Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 748,124	$ 263,238
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	403,957	327,355
Non-cash compensation expense	39,001	24,859
Impairment loss	4,401	0
Income from unconsolidated joint ventures	(72,240)	(42,129)
Gains on Consolidation of Joint Ventures	(385,991)	0
Distributions of net cash flow from operations of unconsolidated joint ventures	29,607	32,359
Gains from investments in securities	(1,872)	(1,202)
Non-cash portion of interest expense	29,149	32,681
Settlement of accreted debt discount on repurchases of unsecured exchangeable senior notes	(56,532)	(68,760)
Gains from early extinguishments of debt	(264)	(1,000)
Gains on sale of real estate from discontinued operations	(88,565)	(38,445)
Gain on forgiveness of debt from discontinued operations	(20,736)	0
Impairment loss from discontinued operations	2,852	0
Change in assets and liabilities:
Cash held in escrows	4,017	7,406
Tenant and other receivables, net	3,628	28,680
Accrued rental income, net	(44,636)	(59,177)
Prepaid expenses and other assets	(41,245)	(29,925)
Accounts payable and accrued expenses	9,179	3,713
Accrued interest payable	35,089	32,769
Other liabilities	(9,352)	(6,939)
Tenant leasing costs	(37,150)	(41,797)
Total adjustments	(197,703)	200,448
Net cash provided by operating activities	550,421	463,686
Cash flows from investing activities:
Acquisitions of real estate	(522,900)	(688,073)
Construction in progress	(279,786)	(238,627)
Building and other capital improvements	(46,805)	(32,159)
Tenant improvements	(78,462)	(108,100)
Proceeds from sales of real estate	160,815	61,963
Cash recorded upon consolidation	79,468	0
Deposits on real estate	0	(15,000)
Repayments of notes receivable, net	12,491	(1,764)
Capital contributions to unconsolidated joint ventures	0	(367)
Capital distributions from unconsolidated joint ventures	223,067	3,057
Investments in securities, net	(1,333)	(1,042)
Net cash used in investing activities	(453,445)	(1,020,112)
Cash flows from financing activities:
Repayments of mortgage notes payable	(96,750)	(248,304)
Proceeds from unsecured senior notes	1,194,753	997,790
Redemption of unsecured senior notes	0	(225,000)
Redemption/Repurchase of unsecured exchangeable senior notes	(393,468)	(507,434)
Deferred financing costs	(15,180)	(8,448)
Net proceeds from preferred units issuance	193,623	0
Net proceeds from ATM stock issuances	0	247,186
Net proceeds from equity transactions	(348)	216
Payments for redemption of preferred units	(43,070)	(18,329)
Distributions	(337,440)	(278,994)
Proceeds from noncontrolling interest in property partnership	6,386	0
Distributions to noncontrolling interest in property partnerships	(6,185)	(2,250)
Net cash provided by (used in) financing activities	502,321	(43,567)
Net decrease)in cash and cash equivalents	599,297	(599,993)
Cash and cash equivalents, beginning of period	1,041,978	1,823,208
Cash and cash equivalents, end of period	1,641,275	1,223,215
Supplemental disclosures:
Cash paid for interest	368,652	344,831
Interest capitalized	50,252	31,409
Non-cash investing and financing activities:
Additions to real estate included in accounts payable and accrued expenses	6,397	11,190
Real estate and related intangibles recorded upon consolidation	3,356,000	0
Debt recorded upon consolidation	2,056,000	0
Working capital recorded upon consolidation	97,847	0
Noncontrolling interest recorded upon consolidation	480,861	0
investment in unconsolidated joint venture elminated upon consolidation	361,808	0
Mortgage note payable extinguished through foreclosure	25,000	0
Real estate transferred upon foreclosure	7,508	0
Land improvements contributed by noncontrolling property partnership	4,546	0
Preferred Units Issued In Connection With Acquisition Of Real Estate	0	79,405
Distributions declared but not paid	112,470	93,461
Issuance of common stock in connection with the exchange of exchangeable senior notes	43,834	0
Conversions of redeemable partnership units to partners' capital	10,406	11,236
Conversion of redeemable preferred units to common units	0	5,852
Issuance of restricted securities to employees and directors	$ 30,077	$ 26,351