Background Schedule of rentable square feet (Details)	Jun. 30, 2016 a ft²
North America
Real Estate Properties [Line Items]
Area of Real Estate Property	18,819,315
Total Square Footage of Asset Base	24,400,303
North America | Future Value-creation Projects [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property, Future Development	5,580,988
North America | Value-creation Pipeline [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property	8,625,669
Asia
Real Estate Properties [Line Items]
Total Square Footage of Asset Base	1,200,683
Asia | Land held for future development
Real Estate Properties [Line Items]
Area of Real Estate Property, Future Development | a	191
Operating properties [Member] | North America
Real Estate Properties [Line Items]
Area of Real Estate Property	15,774,634
Operating properties [Member] | Asia
Real Estate Properties [Line Items]
Area of Real Estate Property	1,200,683
Development and Redevelopment Projects[Member] | North America
Real Estate Properties [Line Items]
Area of Real Estate Property	3,044,681
Projects to be delivered by 4Q16 [Member] | North America
Real Estate Properties [Line Items]
Area of Real Estate Property	1,056,733
Projects to be delivered in 2017 and 2018 [Member] | North America
Real Estate Properties [Line Items]
Area of Real Estate Property	1,987,948