Simon Property 10-Q 3 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Document Information
Entity Registrant Name	SIMON PROPERTY GROUP, INC.
Entity Central Index Key	0001063761
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Entity File Number	001-14469
Entity Tax Identification Number	04-6268599
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	225 West Washington Street
Entity Address, City or Town	Indianapolis
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	46204
City Area Code	317
Local Phone Number	636-1600
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Common stock
Document Information
Title of 12(b) Security	Common stock, $0.0001 par value
Trading Symbol	SPG
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding | shares	328,611,163
Entity Listing, Par Value Per Share | $ / shares	$ 0.0001
Class B common stock
Document Information
Entity Common Stock, Shares Outstanding | shares	8,000
Entity Listing, Par Value Per Share | $ / shares	$ 0.0001
Series J Preferred stock
Document Information
Title of 12(b) Security	83/8% Series J Cumulative Redeemable Preferred Stock, $0.0001 par value
Trading Symbol	SPGJ
Security Exchange Name	NYSE
Simon Property Group, L.P.
Document Information
Entity Registrant Name	SIMON PROPERTY GROUP, L.P.
Entity Central Index Key	0001022344
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Entity File Number	001-36110
Entity Tax Identification Number	34-1755769
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	225 West Washington Street
Entity Address, City or Town	Indianapolis
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	46204
City Area Code	317
Local Phone Number	636-1600
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
ASSETS:
Investment properties, at cost	$ 37,984,645	$ 38,050,196
Less - accumulated depreciation	15,410,030	14,891,937
Investment properties, at cost, net	22,574,615	23,158,259
Cash and cash equivalents	438,423	1,011,613
Tenant receivables and accrued revenue, net	935,053	1,236,734
Right-of-use assets, net	506,236	512,914
Investments held in trust - special purpose acquisition company	345,000
Deferred costs and other assets	1,105,736	1,082,168
Total assets	33,946,139	34,786,846
LIABILITIES:
Mortgages and unsecured indebtedness	25,584,372	26,723,361
Accounts payable, accrued expenses, intangibles, and deferred revenues	1,324,603	1,311,925
Cash distributions and losses in unconsolidated entities, at equity	1,573,563	1,577,393
Dividend payable	1,452	486,922
Lease liabilities	509,071	515,492
Other liabilities	525,361	513,515
Total liabilities	29,518,422	31,128,608
Commitments and contingencies
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests	553,025	185,892
Capital stock (850,000,000 total shares authorized, $0.0001 par value, 238,000,000 shares of excess common stock, 100,000,000 authorized shares of preferred stock):
Series J 83/8% cumulative redeemable preferred stock, 1,000,000 shares authorized, 796,948 issued and outstanding with a liquidation value of $39,847	41,845	42,091
Capital in excess of par value	11,201,333	11,179,688
Accumulated deficit	(5,789,329)	(6,102,314)
Accumulated other comprehensive loss	(191,274)	(188,675)
Common stock held in treasury, at cost, 14,296,445 and 14,355,621 shares, respectively	(1,884,511)	(1,891,352)
Total stockholders' equity	3,378,098	3,039,472
Noncontrolling interests	496,594	432,874
Total equity	3,874,692	3,472,346
Total liabilities and equity	33,946,139	34,786,846
TRG
ASSETS:
Investment, in equity	3,396,169	3,451,897
Klepierre
ASSETS:
Investment, in equity	1,672,858	1,729,690
Unconsolidated Investments excluding Klepierre and TRG
ASSETS:
Investment, in equity	2,972,049	2,603,571
Simon Property Group, L.P.
ASSETS:
Investment properties, at cost	37,984,645	38,050,196
Less - accumulated depreciation	15,410,030	14,891,937
Investment properties, at cost, net	22,574,615	23,158,259
Cash and cash equivalents	438,423	1,011,613
Tenant receivables and accrued revenue, net	935,053	1,236,734
Right-of-use assets, net	506,236	512,914
Investments held in trust - special purpose acquisition company	345,000
Deferred costs and other assets	1,105,736	1,082,168
Total assets	33,946,139	34,786,846
LIABILITIES:
Mortgages and unsecured indebtedness	25,584,372	26,723,361
Accounts payable, accrued expenses, intangibles, and deferred revenues	1,324,603	1,311,925
Cash distributions and losses in unconsolidated entities, at equity	1,573,563	1,577,393
Dividend payable	1,452	486,922
Lease liabilities	509,071	515,492
Other liabilities	525,361	513,515
Total liabilities	29,518,422	31,128,608
Commitments and contingencies
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests	553,025	185,892
Capital stock (850,000,000 total shares authorized, $0.0001 par value, 238,000,000 shares of excess common stock, 100,000,000 authorized shares of preferred stock):
Preferred units, 796,948 units outstanding. Liquidation value of $39,847	41,845	42,091
General Partner, 328,619,163 and 328,501,416 units outstanding, respectively	3,336,253	2,997,381
Limited Partners, 47,263,155 and 47,322,212 units outstanding, respectively	479,827	431,784
Total partners' equity	3,857,925	3,471,256
Nonredeemable noncontrolling interests in properties, net	16,767	1,090
Total equity	3,874,692	3,472,346
Total liabilities and equity	33,946,139	34,786,846
Simon Property Group, L.P. | TRG
ASSETS:
Investment, in equity	3,396,169	3,451,897
Simon Property Group, L.P. | Klepierre
ASSETS:
Investment, in equity	1,672,858	1,729,690
Simon Property Group, L.P. | Unconsolidated Investments excluding Klepierre and TRG
ASSETS:
Investment, in equity	2,972,049	2,603,571
Common stock
Capital stock (850,000,000 total shares authorized, $0.0001 par value, 238,000,000 shares of excess common stock, 100,000,000 authorized shares of preferred stock):
Common stock	$ 34	$ 34

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Capital stock, total shares authorized	850,000,000	850,000,000
Capital stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Capital stock, shares of excess common stock	238,000,000	238,000,000
Capital stock, authorized shares of preferred stock	100,000,000	100,000,000
Common stock held in treasury, shares	14,296,445	14,355,621
Series J Preferred stock
Preferred stock stated dividend rate (as a percent)	8.375%	8.375%
Series J 8 3/8% cumulative redeemable preferred stock, shares authorized	1,000,000	1,000,000
Series J 8 3/8% cumulative redeemable preferred stock, shares issued	796,948	796,948
Series J 8 3/8% cumulative redeemable preferred stock, shares outstanding	796,948	796,948
Preferred units, Liquidation value (in dollars)	$ 39,847	$ 39,847
Common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	511,990,000	511,990,000
Common stock, shares issued	342,907,608	342,849,037
Common stock, shares outstanding	342,907,608	342,849,037
Class B common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	10,000	10,000
Common stock, shares issued	8,000	8,000
Common stock, shares outstanding	8,000	8,000
Simon Property Group, L.P.
Preferred units, units outstanding	796,948	796,948
Preferred units, Liquidation value (in dollars)	$ 39,847	$ 39,847
General Partner, units outstanding	328,619,163	328,501,416
Limited Partners, units outstanding	47,263,155	47,322,212

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
REVENUE:
Lease income	$ 1,207,923	$ 993,831	$ 3,511,806	$ 3,269,572
Management fees and other revenues	27,024	21,345	78,381	71,545
Other income	61,607	45,498	200,465	134,957
Total revenue	1,296,554	1,060,674	3,790,652	3,476,074
EXPENSES:
Property operating	108,556	91,236	291,248	267,479
Depreciation and amortization	311,381	333,755	942,851	986,157
Real estate taxes	117,094	112,311	347,800	347,075
Repairs and maintenance	21,735	18,971	62,126	57,482
Advertising and promotion	38,635	14,751	87,685	60,967
Home and regional office costs	48,667	39,960	132,365	130,420
General and administrative	6,909	3,016	20,739	17,206
Other	31,253	42,650	84,180	99,527
Total operating expenses	684,230	656,650	1,968,994	1,966,313
OPERATING INCOME BEFORE OTHER ITEMS	612,324	404,024	1,821,658	1,509,761
Interest expense	(199,772)	(201,858)	(602,207)	(586,545)
Loss on extinguishment of debt	(28,593)		(31,552)
Gain on exchange of equity interests (Note 6)	159,828		159,828
Income and other tax (expense) benefit	(67,262)	(2,779)	(108,367)	3,065
Income from unconsolidated entities	198,524	61,823	562,138	156,610
Unrealized losses in fair value of equity instruments	(4,944)	(1,279)	(8,121)	(20,125)
Gain (loss) on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net	108,543	(91,285)	201,600	(98,168)
CONSOLIDATED NET INCOME	778,648	168,646	1,994,977	964,598
Net income (loss) attributable to noncontrolling interests	97,878	21,886	249,421	124,351
Preferred dividends	834	834	2,503	2,503
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ 679,936	$ 145,926	$ 1,743,053	$ 837,744
BASIC AND DILUTED EARNINGS PER COMMON SHARE:
Net income attributable to common stockholders - basic (in dollars per share)	$ 2.07	$ 0.48	$ 5.30	$ 2.74
Net income attributable to common stockholders - diluted (in dollars per share)	$ 2.07	$ 0.48	$ 5.30	$ 2.74
Consolidated Net Income	$ 778,648	$ 168,646	$ 1,994,977	$ 964,598
Unrealized gain (loss) on derivative hedge agreements	8,280	(49,175)	45,366	(51,034)
Net gain reclassified from accumulated other comprehensive loss into earnings	(404)	(477)	(7,022)	(1,435)
Currency translation adjustments	(11,199)	20,525	(40,968)	(18,983)
Changes in available-for-sale securities and other	(71)	(27)	(304)	245
Comprehensive income	775,254	139,492	1,992,049	893,391
Comprehensive income attributable to noncontrolling interests	97,451	18,074	249,091	115,008
Comprehensive income attributable to common stockholders	677,803	121,418	1,742,958	778,383
Simon Property Group, L.P.
REVENUE:
Lease income	1,207,923	993,831	3,511,806	3,269,572
Management fees and other revenues	27,024	21,345	78,381	71,545
Other income	61,607	45,498	200,465	134,957
Total revenue	1,296,554	1,060,674	3,790,652	3,476,074
EXPENSES:
Property operating	108,556	91,236	291,248	267,479
Depreciation and amortization	311,381	333,755	942,851	986,157
Real estate taxes	117,094	112,311	347,800	347,075
Repairs and maintenance	21,735	18,971	62,126	57,482
Advertising and promotion	38,635	14,751	87,685	60,967
Home and regional office costs	48,667	39,960	132,365	130,420
General and administrative	6,909	3,016	20,739	17,206
Other	31,253	42,650	84,180	99,527
Total operating expenses	684,230	656,650	1,968,994	1,966,313
OPERATING INCOME BEFORE OTHER ITEMS	612,324	404,024	1,821,658	1,509,761
Interest expense	(199,772)	(201,858)	(602,207)	(586,545)
Loss on extinguishment of debt	(28,593)		(31,552)
Gain on exchange of equity interests (Note 6)	159,828		159,828
Income and other tax (expense) benefit	(67,262)	(2,779)	(108,367)	3,065
Income from unconsolidated entities	198,524	61,823	562,138	156,610
Unrealized losses in fair value of equity instruments	(4,944)	(1,279)	(8,121)	(20,125)
Gain (loss) on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net	108,543	(91,285)	201,600	(98,168)
CONSOLIDATED NET INCOME	778,648	168,646	1,994,977	964,598
Net income (loss) attributable to noncontrolling interests	(405)	(753)	(2,875)	(4,551)
Preferred dividends	1,313	1,313	3,939	3,939
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	777,740	168,086	1,993,913	965,210
NET INCOME ATTRIBUTABLE TO UNITHOLDERS ATTRIBUTABLE TO:
General Partner	679,936	145,928	1,743,053	837,744
Limited Partners	$ 97,804	$ 22,158	$ 250,860	$ 127,466
BASIC AND DILUTED EARNINGS PER COMMON SHARE:
Net income attributable to common stockholders - basic (in dollars per share)	$ 2.07	$ 0.48	$ 5.30	$ 2.74
Net income attributable to common stockholders - diluted (in dollars per share)	$ 2.07	$ 0.48	$ 5.30	$ 2.74
Consolidated Net Income	$ 778,648	$ 168,646	$ 1,994,977	$ 964,598
Unrealized gain (loss) on derivative hedge agreements	8,280	(49,175)	45,366	(51,034)
Net gain reclassified from accumulated other comprehensive loss into earnings	(404)	(477)	(7,022)	(1,435)
Currency translation adjustments	(11,199)	20,525	(40,968)	(18,983)
Changes in available-for-sale securities and other	(71)	(27)	(304)	245
Comprehensive income	775,254	139,492	1,992,049	893,391
Comprehensive income attributable to noncontrolling interests	336	(246)	(215)	483
Comprehensive income attributable to common stockholders	$ 774,918	$ 139,738	$ 1,992,264	$ 892,908

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Consolidated Net Income	$ 1,994,977	$ 964,598
Adjustments to reconcile consolidated net income to net cash provided by operating activities
Depreciation and amortization	985,116	1,017,517
Loss on debt extinguishment	31,552
(Gain) loss on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net	(201,600)	98,168
Gain on exchange of equity interests	(159,828)
Unrealized losses in fair value of equity instruments	8,121	20,125
Straight-line lease loss	19,014	6,539
Equity in income of unconsolidated entities	(562,138)	(156,610)
Distributions of income from unconsolidated entities	319,041	152,712
Changes in assets and liabilities
Tenant receivables and accrued revenue, net	260,470	(625,107)
Deferred costs and other assets	(51,079)	(87,027)
Accounts payable, accrued expenses, intangibles, deferred revenues and other liabilities	108,825	40,706
Net cash provided by operating activities	2,752,471	1,431,621
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions	(157,080)	(107,797)
Funding of loans to related parties	(15,419)	(6,393)
Repayments of loans to related parties	8,381
Capital expenditures, net	(419,477)	(396,004)
Cash impact from the consolidation of properties	5,595
Investments in unconsolidated entities	(48,156)	(172,598)
Purchase of equity instruments	(16,769)	(30,427)
Proceeds from sales of equity instruments		30,000
Insurance proceeds for property restoration	7,030	8,746
Distributions of capital from unconsolidated entities and other	137,031	214,389
Net cash used in investing activities	(498,864)	(460,084)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from sales of common stock and other, net of transaction costs	(246)	(247)
Purchase of shares related to stock grant recipients' tax withholdings	(2,318)	(854)
Redemption of limited partner units	(57)	(16,087)
Purchase of treasury stock		(152,589)
Proceeds from the special purpose acquisition company IPO, net of transaction costs	338,121
Establishment of trust account for special purpose acquisition company	(345,000)
Distributions to noncontrolling interest holders in properties	(1,640)	(5,766)
Contributions from noncontrolling interest holders in properties	16,736	28
Preferred distributions of the Operating Partnership	(1,436)	(1,436)
Distributions to stockholders and preferred dividends	(1,809,156)	(1,044,591)
Distributions to limited partners	(258,995)	(158,650)
Cash paid to extinguish debt	(30,009)
Proceeds from issuance of debt, net of transaction costs	7,353,120	11,363,272
Repayments of debt	(8,085,917)	(10,541,677)
Net cash used in financing activities	(2,826,797)	(558,597)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(573,190)	412,940
CASH AND CASH EQUIVALENTS, beginning of period	1,011,613	669,373
CASH AND CASH EQUIVALENTS, end of period	438,423	1,082,313
Simon Property Group, L.P.
CASH FLOWS FROM OPERATING ACTIVITIES:
Consolidated Net Income	1,994,977	964,598
Adjustments to reconcile consolidated net income to net cash provided by operating activities
Depreciation and amortization	985,116	1,017,517
Loss on debt extinguishment	31,552
(Gain) loss on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net	(201,600)	98,168
Gain on exchange of equity interests	(159,828)
Unrealized losses in fair value of equity instruments	8,121	20,125
Straight-line lease loss	19,014	6,539
Equity in income of unconsolidated entities	(562,138)	(156,610)
Distributions of income from unconsolidated entities	319,041	152,712
Changes in assets and liabilities
Tenant receivables and accrued revenue, net	260,470	(625,107)
Deferred costs and other assets	(51,079)	(87,027)
Accounts payable, accrued expenses, intangibles, deferred revenues and other liabilities	108,825	40,706
Net cash provided by operating activities	2,752,471	1,431,621
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions	(157,080)	(107,797)
Funding of loans to related parties	(15,419)	(6,393)
Repayments of loans to related parties	8,381
Capital expenditures, net	(419,477)	(396,004)
Cash impact from the consolidation of properties	5,595
Investments in unconsolidated entities	(48,156)	(172,598)
Purchase of equity instruments	(16,769)	(30,427)
Proceeds from sales of equity instruments		30,000
Insurance proceeds for property restoration	7,030	8,746
Distributions of capital from unconsolidated entities and other	137,031	214,389
Net cash used in investing activities	(498,864)	(460,084)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from sales of common stock and other, net of transaction costs	(246)	(247)
Purchase of shares related to stock grant recipients' tax withholdings	(2,318)	(854)
Redemption of limited partner units	(57)	(16,087)
Purchase of general partner units		(152,589)
Proceeds from the special purpose acquisition company IPO, net of transaction costs	338,121
Establishment of trust account for special purpose acquisition company	(345,000)
Distributions to noncontrolling interest holders in properties	(1,640)	(5,766)
Contributions from noncontrolling interest holders in properties	16,736	28
Preferred distributions of the Operating Partnership	(2,069,587)	(1,204,677)
Cash paid to extinguish debt	(30,009)
Proceeds from issuance of debt, net of transaction costs	7,353,120	11,363,272
Repayments of debt	(8,085,917)	(10,541,677)
Net cash used in financing activities	(2,826,797)	(558,597)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(573,190)	412,940
CASH AND CASH EQUIVALENTS, beginning of period	1,011,613	669,373
CASH AND CASH EQUIVALENTS, end of period	$ 438,423	$ 1,082,313

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Simon Property Group, L.P.Simon (Managing General Partner)	Simon Property Group, L.P.Limited Partners	Simon Property Group, L.P.Preferred Stock	Simon Property Group, L.P.Noncontrolling Interests	Simon Property Group, L.P.	Preferred Stock	Common Stock	Accumulated Other Comprehensive Income (Loss)	Capital in Excess of Par Value	Accumulated Deficit	Common Stock Held in Treasury	Noncontrolling Interests	Total
Balance at Dec. 31, 2019						$ 42,420	$ 32	$ (118,604)	$ 9,756,073	$ (5,379,952)	$ (1,773,571)	$ 384,852	$ 2,911,250
Balance at Dec. 31, 2019	$ 2,483,978	$ 378,339	$ 42,420	$ 6,513	$ 2,911,250
Increase (Decrease) in Stockholders' Equity
Exchange of limited partner units									1,076			(1,076)
Series J preferred stock premium amortization			(82)		(82)	(82)							(82)
Limited partner units exchanged to common units	1,076	(1,076)
Amortization of stock incentive	1,891				1,891				1,891				1,891
Redemption of limited partner units	(15,127)	(940)			(16,067)				(15,127)			(940)	(16,067)
Treasury stock purchase											(152,589)		(152,589)
Treasury unit purchase	(152,589)				(152,589)
Long-term incentive performance units		4,987			4,987							4,987	4,987
Issuance of unit equivalents and other	3,316			26	3,342				29	3,287		26	3,342
Unrealized gain (loss) on derivative hedge agreements	19,510	2,963			22,473			19,510				2,963	22,473
Currency translation adjustments	(20,505)	(3,099)			(23,604)			(20,505)				(3,099)	(23,604)
Changes in available-for-sale securities and other	715	109			824			715				109	824
Net gain reclassified from accumulated other comprehensive loss into earnings	(417)	(63)			(480)			(417)				(63)	(480)
Other comprehensive income	(697)	(90)			(787)			(697)				(90)	(787)
Adjustment to limited partners' interest from change in ownership in the Operating Partnership	24,233	(24,233)							24,233			(24,233)
Distributions to common stockholders and limited partners, excluding Operating Partnership preferred interests										(645,259)		(98,099)	(743,358)
Distributions to other noncontrolling interest partners												(3,167)	(3,167)
Distributions to limited partners, excluding preferred interests classified as temporary equity	(644,425)	(98,099)	(834)	(3,167)	(746,525)
Net income, excluding preferred distributions on temporary equity preferred units and amounts attributable to noncontrolling redeemable interests in properties	437,605	66,658	834	436	505,533					438,439		67,094	505,533
Balance at Mar. 31, 2020						42,338	32	(119,301)	9,768,175	(5,583,485)	(1,926,160)	329,354	2,510,953
Balance at Mar. 31, 2020	2,139,261	325,546	42,338	3,808	2,510,953
Balance at Dec. 31, 2019						42,420	32	(118,604)	9,756,073	(5,379,952)	(1,773,571)	384,852	2,911,250
Balance at Dec. 31, 2019	2,483,978	378,339	42,420	6,513	2,911,250
Increase (Decrease) in Stockholders' Equity
Unrealized gain (loss) on derivative hedge agreements					(51,034)								(51,034)
Currency translation adjustments					(18,983)								(18,983)
Changes in available-for-sale securities and other					245								245
Net gain reclassified from accumulated other comprehensive loss into earnings					(1,435)								(1,435)
Balance at Sep. 30, 2020						42,173	32	(180,468)	9,761,978	(5,953,166)	(1,917,698)	263,365	2,016,216
Balance at Sep. 30, 2020	1,710,678	259,797	42,173	3,568	2,016,216
Balance at Mar. 31, 2020						42,338	32	(119,301)	9,768,175	(5,583,485)	(1,926,160)	329,354	2,510,953
Balance at Mar. 31, 2020	2,139,261	325,546	42,338	3,808	2,510,953
Increase (Decrease) in Stockholders' Equity
Series J preferred stock premium amortization			(82)		(82)	(82)							(82)
Stock incentive program									(9,317)		9,317
Amortization of stock incentive	4,969				4,969				4,969				4,969
Long-term incentive performance units		3,229			3,229							3,229	3,229
Issuance of unit equivalents and other	22,899	(2)			22,897				1	23,753	(855)	(2)	22,897
Unrealized gain (loss) on derivative hedge agreements	(21,116)	(3,216)			(24,332)			(21,116)				(3,216)	(24,332)
Currency translation adjustments	(13,815)	(2,088)			(15,904)			(13,815)				(2,088)	(15,904)
Changes in available-for-sale securities and other	(479)	(73)			(552)			(479)				(73)	(552)
Net gain reclassified from accumulated other comprehensive loss into earnings	(415)	(63)			(478)			(415)				(63)	(478)
Other comprehensive income	(35,825)	(5,440)			(41,265)			(35,825)				(5,440)	(41,265)
Adjustment to limited partners' interest from change in ownership in the Operating Partnership	(769)	769							(769)			769
Distributions to common stockholders and limited partners, excluding Operating Partnership preferred interests										(398,499)		(60,510)	(459,009)
Distributions to other noncontrolling interest partners												(244)	(244)
Distributions to limited partners, excluding preferred interests classified as temporary equity	(397,664)	(60,510)	(835)	(244)	(459,253)
Net income, excluding preferred distributions on temporary equity preferred units and amounts attributable to noncontrolling redeemable interests in properties	254,213	38,650	835	293	293,991
Net income, excluding attributable to preferred interests in the Operating Partnership and a loss attributable to noncontrolling redeemable interests in properties										255,048		38,943	293,991
Balance at Jun. 30, 2020						42,256	32	(155,126)	9,763,059	(5,703,183)	(1,917,698)	306,099	2,335,439
Balance at Jun. 30, 2020	1,987,084	302,242	42,256	3,857	2,335,439
Increase (Decrease) in Stockholders' Equity
Exchange of limited partner units									403			(403)
Series J preferred stock premium amortization			(83)		(83)	(83)							(83)
Limited partner units exchanged to common units	403	(403)
Amortization of stock incentive	2,594				2,594				2,594				2,594
Redemption of limited partner units	(36)	16			(20)				(36)			16	(20)
Long-term incentive performance units		(4,004)			(4,004)							(4,004)	(4,004)
Issuance of unit equivalents and other	1,831	5			1,836				1	1,830		5	1,836
Unrealized gain (loss) on derivative hedge agreements	(42,683)	(6,492)			(49,175)			(42,683)				(6,492)	(49,175)
Currency translation adjustments	17,778	2,746			20,525			17,778				2,746	20,525
Changes in available-for-sale securities and other	(23)	(4)			(27)			(23)				(4)	(27)
Net gain reclassified from accumulated other comprehensive loss into earnings	(414)	(63)			(477)			(414)				(63)	(477)
Other comprehensive income	(25,342)	(3,813)			(29,155)			(25,342)				(3,813)	(29,155)
Adjustment to limited partners' interest from change in ownership in the Operating Partnership	(4,043)	4,043							(4,043)			4,043
Distributions to common stockholders and limited partners, excluding Operating Partnership preferred interests										(398,573)		(60,447)	(459,020)
Distributions to other noncontrolling interest partners												(43)	(43)
Distributions to limited partners, excluding preferred interests classified as temporary equity	(397,739)	(60,447)	(834)	(43)	(459,063)
Net income, excluding preferred distributions on temporary equity preferred units and amounts attributable to noncontrolling redeemable interests in properties	145,926	22,158	834	(246)	168,672
Net income, excluding attributable to preferred interests in the Operating Partnership and a loss attributable to noncontrolling redeemable interests in properties										146,760		21,912	168,672
Balance at Sep. 30, 2020						42,173	32	(180,468)	9,761,978	(5,953,166)	(1,917,698)	263,365	2,016,216
Balance at Sep. 30, 2020	1,710,678	259,797	42,173	3,568	2,016,216
Balance at Dec. 31, 2020						42,091	34	(188,675)	11,179,688	(6,102,314)	(1,891,352)	432,874	3,472,346
Balance at Dec. 31, 2020	2,997,381	431,784	42,091	1,090	3,472,346
Increase (Decrease) in Stockholders' Equity
Series J preferred stock premium amortization			(82)		(82)	(82)							(82)
Stock incentive program									(7,214)		7,214
Amortization of stock incentive	4,231				4,231				4,231				4,231
Redemption of limited partner units	(34)	(3)			(37)				(34)			(3)	(37)
Long-term incentive performance units		5,014			5,014							5,014	5,014
Issuance of unit equivalents and other	(6,994)			15,822	8,828				(4,313)	(2,681)		15,822	8,828
Unrealized gain (loss) on derivative hedge agreements	31,333	4,514			35,847			31,333				4,514	35,847
Currency translation adjustments	(20,878)	(3,005)			(23,883)			(20,878)				(3,005)	(23,883)
Changes in available-for-sale securities and other	(276)	(40)			(316)			(276)				(40)	(316)
Net gain reclassified from accumulated other comprehensive loss into earnings	(5,370)	(773)			(6,143)			(5,370)				(773)	(6,143)
Other comprehensive income	4,809	696			5,505			4,809				696	5,505
Adjustment to limited partners' interest from change in ownership in the Operating Partnership	4,849	(4,849)							4,849			(4,849)
Distributions to common stockholders and limited partners, excluding Operating Partnership preferred interests										(428,712)		(61,558)	(490,270)
Distributions to other noncontrolling interest partners												(577)	(577)
Distributions to limited partners, excluding preferred interests classified as temporary equity	(427,878)	(61,558)	(834)	(577)	(490,847)
Net income, excluding preferred distributions on temporary equity preferred units and amounts attributable to noncontrolling redeemable interests in properties	445,860	64,225	834	(41)	510,878					446,694		64,184	510,878
Balance at Mar. 31, 2021						42,009	34	(183,866)	11,177,207	(6,087,013)	(1,884,138)	451,603	3,515,836
Balance at Mar. 31, 2021	3,022,224	435,309	42,009	16,294	3,515,836
Balance at Dec. 31, 2020						42,091	34	(188,675)	11,179,688	(6,102,314)	(1,891,352)	432,874	3,472,346
Balance at Dec. 31, 2020	2,997,381	431,784	42,091	1,090	3,472,346
Increase (Decrease) in Stockholders' Equity
Unrealized gain (loss) on derivative hedge agreements					45,366								45,366
Currency translation adjustments					(40,968)								(40,968)
Changes in available-for-sale securities and other					(304)								(304)
Net gain reclassified from accumulated other comprehensive loss into earnings					(7,022)								(7,022)
Balance at Sep. 30, 2021						41,845	34	(191,274)	11,201,333	(5,789,329)	(1,884,511)	496,594	3,874,692
Balance at Sep. 30, 2021	3,336,253	479,827	41,845	16,767	3,874,692
Balance at Mar. 31, 2021						42,009	34	(183,866)	11,177,207	(6,087,013)	(1,884,138)	451,603	3,515,836
Balance at Mar. 31, 2021	3,022,224	435,309	42,009	16,294	3,515,836
Increase (Decrease) in Stockholders' Equity
Exchange of limited partner units									539			(539)
Series J preferred stock premium amortization			(82)		(82)	(82)							(82)
Limited partner units exchanged to common units	539	(539)
Stock incentive program									(1,945)		1,945
Amortization of stock incentive	5,204				5,204				5,204				5,204
Redemption of limited partner units	(19)	(1)			(20)				(19)			(1)	(20)
Long-term incentive performance units		5,333			5,333							5,333	5,333
Issuance of unit equivalents and other	5,806			1,135	6,941				9,336	(1,212)	(2,318)	1,135	6,941
Unrealized gain (loss) on derivative hedge agreements	1,079	160			1,239			1,079				160	1,239
Currency translation adjustments	(5,176)	(710)			(5,886)			(5,176)				(710)	(5,886)
Changes in available-for-sale securities and other	72	10			82			72				10	82
Net gain reclassified from accumulated other comprehensive loss into earnings	(416)	(59)			(475)			(416)				(59)	(475)
Other comprehensive income	(4,441)	(599)			(5,040)			(4,441)				(599)	(5,040)
Adjustment to limited partners' interest from change in ownership in the Operating Partnership	3,452	(3,452)							3,452			(3,452)
Distributions to limited partners, excluding Operating Partnership preferred interests	(460,151)	(66,105)	(835)	(54)	(527,145)
Distributions to common stockholders and limited partners, excluding Operating Partnership preferred interests										(460,986)		(66,105)	(527,091)
Distributions to other noncontrolling interest partners												(54)	(54)
Net income, excluding preferred distributions on temporary equity preferred units and amounts attributable to noncontrolling redeemable interests in properties	617,257	88,830	835	(510)	706,412
Net income, excluding attributable to preferred interests in the Operating Partnership and a loss attributable to noncontrolling redeemable interests in properties										618,092		88,320	706,412
Balance at Jun. 30, 2021						41,927	34	(188,307)	11,193,774	(5,931,119)	(1,884,511)	475,641	3,707,439
Balance at Jun. 30, 2021	3,189,871	458,776	41,927	16,865	3,707,439
Increase (Decrease) in Stockholders' Equity
Series J preferred stock premium amortization			(82)		(82)	(82)							(82)
Amortization of stock incentive	4,718				4,718				4,718				4,718
Long-term incentive performance units		(2,475)			(2,475)							(2,475)	(2,475)
Issuance of unit equivalents and other	(44,669)	(1)		(380)	(45,050)					(44,669)		(381)	(45,050)
Unrealized gain (loss) on derivative hedge agreements	7,239	1,040			8,280			7,239				1,040	8,280
Currency translation adjustments	(9,790)	(1,409)			(11,199)			(9,790)				(1,409)	(11,199)
Changes in available-for-sale securities and other	(62)	(9)			(71)			(62)				(9)	(71)
Net gain reclassified from accumulated other comprehensive loss into earnings	(354)	(50)			(404)			(354)				(50)	(404)
Other comprehensive income	(2,967)	(428)			(3,395)			(2,967)				(428)	(3,395)
Adjustment to limited partners' interest from change in ownership in the Operating Partnership	2,841	(2,841)							2,841			(2,841)
Distributions to common stockholders and limited partners, excluding Operating Partnership preferred interests										(494,311)		(71,009)	(565,320)
Distributions to other noncontrolling interest partners												(54)	(54)
Distributions to limited partners, excluding preferred interests classified as temporary equity	(493,477)	(71,009)	(834)	(54)	(565,374)
Net income, excluding preferred distributions on temporary equity preferred units and amounts attributable to noncontrolling redeemable interests in properties	679,936	97,805	834	336	778,911
Net income, excluding attributable to preferred interests in the Operating Partnership and a loss attributable to noncontrolling redeemable interests in properties										680,770		98,141	778,911
Balance at Sep. 30, 2021						$ 41,845	$ 34	$ (191,274)	$ 11,201,333	$ (5,789,329)	$ (1,884,511)	$ 496,594	$ 3,874,692
Balance at Sep. 30, 2021	$ 3,336,253	$ 479,827	$ 41,845	$ 16,767	$ 3,874,692

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - USD ($)	3 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Exchange of limited partner units, (in shares)		58,571		61,968		132,946
Stock incentive program, units, net - shares forfeited		41,574	37,976	3,825	155,610	1,081
Redemption of Limited Partner Units		170	316	586		116,072
Treasury stock purchase, shares						1,245,654
Shares repurchased		20,374			15,561
Net income attributable to preferred interests in the Operating Partnership (in dollars)	$ 479,000	$ 478,000	$ 479,000	$ 479,000	$ 478,000	$ 479,000
Net loss (gain) attributable to noncontrolling redeemable interests in properties (in dollars)	742,000	$ 1,021,000	$ 897,000	$ 505,000	$ 3,921,000	$ 608,000
Simon Property Group, L.P.
Limited partner units exchanged to common units		58,571		61,968		132,946
Stock incentive program, units, net - shares forfeited		41,574	37,976	3,825	155,610	1,081
Redemption of Limited Partner Units		170	316	586		116,072
Treasury unit purchase, units						1,245,654
Issuance of equivalents units		20,374		632	1,264
Issuance of common units					$ 15,561	$ 38,148
Net income, attributable to preferred distributions on temporary equity preferred units (in dollars)	479,000	$ 478,000	$ 479,000	$ 479,000	478,000	479,000
Net loss (gain) attributable to noncontrolling redeemable interests in properties (in dollars)	$ 742,000	$ 1,021,000	$ 897,000	$ 505,000	$ 3,921,000	$ 608,000

Organization

Organization	9 Months Ended
	Sep. 30, 2021
Organization
Organization	1. Organization Simon Property Group, Inc. is a Delaware corporation that operates as a self-administered and self-managed real estate investment trust, or REIT, under the Internal Revenue Code of 1986, as amended, or the Internal Revenue Code. REITs will generally not be liable for U.S. federal corporate income taxes as long as they distribute not less than 100% of their REIT taxable income. Simon Property Group, L.P. is our majority-owned Delaware partnership subsidiary that owns all of our real estate properties and other assets. According to the Operating Partnership’s partnership agreement, the Operating Partnership is required to pay all expenses of Simon. In these condensed notes to the consolidated financial statements, unless stated otherwise or the context otherwise requires, references to "Simon" mean Simon Property Group, Inc. and references to the "Operating Partnership" mean Simon Property Group, L.P. References to "we," "us" and "our" mean collectively Simon, the Operating Partnership and those entities/subsidiaries owned or controlled by Simon and/or the Operating Partnership. Unless otherwise indicated, these condensed notes to consolidated financial statements apply to both Simon and the Operating Partnership. We own, develop and manage premier shopping, dining, entertainment and mixed-use destinations, which consist primarily of malls, Premium Outlets ® ®

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Basis of Presentation
Basis of Presentation	2. Basis of Presentation The accompanying unaudited consolidated financial statements include the accounts of all controlled subsidiaries, and all significant intercompany amounts have been eliminated. Due to the seasonal nature of certain operational activities, the results for the interim periods ended September 30, 2021 are not necessarily indicative of the results to be expected for the full year. These consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and include all of the information and disclosures required by accounting principles generally accepted in the United States (GAAP) for interim reporting. Accordingly, they do not include all of the disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments necessary for a fair presentation (including normal recurring accruals) have been included. The consolidated financial statements in this Form 10-Q should be read in conjunction with the audited consolidated financial statements and related notes contained in the combined 2020 Annual Report on Form 10-K of Simon and the Operating Partnership. Certain reclassifications considered necessary for a fair presentation have been made to the prior period financial statements in order to conform to the current year presentation. These reclassifications have not changed the results of operations. As of September 30, 2021, we consolidated 131 wholly-owned properties and 18 additional properties that are less than wholly-owned, but which we control or for which we are the primary beneficiary. We account for the remaining 84 properties, or the joint venture properties, as well as our investments in Klépierre, HBS Global Properties, or HBS, TRG, and our retailer investments in Authentic Brands Group, LLC, or ABG, J.C. Penney, Rue Gilt Groupe, or RGG and SPARC Group, which includes Forever 21 as of February 17, 2021, using the equity method of accounting, as we have determined we have significant influence over their operations. We manage the day-to-day operations of 53 of the 84 joint venture properties, but have determined that our partner or partners have substantive participating rights with respect to the assets and operations of these joint venture properties. Our investments in joint ventures in Japan, South Korea, Mexico, Malaysia, Thailand, Canada, Spain, and the United Kingdom comprise 23 of the remaining 31 properties. These international properties are managed by joint ventures in which we share control. Preferred distributions of the Operating Partnership are accrued at declaration and represent distributions on outstanding preferred units of partnership interests, or preferred units, and are included in net income attributable to noncontrolling interests. We allocate net operating results of the Operating Partnership after preferred distributions to limited partners and to Simon based on the partners’ respective weighted average ownership interests in the Operating Partnership. Net operating results of the Operating Partnership attributable to limited partners are reflected in net income attributable to noncontrolling interests. Simon’s weighted average ownership interest in the Operating Partnership was 87.4% and 86.8% for the nine months ended September 30, 2021 and 2020, respectively. As of September 30, 2021 and December 31, 2020, Simon’s ownership interest in the Operating Partnership was 87.4%. We adjust the noncontrolling limited partners’ interests at the end of each period to reflect their interest in the net assets of the Operating Partnership. Preferred unit requirements in the Operating Partnership’s accompanying consolidated statements of operations and comprehensive income represent distributions on outstanding preferred units and are recorded when declared.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Significant Accounting Policies
Significant Accounting Policies	3. Significant Accounting Policies Cash and Cash Equivalents We consider all highly liquid investments purchased with an original maturity of 90 days or less to be cash and cash equivalents. Cash equivalents are carried at cost, which approximates fair value. Cash equivalents generally consist of commercial paper, bankers’ acceptances, Eurodollars, repurchase agreements, and money market deposits or securities. Financial instruments that potentially subject us to concentrations of credit risk include our cash and cash equivalents and our trade accounts receivable. We place our cash and cash equivalents with institutions of high credit quality. However, at certain times, such cash and cash equivalents are in excess of Federal Deposit Insurance Corporation and Securities Investor Protection Corporation insurance limits. Equity Instruments and Debt Securities Equity instruments and debt securities consist primarily of equity instruments, our deferred compensation plan investments, the debt securities of our captive insurance subsidiary, and certain investments held to fund the debt service requirements of debt previously secured by investment properties. At September 30, 2021 and December 31, 2020, we had equity instruments with readily determinable fair values of $94.2 million and $41.9 million, respectively. Changes in the fair value of these equity instruments are recorded in unrealized losses in fair value of equity instruments in our consolidated statements of operations and comprehensive income. At September 30, 2021 and December 31, 2020, we had equity instruments without readily determinable fair values of $250.2 million and $309.3 million, respectively, for which we have elected the measurement alternative. We regularly evaluate these investments for any impairment in their estimated fair value, as well as any observable price changes for an identical or similar equity instrument of the same issuer, and recorded a $14.0 million loss in the third quarter of 2021, which is included in unrealized losses in fair value of equity instruments in our consolidated statements of operations and comprehensive income. Our deferred compensation plan equity instruments are valued based upon quoted market prices. The investments have a matching liability as the amounts are fully payable to the employees that earned the compensation. Changes in value of these securities and changes to the matching liability to employees are both recognized in earnings and, as a result, there is no impact to consolidated net income. At September 30, 2021 and December 31, 2020, we held debt securities of $56.9 million and $40.5 million, respectively, in our captive insurance subsidiary. The types of securities included in the investment portfolio of our captive insurance subsidiary are typically U.S. Treasury or other U.S. government securities as well as corporate debt securities with maturities ranging from less than one year to ten years. These securities are classified as available-for-sale and are valued based upon quoted market prices or other observable inputs when quoted market prices are not available. The amortized cost of debt securities, which approximates fair value, held by our captive insurance subsidiary is adjusted for amortization of premiums and accretion of discounts to maturity. Changes in the values of these securities are recognized in accumulated other comprehensive income (loss) until the gain or loss is realized or until any unrealized loss is deemed to be other-than-temporary. We review any declines in value of these securities for other-than-temporary impairment and consider the severity and duration of any decline in value. To the extent an other-than-temporary impairment is deemed to have occurred, an impairment is recorded and a new cost basis is established. Our captive insurance subsidiary is required to maintain statutory minimum capital and surplus as well as maintain a minimum liquidity ratio. Therefore, our access to these securities may be limited. Fair Value Measurements Level 1 fair value inputs are quoted prices for identical items in active, liquid and visible markets such as stock exchanges. Level 2 fair value inputs are observable information for similar items in active or inactive markets, and appropriately consider counterparty creditworthiness in the valuations. Level 3 fair value inputs reflect our best estimate of inputs and assumptions market participants would use in pricing an asset or liability at the measurement date. The inputs are unobservable in the market and significant to the valuation estimate. We have no investments for which fair value is measured on a recurring basis using Level 3 inputs. The equity instruments with readily determinable fair values we held at September 30, 2021 and December 31, 2020 were primarily classified as having Level 1 and Level 2 fair value inputs. In addition, we had derivative instruments which were classified as having Level 2 inputs, which consist primarily of foreign currency forward contracts and interest rate swap agreements with a gross asset balance of $3.9 million at September 30, 2021 and an insignificant gross asset balance at December 31, 2020, and a gross liability balance of $0.1 million and $44.6 million at September 30, 2021 and December 31, 2020, respectively. Note 7 includes a discussion of the fair value of debt measured using Level 2 inputs. Level 3 inputs to our purchase accounting and impairment analyses include our estimations of net operating results of the property, capitalization rates and discount rates. Noncontrolling Interests Simon Details of the carrying amount of our noncontrolling interests are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of As of ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 Limited partners’ interests in the Operating Partnership ​ $ 479,827 ​ $ 431,784 ​ Nonredeemable noncontrolling interests in properties, net ​ 16,767 ​ 1,090 ​ Total noncontrolling interests reflected in equity ​ $ 496,594 ​ $ 432,874 ​ ​ Net income attributable to noncontrolling interests (which includes nonredeemable and redeemable noncontrolling interests in consolidated properties, limited partners’ interests in the Operating Partnership and preferred distributions payable by the Operating Partnership on its outstanding preferred units) is a component of consolidated net income. In addition, the individual components of other comprehensive income (loss) are presented in the aggregate for both controlling and noncontrolling interests, with the portion attributable to noncontrolling interests deducted from comprehensive income attributable to common stockholders. The Operating Partnership Our evaluation of the appropriateness of classifying the Operating Partnership’s common units of partnership interest, or units, held by Simon and the Operating Partnership's limited partners within permanent equity considered several significant factors. First, as a limited partnership, all decisions relating to the Operating Partnership’s operations and distributions are made by Simon, acting as the Operating Partnership’s sole general partner. The decisions of the general partner are made by Simon's Board of Directors or management. The Operating Partnership has no other governance structure. Secondly, the sole asset of Simon is its interest in the Operating Partnership. As a result, a share of common stock of Simon, or common stock, if owned by the Operating Partnership, is best characterized as being similar to a treasury share and thus not an asset of the Operating Partnership. Limited partners of the Operating Partnership have the right under the Operating Partnership’s partnership agreement to exchange their units for shares of common stock or cash, as selected by Simon as the sole general partner. Accordingly, we classify units held by limited partners in permanent equity because Simon may elect to issue shares of common stock to limited partners exercising their exchange rights rather than using cash. Under the Operating Partnership’s partnership agreement, the Operating Partnership is required to redeem units held by Simon only when Simon has repurchased shares of common stock. We classify units held by Simon in permanent equity because the decision to redeem those units would be made by Simon. Net income attributable to noncontrolling interests (which includes nonredeemable and redeemable noncontrolling interests in consolidated properties) is a component of consolidated net income. Accumulated Other Comprehensive Income (Loss) Simon The total accumulated other comprehensive income (loss) related to Simon’s currency translation adjustment was ($177.0) million and ($136.2) million as of September 30, 2021 and December 31, 2020, respectively. The reclassifications out of accumulated other comprehensive income (loss) consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ ​ ​ September 30, ​ September 30, ​ ​ ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 ​ Affected line item where net income is presented ​ Currency translation adjustments ​ $ — ​ $ — ​ $ 5,660 ​ $ — ​ Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net ​ ​ ​ ​ — ​ ​ — ​ ​ (712) ​ ​ — ​ Net income attributable to noncontrolling interests ​ ​ ​ $ — ​ $ — ​ $ 4,948 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated derivative gains ​ $ 404 $ 477 ​ $ 1,362 $ 1,435 Interest expense ​ ​ ​ (50) (63) ​ (171) (189) Net income attributable to noncontrolling interests ​ ​ ​ $ 354 ​ $ 414 ​ $ 1,191 ​ $ 1,246 ​ ​ ​ ​ ​ The Operating Partnership The total accumulated other comprehensive income (loss) related to the Operating Partnership’s currency translation adjustment was ($202.4) million and ($155.8) million as of September 30, 2021 and December 31, 2020, respectively. The reclassifications out of accumulated other comprehensive income (loss) consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ ​ ​ September 30, ​ September 30, ​ ​ ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 ​ Affected line item where net income is presented ​ Currency translation adjustments ​ $ — $ — ​ $ 5,660 $ — Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated derivative gains ​ $ 404 $ 477 ​ $ 1,362 $ 1,435 Interest expense ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Derivative Financial Instruments Simon Property Group Acquisition Holdings, Inc. The Company sponsored, through a wholly-owned subsidiary, a special purpose acquisition corporation, or SPAC, named Simon Property Group Acquisition Holdings, Inc. On February 18, 2021, the SPAC announced the pricing of its initial public offering, which was consummated on February 23, 2021, generating gross proceeds of $345.0 million, which have been placed in a trust account and is included in the accompanying consolidated balance sheet in Investments held in trust – special purpose acquisition company. The SPAC is a consolidated VIE which was formed for the purpose of effecting a business combination. The Company accounts for the noncontrolling interest in the SPAC as noncontrolling redeemable interests as these instruments are redeemable at the option of the holder and are classified as temporary equity at their redemption value in Simon’s accompanying consolidated balance sheet in Limited partners preferred interest in the Operating Partnership and noncontrolling redeemable interests and in the Operating Partnership’s accompanying consolidated balance sheet in Preferred units, various series, at liquidation value, and noncontrolling redeemable interests. New Accounting Pronouncements In March 2020, the FASB issued Accounting Standards Update (ASU) 2020-04, “Reference Rate Reform,” which provides temporary optional expedients and exceptions to the US GAAP guidance on contract modifications and hedge accounting to ease the financial reporting burdens of the expected market transition from LIBOR and other interbank offered rates to alternative reference rates. Additional optional expedients, exceptions, and clarifications were created in ASU 2021-01. The guidance is effective upon issuance and generally can be applied to any contract modifications or existing and new hedging relationships through December 31, 2022. We are currently evaluating the impact that the expected market transition from LIBOR to alternative references rates will have on our financial statements as well as the applicability of the aforementioned expedients and exceptions provided in ASU 2020-04 and ASU 2021-01.

Real Estate Acquisitions and Di

Real Estate Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2021
Real Estate Acquisitions and Dispositions
Real Estate Acquisitions and Dispositions	4. Real Estate Acquisitions and Dispositions Unless otherwise noted, gains and losses on property transactions are included in gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net in the accompanying consolidated statements of operations and comprehensive income. We capitalize asset acquisition costs and expense costs related to business combinations, as well as disposition related costs as they are incurred. We incurred a minimal amount of transaction expenses during the nine months ended September 30, 2021 and 2020. 2021 Dispositions In July 2021, we recorded a gain of $88.0 million related to the foreclosure of a consolidated property in satisfaction of its $120.9 million non-recourse mortgage. During the first quarter of 2021, we recorded a gain of $89.3 million related to the foreclosure of a consolidated property in satisfaction of its $180 million non-recourse mortgage. 2020 Dispositions On October 1, 2020, we disposed of our interest in one consolidated retail property. A portion of the gross proceeds on this transaction of $33.4 million was used to partially repay a cross-collateralized mortgage. Our share of the $12.3 million gain is included in gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net in the accompanying consolidated statement of operation and comprehensive income.

Per Share and Per Unit Data

Per Share and Per Unit Data	9 Months Ended
	Sep. 30, 2021
Per Share and Per Unit Data
Per Share and Per Unit Data	5. Per Share and Per Unit Data We determine basic earnings per share and basic earnings per unit based on the weighted average number of shares of common stock or units, as applicable, outstanding during the period and we consider any participating securities for purposes of applying the two-class method. We determine diluted earnings per share and diluted earnings per unit based on the weighted average number of shares of common stock or units, as applicable, outstanding combined with the incremental weighted average number of shares or units, as applicable, that would have been outstanding assuming all potentially dilutive securities were converted into shares of common stock or units, as applicable, at the earliest date possible. The following tables set forth the components of basic and diluted earnings per share and basic and diluted earnings per unit. Simon ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended September 30, ​ For the Nine Months Ended September 30, ​ ​ ​ 2021 ​ 2020 2021 2020 Net Income attributable to Common Stockholders — Basic and Diluted $ 679,936 $ 145,926 $ 1,743,053 $ 837,744 Weighted Average Shares Outstanding — Basic and Diluted ​ 328,619,163 ​ 305,913,431 ​ 328,576,315 ​ 306,099,266 ​ ​ For the nine months September 30, 2021 No nine months September 30, 2021 2020 outstanding no The Operating Partnership ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended September 30, ​ For the Nine Months Ended September 30, ​ ​ ​ 2021 ​ 2020 2021 2020 Net Income attributable to Unitholders — Basic and Diluted $ 777,740 $ 168,086 $ 1,993,913 $ 965,210 Weighted Average Units Outstanding — Basic and Diluted ​ 375,882,318 ​ 352,420,845 ​ 375,864,921 ​ 352,673,474 ​ ​ For the nine months September 30, 2021 No nine months September 30, 2021 2020 November 1, 2021 2021

Investment in Unconsolidated En

Investment in Unconsolidated Entities and International Investments	9 Months Ended
	Sep. 30, 2021
Investments in Unconsolidated Entities and International Investments
Investments in Unconsolidated Entities and International Investments	6. Investment in Unconsolidated Entities and International Investments Real Estate Joint Ventures and Investments Joint ventures are common in the real estate industry. We use joint ventures to finance properties, develop new properties and diversify our risk in a particular property or portfolio of properties. As discussed in note 2, we held joint venture interests in 84 properties as of September 30, 2021. Certain of our joint venture properties are subject to various rights of first refusal, buy-sell provisions, put and call rights, or other sale or marketing rights for partners which are customary in real estate joint venture agreements and the industry. We and our partners in these joint ventures may initiate these provisions (subject to any applicable lock up or similar restrictions), which may result in either the sale of our interest or the use of available cash or borrowings, or the use of limited partnership interests in the Operating Partnership, to acquire the joint venture interest from our partner. We may provide financing to joint venture properties primarily in the form of interest bearing construction loans. As of September 30, 2021 and December 31, 2020, we had construction loans and other advances to these related parties totaling $93.4 million and $88.4 million, respectively, which are included in deferred costs and other assets in the accompanying consolidated balance sheets. Unconsolidated Entity Transactions On July 1, 2021, we contributed to ABG all of our interests in both the Forever 21 and Brooks Brothers licensing ventures in exchange for additional interests in ABG, bringing our total interest in ABG to approximately 11%. As a result, in the third quarter of 2021, we recognized a non-cash pre-tax gain of $159.8 million representing the difference between the fair value of the interests received determined using Level 3 inputs and the carrying value of the licensing ventures less costs to sell. In connection with this transaction, we recorded deferred taxes of $47.9 million which is included in income and other tax (expense) benefit in the consolidated statements of operations and comprehensive income. On June 1, 2021, we and our partner, ABG, acquired the licensing rights of Eddie Bauer. Our non-controlling interest in the licensing venture is 49% and was acquired for cash consideration of $100.8 million. During the second quarter of 2021, we sold our interest in one multi-family residential investment. Our share of the gross proceeds from this transaction was $27.1 million. The gain of $14.9 million on the sale is included in other income in the accompanying consolidated statement of operations and comprehensive income. On December 29, 2020, we completed the acquisition of an 80% noncontrolling ownership interest in TRG, which has an interest in 24 regional, super-regional, and outlet malls in the U.S. and Asia. Under the terms of the transaction, we, through the Operating Partnership, acquired all of Taubman Centers, Inc., or Taubman, common stock for $43.00 per share in cash. Total consideration for the acquisition, including the redemption of Taubman’s $192.5 million 6.5% Series J Cumulative Preferred Shares and its $170.00 million 6.25% Series K Cumulative Preferred Shares, and the issuance of 955,705 Operating Partnership units, was approximately $3.5 billion. Our investment includes the 6.38% Series A Cumulative Redeemable Preferred Units for $362.5 million issued to us. The purchase price allocations are preliminary and subject to revision within the measurement period, not to exceed one year from the date of acquisition. Substantially all of our investment has preliminarily been determined to relate to investment property based on estimated fair values at the acquisition date. Our share of net (loss) income was ($11.5 million) and ($49.9 million) for the three and nine months ended September 30, 2021, which includes amortization of our excess investment of $31.6 million and $94.7 million, for the same periods. TRG’s total revenue, operating income before other items and consolidated net income were approximately $422.8 million, $137.3 million, and $55.3 million, respectively, for the nine months ended September 30, 2021, before consideration of the amortization of our excess investment. On December 7, 2020, we and a group of co-investors acquired certain assets and liabilities of J.C. Penney, a department store retailer, out of bankruptcy. Our non-controlling interest in the venture is 41.67% and was acquired for cash consideration of $125.0 million. The purchase price allocations are preliminary and subject to revision within the measurement period, not to exceed one year from the date of acquisition. In the third quarter of 2020, we recorded an other-than-temporary impairment charge of $55.2 million, representing our equity method investment balance in three joint venture properties, which is included in gain (loss) on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net, in the accompanying consolidated statements of operations and comprehensive income. Additionally, in the third quarter of 2020, we recorded an other-than-temporary impairment charge of $36.1 million, which is included in gain (loss) on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net, in the accompanying consolidated statements of operations and comprehensive income, to reduce our investment in HBS to its estimated fair value. On February 19, 2020, we and a group of co-investors acquired certain assets and liabilities of Forever 21, a retailer of apparel and accessories, out of bankruptcy. The interests were acquired through two separate joint ventures, a licensing venture and an operating venture. Our aggregate investment in the ventures was $67.6 million. In connection with the acquisition of our interest, the Forever 21 joint venture recorded a non-cash bargain purchase gain in the second quarter of 2020, of which our share was $35.0 million pre-tax. In the first quarter of 2021, we and our partner, ABG, each acquired additional 12.5% interests in the licensing and operations of Forever 21, our share of which was $56.3 million, bringing our respective interests to 50%. Subsequently, the Forever 21 operations were merged into SPARC Group. On September 15, 2016, we and a group of co-investors acquired certain assets and liabilities of Aéropostale, a retailer of apparel and accessories, out of bankruptcy, and subsequently renamed SPARC Group. The interests were acquired through two separate joint ventures, a licensing venture and an operating venture. In April 2018, we contributed our entire interest in the licensing venture in exchange for additional interests in ABG, a brand development, marketing, and entertainment company. In January 2020, we acquired additional interests of 5.05% and 1.37% in SPARC Group and ABG, respectively, for $6.7 million and $33.5 million, respectively. During the third quarter of 2020, SPARC Group acquired certain assets and operations of Brooks Brothers and Lucky Brands out of bankruptcy. During the second quarter of 2021, SPARC Group acquired certain assets and operations of Eddie Bauer. At September 30, 2021, our noncontrolling equity method interests in the operations venture of SPARC Group was 50.0%. European Investments At September 30, 2021, we owned 63,924,148 shares, or approximately 22.4%, of Klépierre, which had a quoted market price of $22.53 per share. Our share of net income, net of amortization of our excess investment, was $8.9 million and $4.3 million for the three months ended September 30, 2021 and 2020, respectively, and $115.9 million and $13.7 million for the nine months ended September 30, 2021 and 2020, respectively. Based on applicable Euro:USD exchange rates and after our conversion of Klépierre’s results to GAAP, Klépierre’s total revenues, operating income before other items and consolidated net income were approximately $840.4 million, $215.3 million and $619.9 million, respectively, for the nine months ended September 30, 2021 and $882.0 million, $195.2 million and $123.2 million, respectively, for the nine months ended September 30, 2020. During the nine months ended September 30, 2021, Klépierre elected to step-up the tax basis of certain assets in Italy, which triggered a one-time payment at a significantly reduced tax rate. As a result of the step-up in tax basis, a previously established deferred tax liability was reversed resulting in a non-cash gain, of which our share was $118.4 million. ​ During the nine months ended September 30, 2020, we recorded a $7.8 million net loss related to the impairment and disposition of certain assets of Klépierre. This transaction is included in gain (loss) on sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net in the accompanying consolidated statements of operations and comprehensive income. ​ We have an interest in a European investee that had interests in 11 Designer Outlet properties as of September 30, 2021 and ten Designer Outlet properties as of December 31, 2020, seven of which are consolidated by us as of September 30, 2021. As of September 30, 2021, our legal percentage ownership interests in these properties ranged from 23% to 94%. ​ On January 1, 2021 our European investee gained control of Ochtrup Designer Outlets as a result of the expiration of certain participating rights held by a venture partner. This resulted in the consolidation of the property, requiring a remeasurement of our previously held equity interest to fair value and the recognition of a non-cash gain of $3.7 million in earnings during the first quarter of 2021, which includes amounts reclassified from accumulated other comprehensive income (loss) related to the currency translation adjustment previously recorded on our investment. The gain is included in gain (loss) on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net in the accompanying consolidated statements of operations and comprehensive income. The determination of the fair value consisted of Level 2 and 3 inputs and was predominately allocated to investment property. In addition, we have a 50.0% noncontrolling interest in a European property management and development company that provides services to the Designer Outlet properties. We also have minority interests in Value Retail PLC and affiliated entities, which own or have interests in and operate nine luxury outlets located throughout Europe and we also have a direct minority ownership in three of those outlets. At September 30, 2021 and December 31, 2020, the carrying value of these equity instruments without readily determinable fair values was $140.8 million and is included in deferred costs and other assets. Asian Joint Ventures We conduct our international Premium Outlet operations in Japan through a joint venture with Mitsubishi Estate Co., Ltd. We have a 40% noncontrolling ownership interest in this joint venture. The carrying amount of our investment in this joint venture was $211.1 million and $216.8 million as of September 30, 2021 and December 31, 2020, respectively, including all related components of accumulated other comprehensive income (loss). We conduct our international Premium Outlet operations in South Korea through a joint venture with Shinsegae International Co. We have a 50% noncontrolling ownership interest in this joint venture. The carrying amount of our investment in this joint venture was $187.3 million and $184.7 million as of September 30, 2021 and December 31, 2020, respectively, including all related components of accumulated other comprehensive income (loss). Summary Financial Information A summary of the combined balance sheets and statements of operations of our equity method investments and share of income from such investments, excluding our investments in HBS, Klépierre, and TRG as well as our retailer investments in ABG, J.C. Penney, RGG and SPARC Group, follows. COMBINED BALANCE SHEETS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2021 ​ 2020 Assets: ​ ​ ​ ​ ​ ​ ​ Investment properties, at cost ​ $ 19,867,502 ​ $ 20,079,476 ​ Less - accumulated depreciation ​ 8,287,531 ​ 8,003,863 ​ ​ ​ 11,579,971 ​ 12,075,613 ​ Cash and cash equivalents ​ 1,368,859 ​ 1,169,422 ​ Tenant receivables and accrued revenue, net ​ 567,034 ​ 749,231 ​ Right-of-use assets, net ​ ​ 161,758 ​ ​ 185,598 ​ Deferred costs and other assets ​ 415,768 ​ 380,087 ​ Total assets ​ $ 14,093,390 ​ $ 14,559,951 ​ Liabilities and Partners’ Deficit: ​ ​ ​ ​ ​ ​ ​ Mortgages ​ $ 15,311,572 ​ $ 15,569,485 ​ Accounts payable, accrued expenses, intangibles, and deferred revenue ​ 854,603 ​ 969,242 ​ Lease liabilities ​ ​ 165,334 ​ ​ 188,863 ​ Other liabilities ​ 405,134 ​ 426,321 ​ Total liabilities ​ 16,736,643 ​ 17,153,911 ​ Preferred units ​ 67,450 ​ 67,450 ​ Partners’ deficit ​ (2,710,703) ​ (2,661,410) ​ Total liabilities and partners’ deficit ​ $ 14,093,390 ​ $ 14,559,951 ​ Our Share of: ​ ​ ​ ​ ​ ​ ​ Partners’ deficit ​ $ (1,161,814) ​ $ (1,130,713) ​ Add: Excess Investment ​ 1,300,242 ​ 1,399,757 ​ Our net Investment in unconsolidated entities, at equity ​ $ 138,428 ​ $ 269,044 ​ ​ “Excess Investment” represents the unamortized difference of our investment over our share of the equity in the underlying net assets of the joint ventures or other investments acquired and has been determined to relate to the fair value of the investment properties, intangible assets, including goodwill, and debt premiums and discounts. We amortize excess investment over the life of the related depreciable components of assets acquired, typically no greater than 40 years, the terms of the applicable leases, the estimated useful lives of the finite lived intangibles, and the applicable debt maturity, respectively. The amortization is included in the reported amount of income from unconsolidated entities. COMBINED STATEMENTS OF OPERATIONS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 REVENUE: ​ ​ ​ ​ ​ ​ ​ Lease income ​ $ 719,723 ​ $ 601,522 ​ $ 2,053,826 ​ $ 1,919,618 ​ Other income ​ 67,630 ​ 94,630 ​ 204,923 ​ 215,349 ​ Total revenue ​ 787,353 ​ 696,152 ​ 2,258,749 ​ 2,134,967 ​ OPERATING EXPENSES: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Property operating ​ 151,008 ​ 129,024 ​ 420,174 ​ 383,363 ​ Depreciation and amortization ​ 170,568 ​ 175,716 ​ 512,165 ​ 512,705 ​ Real estate taxes ​ 66,221 ​ 68,464 ​ 203,242 ​ 197,487 ​ Repairs and maintenance ​ 18,274 ​ 16,457 ​ 53,625 ​ 49,661 ​ Advertising and promotion ​ 18,238 ​ 9,901 ​ 52,479 ​ 42,669 ​ Other ​ 43,400 ​ 41,857 ​ 113,042 ​ 107,822 ​ Total operating expenses ​ 467,709 ​ 441,419 ​ 1,354,727 ​ 1,293,707 ​ Operating Income Before Other Items ​ 319,644 ​ 254,733 ​ 904,022 ​ 841,260 ​ Interest expense ​ (154,501) ​ (154,579) ​ (453,145) ​ (463,629) ​ Gain on sale or disposal of, or recovery on, assets and interests in unconsolidated entities, net ​ ​ — ​ ​ — ​ ​ 33,371 ​ ​ — ​ Net Income ​ $ 165,143 ​ $ 100,154 ​ $ 484,248 ​ $ 377,631 ​ Third-Party Investors’ Share of Net Income ​ $ 82,639 ​ $ 46,785 ​ $ 243,525 ​ $ 193,633 ​ Our Share of Net Income ​ 82,504 ​ 53,369 ​ 240,723 ​ 183,998 ​ Amortization of Excess Investment ​ (15,199) ​ (20,543) ​ (49,794) ​ (62,144) ​ Our Share of Gain on Sale or Disposal of Assets and Interests in Other Income in the Consolidated Financial Statements ​ ​ — ​ ​ — ​ ​ (14,941) ​ ​ — ​ Income from Unconsolidated Entities ​ $ 67,305 ​ $ 32,826 ​ $ 175,988 ​ $ 121,854 ​ ​ Our share of income from unconsolidated entities in the above table, aggregated with our share of results from our investments in HBS, Klépierre, and TRG as well as our retailer investments, is presented in income from unconsolidated entities in the accompanying consolidated statements of operations and comprehensive income. Unless otherwise noted, our share of the gain on acquisition of controlling interest sale or disposal of assets and interests in unconsolidated entities, net is reflected within gain (loss) on sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net in the accompanying consolidated statements of operations and comprehensive income.

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt
Debt	7. Debt Unsecured Debt At September 30, 2021, our unsecured debt consisted of $18.4 billion of senior unsecured notes of the Operating Partnership, $125.0 million outstanding under the Operating Partnership’s $4.0 billion unsecured revolving credit facility, or Credit Facility, and $500.0 million outstanding under the Operating Partnership’s global unsecured commercial paper note program, or Commercial Paper program. The Credit Facility also included an additional single, delayed-draw $2.0 billion term loan facility, or Term Facility, which the Operating Partnership drew on December 15, 2020. At September 30, 2021, we had an aggregate available borrowing capacity of $6.9 billion under the Credit Facility and the Operating Partnership’s $3.5 billion unsecured revolving credit facility, or Supplemental Facility, and together with the Credit Facility, the Credit Facilities. The maximum aggregate outstanding balance under the Credit Facilities and the Term Facility, during the nine months ended September 30, 2021 was $2.1 billion and the weighted average outstanding balance was $583.8 million. Letters of credit of $12.4 million were outstanding under the Credit Facilities as of September 30, 2021. The Credit Facility can be increased in the form of additional commitments under the Credit Facility in an aggregate amount not to exceed $1.0 billion, for a total aggregate size of $5.0 billion, subject to obtaining additional lender commitments and satisfying certain customary conditions precedent. Borrowings may be denominated in U.S. dollars, Euro, Yen, Sterling, Canadian dollars and Australian dollars. Borrowings in currencies other than the U.S. dollar are limited to 95% of the maximum revolving credit amount, as defined. The initial maturity date of the Credit Facility is June 30, 2024. The Credit Facility can be extended for two additional six-month periods to June 30, 2025, at our sole option, subject to satisfying certain customary conditions precedent. The Supplemental Facility’s initial borrowing capacity of $3.5 billion may be increased to $4.5 billion during its term and provides for borrowings denominated in U.S. dollars, Euro, Yen, Sterling, Canadian dollars and Australian dollars. The initial maturity date of the Supplemental Facility is June 30, 2022 and can be extended for an additional year to June 30, 2023 at our sole option, subject to our continued compliance with the terms thereof. The base interest rate on the Supplemental Facility is LIBOR plus 77.5 basis points with a facility fee of 10 basis points. In October 2021, we amended and extended the Supplemental Facility. The newly refinanced facility will initially mature on January 31, 2026 and can be extended for an additional year to January 31, 2027 at the Company’s sole option, subject to satisfying certain customary conditions precedent. The facility provides for borrowings denominated in U.S. Dollars, Euro, Yen, Sterling, Canadian Dollars, and Australian Dollars. Borrowings under the Supplemental Facility bear interest, at the Company’s election, at either (i) (x) for Term Benchmark Loans, the Adjusted Term SOFR Rate, the applicable Local Rate, the Adjusted EURIBOR Rate, or the Adjusted TIBOR Rate, (y) for RFR Loans, if denominated in Sterling, SONIA plus a benchmark adjustment and if denominated in Dollars, Daily Simple SOFR plus a benchmark adjustment, or (z) for Daily SOFR Loans, the Adjusted Floating Overnight Daily SOFR Rate, in each case of clauses (x) through (z) above, plus a margin determined by the Company’s corporate credit rating of between 0.650% and 1.400% or (ii) for loans denominated in U.S. Dollars only, the base rate (which rate is equal to the greatest of the prime rate, the federal funds effective rate plus 0.500% or Adjusted Term SOFR Rate for one month plus 1.000%) (the “Base Rate”), plus a margin determined by the Company’s corporate credit rating of between 0.000% and 0.400%. The Supplemental Facility includes a facility fee determined by the Company’s corporate credit rating of between 0.100% and 0.300% on the aggregate revolving commitments under the Supplemental Facility. Based upon the Company’s current credit ratings, the interest rate on the new revolver is SOFR plus 72.5 basis points, plus a spread adjustment to account for the transition from LIBOR to SOFR. The Operating Partnership also has available a Commercial Paper program of $2.0 billion, or the non-U.S. dollar equivalent thereof. The Operating Partnership may issue unsecured commercial paper notes, denominated in U.S. dollars, Euro and other currencies. Notes issued in non-U.S. currencies may be issued by one or more subsidiaries of the Operating Partnership and are guaranteed by the Operating Partnership. Notes are sold under customary terms in the U.S. and Euro commercial paper note markets and rank (either by themselves or as a result of the guarantee described above) pari passu with the Operating Partnership’s other unsecured senior indebtedness. The Commercial Paper program is supported by the Credit Facilities and if necessary or appropriate, we may make one or more draws under either of the Credit Facilities to pay amounts outstanding from time to time on the Commercial Paper program. On September 30, 2021, we had $500.0 million outstanding under the Commercial Paper program, fully comprised of U.S. dollar-denominated notes with a weighted average interest rate of 0.20%. These borrowings have a weighted average maturity date of November 1, 2021 and reduce amounts otherwise available under the Credit Facilities. On January 21, 2021, the Operating Partnership completed the issuance of the following senior unsecured notes: $800 million with a fixed interest rate of 1.75% , and $700 million with a fixed interest rate of 2.20% , with maturity dates of February 2028 and 2031, respectively. On January 27, 2021, the Operating Partnership completed the optional redemption of its $550 million 2.50% notes due on July 15, 2021. We recorded a $3.0 million loss on extinguishment of debt as a result of the optional redemption. Further, on February 2, 2021, the Operating Partnership repaid $750 million under the Term Facility. On March 19, 2021, the Operating Partnership completed the issuance of €750 million ( $893.0 million U.S. dollar equivalent as of the issuance date) of senior unsecured notes at a fixed rate of 1.125% with a maturity date of March 19, 2033. Further, on March 23, 2021, the Operating Partnership repaid the remaining $1.25 billion under the Term Facility reducing it to zero . On August 18, 2021, the Operating Partnership completed the issuance of the following senior unsecured notes: $550 million with a fixed interest rate of 1.375% , and $700 million with a fixed interest rate of 2.250% , with maturity dates of January 15 2027, and 2032, respectively. In the third quarter, the Operating Partnership completed the optional redemption of all of its outstanding $550 million 2.350% notes due on January 30, 2022, $600 million 2.625% notes due on June 15, 2022, and $500 million 2.750% notes due on February 1, 2023. We recorded a $28.6 million loss on extinguishment of debt as a result of the optional redemptions. Mortgage Debt Total mortgage indebtedness was $6.6 billion and $7.0 billion at September 30, 2021 and December 31, 2020, respectively. Covenants Our unsecured debt agreements contain financial covenants and other non-financial covenants. The Facilities contain ongoing covenants relating to total and secured leverage to capitalization value, minimum earnings before interest, taxes, depreciation, and amortization, or EBITDA, and unencumbered EBITDA coverage requirements. Payment under the Facilities can be accelerated if the Operating Partnership or Simon is subject to bankruptcy proceedings or upon the occurrence of certain other events. If we were to fail to comply with these covenants, after the expiration of the applicable cure periods, the debt maturity could be accelerated or other remedies could be sought by the lender, including adjustments to the applicable interest rate. As of September 30, 2021, we were in compliance with all covenants of our unsecured debt. At September 30, 2021, our consolidated subsidiaries were the borrowers under 46 non-recourse mortgage notes secured by mortgages on 49 properties and other assets, including two separate pools of cross-defaulted and cross-collateralized mortgages encumbering a total of five properties. Under these cross-default provisions, a default under any mortgage included in the cross-defaulted pool may constitute a default under all mortgages within that pool and may lead to acceleration of the indebtedness due on each property within the pool. Certain of our secured debt instruments contain financial and other non-financial covenants which are specific to the properties that serve as collateral for that debt. If the applicable borrower under these non-recourse mortgage notes were to fail to comply with these covenants, the lender could accelerate the debt and enforce its rights against their collateral. At September 30, 2021, the applicable borrowers under these non-recourse mortgage notes were in compliance with all covenants where non-compliance could individually or in the aggregate, giving effect to applicable cross-default provisions, have a material adverse effect on our financial condition, liquidity or results of operations. Fair Value of Debt The carrying value of our variable-rate mortgages and other loans approximates their fair values. We estimate the fair values of consolidated fixed rate mortgages using cash flows discounted at current borrowing rates and other indebtedness using cash flows discounted at current market rates. We estimate the fair values of consolidated fixed rate unsecured notes using quoted market prices, or, if no quoted market prices are available, we use quoted market prices for securities with similar terms and maturities. The book value of our consolidated fixed rate mortgages and unsecured indebtedness including commercial paper was $24.3 billion and $23.4 billion as of September 30, 2021 and December 31, 2020, respectively. The fair values of these financial instruments and the related discount rate assumptions as of September 30, 2021 and December 31, 2020 are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 2020 ​ Fair value of consolidated fixed rate mortgages and unsecured indebtedness (in millions) ​ $ 25,791 ​ $ 25,327 ​ ​ Weighted average discount rates assumed in calculation of fair value for fixed rate mortgages ​ 2.86 % 2.41 % ​ Weighted average discount rates assumed in calculation of fair value for unsecured indebtedness ​ ​ 3.24 % ​ 2.63 % ​ ​

Equity

Equity	9 Months Ended
	Sep. 30, 2021
Equity
Equity	​ 8. Equity During the nine months ended September 30, 2021, Simon issued 58,571 shares of common stock to seven limited partners of the Operating Partnership in exchange for an equal number of units pursuant to the partnership agreement of the Operating Partnership. During the nine months ended September 30, 2021, the Operating Partnership redeemed 486 units from two limited partners for $0.06 million. These transactions increased Simon’s ownership interest in the Operating Partnership. On February 11, 2019, Simon's Board of Directors authorized a common stock repurchase plan. Under the plan, Simon was authorized to repurchase up to $2.0 billion of its common stock during the two-year period ending February 11, 2021 in the open market or in privately negotiated transactions as market conditions warrant. During the nine months ended September 30, 2020, Simon purchased 1,245,654 shares at an average price of $122.50 per share. As Simon repurchased shares under the program, the Operating Partnership repurchased an equal number of units from Simon. We paid common stock dividends of $1.40 per share and $1.50 per share in the third quarter of 2021 nine months 2021 2020 September 30, 2020 Temporary Equity Simon Simon classifies as temporary equity those securities for which there is the possibility that Simon could be required to redeem the security for cash irrespective of the probability of such a possibility. As a result, Simon classifies one series of preferred units in the Operating Partnership and noncontrolling redeemable interests in properties in temporary equity. Each of these securities is discussed further below. Limited Partners’ Preferred Interest in the Operating Partnership and Noncontrolling Redeemable Interests in Properties ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of As of ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 ​ 7.50% Cumulative Redeemable Preferred Units, 260,000 units authorized, 255,373 issued and outstanding ​ $ 25,537 ​ $ 25,537 ​ Other noncontrolling redeemable interests ​ 527,488 ​ 160,355 ​ Limited partners’ preferred interest in the Operating Partnership and noncontrolling redeemable interests in properties ​ $ 553,025 ​ $ 185,892 ​ ​ Refer to Note 3 for discussion of the noncontrolling redeemable interest related to the SPAC. The Operating Partnership The Operating Partnership classifies as temporary equity those securities for which there is the possibility that the Operating Partnership could be required to redeem the security for cash, irrespective of the probability of such a possibility. As a result, the Operating Partnership classifies one series of preferred units and noncontrolling redeemable interests in properties in temporary equity. The following table summarizes the preferred units and the amount of the noncontrolling redeemable interests in properties as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of As of ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 ​ 7.50% Cumulative Redeemable Preferred Units, 260,000 units authorized, 255,373 issued and outstanding ​ $ 25,537 ​ $ 25,537 ​ Other noncontrolling redeemable interests ​ 527,488 ​ 160,355 ​ Total preferred units, at liquidation value, and noncontrolling redeemable interests in properties ​ $ 553,025 ​ $ 185,892 ​ ​ Refer to Note 3 for discussion of the noncontrolling redeemable interest related to the SPAC. Stock Based Compensation Our long-term incentive compensation awards under our stock based compensation plans primarily take the form of LTIP units, restricted stock grants, and restricted stock units. These awards are either market or performance-based, and are based on various individual, corporate and business unit performance measures as further described below. The expense related to these programs, net of amounts capitalized, is included within home and regional office costs and general and administrative costs in the accompanying statements of operations and comprehensive income. In the first quarter of 2021, the Compensation Committee established and made awards under a 2021 Long-Term Incentive Program, or 2021 LTI Program. Awards under the 2021 LTI Program, took the form of LTIP units and restricted stock units as further discussed below. LTIP Programs. In 2018, the Compensation Committee established and granted awards under a redesigned LTIP program, or the 2018 LTIP program. Awards under the 2018 LTIP program were granted in two tranches, Tranche A LTIP units and Tranche B LTIP units. Each of the Tranche A LTIP units and the Tranche B LTIP units will be considered earned if, and only to the extent to which, the respective goals based on Funds From Operations, or FFO, per share or Relative TSR Goal performance criteria, as defined in the applicable award agreements, are achieved during the applicable two-year and three-year performance periods of the Tranche A LTIP units and Tranche B LTIP units, respectively. One half one-half The grant date fair value of the portion of the LTIP units based on achieving the target FFO performance criteria is $6.1 million for the Tranche A LTIP units and the Tranche B In 2021 and 2019, the Compensation Committee established and granted awards under a redesigned LTIP program, or the 2021 LTIP program and the 2019 LTIP program, respectively. Awards under these programs will be considered earned if, and only to the extent to which, the respective performance conditions (based on Funds From Operations, or FFO, per share, and Objective Criteria Goals) and market conditions (based on Relative or absolute TSR performance), as defined in the applicable award agreements, are achieved during the applicable three-year measurement period, subject to the recipient’s continued employment through the applicable vesting dates. Any units determined to be earned LTIP units under the 2021 The grant date fair values of any LTIP units for market-based awards are estimated using a Monte Carlo model, and the resulting fixed expense is recorded regardless of whether the market condition criteria are achieved if the required service is delivered. The grant date fair values of the market-based awards are being amortized into expense over the period from the grant date to the date at which the awards, if earned, would become vested. The expense of the performance-based award is recorded over the period from the grant date to the date at which the awards, if earned, would become vested, based on our assessment as to whether it is probable that the performance criteria will be achieved during the applicable performance periods. The Compensation Committee approved LTIP unit grants as shown in the table below. The extent to which LTIP units were earned, and the aggregate grant date fair value, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ LTIP Program LTIP Units Earned Grant Date Fair Value of TSR Award Grant Date Target Value of Performance-Based Awards 2018 LTIP program - Tranche A 38,148 $6.1 million $6.1 million 2018 LTIP program - Tranche B - $6.1 million $6.1 million 2019 LTIP program ​ To be determined in 2022 $9.5 million $14.7 million 2021 LTIP program ​ To be determined in 2024 $5.7 million $12.2 million ​ We recorded compensation expense, net of capitalization, related to these LTIP programs of approximately $7.5 million and $3.2 million for the nine months ended September 30, 2021 and 2020, respectively. Restricted Stock and Restricted Stock Units. During 2020, the Compensation Committee established a one-time grant of 312,263 time-based restricted stock units under the 2019 Plan at a weighted average fair market value of $84.37 per share. These awards will vest, subject to the grantee's continued service on each applicable vesting date, in one-third increments on January 1, 2022, January 1, 2023, and January 1, 2024. The grant date fair value of the awards of We recorded compensation expense, net of capitalization, related to restricted stock and restricted stock units of approximately $12.4 million and $8.2 million for the nine months ended September 30, 2021 and 2020, respectively.

Lease Income

Lease Income	9 Months Ended
	Sep. 30, 2021
Lease Income
Lease Income	9. Lease Income Fixed lease income under our operating leases includes fixed minimum lease consideration and fixed common area maintenance, or CAM, reimbursements recorded on a straight-line basis. Variable lease income includes consideration based on sales, as well as reimbursements for real estate taxes, utilities, marketing, and certain other items including negative variable lease income as discussed below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ September 30, ​ September 30, ​ 2021 ​ 2020 2021 2020 Fixed lease income $ 921,521 ​ $ 929,335 ​ $ 2,783,459 ​ $ 2,939,257 Variable lease income 286,402 ​ ​ 64,496 ​ ​ 728,347 ​ ​ 330,315 Total lease income $ 1,207,923 ​ $ 993,831 ​ $ 3,511,806 ​ $ 3,269,572 ​ ​ ​ ​ ​ Tenant receivables and accrued revenue in the accompanying consolidated balance sheets includes straight-line receivables of $573.9 million and $597.6 million at September 30, 2021 and December 31, 2020, respectively. In April 2020, the FASB staff released guidance focused on treatment of concessions related to the effects of COVID-19 on the application of lease modification guidance in Accounting Standards Codification (ASC) 842, “Leases.” The guidance provides a practical expedient to forgo the associated reassessments required by ASC 842 when changes to a lease result in similar or lower future consideration. We have elected to generally account for rent abatements as negative variable lease consideration in the period granted, or in the period we determine we expect to grant an abatement. Further abatements granted in the future will reduce lease income in the period we grant, or determine we expect to grant, an abatement. We have agreed to deferral or abatement arrangements with a number of our tenants as a result of the COVID-19 pandemic. Discussions with our tenants are ongoing and may result in further rent deferrals, lease amendments, abatements and/or lease terminations, as we deem appropriate on a case-by-case basis based on each tenant's unique financial and operating situation. In addition, uncollected rent due from certain of our tenants is subject to ongoing litigation, the outcome of which may affect our ability to collect in full the associated outstanding receivable balances. In connection with rent deferrals or other accruals of unpaid rent payments, if we determine that rent payments are probable of collection, we will continue to recognize lease income on a straight-line basis over the lease term along with associated tenant receivables. However, if we determine that such deferred rent payments or other accrued but unpaid rent payments are not probable of collection, lease income will be recorded on the cash basis, with the corresponding tenant receivable and deferred rent receivable balances charged as a direct write-off against lease income in the period of the change in our collectability determination. Additionally, our assessment of collectability incorporates information regarding a tenant’s financial condition that is obtained from available financial data, the expected outcome of contractual disputes and other matters, and our communications and negotiations with the tenant. When a tenant seeks to reorganize its operations through bankruptcy proceedings, we assess the collectability of receivable balances. Our ongoing assessment incorporates, among other things, the timing of a tenant’s bankruptcy filing and our expectations of the assumptions by the tenant in bankruptcy proceedings of leases at the Company’s properties on substantially similar terms.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies.
Commitments and Contingencies	10. Commitments and Contingencies Litigation We are involved from time-to-time in various legal and regulatory proceedings that arise in the ordinary course of our business, including, but not limited to, commercial disputes, environmental matters, and litigation in connection with transactions such as acquisitions and divestitures. We believe that current proceedings will not have a material adverse effect on our financial condition, liquidity, or results of operations. We record a liability when a loss is considered probable and the amount can be reasonably estimated. Lease Commitments As of September 30, 2021, a total of 23 of our consolidated properties are subject to ground leases. The termination dates of these ground leases range from 2022 to 2090, including periods for which exercising an extension option is reasonably assured. These ground leases generally require us to make fixed annual rental payments, or a fixed annual rental payment plus a percentage rent component based upon the revenues or total sales of the property. In addition, we have several regional office locations that are subject to leases with termination dates ranging from 2021 to 2028. These office leases generally require us to make fixed annual rental payments plus pay our share of common area, real estate taxes, and utility expenses. Some of our ground and office leases include escalation clauses. All of our lease arrangements are classified as operating leases. We incurred ground lease expense and office lease expense, which are included in other expense and home office and regional expense, respectively, as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2021 ​ 2020 2021 ​ 2020 Operating Lease Cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed lease cost ​ $ 8,118 ​ $ 8,015 ​ $ 24,367 ​ $ 23,161 Variable lease cost ​ ​ 3,984 ​ ​ 3,130 ​ ​ 11,821 ​ ​ 10,217 Sublease income ​ (187) ​ (187) ​ (560) ​ (560) Total operating lease cost ​ $ 11,915 ​ $ 10,958 ​ $ 35,628 ​ $ 32,818 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Nine Months Ended ​ ​ September 30, ​ ​ 2021 ​ 2020 Other Information ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 36,098 ​ $ 33,301 ​ ​ ​ ​ ​ ​ ​ Weighted-average remaining lease term - operating leases ​ ​ 33.8 years ​ ​ 34.6 years Weighted-average discount rate - operating leases ​ ​ 4.87% ​ ​ 4.86% ​ Minimum lease payments due under these leases for years ending December 31, excluding applicable extension options and renewal options unless reasonably certain of exercise and any sublease income, are as follows: ​ ​ ​ ​ ​ 2021 $ 32,131 2022 ​ 32,838 2023 ​ 32,979 2024 ​ 33,114 2025 ​ 33,124 Thereafter ​ 888,217 ​ ​ $ 1,052,403 Impact of discounting ​ ​ (543,332) Operating lease liabilities ​ $ 509,071 ​ ​ Guarantees of Indebtedness Joint venture debt is the liability of the joint venture and is typically secured by the joint venture property, which is non-recourse to us. As of September 30, 2021 and December 31, 2020, the Operating Partnership guaranteed joint venture related mortgage indebtedness of $209.2 million and $219.2 million, respectively Mortgages guaranteed by the Operating Partnership are secured by the property of the joint venture which could be sold in order to satisfy the outstanding obligation and which has an estimated fair value in excess of the guaranteed amount. Concentration of Credit Risk Our U.S. Malls, Premium Outlets, and The Mills rely upon anchor tenants to attract customers; however, anchors do not contribute materially to our financial results as many anchors own their spaces. All material operations are within the United States and no customer or tenant accounts for 5% or more of our consolidated revenues. Hurricane Impacts During the third quarter of 2020, one of our properties located in Texas experienced property damage and business interruption as a result of Hurricane Hanna. We wrote-off assets of approximately $9.6 million, and recorded an insurance recovery receivable, and have received $14.0 million of insurance proceeds from third-party carriers. The proceeds were used for property restoration and remediation and reduced the insurance recovery receivable. During the quarter ended September 30, 2021, we recorded a $3.5 million gain related to property insurance recovery of previously depreciated assets. This amount was recorded in gain (loss) on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairments, net. During the third quarter of 2020, one of our properties located in Louisiana experienced property damage and business interruption as a result of Hurricane Laura. We wrote-off assets of approximately $11.1 million and recorded an insurance recovery receivable, and have received $27.5 million of insurance proceeds from third-party carriers. The proceeds were used for property restoration and remediation and reduced the insurance recovery receivable. During the quarter ended September 30, 2021, we recorded a $17.5 million gain related to property insurance recovery of previously depreciated assets. This amount was recorded in gain (loss) on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairments, net. COVID-19 On March 11, 2020, the World Health Organization declared the novel strain of coronavirus, or COVID-19, a global pandemic and recommended containment and mitigation measures worldwide. The COVID-19 pandemic has had a material negative impact on economic and market conditions around the world, and, notwithstanding the fact that vaccines are being administered in the United States and elsewhere, the pandemic continues to adversely impact economic activity in retail real estate. The impact of the COVID-19 pandemic continues to evolve and governments and other authorities, including where we own or hold interests in properties, have imposed measures intended to control its spread, including restrictions on freedom of movement, group gatherings and business operations such as travel bans, border closings, business closures, quarantines, stay-at-home, shelter-in-place orders, density limitations and social distancing measures. As a result of the COVID-19 pandemic and these measures, the Company has experienced and may continue to experience material impacts including changes in the ability to recognize revenue due to changes in our assessment of the probability of collection of lease income and asset impairment charges as a result of changing cash flows generated by our properties and investments.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Significant Accounting Policies
Cash and Cash Equivalents	Cash and Cash Equivalents We consider all highly liquid investments purchased with an original maturity of 90 days or less to be cash and cash equivalents. Cash equivalents are carried at cost, which approximates fair value. Cash equivalents generally consist of commercial paper, bankers’ acceptances, Eurodollars, repurchase agreements, and money market deposits or securities. Financial instruments that potentially subject us to concentrations of credit risk include our cash and cash equivalents and our trade accounts receivable. We place our cash and cash equivalents with institutions of high credit quality. However, at certain times, such cash and cash equivalents are in excess of Federal Deposit Insurance Corporation and Securities Investor Protection Corporation insurance limits.
Equity Instruments and Debt Securities	Equity Instruments and Debt Securities Equity instruments and debt securities consist primarily of equity instruments, our deferred compensation plan investments, the debt securities of our captive insurance subsidiary, and certain investments held to fund the debt service requirements of debt previously secured by investment properties. At September 30, 2021 and December 31, 2020, we had equity instruments with readily determinable fair values of $94.2 million and $41.9 million, respectively. Changes in the fair value of these equity instruments are recorded in unrealized losses in fair value of equity instruments in our consolidated statements of operations and comprehensive income. At September 30, 2021 and December 31, 2020, we had equity instruments without readily determinable fair values of $250.2 million and $309.3 million, respectively, for which we have elected the measurement alternative. We regularly evaluate these investments for any impairment in their estimated fair value, as well as any observable price changes for an identical or similar equity instrument of the same issuer, and recorded a $14.0 million loss in the third quarter of 2021, which is included in unrealized losses in fair value of equity instruments in our consolidated statements of operations and comprehensive income. Our deferred compensation plan equity instruments are valued based upon quoted market prices. The investments have a matching liability as the amounts are fully payable to the employees that earned the compensation. Changes in value of these securities and changes to the matching liability to employees are both recognized in earnings and, as a result, there is no impact to consolidated net income. At September 30, 2021 and December 31, 2020, we held debt securities of $56.9 million and $40.5 million, respectively, in our captive insurance subsidiary. The types of securities included in the investment portfolio of our captive insurance subsidiary are typically U.S. Treasury or other U.S. government securities as well as corporate debt securities with maturities ranging from less than one year to ten years. These securities are classified as available-for-sale and are valued based upon quoted market prices or other observable inputs when quoted market prices are not available. The amortized cost of debt securities, which approximates fair value, held by our captive insurance subsidiary is adjusted for amortization of premiums and accretion of discounts to maturity. Changes in the values of these securities are recognized in accumulated other comprehensive income (loss) until the gain or loss is realized or until any unrealized loss is deemed to be other-than-temporary. We review any declines in value of these securities for other-than-temporary impairment and consider the severity and duration of any decline in value. To the extent an other-than-temporary impairment is deemed to have occurred, an impairment is recorded and a new cost basis is established. Our captive insurance subsidiary is required to maintain statutory minimum capital and surplus as well as maintain a minimum liquidity ratio. Therefore, our access to these securities may be limited.
Fair Value Measurements	Fair Value Measurements Level 1 fair value inputs are quoted prices for identical items in active, liquid and visible markets such as stock exchanges. Level 2 fair value inputs are observable information for similar items in active or inactive markets, and appropriately consider counterparty creditworthiness in the valuations. Level 3 fair value inputs reflect our best estimate of inputs and assumptions market participants would use in pricing an asset or liability at the measurement date. The inputs are unobservable in the market and significant to the valuation estimate. We have no investments for which fair value is measured on a recurring basis using Level 3 inputs. The equity instruments with readily determinable fair values we held at September 30, 2021 and December 31, 2020 were primarily classified as having Level 1 and Level 2 fair value inputs. In addition, we had derivative instruments which were classified as having Level 2 inputs, which consist primarily of foreign currency forward contracts and interest rate swap agreements with a gross asset balance of $3.9 million at September 30, 2021 and an insignificant gross asset balance at December 31, 2020, and a gross liability balance of $0.1 million and $44.6 million at September 30, 2021 and December 31, 2020, respectively. Note 7 includes a discussion of the fair value of debt measured using Level 2 inputs. Level 3 inputs to our purchase accounting and impairment analyses include our estimations of net operating results of the property, capitalization rates and discount rates.
Noncontrolling Interests	Noncontrolling Interests Simon Details of the carrying amount of our noncontrolling interests are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of As of ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 Limited partners’ interests in the Operating Partnership ​ $ 479,827 ​ $ 431,784 ​ Nonredeemable noncontrolling interests in properties, net ​ 16,767 ​ 1,090 ​ Total noncontrolling interests reflected in equity ​ $ 496,594 ​ $ 432,874 ​ ​ Net income attributable to noncontrolling interests (which includes nonredeemable and redeemable noncontrolling interests in consolidated properties, limited partners’ interests in the Operating Partnership and preferred distributions payable by the Operating Partnership on its outstanding preferred units) is a component of consolidated net income. In addition, the individual components of other comprehensive income (loss) are presented in the aggregate for both controlling and noncontrolling interests, with the portion attributable to noncontrolling interests deducted from comprehensive income attributable to common stockholders. The Operating Partnership Our evaluation of the appropriateness of classifying the Operating Partnership’s common units of partnership interest, or units, held by Simon and the Operating Partnership's limited partners within permanent equity considered several significant factors. First, as a limited partnership, all decisions relating to the Operating Partnership’s operations and distributions are made by Simon, acting as the Operating Partnership’s sole general partner. The decisions of the general partner are made by Simon's Board of Directors or management. The Operating Partnership has no other governance structure. Secondly, the sole asset of Simon is its interest in the Operating Partnership. As a result, a share of common stock of Simon, or common stock, if owned by the Operating Partnership, is best characterized as being similar to a treasury share and thus not an asset of the Operating Partnership. Limited partners of the Operating Partnership have the right under the Operating Partnership’s partnership agreement to exchange their units for shares of common stock or cash, as selected by Simon as the sole general partner. Accordingly, we classify units held by limited partners in permanent equity because Simon may elect to issue shares of common stock to limited partners exercising their exchange rights rather than using cash. Under the Operating Partnership’s partnership agreement, the Operating Partnership is required to redeem units held by Simon only when Simon has repurchased shares of common stock. We classify units held by Simon in permanent equity because the decision to redeem those units would be made by Simon. Net income attributable to noncontrolling interests (which includes nonredeemable and redeemable noncontrolling interests in consolidated properties) is a component of consolidated net income.
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Simon The total accumulated other comprehensive income (loss) related to Simon’s currency translation adjustment was ($177.0) million and ($136.2) million as of September 30, 2021 and December 31, 2020, respectively. The reclassifications out of accumulated other comprehensive income (loss) consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ ​ ​ September 30, ​ September 30, ​ ​ ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 ​ Affected line item where net income is presented ​ Currency translation adjustments ​ $ — ​ $ — ​ $ 5,660 ​ $ — ​ Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net ​ ​ ​ ​ — ​ ​ — ​ ​ (712) ​ ​ — ​ Net income attributable to noncontrolling interests ​ ​ ​ $ — ​ $ — ​ $ 4,948 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated derivative gains ​ $ 404 $ 477 ​ $ 1,362 $ 1,435 Interest expense ​ ​ ​ (50) (63) ​ (171) (189) Net income attributable to noncontrolling interests ​ ​ ​ $ 354 ​ $ 414 ​ $ 1,191 ​ $ 1,246 ​ ​ ​ ​ ​ The Operating Partnership The total accumulated other comprehensive income (loss) related to the Operating Partnership’s currency translation adjustment was ($202.4) million and ($155.8) million as of September 30, 2021 and December 31, 2020, respectively. The reclassifications out of accumulated other comprehensive income (loss) consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ ​ ​ September 30, ​ September 30, ​ ​ ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 ​ Affected line item where net income is presented ​ Currency translation adjustments ​ $ — $ — ​ $ 5,660 $ — Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated derivative gains ​ $ 404 $ 477 ​ $ 1,362 $ 1,435 Interest expense ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Derivative Financial Instruments	Derivative Financial Instruments We record all derivatives on our consolidated balance sheets at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether we have designated a derivative as a hedge and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. We may use a variety of derivative financial instruments in the normal course of business to selectively manage or hedge a portion of the risks associated with our indebtedness and interest payments. Our objectives in using interest rate derivatives are to add stability to interest expense and to manage our exposure to interest rate movements. To accomplish this objective, we primarily use interest rate swaps and caps. We require that hedging derivative instruments be highly effective in reducing the risk exposure that they are designated to hedge. We formally designate any instrument that meets these hedging criteria as a hedge at the inception of the derivative contract. We have no credit-risk-related hedging or derivative activities. As of September 30, 2021 and December 31, 2020, we had no outstanding interest rate derivatives. We generally do not apply hedge accounting to interest rate caps, which had a nominal value as of September 30, 2021 and December 31, 2020. We may enter into treasury lock agreements as part of an anticipated debt issuance. Upon completion of the debt issuance, the fair value of these instruments is recorded as part of accumulated other comprehensive income (loss) and is amortized to interest expense over the life of the debt agreement. The unamortized gain on our treasury locks and terminated hedges recorded in accumulated other comprehensive income was $7.1 million as of September 30, 2021, compared to an unamortized gain of $8.7 million as of December 31, 2020. Within the next 12 months, we expect to reclassify to earnings approximately $0.2 million of gains related to terminated interest rate swaps from the current balance held in accumulated other comprehensive income. We are also exposed to foreign currency risk on financings of certain foreign operations. Our intent is to offset gains and losses that occur on the underlying exposures, with gains and losses on the derivative contracts hedging these exposures. We do not enter into either interest rate protection or foreign currency rate protection agreements for speculative purposes. We are also exposed to fluctuations in foreign exchange rates on financial instruments which are denominated in foreign currencies, primarily in Yen and Euro. We use currency forward contracts, cross currency swap contracts and foreign currency denominated debt to manage our exposure to changes in foreign exchange rates on certain Yen and Euro-denominated receivables and net investments. Currency forward contracts involve fixing the Yen:USD or Euro:USD exchange rate for delivery of a specified amount of foreign currency on a specified date. The currency forward contracts are typically cash settled in U.S. dollars for their fair value at or close to their settlement date. We had the following Euro:USD forward contracts designated as net investment hedges at September 30, 2021 and December 31, 2020 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset (Liability) Value as of ​ ​ ​ ​ September 30, December 31, Notional Value ​ Maturity Date ​ 2021 ​ 2020 € 100.0 ​ March 24, 2021 ​ ​ — ​ ​ (3.9) € 100.0 ​ March 24, 2021 ​ ​ — ​ ​ (3.8) € 50.0 ​ March 24, 2021 ​ ​ — ​ ​ (2.3) € 50.0 ​ March 24, 2021 ​ ​ — ​ ​ (2.2) € 50.0 ​ May 14, 2021 ​ ​ — ​ ​ (2.2) € 50.0 ​ May 14, 2021 ​ ​ — ​ ​ (2.2) € 41.0 ​ May 14, 2021 ​ ​ — ​ ​ (1.9) € 20.0 ​ May 14, 2021 ​ ​ — ​ ​ (1.7) € 50.0 ​ May 14, 2021 ​ ​ — ​ ​ (2.1) € 50.0 ​ May 14, 2021 ​ ​ — ​ ​ (6.4) € 30.0 ​ May 14, 2021 ​ ​ — ​ (2.6) € 60.0 ​ December 20, 2021 ​ ​ 0.1 ​ (4.2) € 60.0 ​ December 20, 2021 ​ ​ 0.1 ​ (4.1) € 30.0 ​ December 20, 2021 ​ ​ (0.1) ​ (2.2) € 28.0 ​ December 20, 2021 ​ ​ 0.7 ​ — € 50.0 ​ July 15, 2021 ​ ​ — ​ (0.1) € 41.0 ​ July 15, 2021 ​ ​ — ​ (0.1) € 50.0 ​ July 15, 2021 ​ ​ — ​ (0.1) € 61.0 ​ September 17, 2021 ​ ​ — ​ (1.3) € 61.0 ​ September 17, 2021 ​ ​ — ​ (1.2) € 60.0 ​ March 15, 2022 ​ ​ 1.5 ​ — € 62.0 ​ September 15, 2022 ​ ​ 1.5 ​ — ​ Asset balances in the above table are included in deferred costs and other assets. Liability balances in the above table are included in other liabilities. We have designated certain currency forward contracts and the cross-currency swap as net investment hedges. Accordingly, we report the changes in fair value in other comprehensive income (loss). Changes in the value of these forward contracts are offset by changes in the underlying hedged Euro-denominated joint venture investments. The total accumulated other comprehensive income (loss) related to Simon’s derivative activities, including our share of other comprehensive income (loss) from unconsolidated entities, was ($14.8) million and ($53.2) million as of September 30, 2021 and December 31, 2020, respectively. The total accumulated other comprehensive income (loss) related to the Operating Partnership’s derivative activities, including our share of other comprehensive income (loss) from unconsolidated entities, was ($16.9) million and ($60.9) million as of September 30, 2021 and December 31, 2020, respectively.
Simon Property Group Acquisition Holdings, Inc.	Simon Property Group Acquisition Holdings, Inc. The Company sponsored, through a wholly-owned subsidiary, a special purpose acquisition corporation, or SPAC, named Simon Property Group Acquisition Holdings, Inc. On February 18, 2021, the SPAC announced the pricing of its initial public offering, which was consummated on February 23, 2021, generating gross proceeds of $345.0 million, which have been placed in a trust account and is included in the accompanying consolidated balance sheet in Investments held in trust – special purpose acquisition company. The SPAC is a consolidated VIE which was formed for the purpose of effecting a business combination. The Company accounts for the noncontrolling interest in the SPAC as noncontrolling redeemable interests as these instruments are redeemable at the option of the holder and are classified as temporary equity at their redemption value in Simon’s accompanying consolidated balance sheet in Limited partners preferred interest in the Operating Partnership and noncontrolling redeemable interests and in the Operating Partnership’s accompanying consolidated balance sheet in Preferred units, various series, at liquidation value, and noncontrolling redeemable interests.
New Accounting Pronouncements	New Accounting Pronouncements In March 2020, the FASB issued Accounting Standards Update (ASU) 2020-04, “Reference Rate Reform,” which provides temporary optional expedients and exceptions to the US GAAP guidance on contract modifications and hedge accounting to ease the financial reporting burdens of the expected market transition from LIBOR and other interbank offered rates to alternative reference rates. Additional optional expedients, exceptions, and clarifications were created in ASU 2021-01. The guidance is effective upon issuance and generally can be applied to any contract modifications or existing and new hedging relationships through December 31, 2022. We are currently evaluating the impact that the expected market transition from LIBOR to alternative references rates will have on our financial statements as well as the applicability of the aforementioned expedients and exceptions provided in ASU 2020-04 and ASU 2021-01.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2021
Significant Accounting Policies
Schedule of carrying amount of noncontrolling interests	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of As of ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 Limited partners’ interests in the Operating Partnership ​ $ 479,827 ​ $ 431,784 ​ Nonredeemable noncontrolling interests in properties, net ​ 16,767 ​ 1,090 ​ Total noncontrolling interests reflected in equity ​ $ 496,594 ​ $ 432,874 ​
Schedule of reclassifications out of accumulated other comprehensive income (loss)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ ​ ​ September 30, ​ September 30, ​ ​ ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 ​ Affected line item where net income is presented ​ Currency translation adjustments ​ $ — ​ $ — ​ $ 5,660 ​ $ — ​ Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net ​ ​ ​ ​ — ​ ​ — ​ ​ (712) ​ ​ — ​ Net income attributable to noncontrolling interests ​ ​ ​ $ — ​ $ — ​ $ 4,948 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated derivative gains ​ $ 404 $ 477 ​ $ 1,362 $ 1,435 Interest expense ​ ​ ​ (50) (63) ​ (171) (189) Net income attributable to noncontrolling interests ​ ​ ​ $ 354 ​ $ 414 ​ $ 1,191 ​ $ 1,246 ​ ​ ​
Schedule of Euro:USD forward contracts	We had the following Euro:USD forward contracts designated as net investment hedges at September 30, 2021 and December 31, 2020 (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset (Liability) Value as of ​ ​ ​ ​ September 30, December 31, Notional Value ​ Maturity Date ​ 2021 ​ 2020 € 100.0 ​ March 24, 2021 ​ ​ — ​ ​ (3.9) € 100.0 ​ March 24, 2021 ​ ​ — ​ ​ (3.8) € 50.0 ​ March 24, 2021 ​ ​ — ​ ​ (2.3) € 50.0 ​ March 24, 2021 ​ ​ — ​ ​ (2.2) € 50.0 ​ May 14, 2021 ​ ​ — ​ ​ (2.2) € 50.0 ​ May 14, 2021 ​ ​ — ​ ​ (2.2) € 41.0 ​ May 14, 2021 ​ ​ — ​ ​ (1.9) € 20.0 ​ May 14, 2021 ​ ​ — ​ ​ (1.7) € 50.0 ​ May 14, 2021 ​ ​ — ​ ​ (2.1) € 50.0 ​ May 14, 2021 ​ ​ — ​ ​ (6.4) € 30.0 ​ May 14, 2021 ​ ​ — ​ (2.6) € 60.0 ​ December 20, 2021 ​ ​ 0.1 ​ (4.2) € 60.0 ​ December 20, 2021 ​ ​ 0.1 ​ (4.1) € 30.0 ​ December 20, 2021 ​ ​ (0.1) ​ (2.2) € 28.0 ​ December 20, 2021 ​ ​ 0.7 ​ — € 50.0 ​ July 15, 2021 ​ ​ — ​ (0.1) € 41.0 ​ July 15, 2021 ​ ​ — ​ (0.1) € 50.0 ​ July 15, 2021 ​ ​ — ​ (0.1) € 61.0 ​ September 17, 2021 ​ ​ — ​ (1.3) € 61.0 ​ September 17, 2021 ​ ​ — ​ (1.2) € 60.0 ​ March 15, 2022 ​ ​ 1.5 ​ — € 62.0 ​ September 15, 2022 ​ ​ 1.5 ​ —
Simon Property Group, L.P.
Significant Accounting Policies
Schedule of reclassifications out of accumulated other comprehensive income (loss)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ ​ ​ September 30, ​ September 30, ​ ​ ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 ​ Affected line item where net income is presented ​ Currency translation adjustments ​ $ — $ — ​ $ 5,660 $ — Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated derivative gains ​ $ 404 $ 477 ​ $ 1,362 $ 1,435 Interest expense ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Per Share and Per Unit Data (Ta

Per Share and Per Unit Data (Tables)	9 Months Ended
	Sep. 30, 2021
Per Share And Per Unit Data
Schedule of computation of basic and diluted earnings per share and basic and diluted earnings per unit	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended September 30, ​ For the Nine Months Ended September 30, ​ ​ ​ 2021 ​ 2020 2021 2020 Net Income attributable to Common Stockholders — Basic and Diluted $ 679,936 $ 145,926 $ 1,743,053 $ 837,744 Weighted Average Shares Outstanding — Basic and Diluted ​ 328,619,163 ​ 305,913,431 ​ 328,576,315 ​ 306,099,266 ​
Simon Property Group, L.P.
Per Share And Per Unit Data
Schedule of computation of basic and diluted earnings per share and basic and diluted earnings per unit	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended September 30, ​ For the Nine Months Ended September 30, ​ ​ ​ 2021 ​ 2020 2021 2020 Net Income attributable to Unitholders — Basic and Diluted $ 777,740 $ 168,086 $ 1,993,913 $ 965,210 Weighted Average Units Outstanding — Basic and Diluted ​ 375,882,318 ​ 352,420,845 ​ 375,864,921 ​ 352,673,474 ​

Investment in Unconsolidated _2

Investment in Unconsolidated Entities and International Investments (Tables)	9 Months Ended
	Sep. 30, 2021
Investments in Unconsolidated Entities and International Investments
Summary of equity method investments and share of income from such investments, balance sheet	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, December 31, ​ ​ 2021 ​ 2020 Assets: ​ ​ ​ ​ ​ ​ ​ Investment properties, at cost ​ $ 19,867,502 ​ $ 20,079,476 ​ Less - accumulated depreciation ​ 8,287,531 ​ 8,003,863 ​ ​ ​ 11,579,971 ​ 12,075,613 ​ Cash and cash equivalents ​ 1,368,859 ​ 1,169,422 ​ Tenant receivables and accrued revenue, net ​ 567,034 ​ 749,231 ​ Right-of-use assets, net ​ ​ 161,758 ​ ​ 185,598 ​ Deferred costs and other assets ​ 415,768 ​ 380,087 ​ Total assets ​ $ 14,093,390 ​ $ 14,559,951 ​ Liabilities and Partners’ Deficit: ​ ​ ​ ​ ​ ​ ​ Mortgages ​ $ 15,311,572 ​ $ 15,569,485 ​ Accounts payable, accrued expenses, intangibles, and deferred revenue ​ 854,603 ​ 969,242 ​ Lease liabilities ​ ​ 165,334 ​ ​ 188,863 ​ Other liabilities ​ 405,134 ​ 426,321 ​ Total liabilities ​ 16,736,643 ​ 17,153,911 ​ Preferred units ​ 67,450 ​ 67,450 ​ Partners’ deficit ​ (2,710,703) ​ (2,661,410) ​ Total liabilities and partners’ deficit ​ $ 14,093,390 ​ $ 14,559,951 ​ Our Share of: ​ ​ ​ ​ ​ ​ ​ Partners’ deficit ​ $ (1,161,814) ​ $ (1,130,713) ​ Add: Excess Investment ​ 1,300,242 ​ 1,399,757 ​ Our net Investment in unconsolidated entities, at equity ​ $ 138,428 ​ $ 269,044 ​
Summary of equity method investments and share of income from such investments, statements of operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 REVENUE: ​ ​ ​ ​ ​ ​ ​ Lease income ​ $ 719,723 ​ $ 601,522 ​ $ 2,053,826 ​ $ 1,919,618 ​ Other income ​ 67,630 ​ 94,630 ​ 204,923 ​ 215,349 ​ Total revenue ​ 787,353 ​ 696,152 ​ 2,258,749 ​ 2,134,967 ​ OPERATING EXPENSES: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Property operating ​ 151,008 ​ 129,024 ​ 420,174 ​ 383,363 ​ Depreciation and amortization ​ 170,568 ​ 175,716 ​ 512,165 ​ 512,705 ​ Real estate taxes ​ 66,221 ​ 68,464 ​ 203,242 ​ 197,487 ​ Repairs and maintenance ​ 18,274 ​ 16,457 ​ 53,625 ​ 49,661 ​ Advertising and promotion ​ 18,238 ​ 9,901 ​ 52,479 ​ 42,669 ​ Other ​ 43,400 ​ 41,857 ​ 113,042 ​ 107,822 ​ Total operating expenses ​ 467,709 ​ 441,419 ​ 1,354,727 ​ 1,293,707 ​ Operating Income Before Other Items ​ 319,644 ​ 254,733 ​ 904,022 ​ 841,260 ​ Interest expense ​ (154,501) ​ (154,579) ​ (453,145) ​ (463,629) ​ Gain on sale or disposal of, or recovery on, assets and interests in unconsolidated entities, net ​ ​ — ​ ​ — ​ ​ 33,371 ​ ​ — ​ Net Income ​ $ 165,143 ​ $ 100,154 ​ $ 484,248 ​ $ 377,631 ​ Third-Party Investors’ Share of Net Income ​ $ 82,639 ​ $ 46,785 ​ $ 243,525 ​ $ 193,633 ​ Our Share of Net Income ​ 82,504 ​ 53,369 ​ 240,723 ​ 183,998 ​ Amortization of Excess Investment ​ (15,199) ​ (20,543) ​ (49,794) ​ (62,144) ​ Our Share of Gain on Sale or Disposal of Assets and Interests in Other Income in the Consolidated Financial Statements ​ ​ — ​ ​ — ​ ​ (14,941) ​ ​ — ​ Income from Unconsolidated Entities ​ $ 67,305 ​ $ 32,826 ​ $ 175,988 ​ $ 121,854 ​

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt
Schedule of fair value of financial instruments and the related discount rate assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 2020 ​ Fair value of consolidated fixed rate mortgages and unsecured indebtedness (in millions) ​ $ 25,791 ​ $ 25,327 ​ ​ Weighted average discount rates assumed in calculation of fair value for fixed rate mortgages ​ 2.86 % 2.41 % ​ Weighted average discount rates assumed in calculation of fair value for unsecured indebtedness ​ ​ 3.24 % ​ 2.63 % ​

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2021
Schedule of preferred units of the Operating Partnership and the amount of the noncontrolling redeemable interests in properties	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of As of ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 ​ 7.50% Cumulative Redeemable Preferred Units, 260,000 units authorized, 255,373 issued and outstanding ​ $ 25,537 ​ $ 25,537 ​ Other noncontrolling redeemable interests ​ 527,488 ​ 160,355 ​ Limited partners’ preferred interest in the Operating Partnership and noncontrolling redeemable interests in properties ​ $ 553,025 ​ $ 185,892 ​
Schedule of LTIP units earned and aggregate grant date fair values adjusted for estimated forfeitures	​ ​ ​ ​ ​ ​ ​ ​ LTIP Program LTIP Units Earned Grant Date Fair Value of TSR Award Grant Date Target Value of Performance-Based Awards 2018 LTIP program - Tranche A 38,148 $6.1 million $6.1 million 2018 LTIP program - Tranche B - $6.1 million $6.1 million 2019 LTIP program ​ To be determined in 2022 $9.5 million $14.7 million 2021 LTIP program ​ To be determined in 2024 $5.7 million $12.2 million
Simon Property Group, L.P.
Schedule of preferred units of the Operating Partnership and the amount of the noncontrolling redeemable interests in properties	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of As of ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 ​ 7.50% Cumulative Redeemable Preferred Units, 260,000 units authorized, 255,373 issued and outstanding ​ $ 25,537 ​ $ 25,537 ​ Other noncontrolling redeemable interests ​ 527,488 ​ 160,355 ​ Total preferred units, at liquidation value, and noncontrolling redeemable interests in properties ​ $ 553,025 ​ $ 185,892 ​

Lease Income (Tables)

Lease Income (Tables)	9 Months Ended
	Sep. 30, 2021
Lease Income
Schedule of lease income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ September 30, ​ September 30, ​ 2021 ​ 2020 2021 2020 Fixed lease income $ 921,521 ​ $ 929,335 ​ $ 2,783,459 ​ $ 2,939,257 Variable lease income 286,402 ​ ​ 64,496 ​ ​ 728,347 ​ ​ 330,315 Total lease income $ 1,207,923 ​ $ 993,831 ​ $ 3,511,806 ​ $ 3,269,572

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies.
Schedule of lease cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended ​ For the Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2021 ​ 2020 2021 ​ 2020 Operating Lease Cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed lease cost ​ $ 8,118 ​ $ 8,015 ​ $ 24,367 ​ $ 23,161 Variable lease cost ​ ​ 3,984 ​ ​ 3,130 ​ ​ 11,821 ​ ​ 10,217 Sublease income ​ (187) ​ (187) ​ (560) ​ (560) Total operating lease cost ​ $ 11,915 ​ $ 10,958 ​ $ 35,628 ​ $ 32,818
Schedule of other lease information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Nine Months Ended ​ ​ September 30, ​ ​ 2021 ​ 2020 Other Information ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 36,098 ​ $ 33,301 ​ ​ ​ ​ ​ ​ ​ Weighted-average remaining lease term - operating leases ​ ​ 33.8 years ​ ​ 34.6 years Weighted-average discount rate - operating leases ​ ​ 4.87% ​ ​ 4.86%
Schedule of future minimum lease payments due	​ ​ ​ ​ ​ 2021 $ 32,131 2022 ​ 32,838 2023 ​ 32,979 2024 ​ 33,114 2025 ​ 33,124 Thereafter ​ 888,217 ​ ​ $ 1,052,403 Impact of discounting ​ ​ (543,332) Operating lease liabilities ​ $ 509,071

Organization (Details)

Organization (Details)	Sep. 30, 2021propertystatecountry	Dec. 29, 2020property
TRG
Real Estate Properties
Ownership percentage	80.00%	80.00%
TRG | TRG
Real Estate Properties
Number of regional, super regional and outlet malls	24	24
U.S. and Puerto Rico
Real Estate Properties
Number of properties	201
Number of U.S. states containing property locations | state	37
U.S. and Puerto Rico | Malls
Real Estate Properties
Number of properties	95
U.S. and Puerto Rico | Premium Outlets
Real Estate Properties
Number of properties	69
U.S. and Puerto Rico | The Mills
Real Estate Properties
Number of properties	14
U.S. and Puerto Rico | Community/Lifestyle Centers
Real Estate Properties
Number of properties	6
U.S. and Puerto Rico | Other shopping centers or outlet centers
Real Estate Properties
Number of properties	17
Asia, Europe and Canada | Premium and Designer Outlets
Real Estate Properties
Number of properties | state	32
Europe | Klepierre
Real Estate Properties
Ownership percentage	22.40%
Number of countries | country	15

Basis of Presentation (Details)

Basis of Presentation (Details) - property	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Real Estate Properties
Total number of joint venture properties	84
Number of joint venture properties managed by the entity	53
Number of International joint venture properties	23
Number of joint venture properties managed by others	31
Simon Property Group, L.P.
Ownership interest:
Ownership interest in the Operating Partnership (as a percent)	87.40%		87.40%
Simon Property Group, L.P. | Weighted average
Ownership interest:
Ownership interest in the Operating Partnership (as a percent)	87.40%	86.80%
Wholly owned properties
Real Estate Properties
Number of properties	131
Partially owned properties
Real Estate Properties
Number of properties	18

Significant Accounting Polici_4

Significant Accounting Policies - Equity Instruments and Investments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Equity Instruments and Investments
Equity instruments with readily determinable fair value	$ 94.2	$ 94.2	$ 41.9
Equity instruments without readily determinable fair values	250.2	250.2	309.3
Impairment of equity securities without readily determinable fair value	14
Debt securities of our captive insurance companies	$ 56.9	$ 56.9	$ 40.5
Debt Securities | Securities in captive insurance subsidiary portfolio | Maximum
Equity Instruments and Investments
Short-term investment maturity period		1 year
Investment maturity period		10 years

Significant Accounting Polici_5

Significant Accounting Policies - Fair Value Measurements (Details) $ in Millions	Sep. 30, 2021USD ($)item	Dec. 31, 2020USD ($)
Fair Value Measurements
Number of investments for which fair value is measured on a recurring basis using Level 3 inputs | item	0
Level 2 | Recurring
Fair Value Measurements
Interest rate swap agreements and foreign currency forward contracts, gross asset balance	$ 3.9
Interest rate swap agreements and foreign currency forward contracts, gross liability balance	$ 0.1	$ 44.6

Significant Accounting Polici_6

Significant Accounting Policies - Noncontrolling Interests, Simon Property Group, Inc. (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Significant Accounting Policies
Limited partners' interests in the Operating Partnership	$ 479,827	$ 431,784
Nonredeemable noncontrolling interests in properties, net	16,767	1,090
Total noncontrolling interests reflected in equity	$ 496,594	$ 432,874

Significant Accounting Polici_7

Significant Accounting Policies - Reclassification Out of AOCI, Simon Property Group, Inc. (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Significant Accounting Policies
Total accumulated other comprehensive income (loss)	$ (177,000)		$ (177,000)		$ (136,200)
Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net	108,543	$ (91,285)	201,600	$ (98,168)
Interest expense	(199,772)	(201,858)	(602,207)	(586,545)
Net income attributable to noncontrolling interests	(97,878)	(21,886)	(249,421)	(124,351)
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	679,936	145,926	1,743,053	837,744
Currency translation adjustments | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net			5,660
Currency translation adjustments, attributable to noncontrolling interests | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Net income attributable to noncontrolling interests			(712)
Currency translation adjustments. | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS			4,948
Accumulated derivative losses, net, including noncontrolling interests | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Interest expense	404	477	1,362	1,435
Accumulated derivative losses, attributable to noncontrolling interests | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Net income attributable to noncontrolling interests	(50)	(63)	(171)	(189)
Accumulated derivative gains (losses), net | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ 354	$ 414	$ 1,191	$ 1,246

Significant Accounting Polici_8

Significant Accounting Policies - Reclassification Out Of AOCI, Simon Property Group, L.P. (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Significant Accounting Policies
Total accumulated other comprehensive income (loss)	$ (177,000)		$ (177,000)		$ (136,200)
Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net	108,543	$ (91,285)	201,600	$ (98,168)
Interest expense	(199,772)	(201,858)	(602,207)	(586,545)
Simon Property Group, L.P.
Significant Accounting Policies
Total accumulated other comprehensive income (loss)	(202,400)		(202,400)		$ (155,800)
Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net	108,543	(91,285)	201,600	(98,168)
Interest expense	(199,772)	(201,858)	(602,207)	(586,545)
Currency translation adjustments. | Simon Property Group, L.P. | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Gain on acquisition of controlling interest, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net			5,660
Accumulated derivative gains (losses), net | Simon Property Group, L.P. | Amount reclassified from accumulated other comprehensive income (loss)
Significant Accounting Policies
Interest expense	$ 404	$ 477	$ 1,362	$ 1,435

Significant Accounting Polici_9

Significant Accounting Policies - Derivative Financial Instruments (Details) € in Millions, $ in Millions	Sep. 30, 2021USD ($)DerivativeInstrument	Sep. 30, 2021EUR (€)DerivativeInstrument	Dec. 31, 2020USD ($)DerivativeInstrument	Dec. 31, 2020EUR (€)DerivativeInstrument
Derivative Financial Instruments
Number of credit-risk-related hedging or derivative activities | DerivativeInstrument	0	0
Unamortized gain on treasury locks and terminated hedges	$ 7.1		$ 8.7
Amount expected to be reclassified from accumulated other comprehensive loss to earnings within the next year	0.2
Gross accumulated other comprehensive income (loss) related to derivative activities	$ (14.8)		$ (53.2)
Interest rate swap | Designated as Hedging Instrument
Derivative Financial Instruments
Number of Instruments | DerivativeInstrument	0	0	0	0
USD-Euro currency forward contract | March 24, 2021 | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				€ 100
Forward contract net, fair value			$ (3.9)
USD-Euro currency forward contract | March 24, 2021, One | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				100
Forward contract net, fair value			(3.8)
USD-Euro currency forward contract | March 24, 2021, Two | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				50
Forward contract net, fair value			(2.3)
USD-Euro currency forward contract | March 24, 2021, Three | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				50
Forward contract net, fair value			(2.2)
USD-Euro currency forward contract | May 14, 2021 | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				50
Forward contract net, fair value			(2.2)
USD-Euro currency forward contract | May 14, 2021, One | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				50
Forward contract net, fair value			(2.2)
USD-Euro currency forward contract | May 14, 2021, Two | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				41
Forward contract net, fair value			(1.9)
USD-Euro currency forward contract | May 14, 2021, Three | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				20
Forward contract net, fair value			(1.7)
USD-Euro currency forward contract | May 14, 2021, Four | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				50
Forward contract net, fair value			(2.1)
USD-Euro currency forward contract | May 14, 2021 Five | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				50
Forward contract net, fair value			(6.4)
USD-Euro currency forward contract | May 14, 2021, Six | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				30
Forward contract net, fair value			(2.6)
USD-Euro currency forward contract | December 20, 2021 | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €		€ 60		60
Forward contract net, fair value	$ 0.1		(4.2)
USD-Euro currency forward contract | December 20, 2021, One | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €		60		60
Forward contract net, fair value	0.1		(4.1)
USD-Euro currency forward contract | December 20, 2021, Two | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €		30		30
Forward contract net, fair value	(0.1)		(2.2)
USD-Euro currency forward contract | December 20, 2021, Three | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €		28
Forward contract net, fair value	0.7
USD-Euro currency forward contract | July 15, 2021 | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				50
Forward contract net, fair value			(0.1)
USD-Euro currency forward contract | July 15, 2021, One | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				41
Forward contract net, fair value			(0.1)
USD-Euro currency forward contract | July 15, 2021, Two | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				50
Forward contract net, fair value			(0.1)
USD-Euro currency forward contract | September 17, 2021 | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				61
Forward contract net, fair value			(1.3)
USD-Euro currency forward contract | September 17, 2021, One | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €				€ 61
Forward contract net, fair value			(1.2)
USD-Euro currency forward contract | March 15, 2022 | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €		60
Forward contract net, fair value	1.5
USD-Euro currency forward contract | September 15, 2022 | Net Investment Hedging | Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount | €		€ 62
Forward contract net, fair value	1.5
Simon Property Group, L.P.
Derivative Financial Instruments
Gross accumulated other comprehensive income (loss) related to derivative activities	$ (16.9)		$ (60.9)

Significant Accounting Polic_10

Significant Accounting Policies - Simon Property Group Acquisition Holdings, Inc. - (Details) $ in Millions	Feb. 23, 2021USD ($)
Simon Property Group Acquisition Holdings, Inc
Investment Holdings [Line Items]
Gross proceeds from the special purpose acquisition company IPO	$ 345

Real Estate Acquisitions and _2

Real Estate Acquisitions and Dispositions (Details) - Consolidated properties $ in Millions	Oct. 01, 2020USD ($)property	Jul. 31, 2021USD ($)	Mar. 31, 2021USD ($)
Dispositions
Nets gains on disposition		$ 88	$ 89.3
Non-recourse mortgage		$ 120.9	$ 180
Retail properties | Disposed by Sales
Dispositions
Number of properties disposed of during the period | property	1
Proceeds from sale or disposal of real estate assets	$ 33.4
Gain (loss) on disposition of interest in properties	$ 12.3

Per Share and Per Unit Data (De

Per Share and Per Unit Data (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Per Share And Per Unit Data
Net Income attributable to Common Stockholders - Basic		$ 679,936	$ 145,926	$ 1,743,053	$ 837,744
Net Income attributable to Common Stockholders - Diluted		$ 679,936	$ 145,926	$ 1,743,053	$ 837,744
Weighted Average Shares Outstanding - Basic		328,619,163	305,913,431	328,576,315	306,099,266
Weighted Average Shares Outstanding - Diluted		328,619,163	305,913,431	328,576,315	306,099,266
Dividends
Dividends declared per common share (in dollars per share)	$ 1.65
Simon Property Group, L.P.
Per Share And Per Unit Data
Net Income attributable to Common Stockholders - Basic		$ 777,740	$ 168,086	$ 1,993,913	$ 965,210
Net Income attributable to Common Stockholders - Diluted		$ 777,740	$ 168,086	$ 1,993,913	$ 965,210
Weighted Average Shares Outstanding - Basic		375,882,318	352,420,845	375,864,921	352,673,474
Weighted Average Shares Outstanding - Diluted		375,882,318	352,420,845	375,864,921	352,673,474
Dividends
Distribution declared per unit (in dollars per share)	$ 1.65

Investments in Unconsolidated E

Investments in Unconsolidated Entities and International Investments - Real Estate Joint Ventures and Investments (Details) $ in Millions	Sep. 30, 2021USD ($)property	Dec. 31, 2020USD ($)
Investment in Unconsolidated Entities
Total number of joint venture properties | property	84
Construction and other related party loans
Investment in Unconsolidated Entities
Loans to related party | $	$ 93.4	$ 88.4

Investments in Unconsolidated_2

Investments in Unconsolidated Entities and International Investments - Unconsolidated Entity Transactions (Details) $ / shares in Units, $ in Thousands	Jun. 01, 2021USD ($)	Dec. 29, 2020USD ($)property$ / sharesshares	Dec. 07, 2020USD ($)	Feb. 19, 2020USD ($)item	Sep. 15, 2016item	Jan. 31, 2020USD ($)	Sep. 30, 2021USD ($)property	Jun. 30, 2021USD ($)	Mar. 31, 2021USD ($)	Sep. 30, 2020USD ($)item	Jun. 30, 2020USD ($)	Sep. 30, 2021USD ($)property	Sep. 30, 2020USD ($)	Jul. 01, 2021	Dec. 31, 2020USD ($)
Investment in Unconsolidated Entities
Payments for acquisitions												$ 157,080	$ 107,797
Impairment charge to reduce investment to its estimated fair value										$ 55,200
Income from unconsolidated entities							$ 198,524			61,823		562,138	156,610
Total revenue							1,296,554			1,060,674		3,790,652	3,476,074
Operating Income							612,324			404,024		1,821,658	1,509,761
Consolidated net income							778,648			$ 168,646		1,994,977	964,598
Gain on exchange of equity interests							159,828					159,828
Number of joint ventures with recorded other-than-temporary impairment | item										3
Simon Property Group, L.P.
Investment in Unconsolidated Entities
Payments for acquisitions												157,080	107,797
Income from unconsolidated entities							198,524			$ 61,823		562,138	156,610
Total revenue							1,296,554			1,060,674		3,790,652	3,476,074
Operating Income							612,324			404,024		1,821,658	1,509,761
Consolidated net income							778,648			168,646		1,994,977	$ 964,598
Gain on exchange of equity interests							$ 159,828					$ 159,828
TRG
Investment in Unconsolidated Entities
Ownership interest (as a percent)		80.00%					80.00%					80.00%
Share price (in dollars per share) | $ / shares		$ 43
Payments for acquisitions		$ 3,500,000
Impairment charge to reduce investment to its estimated fair value							$ 31,600					$ 94,700
Income from unconsolidated entities							(11,500)					(49,900)
Total revenue												422,800
Operating Income												137,300
Consolidated net income												55,300
Aggregate investment in ventures							3,396,169					3,396,169			$ 3,451,897
TRG | Series J Cumulative Preferred Shares
Investment in Unconsolidated Entities
Redemption of preferred shares		$ 192,500
Preferred stock stated dividend rate (as a percent)		6.50%
TRG | Series K Cumulative Preferred Shares
Investment in Unconsolidated Entities
Redemption of preferred shares		$ 170,000
Preferred stock stated dividend rate (as a percent)		6.25%
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
Number of units issued in connection with acquisition | shares		955,705
Aggregate investment in ventures							$ 3,396,169					$ 3,396,169			$ 3,451,897
TRG | TRG
Investment in Unconsolidated Entities
Number of regional, super regional and outlet malls | property		24					24					24
Eddie Bauer
Investment in Unconsolidated Entities
Ownership interest (as a percent)	49.00%
Payments for acquisitions	$ 100,800
J.C. Penny Department Store
Investment in Unconsolidated Entities
Ownership interest (as a percent)			41.67%
Payments for acquisitions			$ 125,000
Forever 21
Investment in Unconsolidated Entities
Ownership interest (as a percent)									50.00%
Payments for acquisitions									$ 56,300
Number of joint ventures | item				2
Aggregate investment in ventures				$ 67,600
Bargain purchase gain											$ 35,000
Additional noncontrolling interest purchased									12.50%
SPARC Group
Investment in Unconsolidated Entities
Number of joint ventures | item					2
SPARC Group Retail Operations
Investment in Unconsolidated Entities
Ownership interest (as a percent)							50.00%					50.00%
Payments for acquisitions						$ 6,700
Additional noncontrolling interest purchased						5.05%
Authentic Brands Group LLC
Investment in Unconsolidated Entities
Payments for acquisitions						$ 33,500
Additional noncontrolling interest purchased						1.37%
ABG
Investment in Unconsolidated Entities
Ownership interest (as a percent)														11.00%
Gain on exchange of equity interests							$ 159,800
Deferred Taxes							$ 47,900
HBS
Investment in Unconsolidated Entities
Impairment charge to reduce investment to its estimated fair value										$ 36,100
Multi family residential property
Investment in Unconsolidated Entities
Proceeds from sale or disposal of real estate assets								$ 27,100
Gain (loss) on disposition of interest in properties								$ 14,900

Investments in Unconsolidated_3

Investments in Unconsolidated Entities and International Investments - European Investments (Details) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021USD ($)property$ / sharesshares	Mar. 31, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)property$ / sharesshares	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)property
Investment in Unconsolidated Entities
Income from unconsolidated entities	$ 198,524		$ 61,823	$ 562,138	$ 156,610
Total revenue	1,296,554		1,060,674	3,790,652	3,476,074
Operating Income	612,324		404,024	1,821,658	1,509,761
Consolidated Net Income	$ 778,648		168,646	$ 1,994,977	964,598
European Joint Venture | Designer Outlet properties
Investment in Unconsolidated Entities
Number of properties | property	11			11		10
Number of properties consolidated by entity | property	7			7
European Joint Venture | Designer Outlet properties | Minimum
Investment in Unconsolidated Entities
Ownership interest (as a percent)	23.00%			23.00%
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 | Outlet Center In Ochtrup
Investment in Unconsolidated Entities
Non-cash gain on remeasurement of equity interest to fair value		$ 3,700
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	$ 22.53			$ 22.53
Income from unconsolidated entities	$ 8,900		$ 4,300	$ 115,900	13,700
Total revenue				840,400	882,000
Operating Income				215,300	195,200
Consolidated Net Income				619,900	123,200
Loss on sale or disposal of assets and interests in unconsolidated entities					$ 7,800
Non cash gain due to setup of tax basis of assets				$ 118,400
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

Investments in Unconsolidated_4

Investments in Unconsolidated Entities and International Investments - Asian Joint Ventures (Details) - Premium Outlets - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Japan | Mitsubishi Estate Co., Ltd.
Investment in Unconsolidated Entities
Ownership percentage	40.00%	40.00%
Our net Investment in unconsolidated entities, at equity	$ 211.1	$ 216.8
South Korea | Shinsegae International Co
Investment in Unconsolidated Entities
Ownership percentage	50.00%	50.00%
Our net Investment in unconsolidated entities, at equity	$ 187.3	$ 184.7

Investments in Unconsolidated_5

Investments in Unconsolidated Entities and International Investments - Combined Balance Sheets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
ASSETS:
Investment properties, at cost	$ 37,984,645	$ 38,050,196
Less - accumulated depreciation	15,410,030	14,891,937
Investment properties, at cost, net	22,574,615	23,158,259
Cash and cash equivalents	438,423	1,011,613
Tenant receivables and accrued revenue, net	935,053	1,236,734
Right-of-use assets, net	506,236	512,914
Deferred costs and other assets	1,105,736	1,082,168
Total assets	33,946,139	34,786,846
Liabilities and Partners' Deficit:
Mortgages	25,584,372	26,723,361
Accounts payable, accrued expenses, intangibles, and deferred revenues	1,324,603	1,311,925
Lease liabilities	509,071	515,492
Other liabilities	525,361	513,515
Total liabilities	29,518,422	31,128,608
Preferred units	553,025	185,892
Total liabilities and equity	33,946,139	34,786,846
Unconsolidated properties | Equity Method Investees excluding HBS, Klepierre, TRG, ABG, Forever 21, J.C. Penny, RGG and SPARC Group
ASSETS:
Investment properties, at cost	19,867,502	20,079,476
Less - accumulated depreciation	8,287,531	8,003,863
Investment properties, at cost, net	11,579,971	12,075,613
Cash and cash equivalents	1,368,859	1,169,422
Tenant receivables and accrued revenue, net	567,034	749,231
Right-of-use assets, net	161,758	185,598
Deferred costs and other assets	415,768	380,087
Total assets	14,093,390	14,559,951
Liabilities and Partners' Deficit:
Mortgages	15,311,572	15,569,485
Accounts payable, accrued expenses, intangibles, and deferred revenues	854,603	969,242
Lease liabilities	165,334	188,863
Other liabilities	405,134	426,321
Total liabilities	16,736,643	17,153,911
Preferred units	67,450	67,450
Partners' deficit	(2,710,703)	(2,661,410)
Total liabilities and equity	14,093,390	14,559,951
Our Share of:
Partners' deficit	(1,161,814)	(1,130,713)
Add: Excess Investment	1,300,242	1,399,757
Our net Investment in unconsolidated entities, at equity	$ 138,428	$ 269,044
Unconsolidated properties | Maximum
Our Share of:
Estimated life of investment property	40 years

Investments in Unconsolidated_6

Investments in Unconsolidated Entities and International Investments - Combined Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
REVENUE:
Lease income	$ 1,207,923	$ 993,831	$ 3,511,806	$ 3,269,572
Other income	61,607	45,498	200,465	134,957
Total revenue	1,296,554	1,060,674	3,790,652	3,476,074
EXPENSES:
Property operating	108,556	91,236	291,248	267,479
Depreciation and amortization	311,381	333,755	942,851	986,157
Real estate taxes	117,094	112,311	347,800	347,075
Repairs and maintenance	21,735	18,971	62,126	57,482
Advertising and promotion	38,635	14,751	87,685	60,967
Other	31,253	42,650	84,180	99,527
Total operating expenses	684,230	656,650	1,968,994	1,966,313
OPERATING INCOME BEFORE OTHER ITEMS	612,324	404,024	1,821,658	1,509,761
Interest expense	(199,772)	(201,858)	(602,207)	(586,545)
Gain on sale or disposal of, or recovery on, assets and interests in unconsolidated entities, net	108,543	(91,285)	201,600	(98,168)
CONSOLIDATED NET INCOME	778,648	168,646	1,994,977	964,598
Income from Unconsolidated Entities	198,524	61,823	562,138	156,610
Unconsolidated properties | Equity Method Investees excluding HBS, Klepierre, TRG, ABG, Forever 21, J.C. Penny, RGG and SPARC Group
REVENUE:
Lease income	719,723	601,522	2,053,826	1,919,618
Other income	67,630	94,630	204,923	215,349
Total revenue	787,353	696,152	2,258,749	2,134,967
EXPENSES:
Property operating	151,008	129,024	420,174	383,363
Depreciation and amortization	170,568	175,716	512,165	512,705
Real estate taxes	66,221	68,464	203,242	197,487
Repairs and maintenance	18,274	16,457	53,625	49,661
Advertising and promotion	18,238	9,901	52,479	42,669
Other	43,400	41,857	113,042	107,822
Total operating expenses	467,709	441,419	1,354,727	1,293,707
OPERATING INCOME BEFORE OTHER ITEMS	319,644	254,733	904,022	841,260
Interest expense	(154,501)	(154,579)	(453,145)	(463,629)
Gain on sale or disposal of, or recovery on, assets and interests in unconsolidated entities, net			33,371
CONSOLIDATED NET INCOME	165,143	100,154	484,248	377,631
Third-Party Investors' Share of Net Income	82,639	46,785	243,525	193,633
Our Share of Net Income	82,504	53,369	240,723	183,998
Amortization of Excess Investment	(15,199)	(20,543)	(49,794)	(62,144)
Our Share of Gain on Sale or Disposal of Assets and Interest in Other Income in the Consolidated Financial Statements			(14,941)
Income from Unconsolidated Entities	$ 67,305	$ 32,826	$ 175,988	$ 121,854

Indebtedness - Narrative (Detai

Indebtedness - Narrative (Details) $ in Thousands, € in Millions

Mar. 23, 2021USD ($)

Feb. 02, 2021USD ($)

Jan. 27, 2021USD ($)

Oct. 31, 2021

Sep. 30, 2021USD ($)itemproperty

Sep. 30, 2021USD ($)propertyitem

Aug. 18, 2021USD ($)

Mar. 19, 2021USD ($)

Mar. 19, 2021EUR (€)

Jan. 21, 2021USD ($)

Dec. 31, 2020USD ($)

Dec. 15, 2020USD ($)

Debt

Long-term debt

$ 25,584,372

$ 25,584,372

$ 26,723,361

Loss on debt extinguishment

28,593

31,552

Simon Property Group, L.P.

Debt

Long-term debt

25,584,372

25,584,372

26,723,361

Loss on debt extinguishment

28,593

31,552

Secured Debt | Mortgages

Debt

Long-term debt

$ 6,600,000

$ 6,600,000

$ 7,000,000

Debt covenants

Number of non-recourse mortgage notes under which the Company and subsidiaries are borrowers | item

46

Number of properties pledged as collateral | property

49

Number of cross-defaulted and cross-collateralized mortgage pools | item

2

2

Total number of properties pledged as collateral for cross defaulted and cross collateralized mortgages | property

5

5

Unsecured Debt | Simon Property Group, L.P.

Debt

Maximum borrowing capacity

$ 3,500,000

$ 3,500,000

Loss on debt extinguishment

28,600

Unsecured Debt | Senior unsecured notes | Simon Property Group, L.P.

Debt

Long-term debt

18,400,000

18,400,000

Unsecured Debt | Senior Unsecured Notes 2.50% due 2021 | Simon Property Group, L.P.

Debt

Amount of debt redeemed

$ 550,000

Interest rate on debt (as a percent)

2.50%

Loss on debt extinguishment

$ 3,000

Unsecured Debt | Senior Unsecured Notes Maturing February 2028 | Simon Property Group, L.P.

Debt

Debt issued

$ 800,000

Interest rate on debt (as a percent)

1.75%

Unsecured Debt | Senior Unsecured Notes Maturing February 2031 | Simon Property Group, L.P.

Debt

Debt issued

$ 700,000

Interest rate on debt (as a percent)

2.20%

Unsecured Debt | Senior Unsecured Notes Maturing January 2027 | Simon Property Group, L.P.

Debt

Debt issued

$ 550,000

Interest rate on debt (as a percent)

1.375%

Unsecured Debt | Senior Unsecured Notes Maturing January 2032 | Simon Property Group, L.P.

Debt

Debt issued

$ 700,000

Interest rate on debt (as a percent)

2.25%

Unsecured Debt | Senior Unsecured Notes 2.35% Due January 30, 2022 | Simon Property Group, L.P.

Debt

Amount of debt redeemed

$ 550,000

$ 550,000

Interest rate on debt (as a percent)

2.35%

2.35%

Unsecured Debt | Senior Unsecured Notes 2.63% Due June 15, 2022 | Simon Property Group, L.P.

Debt

Amount of debt redeemed

$ 600,000

$ 600,000

Interest rate on debt (as a percent)

2.625%

2.625%

Unsecured Debt | Senior Unsecured Notes 2.75% Due February 1, 2023 | Simon Property Group, L.P.

Debt

Amount of debt redeemed

$ 500,000

$ 500,000

Interest rate on debt (as a percent)

2.75%

2.75%

Unsecured Debt | Senior unsecured notes 1.125% due March 19,2033 | Simon Property Group, L.P.

Debt

Debt issued

$ 893,000

€ 750

Interest rate on debt (as a percent)

1.125%

1.125%

Unsecured Debt | Commercial Paper | Simon Property Group, L.P.

Debt

Credit facility, amount outstanding

$ 500,000

$ 500,000

Maximum borrowing capacity

2,000,000

2,000,000

Unsecured Debt | U.S Dollar Denominated Notes | Simon Property Group, L.P.

Debt

Credit facility, amount outstanding

$ 500,000

$ 500,000

Weighted average interest rate (as a percent)

0.20%

0.20%

Unsecured Debt | Facilities | Simon Property Group, L.P.

Debt

Available borrowing capacity

$ 6,900,000

$ 6,900,000

Maximum amount outstanding during period

2,100,000

Credit facility, weighted average amount outstanding

583,800

Letters of credit outstanding

12,400

12,400

Unsecured Debt | Credit Facility and Term Facility | Simon Property Group, L.P.

Debt

Maximum borrowing capacity

5,000,000

5,000,000

Additional borrowing capacity

1,000,000

$ 1,000,000

Additional extension period | item

2

Debt extension period

6 months

Unsecured Debt | Credit Facility and Term Facility | Maximum | Simon Property Group, L.P.

Debt

Percentage of borrowings in currencies other than the U.S. dollar

95.00%

Unsecured Debt | Term loan | Simon Property Group, L.P.

Debt

Long-term debt

$ 0

Maximum borrowing capacity

$ 2,000,000

Debt repaid

$ 1,250,000

$ 750,000

Unsecured Debt | Credit Facility | Simon Property Group, L.P.

Debt

Credit facility, amount outstanding

125,000

$ 125,000

Maximum borrowing capacity

4,000,000

$ 4,000,000

Unsecured Debt | Credit Facility | Simon Property Group, L.P. | LIBOR

Debt

Interest rate (as a percent)

1.00%

Unsecured Debt | Credit Facility | Simon Property Group, L.P. | Fed Funds Effective Rate

Debt

Interest rate (as a percent)

0.50%

Unsecured Debt | Credit Facility | Minimum | Simon Property Group, L.P. | LIBOR

Debt

Interest rate (as a percent)

0.65%

Facility fee (in percentage)

0.10%

Unsecured Debt | Credit Facility | Minimum | Simon Property Group, L.P. | Base Rate

Debt

Interest rate (as a percent)

0.00%

Unsecured Debt | Credit Facility | Maximum | Simon Property Group, L.P. | LIBOR

Debt

Interest rate (as a percent)

1.40%

Facility fee (in percentage)

0.30%

Unsecured Debt | Credit Facility | Maximum | Simon Property Group, L.P. | Base Rate

Debt

Interest rate (as a percent)

0.40%

Unsecured Debt | Supplemental Facility | Simon Property Group, L.P.

Debt

Maximum borrowing capacity

3,500,000

$ 3,500,000

Optional expanded maximum borrowing capacity

$ 4,500,000

$ 4,500,000

Additional facility fee (as a percent)

0.10%

Unsecured Debt | Supplemental Facility | Simon Property Group, L.P. | LIBOR

Debt

Interest rate (as a percent)

0.775%

Unsecured Debt | Supplemental Facility | Simon Property Group, L.P. | SOFR

Debt

Interest rate (as a percent)

0.725%

Unsecured Debt | Supplemental Facility | Simon Property Group, L.P. | USD | Fed Funds Effective Rate

Debt

Interest rate on debt (as a percent)

0.50%

Unsecured Debt | Supplemental Facility | Simon Property Group, L.P. | USD | SOFR

Debt

Interest rate (as a percent)

1.00%

Unsecured Debt | Supplemental Facility | Minimum | Simon Property Group, L.P.

Debt

Interest rate (as a percent)

0.65%

Facility fee (in percentage)

0.10%

Unsecured Debt | Supplemental Facility | Minimum | Simon Property Group, L.P. | USD | Base Rate

Debt

Interest rate (as a percent)

0.00%

Unsecured Debt | Supplemental Facility | Maximum | Simon Property Group, L.P.

Debt

Interest rate (as a percent)

1.40%

Facility fee (in percentage)

0.30%

Unsecured Debt | Supplemental Facility | Maximum | Simon Property Group, L.P. | USD | Base Rate

Debt

Interest rate (as a percent)

0.40%

Indebtedness - Fair Value (Deta

Indebtedness - Fair Value (Details) $ in Millions	Sep. 30, 2021USD ($)item	Dec. 31, 2020USD ($)item
Fixed rate mortgages and unsecured indebtedness | Book value
Fair Value of Debt
Fair value of consolidated fixed rate mortgages and unsecured indebtedness | $	$ 24,300	$ 23,400
Fixed rate mortgages and unsecured indebtedness | Fair value
Fair Value of Debt
Fair value of consolidated fixed rate mortgages and unsecured indebtedness | $	$ 25,791	$ 25,327
Discount Rate | Weighted average | Fixed rate mortgages
Fair Value of Debt
Debt percentage- measurement input | item	0.0286	0.0241
Discount Rate | Weighted average | Unsecured Debt
Fair Value of Debt
Debt percentage- measurement input | item	0.0324	0.0263

Equity - Shares or Units Activi

Equity - Shares or Units Activity (Details) $ / shares in Units, $ in Thousands	Nov. 01, 2021$ / shares	Sep. 30, 2021$ / shares	Jul. 23, 2021$ / shares	Feb. 11, 2019USD ($)	Jun. 30, 2021shares	Mar. 31, 2021shares	Sep. 30, 2020$ / sharesshares	Mar. 31, 2020shares	Sep. 30, 2021USD ($)item$ / sharesshares	Sep. 30, 2020$ / sharesshares
Equity
Redemption of units | shares					170	316	586	116,072
Common stock authorized for repurchase | $				$ 2,000,000
Period common stock is authorized to repurchase				2 years
Shares repurchased (in shares) | shares								1,245,654		1,245,654
Average share price repurchased (in dollars per share) | $ / shares										$ 122.50
Common stock dividends paid (in dollars per share) | $ / shares		$ 1.50	$ 1.40				$ 1.30		$ 5.50	3.40
Dividends declared per common share (in dollars per share) | $ / shares	$ 1.65
Simon Property Group, L.P.
Equity
Redemption of units | shares					170	316	586	116,072
Distributions paid per unit (in dollars per unit) | $ / shares		$ 1.50	$ 1.40				$ 1.30		$ 5.50	$ 3.40
Distribution declared per unit (in dollars per share) | $ / shares	$ 1.65
Simon Property Group, L.P. | Limited Partners
Equity
Units issued | shares									58,571
Number of limited partners who received common stock | item									7
Redemption of units | shares									486
Number of limited partners whose common stock redeemed | item									2
Value of units redeemed | $									$ 60

Equity - Temporary Equity (Deta

Equity - Temporary Equity (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021USD ($)itemshares	Dec. 31, 2020USD ($)itemshares
Redeemable preferred stock
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests | $	$ 553,025	$ 185,892
Simon Property Group, L.P.
Redeemable preferred stock
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests | $	$ 553,025	$ 185,892
7.5% Cumulative Redeemable Preferred Units
Redeemable preferred stock
Number of series of units classified into temporary equity | item	1	1
Noncontrolling interests redeemable at amounts in excess of fair value | item	0	0
Preferred stock stated dividend rate (as a percent)	7.50%	7.50%
Temporary equity, shares authorized | shares	260,000	260,000
Temporary equity, shares issued | shares	255,373	255,373
Temporary equity, shares outstanding | shares	255,373	255,373
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests | $	$ 25,537	$ 25,537
7.5% Cumulative Redeemable Preferred Units | Simon Property Group, L.P.
Redeemable preferred stock
Number of series of units classified into temporary equity | item	1	1
Preferred stock stated dividend rate (as a percent)	7.50%	7.50%
Temporary equity, shares authorized | shares	260,000	260,000
Temporary equity, shares issued | shares	255,373	255,373
Temporary equity, shares outstanding | shares	255,373	255,373
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests | $	$ 25,537	$ 25,537
Other noncontrolling redeemable interest
Redeemable preferred stock
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests | $	527,488	160,355
Other noncontrolling redeemable interest | Simon Property Group, L.P.
Redeemable preferred stock
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests | $	$ 527,488	$ 160,355

Equity - Stock Based Compensati

Equity - Stock Based Compensation (Details) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2021USD ($)$ / sharesshares	Sep. 30, 2021USD ($)$ / sharesshares	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2018USD ($)item
Restricted stock
Stock-based incentive plan awards
Compensation expense, net of capitalization		$ 12.4	$ 8.2
Restricted stock | Non-employee Director
Stock-based incentive plan awards
Vesting service period		1 year
Awards granted (in units) | shares		15,859
Weighted average fair value of shares granted during the period (in dollars per share) | $ / shares		$ 122.64
Restricted Stock and Restricted Stock Units | Employees
Stock-based incentive plan awards
Vesting service period		3 years
Awards granted (in units) | shares		25,715
Weighted average fair value of shares granted during the period (in dollars per share) | $ / shares		$ 113.77
2019 Stock Incentive Plan | Time Based Restricted Stock Units
Stock-based incentive plan awards
Vesting service period	3 years			3 years
Awards granted (in units) | shares	37,976			312,263
Grant Date Fair Value	$ 4.3			$ 26.3
Weighted average fair value of shares granted during the period (in dollars per share) | $ / shares	$ 112.92			$ 84.37
LTIP programs
Stock-based incentive plan awards
Percent of distributions of Operating Partnership that participants are entitled to receive during performance period		10.00%
Compensation expense, net of capitalization		$ 7.5	$ 3.2
2018 LTIP program | LTIP Units
Stock-based incentive plan awards
Number of tranches | item					2
Grant Date Fair Value					$ 12.1
2018 LTIP program | LTIP Units | Maximum
Stock-based incentive plan awards
Grant Date Fair Value					$ 18.2
2018 LTIP program | LTIP Units | Tranche A
Stock-based incentive plan awards
Vesting rights each year beginning 2021 (as a percent)					50.00%
Performance period					2 years
Awards granted (in units) | shares		38,148
Grant Date Fair Value		$ 6.1			$ 6.1
Grant Date Target Value		6.1
2018 LTIP program | LTIP Units | Tranche B
Stock-based incentive plan awards
Performance period					3 years
Grant Date Fair Value		6.1			$ 6.1
Grant Date Target Value		$ 6.1
2019 LTIP program | LTIP Units
Stock-based incentive plan awards
Performance period		3 years
Grant Date Fair Value		$ 9.5
Grant Date Target Value		14.7
2019 LTIP program | LTIP Units | Maximum
Stock-based incentive plan awards
Grant Date Target Value		$ 22.1
2021 LTIP program | LTIP Units
Stock-based incentive plan awards
Performance period		3 years
Grant Date Fair Value		$ 5.7
Grant Date Target Value		12.2
2021 LTIP program | LTIP Units | Maximum
Stock-based incentive plan awards
Grant Date Fair Value		$ 18.4

Lease Income (Details)

Lease Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Lessor, Lease, Description [Line Items]
Fixed-lease income	$ 921,521	$ 929,335	$ 2,783,459	$ 2,939,257
Variable lease income	286,402	64,496	728,347	330,315
Total lease income	1,207,923	$ 993,831	3,511,806	$ 3,269,572
Tenant receivables and accrued revenue
Lessor, Lease, Description [Line Items]
Straight-line receivables	$ 573,900		$ 573,900		$ 597,600

Commitments and Contingencies -

Commitments and Contingencies - Lease Commitments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)property	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)property	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Lease Commitments
Properties subject to ground leases | property	23		23
Lease Cost
Fixed lease cost	$ 8,118	$ 8,015	$ 24,367	$ 23,161
Variable lease cost	3,984	3,130	11,821	10,217
Sublease income	(187)	(187)	(560)	(560)
Total operating lease cost	$ 11,915	$ 10,958	35,628	32,818
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases			$ 36,098	$ 33,301
Weighted-average remaining lease term - operating leases	33 years 9 months 18 days	34 years 7 months 6 days	33 years 9 months 18 days	34 years 7 months 6 days
Weighted-average discount rate - operating leases	4.87%	4.86%	4.87%	4.86%
Operating Lease Liabilities
2021	$ 32,131		$ 32,131
2022	32,838		32,838
2023	32,979		32,979
2024	33,114		33,114
2025	33,124		33,124
Thereafter	888,217		888,217
Future minimum gross lease payments	1,052,403		1,052,403
Impact of discounting	(543,332)		(543,332)
Operating lease liabilities	$ 509,071		$ 509,071		$ 515,492

Commitments and Contingencies_2

Commitments and Contingencies - Guarantees of Indebtedness (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Joint Venture Mortgage and Indebtedness
Guarantees of Joint Venture Indebtedness:
Loan guarantee	$ 209.2	$ 219.2

Commitments and Contingencies_3

Commitments and Contingencies - Concentration of Credit Risk (Details)	9 Months Ended
	Sep. 30, 2021
Consolidated revenues | Concentration of credit risk | Maximum
Concentration of Credit Risk
Percentage of consolidated revenues from a single customer or tenant	5.00%

Commitments and Contingencies_4

Commitments and Contingencies - Hurricane Impacts (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)property	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)
Hurricane Impact
Insurance proceeds for property restoration			$ 7,030	$ 8,746
TEXAS
Hurricane Impact
Number of properties significantly damaged | property		1
LOUISIANA
Hurricane Impact
Number of properties significantly damaged | property		1
Loss from Catastrophes | TEXAS
Hurricane Impact
Asset write-offs		$ 9,600
Insurance proceeds for property restoration		14,000
Gain related to property insurance recovery	$ 3,500
Loss from Catastrophes | LOUISIANA
Hurricane Impact
Asset write-offs		11,100
Insurance proceeds for property restoration		$ 27,500
Gain related to property insurance recovery	$ 17,500