REAL ESTATE (Joint Venture Consolidations) (Details) (USD $)	12 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2013 615 Unit Apartment Building [Member] Unit	Dec. 31, 2013 615 Unit Apartment Building [Member]	Mar. 31, 2013 Retail Properties, Western United States [Member] building	Dec. 31, 2013 Retail Properties, Western United States [Member]	Dec. 31, 2013 Ritz-Carlton [Member]	Mar. 31, 2012 KW Property Fund, II, LP [Member]	Dec. 31, 2012 KW Property Fund, II, LP [Member] building	Nov. 30, 2012 KW Property Fund, II, LP [Member]
Real Estate Properties [Line Items]
Number of units				615
Equity method investment, ownership percentage				15.00%
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions				94.00%
Equity Method Investments	$ 724,200,000	$ 518,900,000		$ 0
Acquisition of noncontrolling interest, cash paid	40.6	56.2		15,700,000
Number of buildings acquired						3				2
Notes receivable, eliminated in consolidation											39,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash	7,100,000.0				1,300,000.0		1,400,000.0	4,400,000.0		0.6
Real Estate, net	245,600,000.0				120,100,000.0		20,400,000.0	105,100,000.0		11.1
Investment in joint ventures										75.4
Accounts Receivable and other assets	18,900,000.0				2,300,000.0		9,200,000.0	7,400,000.0
Other assets										2.7
Accounts payable and accrued expenses	11,900,000.0				3,200,000.0		700,000.0	8,000,000.0		1.6
Notes payable										5.8
Mortgage loans	141,600,000.0				93,500,000.0		20,100,000.0	28,000,000.0		8.9
Noncontrolling interests	20,300,000.0				1,800,000.0		500,000.0	18,000,000.0		7.6
Acquisition related gains	$ 56,600,000	$ 25,500,000	$ 6,300,000		$ 9,500,000		$ 2,000,000	$ 45,100,000	$ 22.8