Financial Instruments and Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2012

Financial Instruments and Fair Value Measurements [Abstract]

Derivative activity

	2012					2011
	Interest Rate Swaps			Interest Rate Caps		Interest Rate Swaps			Interest Rate Caps
Notional amounts at January 1	$	1,496.5		$	—	$	268.1		$	—
New contracts		444.2			—		—			—
Acquired contracts		71.0			—		1,337.3			25.7
Matured or expired contracts		(456.0	)		—		(9.6	)		—
Notional amounts at June 30	$	1,555.7		$	—	$	1,595.8		$	25.7

Fair value of debt

	June 30, 2012				December 31, 2011
	Carrying Value		Fair Value		Carrying Value		Fair Value
Debt:
Credit Facilities	$	1,138,414	$	1,143,735	$	936,796	$	940,334
Senior notes		4,684,152		5,201,866		4,772,607		5,038,678
Exchangeable senior notes		877,776		994,694		1,315,448		1,431,805
Secured mortgage debt		3,115,437		3,248,920		1,699,363		1,832,931
Secured mortgage debt of consolidated entities		1,366,837		1,361,701		1,495,047		1,485,808
Other debt of consolidated entities		602,938		612,456		775,763		751,075
Other debt		648,031		650,729		387,384		389,804
Total debt	$	12,433,585	$	13,214,101	$	11,382,408	$	11,870,435