Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended		1 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended					0 Months Ended			9 Months Ended	0 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jul. 31, 2011 LTIP Retention Award to Chairman and CEO	Sep. 30, 2013 LTIP programs	Mar. 16, 2010 LTIP programs item	Mar. 31, 2011 One-year 2010 LTIP Program item	Sep. 30, 2013 One-year 2010 LTIP Program	Mar. 31, 2012 Two-year 2010 LTIP Program item	Sep. 30, 2013 Two-year 2010 LTIP Program	Mar. 31, 2013 Three-year 2010 LTIP Program item	Sep. 30, 2013 Three-year 2010 LTIP Program	Sep. 30, 2013 2011-2013 LTIP Program	Sep. 30, 2013 2012-2014 LTIP Program	Sep. 30, 2013 2013-2015 LTIP program	Sep. 30, 2013 Simon Property partner	Jun. 06, 2013 Simon Property Restricted stock issued under 1998 Stock Incentive Plan Employees	Apr. 02, 2013 Simon Property Restricted stock issued under 1998 Stock Incentive Plan Employees	Feb. 25, 2013 Simon Property Restricted stock issued under 1998 Stock Incentive Plan Employees	Sep. 30, 2013 Simon Property Restricted stock issued under 1998 Stock Incentive Plan Employees	May 14, 2013 Simon Property Restricted stock issued under 1998 Stock Incentive Plan Non-employee Directors	Sep. 30, 2013 Simon Property Restricted stock issued under 1998 Stock Incentive Plan Non-employee Directors
Equity
Number of limited partners who received common stock															10
The number of common stock shares issued in exchange for partnership units															321,354
Compensation expense, net of capitalization	$ 40.0	$ 35.1
Number of programs approved					3
Post performance period service based vesting period							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	3 years
Restricted stock awards granted (in shares)			1,000,000			133,673													107,528	3,487
Vesting period (in installments)						2		2		2
Units earned under LTIP program (in shares)								337,006		489,654
Vesting rights (as a percent)													50.00%	50.00%
Aggregate grant date fair value			$ 120.3				$ 7.2		$ 14.8		$ 23.0	$ 35.0	$ 35.0	$ 33.5
Weighted average fair value of shares granted during the year (in dollars per share)																$ 166.56	$ 159.32	$ 157.37		$ 179.23
Vesting period																			3 years		1 year
Vesting rights (as a percent)			33.00%
Service period			8 years