Organization and Principles of Consolidation (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($) retail_shopping_center	Jun. 30, 2018	Jun. 30, 2019 USD ($) retail_shopping_center	Jun. 30, 2018
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Document Period End Date			Jun. 30, 2019
Unsecured public and private notes | $	$ 500		$ 500
Operating Partnership [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership percentage of outstanding common partnership units			99.80%
Wholly Owned Properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of Real Estate Properties	304		304
Ownership percentage of outstanding common partnership units	100.00%	100.00%	100.00%	100.00%
Unconsolidated Properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of Real Estate Properties	117		117