CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (USD $) In Thousands, unless otherwise specified	Total	PREFERRED SHARES	COMMON SHARES, $0.01 PAR VALUE	PAID IN CAPITAL	Retained Earnings [Member]	ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME	OPERATING PARTNERSHIP	Partially Owned Properties [Member]	Series N Preferred Stock [Member]
Beginning Balance, Noncontrolling Interest at Dec. 31, 2010							$ 110,399	$ 7,991
Beginning Balance, Parent at Dec. 31, 2010		200,000	2,902	4,741,521	203,581	(57,818)
Preferred Shares:
Preferred Stock Preference Units Dividend Rate Percentage									6.48%
Payments for Repurchase of Preferred Stock and Preference Stock	0	0
Common Share Issuance:
Conversion of OP Units into Common Shares			3	8,577			(8,580)
Issuance of Common Shares	201,900		39	201,903
Exercise of share options			29	95,293
Employee Share Purchase Plan (ESPP)			1	5,261
Conversion of restricted shares to LTIP Units			(1)	(3,933)			3,934
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition			2	9,100
Share-based employee compensation expense:
Share options				9,545
ESPP discount				1,194
Offering costs				(3,596)
Premium on Redemption of Preferred Shares Preference Units Original Issuance				0	0
Supplemental Executive Retirement Plan (SERP)				10,765
Acquisition of Noncontrolling Interests - Partially Owned Properties				(4,784)				(8,025)
Change in market value	22,714			(22,714)
Adjustment for Noncontrolling Interests ownership in Operating Partnership				(946)			946
Net income attributable to controlling interests	893,585				893,585
Common Share distributions					(467,729)
Preferred Share distributions					(13,865)
Premium on Redemption of Preferred Shares Cash	0				0
Accumulated other comprehensive (loss) income - derivative instruments:
Unrealized holding gains (losses) arising during the year	(143,598)					(143,598)
Losses reclassified into earnings from other comprehensive income	(4,343)					4,343
Accumulated other comprehensive income (loss) - other instruments:
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	355					355
Gain on Sale of Securities, Net	0
Currency translation adjustments arising during the year	0
Issuance of OP Units to Noncontrolling Interests							0
Issuance of LTIP Units to Noncontrolling Interests							0
Conversion of OP Units held by Noncontrolling Interests into OP Units held by General Partner			3	8,577			(8,580)
Equity Compensation associated with Noncontrolling Interests							3,641
Net income	935,197						40,780	832
Distributions to Noncontrolling Interests							(21,434)	(1,163)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership	10,150						(10,150)
Contributions - Noncontrolling Interests - Partially Owned Properties	75,911							75,911
Archstone Acquisition Noncontrolling Interests Partially Owned Properties								0
Other								(1,240)
Ending Balance, Noncontrolling Interest at Dec. 31, 2011							119,536	74,306
Ending Balance, Parent at Dec. 31, 2011		200,000	2,975	5,047,186	615,572	(196,718)
Preferred Shares:
Preferred Stock Preference Units Dividend Rate Percentage									6.48%
Payments for Repurchase of Preferred Stock and Preference Stock	(150,000)	(150,000)
Common Share Issuance:
Conversion of OP Units into Common Shares			7	18,922			(18,929)
Issuance of Common Shares	192,300		250	1,388,333
Exercise of share options			16	49,023
Employee Share Purchase Plan (ESPP)			1	5,398
Conversion of restricted shares to LTIP Units			0	0			0
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition			2	8,934
Share-based employee compensation expense:
Share options				11,752
ESPP discount				965
Offering costs				(39,359)
Premium on Redemption of Preferred Shares Preference Units Original Issuance				5,129	(5,129)
Supplemental Executive Retirement Plan (SERP)				282
Acquisition of Noncontrolling Interests - Partially Owned Properties				1,293				(1,306)
Change in market value	(38,734)			38,734
Adjustment for Noncontrolling Interests ownership in Operating Partnership				5,763			(5,763)
Net income attributable to controlling interests	841,719				841,719
Common Share distributions					(554,429)
Preferred Share distributions					(10,355)
Premium on Redemption of Preferred Shares Cash	(23)				(23)
Accumulated other comprehensive (loss) income - derivative instruments:
Unrealized holding gains (losses) arising during the year	(11,772)					(11,772)
Losses reclassified into earnings from other comprehensive income	(14,678)					14,678
Accumulated other comprehensive income (loss) - other instruments:
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	664					664
Gain on Sale of Securities, Net	0
Currency translation adjustments arising during the year	0
Issuance of OP Units to Noncontrolling Interests							66,606
Issuance of LTIP Units to Noncontrolling Interests							5
Conversion of OP Units held by Noncontrolling Interests into OP Units held by General Partner			7	18,922			(18,929)
Equity Compensation associated with Noncontrolling Interests							5,307
Net income	881,204						38,641	844
Distributions to Noncontrolling Interests							(25,095)	(5,131)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership	20,702						(20,702)
Contributions - Noncontrolling Interests - Partially Owned Properties	8,221							8,221
Archstone Acquisition Noncontrolling Interests Partially Owned Properties								0
Other								754
Ending Balance, Noncontrolling Interest at Dec. 31, 2012	7,527,107						159,606	77,688
Ending Balance, Parent at Dec. 31, 2012	7,289,813	50,000	3,251	6,542,355	887,355	(193,148)
Preferred Shares:
Preferred Stock Preference Units Dividend Rate Percentage									6.48%
Payments for Repurchase of Preferred Stock and Preference Stock	0	0							(150,000)
Common Share Issuance:
Conversion of OP Units into Common Shares			1	1,698			(1,699)
Issuance of Common Shares			345	1,929,523
Exercise of share options			5	17,247
Employee Share Purchase Plan (ESPP)			1	3,400
Conversion of restricted shares to LTIP Units			0	0			0
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition			2	13,262
Share-based employee compensation expense:
Share options				10,514
ESPP discount				632
Offering costs				(1,047)
Premium on Redemption of Preferred Shares Preference Units Original Issuance				0	0				5,100
Supplemental Executive Retirement Plan (SERP)				(422)
Acquisition of Noncontrolling Interests - Partially Owned Properties				0				0
Change in market value	(79,667)			79,667
Adjustment for Noncontrolling Interests ownership in Operating Partnership				(35,329)			35,329
Net income attributable to controlling interests	1,830,613				1,830,613
Common Share distributions					(666,565)
Preferred Share distributions					(4,145)
Premium on Redemption of Preferred Shares Cash	0				0
Accumulated other comprehensive (loss) income - derivative instruments:
Unrealized holding gains (losses) arising during the year	18,771					18,771
Losses reclassified into earnings from other comprehensive income	(20,141)					20,141
Accumulated other comprehensive income (loss) - other instruments:
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	583					583
Gain on Sale of Securities, Net	(2,122)
Currency translation adjustments arising during the year	613
Issuance of OP Units to Noncontrolling Interests							0
Issuance of LTIP Units to Noncontrolling Interests							5
Conversion of OP Units held by Noncontrolling Interests into OP Units held by General Partner			1	1,698			(1,699)
Equity Compensation associated with Noncontrolling Interests							13,609
Net income	1,905,353						75,278	(538)
Distributions to Noncontrolling Interests							(26,277)	(6,490)
Change in carrying value of Redeemable Noncontrolling Interests - Operating Partnership	44,439						(44,439)
Contributions - Noncontrolling Interests - Partially Owned Properties	27,660							27,660
Archstone Acquisition Noncontrolling Interests Partially Owned Properties								28,263
Other								0
Ending Balance, Noncontrolling Interest at Dec. 31, 2013	10,845,196						211,412	126,583
Ending Balance, Parent at Dec. 31, 2013	$ 10,507,201	$ 50,000	$ 3,605	$ 8,561,500	$ 2,047,258	$ (155,162)