Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Assets:
Operating real estate, net of accumulated depreciation of $1,618,626 and $1,549,380, respectively	$ 6,730,008	$ 6,708,373
Investments and advances in real estate joint ventures	1,436,361	1,382,749
Real estate under development	321,574	335,007
Other real estate investments	400,177	418,564
Mortgages and other financing receivables	108,605	108,493
Cash and cash equivalents	144,067	125,154
Marketable securities	44,898	223,991
Accounts and notes receivable	134,986	130,536
Other assets	384,004	401,008
Total assets	9,704,680	9,833,875
Liabilities:
Notes payable	2,899,069	2,982,421
Mortgages payable	1,041,082	1,046,313
Construction loans payable	40,218	30,253
Dividends payable	88,093	89,037
Other liabilities	429,514	429,505
Total liabilities	4,497,976	4,577,529
Redeemable noncontrolling interests	95,059	95,060
Stockholders' Equity:
Common Stock, $.01 par value, authorized 750,000,000 shares Issued and outstanding 406,958,596 and 406,423,514 shares, respectively	4,070	4,064
Paid-In Capital	5,484,402	5,469,841
Cumulative distributions in excess of net income	(624,129)	(515,164)
[TotalStockholdersEquityExcludingAccumulatedOtherComprehensiveIncome]	4,865,297	4,959,695
Accumulated Other Comprehensive Income	27,989	(23,853)
Total Stockholders' Equity	4,893,286	4,935,842
Noncontrolling Interests	218,359	225,444
Total Equity	5,111,645	5,161,286
Total Liabilities and Equity	9,704,680	9,833,875
Preferred Stock [Member]
Stockholders' Equity:
Preferred Stock, Value	0	0
Series F Preferred Stock [Member]
Stockholders' Equity:
Preferred Stock, Value	700	700
Series G Preferred Stock [Member]
Stockholders' Equity:
Preferred Stock, Value	184	184
Series H Preferred Stock [Member]
Stockholders' Equity:
Preferred Stock, Value	$ 70	$ 70