Business and Organization (Details) (USD $) In Billions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 decades
Business and Organization [Abstract]
Investment across a range of real estate sectors over the past two decades (more than $35 billion at December 31, 2012)	$ 35
Period over which the entity has made the investment across a range of real estate (in decades)	2