Consolidated Statements of Cash Flows (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash Flows from Operating Activities:
Net income	$ 338,492,000	$ 576,790,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization (including amortization of deferred financing costs)	285,617,000	273,980,000
Equity in net income of partially owned entities, including Toys R Us	(129,504,000)	(131,993,000)
Net gains on sale of real estate	(72,713,000)	(51,623,000)
(Loss) income from the mark-to-market of J.C. Penney derivative position	57,687,000	(10,401,000)
Straight-lining of rental income	(43,124,000)	(22,291,000)
Distributions of income from partially owned entities	34,613,000	43,741,000
Unrealized gain on Real Estate Fund assets	(27,979,000)	(13,570,000)
Amortization of below-market leases, net	(26,457,000)	(33,704,000)
Other non-cash adjustments	20,993,000	14,381,000
Impairment losses	13,511,000	0
Net gain on disposition of wholly owned and partially owned assets	(4,856,000)	(6,677,000)
Net gain on extinguishment of debt	0	(83,907,000)
Mezzanine loans loss reversal and net gain on disposition	0	(82,744,000)
Changes in operating assets and liabilities:
Real Estate Fund investments	(85,867,000)	(97,802,000)
Accounts receivable, net	(8,971,000)	(11,478,000)
Prepaid assets	(100,012,000)	(117,503,000)
Other assets	(18,582,000)	(10,424,000)
Accounts payable and accrued expenses	25,940,000	13,250,000
Other liabilities	5,076,000	12,015,000
Net cash provided by operating activities	263,864,000	260,040,000
Cash Flows from Investing Activities:
Proceeds from sales of real estate and related investments	370,037,000	130,789,000
Additions to real estate	(83,368,000)	(86,944,000)
Funding of J.C. Penney derivative collateral	(70,000,000)	0
Proceeds from sales of marketable securities	58,460,000	19,301,000
Development costs and construction in progress	(58,069,000)	(32,489,000)
Investments in partially owned entities	(57,237,000)	(426,376,000)
Acquisitions of real estate and other	(32,156,000)	0
Return of J.C. Penney derivative collateral	24,950,000	0
Distributions of capital from partially owned entities	17,963,000	271,375,000
Restricted cash	(14,658,000)	91,127,000
Proceeds from the repayment of loan to officer	13,123,000	0
Proceeds from sales and repayments of mezzanine loans	1,994,000	99,990,000
Investments in mezzanine loans receivable and other	(145,000)	(43,516,000)
Net cash provided by investing activities	170,894,000	23,257,000
Cash Flows from Financing Activities:
Repayments of borrowings	(1,507,220,000)	(1,636,817,000)
Proceeds from borrowings	1,225,000,000	1,284,167,000
Dividends paid on common shares	(256,119,000)	(254,099,000)
Contributions from noncontrolling interests	108,349,000	109,605,000
Distributions to noncontrolling interests	(69,367,000)	(62,111,000)
Dividends paid on preferred shares	(35,576,000)	(27,117,000)
Repurchase of shares related to stock compensation agreements and/or related tax withholdings	(30,034,000)	(748,000)
Debt issuance and other costs	(14,648,000)	(23,319,000)
Proceeds received from exercise of employee share options	9,667,000	21,330,000
Proceeds from the issuance of Series J preferred shares	0	214,538,000
Purchase of outstanding preferred units and shares	0	(8,000,000)
Net cash used in financing activities	(569,948,000)	(382,571,000)
Net decrease in cash and cash equivalents	(135,190,000)	(99,274,000)
Cash and cash equivalents at beginning of period	606,553,000	690,789,000
Cash and cash equivalents at end of period	471,363,000	591,515,000
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, net of capitalized interest of $361 and $0	163,928,000	256,776,000
Cash payments for income taxes	6,494,000	5,416,000
Non-Cash Investing and Financing Activities:
Change in unrealized net (loss) gain on securities available-for-sale	(220,525,000)	40,844,000
Adjustment to carry redeemable Class A units at redemption value	(110,581,000)	(104,693,000)
L.A. Mart seller financing	35,000,000	0
Common shares issued upon redemption of Class A units, at redemption value	24,976,000	35,208,000
Contribution of mezzanine loan receivable to a joint venture	0	73,750,000
Like-kind exchange of real estate	0	(45,625,000)
Decrease in assets and liabilities resulting from deconsolidation of discontinued operations:
Assets related to discontinued operations	0	(145,333,000)
Liabilities related to discontinued operations	0	(232,502,000)
Write-off of fully depreciated assets	(131,770,000)	(32,794,000)
Toys R Us [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in net income of partially owned entities, including Toys R Us	(97,281,000)	(90,098,000)
All Equity Method Investees Excluding Toys [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in net income of partially owned entities, including Toys R Us	$ (32,223,000)	$ (41,895,000)