Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 309,909	$ 163,657
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	322,067	308,898
Non-cash compensation expense	16,480	16,899
Income from unconsolidated joint ventures	(17,912)	(5,650)
Distributions of net cash flow from operations of unconsolidated joint ventures	5,769	2,205
Gains from investments in securities	(369)	(948)
Non-cash portion of interest expense	(21,852)	(18,171)
Settlement of accreted debt discount on repurchases of unsecured exchangeable senior notes	0	(92,979)
Gains on sales of real estate	(95,084)	0
Change in assets and liabilities:
Cash held in escrows	(175)	(2,047)
Tenant and other receivables, net	(8,588)	8,116
Accrued rental income, net	(40,173)	(21,984)
Prepaid expenses and other assets	63,545	51,442
Accounts payable and accrued expenses	(5,973)	(4,704)
Accrued interest payable	15,016	(11,499)
Other liabilities	(56,580)	(39,253)
Tenant leasing costs	(43,004)	(44,989)
Total adjustments	133,167	145,336
Net cash provided by operating activities	443,076	308,993
Cash flows from investing activities:
Construction in progress	(154,430)	(206,603)
Building and other capital improvements	(48,133)	(37,285)
Tenant improvements	(51,444)	(53,935)
Proceeds from sales of real estate	194,821	0
Proceeds from sales of real estate placed in escrow	(200,612)	0
Proceeds from sales of real estate released from escrow	441,903	0
Cash placed in escrow for land sale contracts	(7,111)	0
Cash released from scrow for land sale contracts	758	0
Deposit on real estate	(5,000)	0
Capital contributions to unconsolidated joint ventures	(14,989)	(47,767)
Capital distributions from unconsolidated joint ventures	24,527	357
Investments in securities, net	(1,125)	(1,338)
Net cash provided by (used in) investing activities	179,165	(346,571)
Cash flows from financing activities:
Repayments of mortgage notes payable	(12,909)	(12,207)
Repayment of unsecured exchangeable senior notes	0	(654,521)
Proceeds from real estate financing transaction	6,000	0
Payments on real estate financing transaction	(1,523)	0
Deferred financing costs	(163)	(31)
Net proceeds from equity transactions	332	1,162
Redemption of preferred units	(633)	0
Dividends and distributions	(997,840)	(612,612)
Contributions from noncontrolling interests in property partnerships	1,089	1,675
Distributions to noncontrolling interests in property partnerships	(36,922)	(14,449)
Net cash used in financing activities	(1,042,569)	(1,290,983)
Net decrease in cash and cash equivalents	(420,328)	(1,328,561)
Cash and cash equivalents, beginning of period	1,763,079	2,365,137
Cash and cash equivalents, end of period	1,342,751	1,036,576
Supplemental disclosures:
Cash paid for interest	240,942	379,766
Interest capitalized	16,815	32,586
Non-cash investing and financing activities:
Additions to real estate included in accounts payable and accrued expenses	17,604	4,831
Dividends and distributions declared but not paid	112,892	112,420
Conversions of noncontrolling interests to stockholders’ equity	10,843	2,241
Conversions of redeemable preferred units to common units	0	33,306
Issuance of restricted securities to employees	$ 43,363	$ 27,445