Investments in Partially Owned Entities (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Partially Owned Property Balance Sheet Schedule
Partially Owned Consolidated Properties	19		19
Partially Owned Unconsolidated Properties	1		1
Partially Owned Consolidated Units	3,752		3,752
Partially Owned Unconsolidated Units	336		336
ASSETS
Real Estate Investment Property, at Cost	$ 26,988,907,000		$ 26,988,907,000		$ 21,008,429,000
Real Estate Investment Property, Accumulated Depreciation	(4,547,327,000)		(4,547,327,000)		(4,912,221,000)
Investment in real estate, net	22,441,580,000		22,441,580,000		16,096,208,000
Cash and Cash Equivalents, at Carrying Value	152,564,000	44,585,000	152,564,000	44,585,000	612,590,000	383,921,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	188,582,000		188,582,000		17,877,000
Restricted Cash and Cash Equivalents	197,267,000		197,267,000		250,442,000
Deferred Finance Costs, Net	71,013,000		71,013,000		44,382,000
Other Assets	390,020,000		390,020,000		170,372,000
Total assets	23,482,383,000		23,482,383,000		17,201,000,000
LIABILITIES AND EQUITY
Secured Debt	6,247,612,000		6,247,612,000		3,898,369,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	84,603,000		84,603,000		38,372,000
Interest Payable	86,083,000		86,083,000		76,223,000
Other Liabilities	318,622,000		318,622,000		304,518,000
Security Deposit Liability	71,857,000		71,857,000		66,988,000
Total liabilities	12,435,577,000		12,435,577,000		9,275,521,000
Noncontrolling Interests Partially Owned Properties	107,493,000		107,493,000		77,688,000
Total liabilities and equity	23,482,383,000		23,482,383,000		17,201,000,000
Partially Owned Property Income Statement Schedule
Operating revenue	635,078,000	448,351,000	1,156,751,000	878,614,000
Depreciation	327,985,000	145,438,000	528,328,000	289,273,000
General and Administrative Expense	16,086,000	13,391,000	32,582,000	27,079,000
Operating Income (Loss)	71,033,000	128,560,000	182,281,000	237,412,000
Interest and Other Income	249,000	258,000	504,000	427,000
Interest:
Interest Expense, Debt	122,950,000	114,627,000	317,417,000	232,254,000
Amortization of Financing Costs	4,353,000	4,017,000	11,301,000	6,945,000
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of land parcels and discontinued operations	(57,469,000)	687,000	(169,036,000)	(17,797,000)
Income and other tax (expense) benefit	(428,000)	(213,000)	(833,000)	(380,000)
(Loss) from investments in unconsolidated entities due to operations	(1,175,000)	0	(1,530,000)	0
Net gain on sales of land parcels	14,616,000	0	14,616,000	0
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	389,952,000	71,097,000	1,588,874,000	204,053,000
Net income	336,732,000	108,315,000	1,397,766,000	260,482,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Joint Venture Partner Ownership Percentage	80.00%		80.00%
Equity Method Investment, Ownership Percentage	20.00%		20.00%
Variable Interest Entity, Consolidated, Carrying Amount, Assets	5,000,000		5,000,000
Project Cost	232,800,000		232,800,000
Debt Instrument, Maturity Date			Sep. 01, 2014
Preferred Interests			65,000,000
Business Acquisition, Cost of Acquired Entity, Purchase Price	108,000,000		108,000,000
Investment in Joint Venture	230,725,964		230,725,964
Number of Joint Ventures	2		2
Partners Payments To Acquire Equity Method Investments			40,100,000
Number of joint venture loans	2		2
Consolidated Development Projects Held for and or Under Development [Member]
Partially Owned Property Balance Sheet Schedule
Partially Owned Consolidated Properties	0		0
Partially Owned Consolidated Units	0		0
ASSETS
Real Estate Investment Property, at Cost	250,816,000		250,816,000
Real Estate Investment Property, Accumulated Depreciation	0		0
Investment in real estate, net	250,816,000		250,816,000
Cash and Cash Equivalents, at Carrying Value	2,656,000		2,656,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0		0
Restricted Cash and Cash Equivalents	43,623,000		43,623,000
Deferred Finance Costs, Net	0		0
Other Assets	5,837,000		5,837,000
Total assets	302,932,000		302,932,000
LIABILITIES AND EQUITY
Secured Debt	0		0
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	4,329,000		4,329,000
Interest Payable	0		0
Other Liabilities	1,003,000		1,003,000
Security Deposit Liability	0		0
Total liabilities	5,332,000		5,332,000
Noncontrolling Interests Partially Owned Properties	93,348,000		93,348,000
Parent Equity Interest	204,252,000		204,252,000
Total Equity Interest	297,600,000		297,600,000
Total liabilities and equity	302,932,000		302,932,000
Partially Owned Property Income Statement Schedule
Operating revenue			0
Operating Expenses			179,000
Gross Profit			(179,000)
Depreciation			0
General and Administrative Expense			503,000
Operating Income (Loss)			(682,000)
Interest and Other Income			1,000
Other Nonoperating Income (Expense)			(181,000)
Interest:
Interest Expense, Debt			0
Amortization of Financing Costs			0
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of land parcels and discontinued operations			(862,000)
Income and other tax (expense) benefit			(11,000)
(Loss) from investments in unconsolidated entities due to operations			0
Net gain on sales of land parcels			(17,000)
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income			(890,000)
Consolidated Operating [Domain]
Partially Owned Property Balance Sheet Schedule
Partially Owned Consolidated Properties	19		19
Partially Owned Consolidated Units	3,752		3,752
ASSETS
Real Estate Investment Property, at Cost	671,667,000		671,667,000
Real Estate Investment Property, Accumulated Depreciation	(158,035,000)		(158,035,000)
Investment in real estate, net	513,632,000		513,632,000
Cash and Cash Equivalents, at Carrying Value	14,936,000		14,936,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	55,858,000		55,858,000
Restricted Cash and Cash Equivalents	197,000		197,000
Deferred Finance Costs, Net	2,606,000		2,606,000
Other Assets	26,661,000		26,661,000
Total assets	613,890,000		613,890,000
LIABILITIES AND EQUITY
Secured Debt	358,632,000		358,632,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	1,592,000		1,592,000
Interest Payable	1,218,000		1,218,000
Other Liabilities	1,363,000		1,363,000
Security Deposit Liability	1,809,000		1,809,000
Total liabilities	364,614,000		364,614,000
Noncontrolling Interests Partially Owned Properties	14,145,000		14,145,000
Parent Equity Interest	235,131,000		235,131,000
Total Equity Interest	249,276,000		249,276,000
Total liabilities and equity	613,890,000		613,890,000
Partially Owned Property Income Statement Schedule
Operating revenue			38,352,000
Operating Expenses			12,293,000
Gross Profit			26,059,000
Depreciation			17,056,000
General and Administrative Expense			31,000
Operating Income (Loss)			8,972,000
Interest and Other Income			3,000
Other Nonoperating Income (Expense)			(3,000)
Interest:
Interest Expense, Debt			(6,712,000)
Amortization of Financing Costs			(131,000)
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of land parcels and discontinued operations			2,129,000
Income and other tax (expense) benefit			(56,000)
(Loss) from investments in unconsolidated entities due to operations			(342,000)
Net gain on sales of land parcels			0
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			26,686,000
Net income			28,417,000
Consolidated Total [Domain]
Partially Owned Property Balance Sheet Schedule
Partially Owned Consolidated Properties	19		19
Partially Owned Consolidated Units	3,752		3,752
ASSETS
Real Estate Investment Property, at Cost	922,483,000		922,483,000
Real Estate Investment Property, Accumulated Depreciation	(158,035,000)		(158,035,000)
Investment in real estate, net	764,448,000		764,448,000
Cash and Cash Equivalents, at Carrying Value	17,592,000		17,592,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	55,858,000		55,858,000
Restricted Cash and Cash Equivalents	43,820,000		43,820,000
Deferred Finance Costs, Net	2,606,000		2,606,000
Other Assets	32,498,000		32,498,000
Total assets	916,822,000		916,822,000
LIABILITIES AND EQUITY
Secured Debt	358,632,000		358,632,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	5,921,000		5,921,000
Interest Payable	1,218,000		1,218,000
Other Liabilities	2,366,000		2,366,000
Security Deposit Liability	1,809,000		1,809,000
Total liabilities	369,946,000		369,946,000
Noncontrolling Interests Partially Owned Properties	107,493,000		107,493,000
Parent Equity Interest	439,383,000		439,383,000
Total Equity Interest	546,876,000		546,876,000
Total liabilities and equity	916,822,000		916,822,000
Partially Owned Property Income Statement Schedule
Operating revenue			38,352,000
Operating Expenses			12,472,000
Gross Profit			25,880,000
Depreciation			17,056,000
General and Administrative Expense			534,000
Operating Income (Loss)			8,290,000
Interest and Other Income			4,000
Other Nonoperating Income (Expense)			(184,000)
Interest:
Interest Expense, Debt			(6,712,000)
Amortization of Financing Costs			(131,000)
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of land parcels and discontinued operations			1,267,000
Income and other tax (expense) benefit			(67,000)
(Loss) from investments in unconsolidated entities due to operations			(342,000)
Net gain on sales of land parcels			(17,000)
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			26,686,000
Net income			27,527,000
Unconsolidated Development Projects Held for and or Under Development [Domain]
Partially Owned Property Balance Sheet Schedule
Partially Owned Unconsolidated Properties	0		0
Partially Owned Unconsolidated Units	0		0
ASSETS
Real Estate Investment Property, at Cost	304,921,000		304,921,000
Real Estate Investment Property, Accumulated Depreciation	0		0
Investment in real estate, net	304,921,000		304,921,000
Cash and Cash Equivalents, at Carrying Value	1,581,000		1,581,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0		0
Restricted Cash and Cash Equivalents	0		0
Deferred Finance Costs, Net	62,000		62,000
Other Assets	415,000		415,000
Total assets	306,979,000		306,979,000
LIABILITIES AND EQUITY
Secured Debt	145,767,000		145,767,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	8,423,000		8,423,000
Interest Payable	552,000		552,000
Other Liabilities	230,000		230,000
Security Deposit Liability	79,000		79,000
Total liabilities	155,051,000		155,051,000
Noncontrolling Interests Partially Owned Properties	115,425,000		115,425,000
Parent Equity Interest	36,503,000		36,503,000
Total Equity Interest	151,928,000		151,928,000
Total liabilities and equity	306,979,000		306,979,000
Partially Owned Property Income Statement Schedule
Operating revenue			1,203,000
Operating Expenses			1,091,000
Gross Profit			112,000
Depreciation			0
General and Administrative Expense			11,000
Operating Income (Loss)			101,000
Interest and Other Income			0
Other Nonoperating Income (Expense)			0
Interest:
Interest Expense, Debt			(208,000)
Amortization of Financing Costs			0
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of land parcels and discontinued operations			(107,000)
Income and other tax (expense) benefit			0
(Loss) from investments in unconsolidated entities due to operations			0
Net gain on sales of land parcels			0
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income			(107,000)
Unconsolidated Operating [Domain]
Partially Owned Property Balance Sheet Schedule
Partially Owned Unconsolidated Properties	1		1
Partially Owned Unconsolidated Units	336		336
ASSETS
Real Estate Investment Property, at Cost	55,025,000		55,025,000
Real Estate Investment Property, Accumulated Depreciation	(2,158,000)		(2,158,000)
Investment in real estate, net	52,867,000		52,867,000
Cash and Cash Equivalents, at Carrying Value	1,604,000		1,604,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0		0
Restricted Cash and Cash Equivalents	0		0
Deferred Finance Costs, Net	5,000		5,000
Other Assets	1,548,000		1,548,000
Total assets	56,024,000		56,024,000
LIABILITIES AND EQUITY
Secured Debt	30,550,000		30,550,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	(45,000)		(45,000)
Interest Payable	0		0
Other Liabilities	1,817,000		1,817,000
Security Deposit Liability	0		0
Total liabilities	32,322,000		32,322,000
Noncontrolling Interests Partially Owned Properties	20,450,000		20,450,000
Parent Equity Interest	3,252,000		3,252,000
Total Equity Interest	23,702,000		23,702,000
Total liabilities and equity	56,024,000		56,024,000
Partially Owned Property Income Statement Schedule
Operating revenue			1,610,000
Operating Expenses			671,000
Gross Profit			939,000
Depreciation			2,158,000
General and Administrative Expense			0
Operating Income (Loss)			(1,219,000)
Interest and Other Income			2,000
Other Nonoperating Income (Expense)			0
Interest:
Interest Expense, Debt			(373,000)
Amortization of Financing Costs			0
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of land parcels and discontinued operations			(1,590,000)
Income and other tax (expense) benefit			0
(Loss) from investments in unconsolidated entities due to operations			0
Net gain on sales of land parcels			0
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income			(1,590,000)
Unconsolidated Total [Domain]
Partially Owned Property Balance Sheet Schedule
Partially Owned Unconsolidated Properties	1		1
Partially Owned Unconsolidated Units	336		336
ASSETS
Real Estate Investment Property, at Cost	359,946,000		359,946,000
Real Estate Investment Property, Accumulated Depreciation	(2,158,000)		(2,158,000)
Investment in real estate, net	357,788,000		357,788,000
Cash and Cash Equivalents, at Carrying Value	3,185,000		3,185,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0		0
Restricted Cash and Cash Equivalents	0		0
Deferred Finance Costs, Net	67,000		67,000
Other Assets	1,963,000		1,963,000
Total assets	363,003,000		363,003,000
LIABILITIES AND EQUITY
Secured Debt	176,317,000		176,317,000
Accounts Payable And Accrued Liabilities Current And Noncurrent Other Than Interest And Dividend Payable	8,378,000		8,378,000
Interest Payable	552,000		552,000
Other Liabilities	2,047,000		2,047,000
Security Deposit Liability	79,000		79,000
Total liabilities	187,373,000		187,373,000
Noncontrolling Interests Partially Owned Properties	135,875,000		135,875,000
Parent Equity Interest	39,755,000		39,755,000
Total Equity Interest	175,630,000		175,630,000
Total liabilities and equity	363,003,000		363,003,000
Partially Owned Property Income Statement Schedule
Operating revenue			2,813,000
Operating Expenses			1,762,000
Gross Profit			1,051,000
Depreciation			2,158,000
General and Administrative Expense			11,000
Operating Income (Loss)			(1,118,000)
Interest and Other Income			2,000
Other Nonoperating Income (Expense)			0
Interest:
Interest Expense, Debt			(581,000)
Amortization of Financing Costs			0
(Loss) income before income and other taxes, (loss) from investments in unconsolidated entities, net gain on sales of land parcels and discontinued operations			(1,697,000)
Income and other tax (expense) benefit			0
(Loss) from investments in unconsolidated entities due to operations			0
Net gain on sales of land parcels			0
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax			0
Net income			(1,697,000)
Residual JV [Domain]
ASSETS
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	105,200,000		105,200,000
Joint Venture Partner [Member]
LIABILITIES AND EQUITY
Noncontrolling Interests Partially Owned Properties	90,775,479		90,775,479
Investments In Partially Owned Entities (Textuals) [Abstract]
Land purchase price	57,900,000		57,900,000
Business Acquisition, Cost of Acquired Entity, Purchase Price	75,700,000		75,700,000
Company's Portion [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Land purchase price	76,100,000		76,100,000
Business Acquisition, Cost of Acquired Entity, Purchase Price	102,500,000		102,500,000
Nexus Sawgrass [Member]
LIABILITIES AND EQUITY
Secured Debt	42,600,000		42,600,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Maximum Debt Commitment	48,700,000		48,700,000
Debt Instrument, Interest Rate, Stated Percentage	5.60%		5.60%
Debt Instrument, Maturity Date			Jan. 01, 2021
Domain [Member]
LIABILITIES AND EQUITY
Secured Debt	72,100,000		72,100,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Maximum Debt Commitment	98,600,000		98,600,000
Debt Instrument, Interest Rate, Stated Percentage	5.75%		5.75%
Debt Instrument, Maturity Date			Jan. 01, 2022
Archstone Transaction [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Liquidation Value Preferred Interests	88,300,000		88,300,000
Business Acquisition, Percentage of Voting Interests Acquired	60.00%		60.00%
Joint Venture Partner Ownership Percentage	40.00%		40.00%
Company's Portion [Member]
Investments In Partially Owned Entities (Textuals) [Abstract]
Preferred Interests			39,000,000
Enclave at Wellington [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	95.00%		95.00%
Partially Owned Consolidated Properties	268		268
Initial Basis of Land, Consolidated	26,200,000		26,200,000
Project Cost	50,000,000		50,000,000
East Palmetto Park [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	90.00%		90.00%
Partially Owned Consolidated Properties	377		377
Initial Basis of Land, Consolidated	20,200,000		20,200,000
Wisconsin Place [Domain]
Partially Owned Property Balance Sheet Schedule
Partially Owned Consolidated Units	432		432
ASSETS
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	56,500,000		56,500,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired	75.00%		75.00%
Initial Basis of Land, Consolidated	198,500,000		198,500,000
San Norterra [Domain]
Variable Interest Entity [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR plus 2.00%
LIABILITIES AND EQUITY
Secured Debt	28,400,000		28,400,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Equity Method Investment, Ownership Percentage	85.00%		85.00%
Project Cost	56,300,000		56,300,000
Partially Owned Unconsolidated Units To Be Developed	388		388
Initial Basis of Land, Unconsolidated	16,900,000		16,900,000
Maximum Debt Commitment	34,800,000		34,800,000
Debt Instrument, Maturity Date			Jan. 06, 2015
Waterton Tenside [Domain]
Partially Owned Property Balance Sheet Schedule
Partially Owned Unconsolidated Units	336		336
LIABILITIES AND EQUITY
Secured Debt	30,600,000		30,600,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Equity Method Investment, Ownership Percentage	20.00%		20.00%
Initial Basis of Land, Unconsolidated	5,100,000		5,100,000
Debt Instrument, Interest Rate, Stated Percentage	3.66%		3.66%
Debt Instrument, Maturity Date			Dec. 01, 2018
Mission Gorge [Domain]
Investments In Partially Owned Entities (Textuals) [Abstract]
Equity Method Investment, Ownership Percentage	23.08%		23.08%
Partially Owned Unconsolidated Units To Be Developed	444		444
Initial Basis of Land, Unconsolidated	4,100,000		4,100,000
Parkside at Emeryville [Domain]
Variable Interest Entity [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR plus 2.25%
LIABILITIES AND EQUITY
Secured Debt	2,700,000		2,700,000
Investments In Partially Owned Entities (Textuals) [Abstract]
Equity Method Investment, Ownership Percentage	5.00%		5.00%
Project Cost	75,000,000		75,000,000
Partially Owned Unconsolidated Units To Be Developed	180		180
Initial Basis of Land, Unconsolidated	2,100,000		2,100,000
Maximum Debt Commitment	39,500,000		39,500,000
Debt Instrument, Maturity Date			Aug. 14, 2015
Unconsolidated Project Under Development Commitment Fund	$ 19,700,000		$ 19,700,000