Equity - Changes in Equity, Simon Property Group, L.P. (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Increase (Decrease) in Stockholders' Equity
Issuance of limited partner units	$ 84,103
Redemption of limited partner units	(7,619)
Cumulative effect of accounting change	7,264
Purchase and disposition of noncontrolling interests, net and other	(12,701)
Comprehensive income, excluding $1,436 attributable to preferred interests in the Operating Partnership and a $379 loss attributable to noncontrolling redeemable interests in properties	1,978,492
Comprehensive income attributable to preferred interests	1,436
Comprehensive loss attributable to noncontrolling redeemable interests in properties	379
Simon Property Group, L.P.
Increase (Decrease) in Stockholders' Equity
Balance	4,238,764
Issuance of limited partner units	84,103
Treasury unit purchase	(307,296)
Redemption of limited partner units	(7,619)
LTIP Units	23,654
Cumulative effect of accounting change	7,264
Purchase and disposition of noncontrolling interests, net and other	(12,701)
Distributions to limited partners, excluding preferred interests classified as temporary equity	(2,107,160)
Comprehensive income, excluding $1,436 attributable to preferred interests in the Operating Partnership and a $379 loss attributable to noncontrolling redeemable interests in properties	1,978,492
Balance	3,897,501
Comprehensive income attributable to preferred interests	1,436
Comprehensive loss attributable to noncontrolling redeemable interests in properties	379
Simon Property Group, L.P. | Preferred Stock
Increase (Decrease) in Stockholders' Equity
Balance	43,077
Purchase and disposition of noncontrolling interests, net and other	(247)
Distributions to limited partners, excluding preferred interests classified as temporary equity	(2,503)
Comprehensive income, excluding $1,436 attributable to preferred interests in the Operating Partnership and a $379 loss attributable to noncontrolling redeemable interests in properties	2,503
Balance	42,830
Simon Property Group, L.P. | Simon (Managing General Partner)
Increase (Decrease) in Stockholders' Equity
Balance	3,643,091
Limited partner units exchanged to units	1,004
Treasury unit purchase	(307,296)
Redemption of limited partner units	(7,047)
Cumulative effect of accounting change	7,264
Purchase and disposition of noncontrolling interests, net and other	(12,615)
Adjustment to limited partners' interest from change in ownership in the Operating Partnership	127,707
Distributions to limited partners, excluding preferred interests classified as temporary equity	(1,827,107)
Comprehensive income, excluding $1,436 attributable to preferred interests in the Operating Partnership and a $379 loss attributable to noncontrolling redeemable interests in properties	1,715,785
Balance	3,340,786
Simon Property Group, L.P. | Limited Partners
Increase (Decrease) in Stockholders' Equity
Balance	548,858
Issuance of limited partner units	84,103
Limited partner units exchanged to units	(1,004)
Redemption of limited partner units	(572)
LTIP Units	23,654
Adjustment to limited partners' interest from change in ownership in the Operating Partnership	(127,707)
Distributions to limited partners, excluding preferred interests classified as temporary equity	(276,530)
Comprehensive income, excluding $1,436 attributable to preferred interests in the Operating Partnership and a $379 loss attributable to noncontrolling redeemable interests in properties	259,141
Balance	509,943
Simon Property Group, L.P. | Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity
Balance	3,738
Purchase and disposition of noncontrolling interests, net and other	161
Distributions to limited partners, excluding preferred interests classified as temporary equity	(1,020)
Comprehensive income, excluding $1,436 attributable to preferred interests in the Operating Partnership and a $379 loss attributable to noncontrolling redeemable interests in properties	1,063
Balance	$ 3,942