Summary of Significant Accounting Policies - Reclassification Out Of AOCI, Simon Property Group, L.P. (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Significant Accounting Policies
Total accumulated other comprehensive income (loss)	$ (175,100)				$ (136,200)				$ (175,100)	$ (136,200)	$ (160,400)
Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net									206,855	(114,960)	14,883
Interest expense									(795,712)	(784,400)	(789,353)
Loss on extinguishment of debt									(51,841)		(116,256)
Net Income attributable to Common Stockholders - Basic	503,241	$ 679,936	$ 617,257	$ 445,860	271,483	$ 145,926	$ 254,213	$ 437,605	2,246,294	1,109,227	2,098,247
Simon Property Group, L.P.
Significant Accounting Policies
Total accumulated other comprehensive income (loss)	(200,200)				(155,800)				(200,200)	(155,800)	(184,800)
Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net									206,855	(114,960)	14,883
Interest expense									(795,712)	(784,400)	(789,353)
Loss on extinguishment of debt									(51,841)		(116,256)
Net Income attributable to Common Stockholders - Basic	$ 575,596	$ 777,740	$ 706,087	$ 510,085	$ 311,238	$ 168,086	$ 292,863	$ 504,263	2,569,508	1,276,450	2,416,945
Currency translation adjustments. | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Net Income attributable to Common Stockholders - Basic									4,948	(1,520)
Currency translation adjustments. | Simon Property Group, L.P. | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net									5,660	(1,739)
Accumulated derivative gains (losses), net | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Net Income attributable to Common Stockholders - Basic									1,421	1,613	(11,832)
Accumulated derivative gains (losses), net | Simon Property Group, L.P. | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Interest expense									1,625	1,845	(2,782)
Loss on extinguishment of debt											(10,852)
Net Income attributable to Common Stockholders - Basic									$ 1,625	$ 1,845	$ (13,634)