Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2012

Schedule of Fair Values of Financial Assets and Liabilities by Levels Table

			As of March 31, 2012
(Amounts in thousands)			Total		Level 1		Level 2		Level 3
	Marketable securities		$	754,510	$	754,510	$	-	$	-
	Real Estate Fund investments (75% of which is attributable to
		noncontrolling interests)		324,514		-		-		324,514
	Deferred compensation plan assets (included in other assets)			99,810		40,929		-		58,881
	Derivative positions in marketable equity securities
		(included in other assets)		31,645		-		31,645		-
		Total assets	$	1,210,479	$	795,439	$	31,645	$	383,395
	Mandatorily redeemable instruments (included in other liabilities)		$	55,097	$	55,097	$	-	$	-
			As of December 31, 2011
(Amounts in thousands)			Total		Level 1		Level 2		Level 3
	Marketable securities		$	741,321	$	741,321	$	-	$	-
	Real Estate Fund investments (75% of which is attributable to
		noncontrolling interests)		346,650		-		-		346,650
	Deferred compensation plan assets (included in other assets)			95,457		39,236		-		56,221
	Derivative positions in marketable equity securities
		(included in other assets)		30,600		-		30,600		-
		Total assets	$	1,214,028	$	780,557	$	30,600	$	402,871
	Mandatorily redeemable instruments (included in other liabilities)		$	54,865	$	54,865	$	-	$	-

Fair Value Inputs, Assets, Quantitative Information [Table Text Block]

			Weighted Average
			(based on fair
Unobservable Quantitative Input		Range	value of investments)
	Discount rates	12.5% to 23.3%	15.0%
	Terminal capitalization rates	5.5% to 6.8%	5.9%

Schedule Of Carrying Amounts And Fair Values Of Financial Instruments

			As of March 31, 2012				As of December 31, 2011
			Carrying		Fair		Carrying		Fair
(Amounts in thousands)			Amount		Value		Amount		Value
	Mezzanine loans receivable		$	133,143	$	128,000	$	133,948	$	129,000
	Debt:
		Notes and mortgages payable	$	8,434,938	$	8,505,000	$	8,558,275	$	8,686,000
		Senior unsecured notes		1,357,748		1,439,000		1,357,661		1,426,000
		Exchangeable senior debentures		499,680		501,000		497,898		510,000
		Convertible senior debentures		10,233		10,000		10,168		10,000
		Revolving credit facility debt		-		-		138,000		138,000
			$	10,302,599	$	10,455,000	$	10,562,002	$	10,770,000

Real Estate Fund Investments [Member]

Summary of Changes in Level 3 Assets [Table Text Block]

	For the Three Months Ended March 31,
(Amounts in thousands)	2012		2011
Beginning balance	$	346,650	$	144,423
Purchases		-		100,238
Sales		(31,052)		-
Realized and unrealized gains		6,844		698
Other, net		2,072		(14,702)
Ending balance	$	324,514	$	230,657

Deferred Compensation Plan Assets [Member]

Summary of Changes in Level 3 Assets [Table Text Block]

	For the Three Months Ended March 31,
(Amounts in thousands)	2012		2011
Beginning balance	$	56,221	$	47,850
Purchases		3,611		1,286
Sales		(3,395)		-
Realized and unrealized gains		2,392		3,623
Other, net		52		(1,147)
Ending balance	$	58,881	$	51,612