Schedule III - Real Estate and Accumulated Depreciation (Summary - Investment in Real Estate and Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investment in real estate:
Beginning balance	$ 36,027,915	$ 33,590,388	$ 30,581,948
Acquisitions and development	1,174,148	4,807,418	4,598,670
Improvements	242,147	328,824	266,183
Impairment of assets	(135,608)	(28,074)	(71,336)
Dispositions	(3,782,120)	(2,673,203)	(1,330,679)
Foreign currency translation	143,524	187,853	(454,398)
Other	0	(185,291)	0
Ending balance	33,670,006	36,027,915	33,590,388
Accumulated depreciation:
Beginning balance	5,715,459	5,499,958	4,838,370
Depreciation and amortization expenses	1,038,437	1,027,073	950,459
Amortization of above market leases	5,217	5,752	6,375
Disposition and other	(684,395)	(772,273)	(205,562)
Foreign currency translation	29,579	(45,051)	(89,684)
Ending balance	6,104,297	$ 5,715,459	$ 5,499,958
Reconciliation of real property (Textual) [Abstract]
Aggregate cost for tax purposes for real property	$ 30,050,020