JFK Redevelopment (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
JFK Redevelopment [Abstract]
Estimated Cost Of Project	$ 1,200,000,000
Special Project Bonds Face Amount	800,000,000
Term of agreement to sublease space	33
Construction in Progress, Gross	585,000,000
Construction Payable	$ 473,000,000