Business Segments - Segment Reporting, Reconciliation of Revenues, Operating Income and Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Total revenues	$ 430,185		$ 499,462	$ 1,333,740	$ 1,473,630
General and administrative expenses	(55,034)		(55,886)	(166,140)	(167,460)
Depreciation and amortization	(158,889)		(190,148)	(492,690)	(547,036)
Merger, acquisition and other integration expenses			(20,659)		(52,573)
Earnings from unconsolidated entities, net	26,365		2,563	59,554	20,447
Interest expense	(84,885)		(122,817)	(292,383)	(383,369)
Interest and other income, net	5,653		8,758	21,772	19,771
Gains on acquisitions and dispositions of investments in real estate, net	46,074	56,900	12,677	445,954	280,968
Gains (losses) on early extinguishment of debt, net	(114,196)			(164,155)	4,919
Impairment of other assets					(16,135)
Consolidated net earnings (loss)	(7,167)		(32,898)	284,780	184,868
Earnings (loss) before income taxes	(35,157)		(29,477)	307,963	166,157
Total assets	24,789,543			24,789,543		27,310,145
Assets held for sale	3,958			3,958		26,027
Cash and cash equivalents	121,693		158,188	121,693	158,188	100,810	176,072
Americas [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	328,702		303,465	961,042	883,758
Europe [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	26,199		104,804	154,961	326,120
Asia [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	26,962		59,479	92,172	168,688
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	430,185		499,462	1,333,740	1,473,630
Consolidated net earnings (loss)	292,880		351,721	896,036	1,039,518
Total assets	20,059,846			20,059,846		24,611,053
Operating Segments [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Total revenues	381,863		467,748	1,208,175	1,378,566
Consolidated net earnings (loss)	266,581		335,737	837,409	992,140
Total assets	19,972,339			19,972,339		24,519,306
Operating Segments [Member] | Investment Management [Member]
Segment Reporting Information [Line Items]
Total revenues	48,322		31,714	125,565	95,064
Consolidated net earnings (loss)	26,299		15,984	58,627	47,378
Total assets	87,507			87,507		91,747
Operating Segments [Member] | Americas [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Consolidated net earnings (loss)	228,688		210,004	666,768	614,594
Total assets	15,885,306			15,885,306		15,304,053
Operating Segments [Member] | Americas [Member] | Investment Management [Member]
Segment Reporting Information [Line Items]
Total revenues	18,357		16,934	49,972	51,758
Consolidated net earnings (loss)	5,578		7,581	8,822	23,326
Total assets	23,280			23,280		24,373
Operating Segments [Member] | Europe [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Consolidated net earnings (loss)	18,625		79,103	104,324	246,158
Total assets	2,160,506			2,160,506		5,738,257
Operating Segments [Member] | Europe [Member] | Investment Management [Member]
Segment Reporting Information [Line Items]
Total revenues	20,037		9,537	44,504	28,000
Consolidated net earnings (loss)	14,115		5,762	28,516	16,564
Total assets	60,089			60,089		61,266
Operating Segments [Member] | Asia [Member] | Real Estate Operations [Member]
Segment Reporting Information [Line Items]
Consolidated net earnings (loss)	19,268		46,630	66,317	131,388
Total assets	1,926,527			1,926,527		3,476,996
Operating Segments [Member] | Asia [Member] | Investment Management [Member]
Segment Reporting Information [Line Items]
Total revenues	9,928		5,243	31,089	15,306
Consolidated net earnings (loss)	6,606		2,641	21,289	7,488
Total assets	4,138			4,138		6,108
Reconciling Items [Member]
Segment Reporting Information [Line Items]
General and administrative expenses	(55,034)		(55,886)	(166,140)	(167,460)
Depreciation and amortization	(158,889)		(190,148)	(492,690)	(547,036)
Merger, acquisition and other integration expenses			(20,659)		(52,573)
Impairment of real estate properties			(9,778)		(12,963)
Earnings from unconsolidated entities, net	26,365		2,563	59,554	20,447
Interest expense	(84,885)		(122,817)	(292,383)	(383,369)
Interest and other income, net	5,653		8,758	21,772	19,771
Gains on acquisitions and dispositions of investments in real estate, net	46,074		12,677	445,954	280,968
Foreign currency and derivative gains (losses), net	6,875		(5,908)	15	(19,930)
Gains (losses) on early extinguishment of debt, net	(114,196)			(164,155)	4,919
Impairment of other assets					(16,135)
Consolidated net earnings (loss)	(328,037)		(381,198)	(588,073)	(873,361)
Investments in and advances to other unconsolidated entities	4,210,305			4,210,305		2,195,782
Notes receivable backed by real estate	189,663			189,663		188,000
Assets held for sale	3,958			3,958		26,027
Cash and cash equivalents	121,693			121,693		100,810
Other assets	204,078			204,078		188,473
Total reconciling items	$ 4,729,697			$ 4,729,697		$ 2,699,092