Equity - Shares or Units Activity (Details) $ / shares in Units, $ in Millions			3 Months Ended
	Feb. 11, 2019 USD ($)	Feb. 13, 2017 USD ($)	Mar. 31, 2019 USD ($) item $ / shares shares	Mar. 31, 2018 $ / shares shares
Equity
Exchange of limited partner units, (in shares)			24,000	6,000
Stock repurchase program, extension period	2 years	2 years
Common stock authorized for repurchase | $	$ 2,000.0	$ 2,000.0
Shares repurchased (in shares)			46,377	1,473,588
Average share price repurchased (in dollars per share) | $ / shares			$ 164.49	$ 154.66
Common stock dividends paid (in dollars per share) | $ / shares			2.05	$ 1.95
Dividends declared per common share (in dollars per share) | $ / shares			$ 2.05
Limited Partners
Equity
Exchange of limited partner units, (in shares)			24,000
Simon Property Group, L.P.
Equity
Redemption of units			774	40,503
Distributions paid per unit (in dollars per share) | $ / shares			$ 2.05	$ 1.95
Simon Property Group, L.P. | Limited Partners
Equity
Redemption of units			774
Number of limited partners who received common stock | item			3
Value of units redeemed | $			$ 0.1