Investments in Unconsolidated Entities and International Investments - European Investments (Details) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020 USD ($) property $ / shares shares	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) property	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) property $ / shares shares	Dec. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($) property
Investment in Unconsolidated Entities
Income from unconsolidated entities									$ 219,870	$ 444,349	$ 475,250
Assets	$ 34,786,846				$ 31,231,630				34,786,846	31,231,630
Liabilities	31,128,608				28,101,319				31,128,608	28,101,319
Noncontrolling interests	432,874				384,852				432,874	384,852
Total revenue	1,131,429	$ 1,060,674	$ 1,062,041	$ 1,353,360	1,488,615	$ 1,416,554	$ 1,397,186	$ 1,452,834	4,607,503	5,755,189	5,645,288
Operating Income	462,047	404,024	450,868	654,869	776,876	705,302	680,631	745,021	1,971,809	2,907,831	2,926,299
Consolidated Net Income	$ 312,726	$ 168,646	$ 290,548	$ 505,404	$ 590,416	$ 628,724	$ 572,102	$ 631,947	$ 1,277,324	2,423,188	2,822,343
Klepierre | Disposed by Sales | Shopping centers
Investment in Unconsolidated Entities
Gain (loss) on sale or disposal of assets and interests in unconsolidated entities										$ 58,600	$ 20,200
European Joint Venture | Designer Outlet properties
Investment in Unconsolidated Entities
Number of properties | property	10				9				10	9	9
European Joint Venture | Designer Outlet properties | Minimum
Investment in Unconsolidated Entities
Ownership interest (as a percent)	45.00%								45.00%
European Joint Venture | Designer Outlet properties | Maximum
Investment in Unconsolidated Entities
Ownership interest (as a percent)	94.00%								94.00%
European Property Management and Development | Designer Outlet properties
Investment in Unconsolidated Entities
Ownership interest (as a percent)	50.00%								50.00%
Europe | Klepierre
Investment in Unconsolidated Entities
Shares owned | shares	63,924,148								63,924,148
Ownership interest (as a percent)	22.40%								22.40%
Quoted market price per share (in dollars per share) | $ / shares	$ 22.55								$ 22.55
Income from unconsolidated entities									$ 26,500	$ 145,200	$ 98,800
Impairment and disposition of certain assets									$ 4,300
Europe | Value Retail PLC
Investment in Unconsolidated Entities
Number of luxury outlets owned and operated | property	9								9
Number of outlets in which the entity has a minority direct ownership | property	3								3
Europe | Value Retail PLC | Deferred costs and other assets
Investment in Unconsolidated Entities
Value of equity instruments	$ 140,800				$ 140,800				$ 140,800	140,800
Europe | Klepierre | Klepierre
Investment in Unconsolidated Entities
Assets	20,900,000				19,600,000				20,900,000	19,600,000
Liabilities	14,400,000				12,900,000				14,400,000	12,900,000
Noncontrolling interests	$ 1,400,000				$ 1,300,000				1,400,000	1,300,000
Total revenue									1,300,000	1,500,000	1,600,000
Operating Income									327,300	626,300	670,400
Consolidated Net Income									$ 211,200	$ 655,500	$ 693,000