CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income	$ 400,975	$ 435,197
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation expense	282,060	259,685
Amortization of deferred financing costs	3,873	3,827
Amortization of debt premium	(6,454)	(9,436)
Loss on extinguishment of debt, net	24,162	2,461
Amortization of stock-based compensation	9,658	8,482
Equity in (income) loss of, and return on, unconsolidated real estate entities and noncontrolling interests, net of eliminations	(4,473)	7,255
Casualty and impairment loss (gain), net	11,688	(3,935)
Abandonment of development pursuits	388	0
Cash flow hedge losses reclassified to earnings	3,534	2,935
Gain on sale of real estate assets	(141,079)	(135,735)
Increase in cash in operating escrows	(13,296)	(2,221)
Increase in resident security deposits, prepaid expenses and other assets	(13,174)	(9,936)
Increase (decrease) in accrued expenses, other liabilities and accrued interest payable	4,498	(5,401)
Net cash provided by operating activities	562,360	553,178
Cash flows from investing activities:
Development/redevelopment of real estate assets including land acquisitions and deferred development costs	(495,868)	(587,287)
Acquisition of real estate assets, including partnership interest	0	(170,022)
Capital expenditures - existing real estate assets	(22,415)	(24,696)
Capital expenditures - non-real estate assets	(6,334)	(3,919)
Proceeds from sale of real estate, net of selling costs	270,481	116,941
Increase in cash in deposit escrows	(112,890)	0
Insurance proceeds for property damage claims	6,192	17,196
Mortgage note receivable lending	(11,069)	0
(Decrease) increase in payables for construction	(6,463)	2,074
Distributions from unconsolidated real estate entities	21,852	58,870
Investments in unconsolidated real estate entities	(10,100)	(121,648)
Net cash used in investing activities	(366,614)	(712,491)
Cash flows from financing activities:
Issuance of common stock, net	110,033	12,804
Dividends paid	(380,723)	(356,235)
Net borrowings under unsecured credit facility	105,000	0
Issuance of mortgage notes payable	185,100	0
Repayments of mortgage notes payable, including prepayment penalties	(1,285,555)	(157,552)
Issuance of unsecured notes	948,616	474,838
Payment of deferred financing costs	(11,466)	(10,014)
Payment of capital lease obligation	(18,422)	0
Receipts (payments) for termination of forward interest rate swaps	391	(14,847)
Payments related to tax withholding for share-based compensation	(10,441)	(7,659)
Distributions to DownREIT partnership unitholders	(21)	(20)
Contributions from joint venture and profit-sharing partners	1,038	0
Distributions to joint venture and profit-sharing partners	(213)	(203)
Preferred interest obligation redemption and dividends	(600)	0
Net cash used in financing activities	(357,263)	(58,888)
Net decrease in cash and cash equivalents	(161,517)	(218,201)
Cash and cash equivalents, beginning of period	214,994	400,507
Cash and cash equivalents, end of period	53,477	182,306
Cash paid during the period for interest, net of amount capitalized	$ 102,624	$ 90,355