Note 8 - Investment and Advances in Real Estate Joint Ventures (Detail) - Investment and Advances to Real Estate Joint Ventures - Balance Sheet (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets:
Assets	$ 12,192.0	$ 12,675.4
Liabilities and Partners’/Members’ Capital:
Noncontrolling interests	36.1	36.1
Partners’/Members’ capital	4,191.9	4,286.3
	12,192.0	12,675.4
Real Estate [Member]
Assets:
Assets	11,479.7	11,850.4
Other Assets [Member]
Assets:
Assets	712.3	825.0
Notes Payable [Member]
Liabilities and Partners’/Members’ Capital:
Liabilities	150.5	189.3
Mortgage Payable [Member]
Liabilities and Partners’/Members’ Capital:
Liabilities	7,440.8	7,683.5
Construction Loans [Member]
Liabilities and Partners’/Members’ Capital:
Liabilities	109.4	89.9
Other Liabilities [Member]
Liabilities and Partners’/Members’ Capital:
Liabilities	$ 263.3	$ 390.3