Summary of Significant Accounting Policies - Reclassification Out Of AOCI, Simon Property Group, L.P. (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Significant Accounting Policies
Interest expense	$ (202,382)	$ (199,469)	$ (599,541)	$ (611,585)
Simon Property Group, L.P.
Significant Accounting Policies
Interest expense	(202,382)	(199,469)	(599,541)	(611,585)
Accumulated derivative gains (losses), net | Simon Property Group, L.P. | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Interest expense	$ (1,087)	$ (1,591)	$ (3,261)	$ (5,929)