Unconsolidated Investments (Cash Distributions by Investment Type and Location) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	$ 50.0
Distributions from unconsolidated investments	50.3
Multifamily [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	6.5
Distributions from unconsolidated investments	1.5
Commercial [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	39.9
Distributions from unconsolidated investments	44.5
Residential [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	3.6
Distributions from unconsolidated investments	4.3
Western United States [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	11.4
Distributions from unconsolidated investments	9.2
Western United States [Member] | Multifamily [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	4.8
Distributions from unconsolidated investments	1.5
Western United States [Member] | Commercial [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	3.0
Distributions from unconsolidated investments	4.4
Western United States [Member] | Residential [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	3.6
Distributions from unconsolidated investments	3.3
Japan [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	1.7
Distributions from unconsolidated investments	0
Japan [Member] | Multifamily [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	1.7
Distributions from unconsolidated investments	0
Japan [Member] | Commercial [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	0
Japan [Member] | Residential [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	0
United Kingdom [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	5.3
Distributions from unconsolidated investments	9.8
United Kingdom [Member] | Multifamily [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	0
United Kingdom [Member] | Commercial [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	5.3
Distributions from unconsolidated investments	9.8
United Kingdom [Member] | Residential [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	0
Ireland [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	31.6
Distributions from unconsolidated investments	30.3
Ireland [Member] | Multifamily [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	0
Ireland [Member] | Commercial [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	31.6
Distributions from unconsolidated investments	30.3
Ireland [Member] | Residential [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	0
Other [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	1.0
Other [Member] | Multifamily [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	0
Other [Member] | Commercial [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	0
Other [Member] | Residential [Member]
Schedule of Equity Method Investments [Line Items]
Operating distributions from unconsolidated investments	0
Distributions from unconsolidated investments	$ 1.0