Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Entity Registrant Name	SIMON PROPERTY GROUP INC /DE/
Entity Central Index Key	0001063761
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 49,945
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Common stock
Entity Common Stock, Shares Outstanding		320,328,774
Class B common stock
Entity Common Stock, Shares Outstanding		8,000