CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income		$ 237,877	$ 208,053
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation expense	[1]	127,216	116,853
Amortization of deferred financing costs		1,936	1,664
Amortization of debt premium		(4,779)	(8,660)
Amortization of stock-based compensation		3,835	4,038
Equity in loss of, and return on, unconsolidated entities and noncontrolling interests, net of eliminations		6,438	3,805
Casualty and impairment (gain) loss, net		(2,202)	4,995
Cash flow hedge losses reclassified to earnings		1,374	1,565
Gain on sale of real estate assets		(81,055)	(79,033)
Decrease (increase) in cash in operating escrows		3,009	(7,815)
Increase in resident security deposits, prepaid expenses and other assets		(8,559)	(2,351)
Increase in accrued expenses, other liabilities and accrued interest payable		(7,308)	(6,734)
Net cash provided by operating activities		277,782	236,380
Cash flows from investing activities:
Development/redevelopment of real estate assets including land acquisitions and deferred development costs		(266,588)	(578,632)
Payments to Acquire Other Real Estate		(170,022)	0
Capital expenditures - existing real estate assets		(11,618)	(7,820)
Capital expenditures - non-real estate assets		(3,264)	(859)
Proceeds from sale of real estate, net of selling costs		68,709	112,504
Insurance proceeds for property damage claims		8,702	0
Increase (decrease) in payables for construction		842	(7,885)
Increase (Decrease) in Restricted Cash		(69,227)	0
Distributions from unconsolidated real estate entities		58,652	40,493
Investments in unconsolidated real estate entities		(913)	0
Net cash used in investing activities		(384,727)	(442,199)
Cash flows from financing activities:
Issuance of common stock, net		1,102	1,973
Dividends paid		(171,151)	(153,095)
Repayments of mortgage notes payable, including prepayment penalties		(19,682)	(4,209)
Issuance of unsecured notes		0	50,000
Payment of deferred financing costs		(6,176)	(578)
Distributions to DownREIT partnership unitholders		(10)	(9)
Distributions to joint venture and profit-sharing partners		(104)	(91)
Redemption of preferred interest obligation		0	(1,520)
Net cash used in financing activities		(196,021)	(107,529)
Net decrease in cash and cash equivalents		(302,966)	(313,348)
Cash and cash equivalents, beginning of period		400,507	508,276
Cash and cash equivalents, end of period		97,541	194,928
Cash paid during the period for interest, net of amount capitalized		$ 46,011	$ 59,624

[1] Represents NOI from real estate assets sold or held for sale that are not otherwise classified as discontinued operations.