CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 82,732	$ 1,061,034
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	185,167	220,038
Amortization of deferred financing costs	2,792	7,176
Amortization of Intangible Assets	829	292
Amortization of discounts and premiums on debt	(2,938)	(7,071)
Amortization of deferred settlements on derivative instruments	3,996	8,139
Write-off of pursuit costs	452	2,533
Loss from investments in unconsolidated entities	1,409	46,366
Distributions from unconsolidated entities - return on capital	914	257
Net loss on sales of land parcels	30	0
Net (gain) on sales of discontinued operations	(71)	(1,198,922)
Unrealized (gain) on derivative instruments	(3)	0
Compensation paid with Company Common Shares	12,981	10,236
Changes in assets and liabilities:
(Increase) decrease in deposits – restricted	(418)	1,733
Decrease in mortgage deposits	375	1,651
Decrease in other assets	18,613	15,220
Increase in accounts payable and accrued expenses	55,263	47,498
(Decrease) increase in accrued interest payable	(169)	1,039
(Decrease) in other liabilities	(26,194)	(18,437)
Increase (decrease) in security deposits	1,143	(5,268)
Net cash provided by operating activities	336,903	193,514
CASH FLOWS FROM INVESTING ACTIVITIES:
Payments to Acquire Businesses, Net of Cash Acquired	0	(4,000,643)
Investment in real estate – acquisitions	(148,535)	0
Investment in real estate - development/other	(122,340)	(65,232)
Improvements to real estate	(32,191)	(26,599)
Additions to non-real estate property	(159)	(1,942)
Interest capitalized for real estate and unconsolidated entities under development	(12,792)	(8,413)
Proceeds from disposition of real estate, net	0	2,955,398
Investments in unconsolidated entities	(6,254)	(283)
Proceeds From Distributions Received From Unconsolidated Subsidiaries	7,680	0
Decrease in deposits on real estate acquisitions and investments, net	12,904	101,668
(Increase) decrease in mortgage deposits	(91)	4,473
Acquisition of Noncontrolling Interests – Partially Owned Properties	(2,501)	0
Net cash (used for) investing activities	(304,279)	(1,041,573)
CASH FLOWS FROM FINANCING ACTIVITIES:
Loan and bond acquisition costs	(60)	(13,869)
Mortgage Deposits	(1,643)	(632)
Mortgage notes payable:
Lump sum payoffs	0	(584,020)
Scheduled principal repayments	(3,034)	(3,244)
Notes, net:
Proceeds from Notes Payable	0	750,000
Line of Credit Facility:
Proceeds	1,751,000	5,850,000
Repayments	(1,568,000)	(5,455,000)
Proceeds from Employee Stock Purchase Plan	1,741	1,763
Proceeds from exercise of options	15,785	7,174
Payments for Repurchase of Common Stock	(1,777)	0
Payment of offering costs	0	(406)
Contributions - Noncontrolling Interests - Partially Owned Properties	5,684	3,299
Contributions - Noncontrolling Interests - Operating Partnership	3	3
Distributions:
Common Shares	(234,282)	(249,330)
Preferred Shares	(1,036)	0
Noncontrolling Interests – Operating Partnership	(9,217)	(10,837)
Noncontrolling Interests – Partially Owned Properties	(4,113)	(3,345)
Net cash (used for) provided by financing activities	(48,949)	291,556
Net (decrease) in cash and cash equivalents	(16,325)	(556,503)
Cash and cash equivalents, beginning of period	53,534	612,590
Cash and cash equivalents, end of period	37,209	56,087
SUPPLEMENTAL INFORMATION:
Cash paid for interest, net of amounts capitalized	112,152	182,356
Net cash paid for income and other taxes	596	483
AmortizationOfDeferredFinancingCosts [Abstract]
Amortization Of Deferred Financing Costs Investment In Real Estate Net	0	(1)
Amortization Of Deferred Financing Costs Deferred Financing Costs Net	2,792	7,177
Amortization of discounts and premiums on debt:
Mortgage notes payable	(3,506)	(7,557)
Notes, net	568	486
Amortization of deferred settlements on derivative instruments:
Other liabilities	(133)	(133)
Losses reclassified into earnings from other comprehensive income	4,129	8,272
Loss From Investments In Unconsolidated Entities [Abstract]
Income Loss From Equity Method Investments Merger	472	42,213
Other Liabilities Loss From Investments in unconsolidated entities	937	4,153
Distributions from unconsolidated entities return on capital [Abstract]
Distributions from unconsolidated entities investments in unconsolidated entities	862	257
Distributions from unconsolidated entities other liabilities	52	0
Unrealized (gain) on derivative instruments:
Other assets	7,279	1,471
Notes, net	0	(1,471)
Other liabilities	4,670	(2,814)
Unrealized holding (losses) gains arising during the period	(11,952)	2,814
Acquisition of Archstone, net of cash acquired [Abstract]
Acquisition of Archstone Investment in Real Estate Net	39,929	(8,707,967)
Acquisition of Archstone Investments in Unconsolidated Entities	(33,993)	(218,197)
Acquisition of Archstone Deposits Restricted	0	(474)
Acquisition of Archstone Escrow Deposits Mortgage	0	(35,898)
Acquisition of Archstone Deferred Financing Costs	0	(25,780)
Acquisition of Archstone Other Assets	(2,586)	(204,523)
Acquisition of Archstone Mortgage Notes Payable	0	3,076,876
Acquisition of Archstone Accounts Payable And Accrued Liabilities	(146)	17,593
Acqusition of Archstone Interest Payable	0	11,256
Acquisition of Archstone Other Liabilities	(3,204)	117,391
Acquisition of Archstone Security Deposits	0	10,949
Acquisition of Archstone Common Shares Issued	0	1,929,868
Acquisition of Archstone Noncontrolling Interests Partially Owned Properties	0	28,263
Interest capitalized for real estate and unconsolidated entities under development:
Investment in real estate, net	(12,774)	(8,089)
Investments in unconsolidated entities	(18)	(324)
Investments in unconsolidated entities [Abstract]
Investments in unconsolidated entities	(1,454)	(283)
Investments in unconsolidated entities other liabilities	(4,800)	0
Other:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	$ (91)	$ 873