Investments in Unconsolidated Entities (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loan To SPG-FCM
Interest income from SPG-FCM and Mills loans, net of inter-entity eliminations	$ 2.0	$ 9.8	$ 9.9

Interest income earned on notes receivable from related parties during the reporting period, net of inter-entity eliminations.

No definition available.

Name:	spg_RelatedPartyInterestIncomeNet
Namespace Prefix:	spg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration