Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net income (loss)	$ 888,549	$ 512,300	$ 138,280
Adjustments to reconcile net income to net cash provided from (used in) operating activities:
Depreciation and amortization expenses	826,240	844,130	873,960
Other amortization expenses	4,991	6,971	8,097
Provision for loan losses	0	0	2,110
Impairment of assets	2,220	0	0
Stock-based compensation expense	30,844	32,075	20,177
Loss on derivatives	(58,427)	(1,495)	4,470
Loss (gain) on extinguishment of debt, net	34,677	9,558	(909)
Income from unconsolidated entities	21,504	27,426	8,187
Rental income less than (in excess of) cash received	(115,756)	(74,552)	(46,068)
Amortization related to above (below) market leases, net	4,018	739	460
Gain Loss On Sale Of Properties	(280,387)	(153,522)	(49,138)
Other (income) expense	31,979	0	0
Distributions by unconsolidated entities operating	637	9,060	8,885
Increase (decrease) in accrued expenses and other liabilities	(18,099)	(48,381)	67,557
Decrease (increase) in receivables and other assets	478	(25,639)	(47,571)
Net cash provided from (used in) operating activities	1,373,468	1,138,670	988,497
Investing activities
Cash disbursed for acquisitions	(3,364,891)	(2,210,600)	(3,597,955)
Cash disbursed for capital improvements to existing properties	(187,752)	(132,780)	(135,832)
Cash disbursed for construction in progress	(244,561)	(197,881)	(247,560)
Capitalized interest	(8,670)	(7,150)	(6,700)
Investment in real estate loans receivable	(598,722)	(202,207)	(117,059)
Other investments, net of payments	(141,994)	(100,033)	(15,634)
Principal collected on real estate loans receivable	131,830	105,496	102,886
Contributions to unconsolidated entities	(160,323)	(353,496)	(99,769)
Distributions by unconsolidated entities investing	130,880	57,183	30,853
Proceeds from (payments on) derivatives investing	106,360	10,269	(6,803)
Decrease (increase) in restricted cash	29,719	(6,072)	79,957
Proceeds from sales of real property	823,964	911,065	482,023
Net cash provided from (used in) investing activities	(3,484,160)	(2,126,206)	(3,531,593)
Financing activities
Net increase (decrease) under unsecured lines of credit arrangements	835,000	(130,000)	130,000
Proceeds from issuance of senior unsecured notes	1,451,434	773,992	1,756,192
Payments to extinguish senior unsecured notes	(558,830)	(365,188)	(517,625)
Secured debt issued	228,685	109,503	89,208
Payments on secured debt	(573,390)	(341,839)	(674,103)
Net proceeds from the issuance of common stock	1,755,722	2,343,868	1,854,637
Decrease (increase) in deferred loan expenses	(11,513)	(16,782)	(13,503)
Contributions by noncontrolling interests	173,018	9,962	5,072
Distributions to noncontrolling interests	(50,877)	(43,691)	(35,592)
Acquisitions of non controlling interests	(5,663)	(1,175)	(23,247)
Cash distributions to stockholders	(1,210,133)	(1,035,069)	(906,275)
Other financing activities	(27,004)	(409)	2,906
Net cash provided from (used in) financing activities	2,006,449	1,303,172	1,667,670
Effect of foreign currency translation on cash and cash equivalents	(8,575)	(690)	442
Increase (decrease) in cash and cash equivalents	(112,818)	314,946	(874,984)
Cash and cash equivalents at beginning of period	473,726	158,780	1,033,764
Cash and cash equivalents at end of period	360,908	473,726	158,780
Supplemental cash flow information:
Interest paid	492,771	504,165	447,108
Income taxes paid	$ 12,214	$ 18,548	$ 12,110