Investment in Unconsolidated Entities (Details 7) (USD $) In Thousands, unless otherwise specified	0 Months Ended	3 Months Ended
	May 28, 2014 property	Mar. 31, 2015	Dec. 31, 2014
Assets:
Investment properties, at cost		32,537,403	$ 31,318,532
Less - accumulated depreciation		9,146,094	8,950,747
Investment properties, net		23,391,309	22,367,785
Cash and cash equivalents		833,732	612,282
Tenant receivables and accrued revenue, net		523,734	580,197
Deferred costs and other assets		1,851,798	1,806,789
Liabilities and Partners' Deficit:
Mortgages and unsecured indebtedness		21,694,055	20,852,993
Accounts payable, accrued expenses, intangibles, and deferred revenues		1,122,444	1,259,681
Other liabilities		295,853	275,451
Total liabilities		24,484,927	23,555,288
Partners' deficit		(4,289,099)	(4,208,183)
Total liabilities and equity		30,275,527	29,532,330
Our Share of:
Our net investment in unconsolidated entities, at equity		2,158,205	2,378,800
Unconsolidated properties
Our Share of:
Number of properties merged under spin off into Washington Prime, an independent publicly traded REIT	10
Equity Method Investments | Unconsolidated properties
Assets:
Investment properties, at cost		16,010,766	16,087,282
Less - accumulated depreciation		5,525,606	5,457,899
Investment properties, net		10,485,160	10,629,383
Cash and cash equivalents		763,917	993,178
Tenant receivables and accrued revenue, net		308,358	362,201
Investment in unconsolidated entities, at equity			11,386
Deferred costs and other assets		507,735	536,600
Total assets		12,065,170	12,532,748
Liabilities and Partners' Deficit:
Mortgages and unsecured indebtedness		13,629,050	13,272,557
Accounts payable, accrued expenses, intangibles, and deferred revenues		861,041	1,015,334
Other liabilities		440,651	493,718
Total liabilities		14,930,742	14,781,609
Preferred units		67,450	67,450
Partners' deficit		(2,933,022)	(2,316,311)
Total liabilities and equity		12,065,170	12,532,748
Our Share of:
Partners' deficit		(1,064,025)	(663,700)
Add: Excess investment		1,849,655	1,875,337
Our net investment in unconsolidated entities, at equity		785,630	$ 1,211,637
Equity Method Investments | Unconsolidated properties | Maximum
Our Share of:
Life of joint ventures with excess investment		40 years