Unconsolidated Entities - Earnings on Investment in Co-Investment Ventures (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011 Property	Sep. 30, 2012	Sep. 30, 2011 Property
Schedule of Equity Method Investments [Line Items]
Gain (loss) on Disposal of properties	$ (1.3)		$ (2.1)	$ 33.6
Extinguishment of debt			5.0
Number of properties disposed		13		13
Prologis [Member]
Schedule of Equity Method Investments [Line Items]
Gain (loss) on Disposal of properties		13.9		$ 13.9