The number of properties owned via an International joint venture.

No definition available.

Name:	spg_InternationalJointVentureProperties
Namespace Prefix:	spg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of properties owned via a joint venture in which daily operations are managed by groups other than the entity.

+ References

No definition available.

+ Details

Name:	spg_JointVenturePropertiesManagedByOthers
Namespace Prefix:	spg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of properties owned via a joint venture in which daily operations are managed by the entity.

+ References

No definition available.

+ Details

Name:	spg_JointVenturePropertiesManagedNumber
Namespace Prefix:	spg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of properties owned via a joint venture and accounted for using the equity method of accounting.

+ References

No definition available.

+ Details

Name:	spg_JointVenturePropertiesNumber
Namespace Prefix:	spg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

Name:	spg_OwnershipInterestItemListAbstract
Namespace Prefix:	spg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_OwnershipAxis=spg_SimonPropertyGroupLimitedPartnershipMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstatePropertiesAxis=us-gaap_WhollyOwnedPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstatePropertiesAxis=us-gaap_PartiallyOwnedPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Basis of Presentation (Details) - property	9 Months Ended		12 Months Ended
Basis of Presentation (Details) - property	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Real Estate Properties
Total number of joint venture properties	82
Number of joint venture properties managed by the entity	57
Number of International joint venture properties	21
Number of joint venture properties managed by others	25
Simon Property Group, L.P.
Ownership interest:
Ownership interest in the Operating Partnership (as a percent)	86.80%		86.80%
Simon Property Group, L.P. \| Weighted average
Ownership interest:
Ownership interest in the Operating Partnership (as a percent)	86.80%	86.90%
Wholly owned properties
Real Estate Properties
Number of properties	133
Partially owned properties
Real Estate Properties
Number of properties	18