Equity - Shares or Units Activity (Details) $ / shares in Units, $ in Millions			3 Months Ended
	Feb. 11, 2019 USD ($)	Feb. 13, 2017 USD ($)	Mar. 31, 2020 USD ($) item $ / shares shares	Mar. 31, 2019 $ / shares shares
Equity
Redemption of units			116,072	774
Exchange of limited partner units, (in shares)			132,946	24,000
Common stock authorized for repurchase | $	$ 2,000.0	$ 2,000.0
Period common stock is authorized to repurchase	2 years
Stock repurchase program, extension period		2 years
Shares repurchased (in shares)			1,245,654	46,377
Average share price repurchased (in dollars per share) | $ / shares			$ 122.50
Common stock dividends paid (in dollars per share) | $ / shares			$ 2.10	$ 2.05
Limited Partners
Equity
Exchange of limited partner units, (in shares)			132,946
Number of limited partners who received common stock | item			4
2017 Share Repurchase Program
Equity
Shares repurchased (in shares)				46,377
Average share price repurchased (in dollars per share) | $ / shares				$ 164.49
Simon Property Group, L.P.
Equity
Redemption of units			116,072	774
Distributions paid per unit (in dollars per share) | $ / shares			$ 2.10	$ 2.05
Simon Property Group, L.P. | Limited Partners
Equity
Redemption of units			116,072
Number of limited partners who received common stock | item			2
Value of units redeemed | $			$ 16.1