Equity (Details) (USD $)	1 Months Ended		1 Months Ended			6 Months Ended		12 Months Ended	3 Months Ended	6 Months Ended
	Jul. 31, 2012	Jul. 20, 2012	Jun. 30, 2012 Non-employee Directors	Mar. 31, 2012 Restricted stock issued under 1998 Stock Incentive Plan	Jul. 31, 2011 LTIP Retention Award to Chairman and CEO	Jun. 30, 2012 2010 LTIP Program	Jun. 30, 2012 One-year 2010 LTIP Program	Dec. 31, 2011 One-year 2010 LTIP Program installment	Mar. 31, 2012 Two-year 2011 LTIP Program installment	Jun. 30, 2012 Two-year 2011 LTIP Program	Jun. 30, 2012 Three-year 2012 LTIP Program	Jun. 30, 2012 2011-2013 LTIP Program	Jun. 30, 2012 2012-2014 LTIP Program	Jun. 30, 2012 Simon Property partner	Mar. 14, 2012 Simon Property
Equity
Number of units issued in exchange for equal number of shares of common stock														221,109
Number of limited partners who received common stock														16
Shares of common stock issued in a public offering															9,137,500
Shares of common stock issued in a public offering, price (in dollars per share)															$ 137.00
Proceeds from common stock issued in a public offering														$ 1,200,000,000
Issuance of units related to Simon Property public offerings															9,137,000
Operating Partnership redeemed units	2,000,000
Operating Partnership, redemption price per unit		$ 124.00
Award of restricted stock to employees (in shares)			4,094	12,034	1,000,000			133,673
Award of restricted stock to employees, fair market value (in dollars per share)			$ 143.51	$ 138.41
Award of restricted stock to employees, fair market value, March 14th (in dollars per share)				$ 141.12
Vesting period			1 year	3 years	8 years	2 years				2 years	2 years	2 years	2 years
Percent of distributions that participants are entitled to receive during performance period						10.00%
Performance period							1 year			2 years	3 years	3 years	3 years
Vesting rights						50.00%
Vesting rights					33.00%
Aggregate grant date fair value					$ 120,300,000		$ 7,200,000			$ 14,800,000	$ 23,000,000	$ 35,000,000	$ 35,000,000
Units earned									337,006
Vesting period (in installments)								2	2