Subsequent Events (Narratives) (Details) (USD $)	0 Months Ended			0 Months Ended
	Oct. 31, 2014	Sep. 30, 2014	Dec. 31, 2013	Oct. 31, 2014 Subsequent Event [Member] Office Building [Member] New York Office 1740 Broadway [Member] sqft	Oct. 27, 2014 Subsequent Event [Member] Retail And Office Property [Member] New York Office 655 Fifth Avenue [Member] Extensions sqft
Subsequent Event [Line Items]
Mortgages payable (in US Dollars)		$ 9,273,212,000	$ 8,331,993,000		$ 140,000,000
Square Footage Of Real Estate Property				601,000	57,500
Spread Over LIBOR (in percentage)					1.40%
Debt Instrument Maturity					October 2019
Number of extension options					2
Duration Of Extension Available, in years					1 year
Sale price of real estate				605,000,000
Net proceeds from sale of real estate				585,000,000
Net realized gain on sale of investment	443,000,000
Tax Gain On Sale Of Real Estate				$ 483,000,000