Significant Accounting Policies - Reclassification Out of AOCI, Simon Property Group, Inc. (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Significant Accounting Policies
Total accumulated other comprehensive income (loss)	$ (180,900)		$ (160,400)
Interest expense	(187,627)	$ (198,733)
Net income attributable to noncontrolling interests	(66,965)	(82,638)
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	437,605	548,475
Accumulated derivative losses, net, including noncontrolling interests | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Interest expense	480	(1,088)
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)	143
Accumulated derivative gains (losses), net | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ 417	$ (945)