Significant Accounting Policies (Details 5) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Noncontrolling interests:
Balance, at beginning of period			$ 5,633,752
Other comprehensive income (loss) allocable to noncontrolling interests:
Unrealized loss on derivative hedge agreements	(7,740)	7,478	(19,023)	4,410
Net loss on derivative instruments reclassified from accumulated other comprehensive loss into interest expense	3,824	3,945	7,768	7,785
Currency translation adjustments	8,754	(14,610)	30,653	(23,510)
Changes in available-for-sale securities and other	25,713	(46,762)	27,954	(67,952)
Issuance of unit equivalents and other			16,139
Balance, at end of period	5,569,101		5,569,101
Transaction Expenses
Transaction expenses		11,269		14,969
Noncontrolling interests
Noncontrolling interests:
Balance, at beginning of period	771,152	705,107	802,972	724,825
Net income attributable to noncontrolling interests after preferred distributions	44,088	33,173	83,029	37,726
Distributions to noncontrolling interest holders	(49,993)	(39,459)	(120,386)	(80,474)
Other comprehensive income (loss) allocable to noncontrolling interests:
Unrealized loss on derivative hedge agreements	(1,294)	1,284	(3,194)	1,198
Net loss on derivative instruments reclassified from accumulated other comprehensive loss into interest expense	647	657	1,318	1,302
Currency translation adjustments	1,489	(2,431)	5,228	(3,836)
Changes in available-for-sale securities and other	4,334	(7,842)	4,677	(11,885)
Other comprehensive income (loss)	5,176	(8,332)	8,029	(13,221)
Adjustment to limited partners' interest from (decreased) increased ownership in the Operating Partnership	(947)	(9,263)	(6,585)	11,343
Units issued to limited partners		54,557	202	57,852
Units converted to common shares	(3,712)	(300)	(5,923)	(2,568)
Issuance of unit equivalents and other	8,130	601	12,556	601
Balance, at end of period	$ 773,894	$ 736,084	$ 773,894	$ 736,084