Investments in Unconsolidated Entities and International Investments - Unconsolidated Property Transactions (Details) $ in Thousands			3 Months Ended				6 Months Ended
	Dec. 19, 2022 USD ($)	Dec. 20, 2021 USD ($)	Jun. 30, 2023 USD ($) property	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2023 USD ($) property	Jun. 30, 2022 USD ($)
Investment in Unconsolidated Entities
Payments for acquisitions							$ 27,712	$ 14,000
Total revenue			$ 1,369,601		$ 1,279,842		2,720,450	2,575,763
Operating income before other items			657,925		626,761		1,320,648	1,247,152
Consolidated net income			557,505		569,480		1,076,760	1,057,790
Gain (loss) on exchange of equity interests			36,437				36,437
TRG
Investment in Unconsolidated Entities
Total revenue			163,097		179,922		332,825	342,531
Operating income before other items			61,916		73,206		136,694	135,059
Consolidated net income			25,722		49,135		70,675	87,804
Our share of net income (loss)			20,216		38,886		55,064	69,429
Amortization of Excess Investment			(47,390)		(49,025)		(94,780)	(98,050)
Other Platform Investments
Investment in Unconsolidated Entities
Total revenue			3,192,530		3,562,900		6,149,251	6,703,758
Operating income before other items			103,118		374,336		85,250	259,115
Consolidated net income			(9,401)		333,019		(128,366)	173,607
Our share of net income (loss)			8,053		78,798		(29,736)	88,687
Amortization of Excess Investment			(1,665)		(1,665)		(3,329)	(3,329)
Simon Property Group, L.P.
Investment in Unconsolidated Entities
Payments for acquisitions							27,712	14,000
Total revenue			1,369,601		1,279,842		2,720,450	2,575,763
Operating income before other items			657,925		626,761		1,320,648	1,247,152
Consolidated net income			557,505		$ 569,480		1,076,760	$ 1,057,790
Gain (loss) on exchange of equity interests			$ 36,437				$ 36,437
Jamestown
Investment in Unconsolidated Entities
Ownership interest (as a percent)	50.00%
Payments for acquisitions	$ 173,400
TRG
Investment in Unconsolidated Entities
Ownership interest (as a percent)			80.00%				80.00%
Aggregate investment in ventures			$ 2,978,024	$ 3,074,345			$ 2,978,024
TRG | Series A Cumulative Preferred Shares
Investment in Unconsolidated Entities
Preferred stock stated dividend rate (as a percent)							6.38%
Issuance of preferred units							$ 362,500
TRG | Simon Property Group, L.P.
Investment in Unconsolidated Entities
Aggregate investment in ventures			$ 2,978,024	3,074,345			$ 2,978,024
TRG | TRG
Investment in Unconsolidated Entities
Number of regional, super regional and outlet malls | property			24				24
JC Penney [Member]
Investment in Unconsolidated Entities
Ownership interest (as a percent)			41.67%				41.67%
SPARC Group
Investment in Unconsolidated Entities
Ownership interest (as a percent)			50.00%				50.00%
ABG
Investment in Unconsolidated Entities
Ownership interest (as a percent)			11.80%				11.80%
Payments for acquisitions		$ 100,000
Aggregate investment in ventures				98,800		$ 102,700
Gain (Loss) on Exchange of Equity Interests			$ 36,400	159,000		159,800
Deferred Taxes			$ 9,100	$ 39,700		$ 47,900	$ 9,100
Pre-tax gain		18,800
Tax expense		$ 8,000
RGG
Investment in Unconsolidated Entities
Ownership interest (as a percent)			45.00%				45.00%