Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash Flows from Operating Activities:
Net income	$ 603,499	$ 602,648
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization (including amortization of deferred financing costs)	419,249	419,007
Net gains on sale of real estate	(286,990)	(203,801)
Other non-cash adjustments	60,957	39,360
Net unrealized gain on Real Estate Fund investments	(59,476)	(33,537)
Return of capital from Real Estate Fund investments	56,664	61,052
Straight-lining of rental income	(48,561)	(55,553)
Equity in net loss (income) of partially owned entities, including Toys "R" Us	45,620	(142,187)
Amortization of below-market leases, net	(40,341)	(39,693)
Non-cash impairment loss on J.C. Penney common shares	39,487	0
Distributions of income from partially owned entities	34,350	59,322
Loss from the mark-to-market of J.C. Penney derivative position	33,487	53,343
Net loss (gain) on disposition of wholly owned and partially owned assets	20,581	(4,856)
Impairment losses	4,727	13,511
Gain on sale of Canadian Trade Shows	0	(31,105)
Changes in operating assets and liabilities:
Real Estate Fund investments	(32,392)	(163,307)
Accounts receivable, net	63,280	(9,444)
Prepaid assets	(60,388)	(52,895)
Other assets	(25,854)	(43,103)
Accounts payable and accrued expenses	(38,904)	34,546
Other liabilities	597	7,338
Net cash provided by operating activities	789,592	510,646
Cash Flows from Investing Activities:
Proceeds from sales of real estate and related investments	734,427	408,856
Proceeds from sales of marketable securities	378,676	58,460
Distributions of capital from partially owned entities	287,944	26,665
Proceeds from the sale of LNR	240,474	0
Investments in partially owned entities	(212,624)	(116,264)
Funding of J.C. Penney derivative collateral; and settlement of derivative in 2013	(186,079)	(121,117)
Additions to real estate	(170,424)	(138,060)
Development costs and construction in progress	(149,010)	(106,502)
Return of J.C. Penney derivative collateral	101,150	89,850
Acquisitions of real estate and other	(75,079)	(73,069)
Proceeds from repayments of mortgage and mezzanine loans receivable and other	49,452	2,379
Restricted cash	21,883	(62,813)
Investment in mortgage and mezzanine loans receivable	(390)	0
Proceeds from the sale of Canadian Trade Shows	0	52,504
Proceeds from the repayment of loan to officer	0	13,123
Net cash provided by investing activities	1,020,400	34,012
Cash Flows from Financing Activities:
Repayments of borrowings	(2,851,420)	(2,070,295)
Proceeds from borrowings	1,600,357	1,773,000
Dividends paid on common shares	(409,332)	(384,353)
Purchases of outstanding preferred units and shares	(299,400)	(243,300)
Proceeds from the issuance of preferred shares	290,536	291,144
Distributions to noncontrolling interests	(200,667)	(80,994)
Dividends paid on preferred shares	(62,820)	(54,034)
Contributions from noncontrolling interests	40,015	120,746
Debt issuance and other costs	(9,982)	(17,417)
Proceeds received from exercise of employee share options	5,057	10,210
Repurchase of shares related to stock compensation agreements and/or related tax withholdings	(332)	(30,034)
Net cash used in financing activities	(1,897,988)	(685,327)
Net decrease in cash and cash equivalents	(87,996)	(140,669)
Cash and cash equivalents at beginning of period	960,319	606,553
Cash and cash equivalents at end of period	872,323	465,884
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $28,024 and $7,884	350,899	368,018
Cash payments for income taxes	7,529	19,222
Decrease in assets and liabilities resulting from the deconsolidation of Independence Plaza:
Real Estate, net	(852,166)	0
Notes and mortgages payable	(322,903)	0
Financing provided to purchaser of L.A. Mart	0	35,000
Marriot Marquis Times Square- retail and signage capital lease:
Asset (included in development costs and construction in progress)	0	240,000
Liability (included in other liabilities)	0	(240,000)
Like-kind exchange of real estate	(155,805)	(230,913)
Toys R Us [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in net loss (income) of partially owned entities, including Toys "R" Us	69,311	(88,696)
All Equity Method Investees Excluding Toys [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in net loss (income) of partially owned entities, including Toys "R" Us	$ (23,691)	$ (53,491)