unconsolidated entities due to merger expenses	(54,004,000)	0	0
Net gain on sales of unconsolidated entities	7,000	0	0
Net gain on sales of land parcels	12,227,000	0	4,217,000
(Loss) income from continuing operations	(168,174,000)	160,298,000	(72,941,000)
Discontinued operations, net	2,073,527,000	720,906,000	1,008,138,000
Net income	1,905,353,000	881,204,000	935,197,000
Net loss (income) attributable to Noncontrolling Interests - Partially Owned Properties	538,000	(844,000)	(832,000)
Net income attributable to controlling interests	1,905,891,000	880,360,000	934,365,000
ALLOCATION OF NET INCOME:
Preference Units	4,145,000	10,355,000	13,865,000
Redemption Premium	0	5,152,000	0
General Partner	1,826,468,000	826,212,000	879,720,000
Limited Partners	75,278,000	38,641,000	40,780,000
Net income available to Units	$ 1,901,746,000	$ 864,853,000	$ 920,500,000
Earnings per Unit - basic:
(Loss) income from continuing operations available to Common Shares	$ (0.466)	$ 0.454	$ (0.284)
Net income available to Units	$ 5.155	$ 2.729	$ 2.984
Weighted average Units outstanding	368,038	316,554	308,062
Earnings per Unit - diluted:
(Loss) income from Continuing Operations, Per Diluted Share	$ (0.466)	$ 0.450	$ (0.284)
Net income available to Units	$ 5.155	$ 2.705	$ 2.984
Weighted average Units outstanding	368,038	319,766	308,062