Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash Flows from Operating Activities:
Net income	$ 602,648,000	$ 643,013,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization (including amortization of deferred financing costs)	419,007,000	414,992,000
Net gains on sale of real estate	(203,801,000)	(51,623,000)
Equity in net income of partially owned entities, including Toys "R" Us	(142,187,000)	(135,829,000)
Return of capital from Real Estate Fund investments	61,052,000	0
Distributions of income from partially owned entities	59,322,000	75,612,000
Straight-lining of rental income	(55,553,000)	(38,262,000)
Loss from the mark-to-market of J.C. Penney derivative position	53,343,000	27,136,000
Amortization of below-market leases, net	(39,693,000)	(49,988,000)
Other non-cash adjustments	39,360,000	20,261,000
Net unrealized gain on Real Estate Fund investments	(33,537,000)	(19,209,000)
Gain on sale of Canadian Trade Shows	(31,105,000)	0
Impairment losses	13,511,000	0
Net gain on disposition of wholly owned and partially owned assets	(4,856,000)	(7,975,000)
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	(163,307,000)	(97,785,000)
Accounts receivable, net	(9,444,000)	11,292,000
Prepaid assets	(52,895,000)	(68,558,000)
Other assets	(43,103,000)	(44,617,000)
Accounts payable and accrued expenses	34,546,000	32,227,000
Other liabilities	7,338,000	22,635,000
Net cash provided by operating activities	510,646,000	566,671,000
Cash Flows from Investing Activities:
Proceeds from sales of real estate and related investments	408,856,000	135,762,000
Additions to real estate	(138,060,000)	(109,963,000)
Funding of J.C. Penney derivative collateral	(121,117,000)	(33,850,000)
Investments in partially owned entities	(116,264,000)	(440,865,000)
Development costs and construction in progress	(106,502,000)	(52,816,000)
Return of J.C. Penney derivative collateral	89,850,000	28,700,000
Acquisitions of real estate and other	(73,069,000)	0
Restricted cash	(62,813,000)	121,463,000
Proceeds from sales of marketable securities	58,460,000	19,301,000
Proceeds from the sale of Canadian Trade Shows	52,504,000	0
Distributions of capital from partially owned entities	26,665,000	274,283,000
Proceeds from the repayment of loan to officer	13,123,000	0
Proceeds from sales and repayments of mezzanine loans and other	2,379,000	100,525,000
Investments in mezzanine loans receivable	0	(44,215,000)
Net cash provided by (used in) investing activities	34,012,000	(1,675,000)
Cash Flows from Financing Activities:
Repayments of borrowings	(2,070,295,000)	(2,666,610,000)
Proceeds from borrowings	1,773,000,000	2,184,167,000
Distributions to Vornado	(384,353,000)	(381,382,000)
Proceeds from the issuance of preferred units	291,144,000	239,037,000
Purchases of outstanding preferred units	(243,300,000)	(28,000,000)
Contributions from noncontrolling interests in consolidated subsidiaries	120,746,000	109,605,000
Distributions to redeemable security holders and noncontrolling interests	(80,994,000)	(77,330,000)
Distributions to preferred unitholders	(54,034,000)	(43,675,000)
Repurchase of Class A units related to stock compensation agreements and/or related tax withholdings	(30,034,000)	(747,000)
Debt issuance and other costs	(17,417,000)	(28,614,000)
Proceeds received from exercise of Vornado stock options	10,210,000	22,947,000
Net cash used in financing activities	(685,327,000)	(670,602,000)
Net decrease in cash and cash equivalents	(140,669,000)	(105,606,000)
Cash and cash equivalents at beginning of period	606,553,000	690,789,000
Cash and cash equivalents at end of period	465,884,000	585,183,000
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $7,884 and $0	368,018,000	388,938,000
Cash payments for income taxes	19,222,000	10,299,000
Non-Cash Investing and Financing Activities:
Change in unrealized net loss on securities available-for-sale	(202,167,000)	(120,334,000)
Adjustment to carry redeemable Class A units at redemption value	(63,657,000)	114,628,000
L.A. Mart seller financing	35,000,000	0
Common shares issued upon redemption of Class A units, at redemption value	51,216,000	38,220,000
Contribution of mezzanine loan receivable to a joint venture	0	73,750,000
Marriott Marquis Times Square Hotel - retail and signage capital lease: Asset (included in development costs and construction in progress)	240,000,000	0
Marriott Marquis Times Square Hotel - retail and signage capital lease: Liability (included in other liabilities)	(240,000,000)	0
Like-kind exchange of real estate	230,913,000	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	(151,496,000)	(58,279,000)
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	(88,696,000)	(80,794,000)
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	$ (53,491,000)	$ (55,035,000)