Equity - Permanent Equity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Series J Preferred stock
Equity
Preferred stock stated dividend rate percentage	8.375%	8.375%
Redemption price of preferred stock (in dollars per share)	$ 50.00
Premium received on preferred stock issued	$ 7.5
Preferred stock unamortized premium	$ 2.6	$ 2.9
Series J 8 3/8% cumulative redeemable preferred stock, shares authorized	1,000,000	1,000,000
Simon Property Group, L.P.
Equity
J 8 3/8% cumulative redeemable preferred stock, units outstanding	796,948	796,948
Simon Property Group, L.P. | Series J Preferred stock
Equity
Preferred stock stated dividend rate percentage	8.375%	8.375%
Redemption price of preferred stock (in dollars per share)	$ 50.00
Premium received on preferred stock issued	$ 7.5
Preferred stock unamortized premium	$ 2.6	$ 2.9
Series J 8 3/8% cumulative redeemable preferred stock, shares authorized	1,000,000
J 8 3/8% cumulative redeemable preferred stock, units issued	796,948
J 8 3/8% cumulative redeemable preferred stock, units outstanding	796,948