Schedule III - Real Estate and Accumulated Depreciation (Summary - Investment in Real Estate and Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investment in real estate:
Beginning balance	$ 33,590,388	$ 30,581,948	$ 30,041,058
Acquisitions and development	4,807,418	4,598,670	1,276,636
Improvements	328,824	266,183	250,276
Deconsolidation of previously consolidated venture	0	0	(144,897)
Impairment of assets	(28,074)	(71,336)	(101,527)
Dispositions	(2,673,203)	(1,330,679)	(1,203,247)
Foreign currency translation	187,853	(454,398)	415,879
Other	(185,291)	0	47,770
Ending balance	36,027,915	33,590,388	30,581,948
Accumulated depreciation:
Beginning balance	5,499,958	4,838,370	4,093,494
Depreciation and amortization expenses	1,027,073	950,459	921,720
Amortization of above market leases	5,752	6,375	7,303
Disposition and other	(772,273)	(205,562)	(192,029)
Foreign currency translation	(45,051)	(89,684)	7,882
Ending balance	5,715,459	$ 5,499,958	$ 4,838,370
Reconciliation of real property (Textual) [Abstract]
Aggregate cost for tax purposes for real property	$ 30,691,276