Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Fixed interest rate related to the interest rate derivative.

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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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Fixed interest rate that will be received or paid upon exercise of the interest rate swaption contract.

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- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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- Definition

Number of credit risk derivative instruments held.

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Number of interest rate derivative instruments held by the entity at the reporting date.

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Summary of Significant Accounting Policies - Derivative Financial Instruments (Details) € in Millions, $ in Millions	Mar. 31, 2018 USD ($) DerivativeInstrument item	Mar. 31, 2018 EUR (€) DerivativeInstrument item	Dec. 31, 2017 USD ($) DerivativeInstrument	Dec. 31, 2017 EUR (€) DerivativeInstrument
Derivative Financial Instruments
Number of credit-risk-related hedging or derivative activities \| item	0	0
Interest rate swap \| Designated as Hedging Instrument
Derivative Financial Instruments
Number of Instruments \| DerivativeInstrument	0	0	0	0
Interest rate swap \| Deferred costs and other assets \| Designated as Hedging Instrument
Derivative Financial Instruments
Interest rate derivative asset, fair value	$ 0.1
USD-Euro currency forward contract \| May 15, 2018 \| Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount \| €		€ 65.0
Forward contract net, fair value	0.9
USD-Euro currency forward contract \| May 15, 2019 \| Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount \| €		50.0		€ 50.0
Forward contract net, fair value	(3.9)		$ (2.4)
USD-Euro currency forward contract \| May 15, 2019 \| Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount \| €		50.0		50.0
Forward contract net, fair value	(6.4)		(4.9)
USD-Euro currency forward contract \| May 15, 2020 \| Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount \| €		50.0		50.0
Forward contract net, fair value	(7.0)		(5.2)
USD-Euro currency forward contract \| May 14, 2021 \| Designated as Hedging Instrument
Derivative Financial Instruments
Notional Amount \| €		€ 50.0		€ 50.0
Forward contract net, fair value	(7.4)		(5.5)
US denominated cross currency swap
Derivative Financial Instruments
Notional Amount	$ 150.0
Swapping interest rate	4.38%	4.38%
Euro denominated cross currency swap
Derivative Financial Instruments
Notional Amount \| €		€ 121.6
Fixed exchange rate	1.37%	1.37%
Simon Property Group, L.P.
Derivative Financial Instruments
Gross accumulated other comprehensive income related to derivative activities	$ 5.3		$ 9.3