Significant Accounting Policies - AOCI, Simon Property Group L.P. (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)
Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	$ 5,212,913
Ending balance	5,322,529
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	10,263
Amounts reclassified from accumulated other comprehensive income (loss)	126,591
Net current-period other comprehensive income (loss)	136,854
Accumulated Other Comprehensive Income (Loss) | Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	(295,007)
Other comprehensive income (loss) before reclassifications	15,912
Amounts reclassified from accumulated other comprehensive income (loss)	145,737
Net current-period other comprehensive income (loss)	161,649
Ending balance	(133,358)
Currency translation adjustments, attributable to parent
Changes in accumulated other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	12,911
Amounts reclassified from accumulated other comprehensive income (loss)	118,833
Net current-period other comprehensive income (loss)	131,744
Currency translation adjustments, attributable to parent | Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	(289,866)
Other comprehensive income (loss) before reclassifications	18,888
Amounts reclassified from accumulated other comprehensive income (loss)	136,806
Net current-period other comprehensive income (loss)	155,694
Ending balance	(134,172)
Accumulated derivative losses, attributable to parent
Changes in accumulated other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	(14,094)
Amounts reclassified from accumulated other comprehensive income (loss)	7,758
Net current-period other comprehensive income (loss)	(6,336)
Accumulated derivative losses, attributable to parent | Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	(17,704)
Other comprehensive income (loss) before reclassifications	(15,979)
Amounts reclassified from accumulated other comprehensive income (loss)	8,931
Net current-period other comprehensive income (loss)	(7,048)
Ending balance	(24,752)
Realized gain on sale of marketable securities
Changes in accumulated other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	11,446
Net current-period other comprehensive income (loss)	11,446
Realized gain on sale of marketable securities | Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	12,563
Other comprehensive income (loss) before reclassifications	13,003
Net current-period other comprehensive income (loss)	13,003
Ending balance	$ 25,566