SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Carrying cost:
Balance at beginning of period	$ 17,029,404	$ 6,600,886	$ 6,292,621
Additions during period:
Acquisitions	1,889,592	10,491,275	315,538
Capital expenditures	184,675	102,918	21,038
Dispositions:
Sales and/or transfers to assets held for sale	(349,456)	(157,764)	(46,083)
Foreign currency translation	9,688	(7,911)	17,772
Balance at end of period	18,763,903	17,029,404	6,600,886
Accumulated depreciation:
Balance at beginning of period	1,729,976	1,368,219	1,177,911
Additions during period:
Depreciation expense	620,076	380,734	197,256
Dispositions:
Sales and/or transfers to assets held for sale	(61,583)	(16,536)	(8,259)
Foreign currency translation	1,314	(2,441)	1,311
Balance at end of period	$ 2,289,783	$ 1,729,976	$ 1,368,219