Significant Accounting Policies - Reclassification Out of AOCI, Simon Property Group, Inc. (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Significant Accounting Policies
Total accumulated other comprehensive income (loss)	$ (194,700)		$ (194,700)		$ (160,400)
Interest expense	(197,061)	$ (198,425)	(384,688)	$ (397,160)
Net income attributable to noncontrolling interests	(35,501)	(75,944)	(102,465)	(158,580)
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	254,213	495,324	691,818	1,043,799
Accumulated derivative losses, net, including noncontrolling interests | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Interest expense	478	(1,086)	958	(2,174)
Accumulated derivative losses, attributable to noncontrolling interests | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Net income attributable to noncontrolling interests	(63)	144	(126)	287
Accumulated derivative gains (losses), net | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ 415	$ (942)	$ 832	$ (1,887)