Segment Disclosures (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Reconciliation from reported net income to NOI and Adjusted NOI
Net income	$ 199,043	$ 175,471	$ 600,582	$ 483,707
Interest income	(10,278)	(577)	(12,313)	(99,199)
Investment management fee income	(460)	(494)	(1,423)	(1,605)
Interest expense	103,513	103,459	309,875	315,695
Depreciation and amortization	88,686	86,672	259,039	265,742
General and administrative	19,443	19,647	54,356	76,471
Impairments	7,878	15,400	7,878	15,400
Other income (expense), net	(770)	772	(2,233)	(17,056)
Income taxes	(598)	5	(1,131)	289
Equity income from unconsolidated joint ventures	(13,396)	(17,050)	(42,803)	(32,798)
Total discontinued operations, net of income taxes	(984)	(809)	(2,440)	(3,796)
NOI	392,077	382,496	1,169,387	1,002,850
Straight-line rents	(11,821)	(14,024)	(33,608)	(46,936)
DFL accretion	(23,433)	(23,571)	(71,072)	(48,508)
Amortization of above and below market lease intangibles, net	(533)	(1,178)	(1,855)	(3,271)
Lease termination fees	(175)	(239)	(574)	(3,417)
NOI adjustments related to discontinued operations	335	516	1,437	1,585
Adjusted NOI	$ 356,450	$ 344,000	$ 1,063,715	$ 902,303