Variable Interest Entities (Narrative) (Details) $ in Millions	1 Months Ended	9 Months Ended	12 Months Ended
	May. 31, 2015 USD ($)	Sep. 30, 2015 property joint_venture	Dec. 31, 2014 property joint_venture
Consolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Number of VIE real estate joint ventures		1	1
Number of neighborhood/community shopping centers | property		15	15
Joint venture amendment, additional contribution | $	$ 43
Unconsolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Number of VIE real estate joint ventures		1	1