Investments in Unconsolidated Entities and International Investments - Combined Balance Sheets (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
ASSETS:
Investment properties, at cost	$ 37,938,181	$ 38,050,196
Less - accumulated depreciation	15,176,790	14,891,937
Investment properties, at cost, net	22,761,391	23,158,259
Cash and cash equivalents	1,290,799	1,011,613
Tenant receivables and accrued revenue, net	952,731	1,236,734
Right-of-use assets, net	508,371	512,914
Deferred costs and other assets	1,100,745	1,082,168
Total assets	34,827,856	34,786,846
Liabilities and Partners' Deficit:
Mortgages	26,231,704	26,723,361
Accounts payable, accrued expenses, intangibles, and deferred revenues	1,230,595	1,311,925
Lease liabilities	511,211	515,492
Other liabilities	546,619	513,515
Total liabilities	30,613,003	31,128,608
Preferred units	507,414	185,892
Total liabilities and equity	$ 34,827,856	34,786,846
Unconsolidated properties | Maximum
Our Share of:
Estimated life of investment property	40 years
Equity Method Investees excluding HBS, Klepierre, TRG, ABG, Forever 21, J.C. Penny, RGG and SPARC Group | Unconsolidated properties
ASSETS:
Investment properties, at cost	$ 19,885,109	20,079,476
Less - accumulated depreciation	8,157,942	8,003,863
Investment properties, at cost, net	11,727,167	12,075,613
Cash and cash equivalents	1,356,266	1,169,422
Tenant receivables and accrued revenue, net	571,652	749,231
Right-of-use assets, net	168,752	185,598
Deferred costs and other assets	387,285	380,087
Total assets	14,211,122	14,559,951
Liabilities and Partners' Deficit:
Mortgages	15,430,065	15,569,485
Accounts payable, accrued expenses, intangibles, and deferred revenues	840,432	969,242
Lease liabilities	172,281	188,863
Other liabilities	395,463	426,321
Total liabilities	16,838,241	17,153,911
Preferred units	67,450	67,450
Partners' deficit	(2,694,569)	(2,661,410)
Total liabilities and equity	14,211,122	14,559,951
Our Share of:
Partners' deficit	(1,150,296)	(1,130,713)
Add: Excess Investment	1,317,383	1,399,757
Our net Investment in unconsolidated entities, at equity	$ 167,087	$ 269,044