CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income	$ 639,174	$ 791,525
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation expense	427,050	391,414
Amortization of deferred financing costs	5,729	5,664
Amortization of debt premium	(6,254)	(14,146)
Loss on extinguishment of debt, net	24,162	2,461
Amortization of stock-based compensation	13,979	12,103
Equity in (income) loss of, and return on, unconsolidated real estate entities and noncontrolling interests, net of eliminations	(21,627)	11,756
Casualty and impairment loss (gain), net	8,568	(3,935)
Abandonment of development pursuits	388	1,598
Cash flow hedge losses reclassified to earnings	5,301	4,682
Gain on sale of real estate assets	(200,110)	(348,675)
Increase in cash in operating escrows	(16,205)	(4,563)
Increase in resident security deposits, prepaid expenses and other assets	(27,384)	(16,127)
Increase in accrued expenses, other liabilities and accrued interest payable	64,802	26,970
Net cash provided by operating activities	917,573	860,727
Cash flows from investing activities:
Development/redevelopment of real estate assets including land acquisitions and deferred development costs	(743,275)	(869,342)
Acquisition of real estate assets, including partnership interest	(228,011)	(393,916)
Capital expenditures - existing real estate assets	(41,809)	(43,020)
Capital expenditures - non-real estate assets	(5,308)	(5,513)
Proceeds from sale of real estate, net of selling costs	336,542	404,731
Increase in cash in deposit escrows	(51,479)	(59,263)
Insurance proceeds for property damage claims	13,268	17,196
Mortgage note receivable lending	(14,244)	(11,074)
(Decrease) increase in payables for construction	(16,660)	1,311
Distributions from unconsolidated real estate entities	89,305	94,748
Investments in unconsolidated real estate entities	(14,560)	(2,449)
Net cash used in investing activities	(676,231)	(866,591)
Cash flows from financing activities:
Issuance of common stock, net	110,117	14,147
Dividends paid	(576,685)	(541,485)
Net borrowings under unsecured credit facility	242,000	170,000
Issuance of mortgage notes payable	185,100	0
Repayment of unsecured notes, including prepayment penalties	0	(250,000)
Repayments of mortgage notes payable, including prepayment penalties	(1,287,636)	(161,095)
Issuance of unsecured notes	948,616	474,838
Payment of deferred financing costs	(11,743)	(10,910)
Payment of capital lease obligation	(18,683)	0
Receipts (payments) for termination of forward interest rate swaps	391	(14,847)
Payments related to tax withholding for share-based compensation	(10,460)	(7,659)
Distributions to DownREIT partnership unitholders	(32)	(30)
Contributions from joint venture and profit-sharing partners	1,038	0
Distributions to joint venture and profit-sharing partners	(317)	(303)
Preferred interest obligation redemption and dividends	(2,000)	(1,400)
Net cash used in financing activities	(420,294)	(328,744)
Net decrease in cash and cash equivalents	(178,952)	(334,608)
Cash and cash equivalents, beginning of period	214,994	400,507
Cash and cash equivalents, end of period	36,042	65,899
Cash paid during the period for interest, net of amount capitalized	$ 124,585	$ 137,720