Document and Entity Information (USD $)	3 Months Ended
	Mar. 31, 2015
Entity Registrant Name	SIMON PROPERTY GROUP INC /DE/
Entity Central Index Key	0001063761
Document Type	10-Q
Document Period End Date	Mar. 31, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Common stock
Entity Common Stock, Shares Outstanding	311,260,775
Entity Listing, Par Value Per Share	0.0001
Class B common stock
Entity Common Stock, Shares Outstanding	8,000
Entity Listing, Par Value Per Share	0.0001