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Number of pools of cross-defaulted and cross-collateralized mortgages encumbering the entity's properties.

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Number of mortgage loans within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Face (par) amount of the original debt instrument that was repurchased.

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Weighted average interest rate of debt outstanding.

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Average amount borrowed under the credit facility during the period.

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The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

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Maximum amount borrowed under the credit facility at any time during the period.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Debt (Details) $ in Thousands, € in Millions			9 Months Ended
Debt (Details) $ in Thousands, € in Millions	Jul. 10, 2020 USD ($)	Mar. 16, 2020 USD ($) item	Sep. 30, 2020 USD ($) item property	Aug. 06, 2020 EUR (€)	Jul. 22, 2020 USD ($)	Jul. 09, 2020 USD ($)	Mar. 15, 2020 USD ($)	Dec. 31, 2019 USD ($)	Aug. 17, 2015 USD ($)
Debt
Unsecured debt			$ 25,139,682					$ 24,163,230
Simon Property Group, L.P.
Debt
Unsecured debt			25,139,682					24,163,230
Secured Debt \| Mortgages
Debt
Unsecured debt			$ 6,900,000					$ 6,900,000
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			50
Number of cross-defaulted and cross-collateralized mortgage pools \| item			2
Total number of properties pledged as collateral for cross defaulted and cross collateralized mortgages \| property			5
Unsecured Debt \| Senior unsecured notes \| Simon Property Group, L.P.
Debt
Unsecured debt			$ 17,000,000
Unsecured Debt \| Senior Unsecured Notes Maturing September 2025 \| Simon Property Group, L.P.
Debt
Unsecured debt						$ 500,000			$ 600,000
Interest rate on debt (as a percent)						3.50%			3.50%
Unsecured Debt \| Senior Unsecured Notes Maturing June 2030 \| Simon Property Group, L.P.
Debt
Unsecured debt						$ 750,000
Interest rate on debt (as a percent)						2.65%
Unsecured Debt \| Senior Unsecured Notes Maturing June 2050 \| Simon Property Group, L.P.
Debt
Unsecured debt						$ 750,000
Interest rate on debt (as a percent)						3.80%
Unsecured Debt \| Senior Unsecured Notes Maturing September 2020 \| Simon Property Group, L.P.
Debt
Amount of debt redeemed					$ 500,000
Interest rate on debt (as a percent)					2.50%
Unsecured Debt \| Senior Unsecured Notes Maturing October 2020 \| Simon Property Group, L.P.
Debt
Amount of debt redeemed \| €				€ 375
Interest rate on debt (as a percent)				2.375%
Unsecured Debt \| Commercial Paper \| Simon Property Group, L.P.
Debt
Credit facility, amount outstanding			622,700
Maximum borrowing capacity			2,000,000
Unsecured Debt \| U.S Dollar Denominated Notes \| Simon Property Group, L.P.
Debt
Credit facility, amount outstanding			$ 622,700
Weighted average interest rate (as a percent)			0.19%
Unsecured Debt \| Facilities \| Simon Property Group, L.P.
Debt
Available borrowing capacity			$ 8,200,000
Maximum amount outstanding during period			3,900,000
Credit facility, weighted average amount outstanding			2,000,000
Letters of credit outstanding			$ 12,300
Unsecured Debt \| Credit Facility and Term Facility \| Simon Property Group, L.P.
Debt
Maximum borrowing capacity		$ 7,000,000
Additional borrowing capacity		$ 1,000,000
Additional extension period \| item		2
Debt extension period		6 months
Debt single draw period		9 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
Maximum borrowing capacity		$ 2,000,000
Ticking fee (in percentage)			0.10%
Ticketing fee accruing after closing term facility			45 days
Unsecured Debt \| Term loan \| Simon Property Group, L.P. \| LIBOR
Debt
Interest rate (as a percent)			1.00%
Unsecured Debt \| Term loan \| Simon Property Group, L.P. \| Fed Funds Effective Rate
Debt
Interest rate (as a percent)			0.50%
Unsecured Debt \| Term loan \| Minimum \| Simon Property Group, L.P. \| LIBOR
Debt
Interest rate (as a percent)			0.725%
Unsecured Debt \| Term loan \| Minimum \| Simon Property Group, L.P. \| Base Rate
Debt
Interest rate (as a percent)			0.00%
Unsecured Debt \| Term loan \| Maximum \| Simon Property Group, L.P. \| LIBOR
Debt
Interest rate (as a percent)			1.60%
Unsecured Debt \| Term loan \| Maximum \| Simon Property Group, L.P. \| Base Rate
Debt
Interest rate (as a percent)			0.60%
Unsecured Debt \| Credit Facility \| Simon Property Group, L.P.
Debt
Credit facility, amount outstanding			$ 625,000
Maximum borrowing capacity		$ 3,500,000	$ 4,000,000				$ 4,000,000
Credit facility, amount repaid	$ 1,750,000
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
Credit facility, amount repaid	$ 750,000
Optional expanded maximum borrowing capacity			$ 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%