Summary of Significant Accounting Policies (Details 6) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Loans Held for Investment
Interest income on loans held for investment	$ 6.8	$ 24.3

Represents the interest income on the mortgage loan receivable.

No definition available.

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