Investment in Unconsolidated Entities (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010
Assets:
Investment properties at cost	$ 34,063,214		$ 34,063,214		$ 29,657,046
Less - accumulated depreciation	8,827,205		8,827,205		8,388,130
Investment properties, net	25,236,009		25,236,009		21,268,916
Cash and cash equivalents	638,499	789,713	638,499	789,713	798,650	796,718
Tenant receivables and accrued revenue, net	423,917		423,917		486,731
Investment in unconsolidated entities, at equity	2,000,509		2,000,509		1,378,084
Deferred costs and other assets	1,745,496		1,745,496		1,633,544
Total assets	31,986,583		31,986,583		26,216,925
Liabilities and Partners' (Deficit) Equity:
Mortgages and other indebtedness	22,466,558		22,466,558		18,446,440
Accounts payable, accrued expenses, intangibles, and deferred revenues	1,168,636		1,168,636		1,091,712
Other liabilities	226,675		226,675		170,971
Total liabilities	24,592,505		24,592,505		20,404,692
Total liabilities and equity	31,986,583		31,986,583		26,216,925
Revenue:
Minimum rent	746,198	649,570	1,448,295	1,293,902
Overage rent	31,427	21,980	59,107	39,121
Tenant reimbursements	330,470	285,623	636,857	567,048
Other income	51,624	52,429	102,142	98,913
Total revenue	1,188,066	1,040,861	2,307,035	2,060,735
Operating Expenses:
Property operating	116,018	109,025	220,758	208,567
Depreciation and amortization	311,863	261,298	596,972	527,608
Real estate taxes	106,777	93,424	205,479	186,688
Repairs and maintenance	26,665	24,657	52,307	55,492
Advertising and promotion	28,549	24,958	49,648	46,846
(Recovery of)/Provision for credit losses	2,906	274	6,451	1,679
Other	24,096	19,226	41,873	38,244
Total operating expenses	666,711	573,289	1,270,072	1,142,273
Operating Income	521,355	467,572	1,036,963	918,462
Interest expense	(288,560)	(244,517)	(546,636)	(492,634)
Income (loss) from unconsolidated entities	29,132	13,821	59,484	32,441
Real Estate joint ventures
Assets:
Investment properties at cost	14,491,236		14,491,236		20,481,657
Less - accumulated depreciation	4,725,920		4,725,920		5,264,565
Investment properties, net	9,765,316		9,765,316		15,217,092
Cash and cash equivalents	483,433		483,433		806,895
Tenant receivables and accrued revenue, net	198,773		198,773		359,208
Investment in unconsolidated entities, at equity	39,855		39,855		133,576
Deferred costs and other assets	366,900		366,900		526,101
Total assets	10,854,277		10,854,277		17,042,872
Liabilities and Partners' (Deficit) Equity:
Mortgages and other indebtedness	11,499,568		11,499,568		15,582,321
Accounts payable, accrued expenses, intangibles, and deferred revenues	527,701		527,701		775,733
Other liabilities	308,912		308,912		981,711
Total liabilities	12,336,181		12,336,181		17,339,765
Preferred units	67,450		67,450		67,450
Partners' (deficit) equity	(1,549,354)		(1,549,354)		(364,343)
Total liabilities and equity	10,854,277		10,854,277		17,042,872
Our Share of:
Partners' (deficit) equity	(708,641)		(708,641)		(32,000)
Add: Excess Investment	1,978,514		1,978,514		714,515
Our net Investment in Unconsolidated Entities, at equity	1,269,873		1,269,873		682,515
Revenue:
Minimum rent	371,664	360,466	738,019	710,027
Overage rent	36,143	27,126	84,837	57,354
Tenant reimbursements	170,478	166,726	342,571	332,346
Other income	37,488	40,546	88,435	71,898
Total revenue	615,773	594,864	1,253,862	1,171,625
Operating Expenses:
Property operating	115,615	112,918	233,520	224,266
Depreciation and amortization	126,783	123,032	258,174	245,092
Real estate taxes	45,164	47,103	93,216	92,690
Repairs and maintenance	15,919	15,595	30,807	32,311
Advertising and promotion	12,917	11,559	28,344	25,000
(Recovery of)/Provision for credit losses	(1,102)	1,113	(114)	1,917
Other	38,793	44,158	92,356	73,289
Total operating expenses	354,089	355,478	736,303	694,565
Operating Income	261,684	239,386	517,559	477,060
Interest expense	(155,393)	(153,970)	(315,554)	(305,002)
Income (loss) from unconsolidated entities	(316)	(631)	(631)	(459)
Net Income from continuing operations	105,975	84,785	201,374	171,599
Loss from operations of discontinued joint venture interests	(1,173)	(9,559)	(11,623)	(15,661)
Gain on disposal or sale of discontinued operations, net		15,506		15,506
Net Income	104,802	90,732	189,751	171,444
Third-Party Investors' Share of Net Income	56,787	56,455	96,800	106,470
Our Share of Net Income	48,015	34,277	92,951	64,974
Amortization of Excess Investment	(18,749)	(12,703)	(33,333)	(24,780)
Our Share of Gain on Sale or Disposal of Assets and Interests in Unconsolidated Entities, net		(7,753)		(7,753)
Income from unconsolidated entities	$ 29,266	$ 13,821	$ 59,618	$ 32,441
Real Estate joint ventures | Maximum
Our Share of:
Amortization period			40 years