Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash Flows from Operating Activities:
Net income	$ 471,248	$ 338,492
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization (including amortization of deferred financing costs)	289,643	285,617
Net gains on sale of real estate	(267,994)	(72,713)
Return of capital from Real Estate Fund investments	56,664	0
Net unrealized gain on Real Estate Fund investments	(47,109)	(27,979)
Other non-cash adjustments	42,339	20,993
Non-cash impairment loss on J.C. Penney common shares	39,487	0
Net loss (gain) on disposition of wholly owned and partially owned assets	35,719	(4,856)
Straight-lining of rental income	(32,730)	(43,124)
Amortization of below-market leases, net	(28,511)	(26,457)
Distributions of income from partially owned entities	23,774	34,613
Loss from the mark-to-market of J.C. Penney derivative position	13,475	57,687
Equity in net loss (income) of partially owned entities including Toys "R" Us	12,864	(129,504)
Impairment losses	4,007	13,511
Changes in operating assets and liabilities:
Real Estate Fund investments	(30,893)	(85,867)
Accounts receivable, net	53,821	(8,971)
Prepaid assets	(104,149)	(100,012)
Other assets	(35,570)	(18,582)
Accounts payable and accrued expenses	(50,690)	25,940
Other liabilities	(595)	5,076
Net cash provided by operating activities	444,800	263,864
Cash Flows from Investing Activities:
Proceeds from sales of real estate and related investments	648,167	370,037
Distributions of capital from partially owned entities	281,991	17,963
Proceeds from the sale of LNR	240,474	0
Proceeds from sales of marketable securities	160,715	58,460
Additions to real estate	(113,060)	(83,368)
Funding of J.C. Penney derivative collateral	(98,447)	(70,000)
Development costs and construction in progress	(85,550)	(58,069)
Return of J.C. Penney derivative collateral	85,450	24,950
Investments in partially owned entities	(59,472)	(57,237)
Acquisitions of real estate and other	(53,992)	(32,156)
Proceeds from repayments of mortgage and mezzanine loans receivable and other	47,950	1,994
Restricted cash	16,596	(14,658)
Investment in mortgage and mezzanine loans receivable and other	(137)	(145)
Proceeds from the repayment of loan to officer	0	13,123
Net cash provided by investing activities	1,070,685	170,894
Cash Flows from Financing Activities:
Repayments of borrowings	(2,800,441)	(1,507,220)
Proceeds from borrowings	1,583,357	1,225,000
Purchases of outstanding preferred units	(299,400)	0
Proceeds from the issuance of preferred units	290,536	0
Distributions to Vornado	(272,825)	(256,119)
Distributions to redeemable security holders and noncontrolling interests	(181,510)	(69,367)
Distributions to preferred unitholders	(42,451)	(35,576)
Contributions from noncontrolling interests in consolidated subsidiaries	33,967	108,349
Debt issuance and other costs	(9,520)	(14,648)
Proceeds received from exercise of Vornado stock options	4,470	9,667
Repurchase of Class A units related to stock compensation agreements and/or related tax withholdings	(332)	(30,034)
Net cash used in financing activities	(1,694,149)	(569,948)
Net decrease in cash and cash equivalents	(178,664)	(135,190)
Cash and cash equivalents at beginning of period	960,319	606,553
Cash and cash equivalents at end of period	781,655	471,363
Supplemental Disclosure of Cash Flow Information [Abstract]
Cash payments for interest, excluding capitalized interest of $17,492 and $361	235,588	251,434
Cash payments for income taxes	4,732	6,494
Non-Cash Investing and Financing Activities:
Change in unrealized net gain (loss) on available-for-sale securities	169,138	(220,525)
Adjustments to carry redeemable Class A units at redemption value	(29,393)	(110,581)
Class A units issued upon redemption of redeemable Class A units, at redemption value	14,980	24,976
Decrease in assets and liabilities resulting from the deconsolidation of discontinued operations and/or investments that were previously consolidated:
Real Estate, net	(852,166)	0
Notes and mortgages payable	(322,903)	0
Cash restricted for like kind exchange of real estate	(155,810)	0
L.A. Mart seller financing	0	35,000
Write-off of fully depreciated assets	(47,598)	(131,770)
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	35,102	(97,281)
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	$ (22,238)	$ (32,223)