Quarterly report pursuant to Section 13 or 15(d)

Noncontrolling Interests In Subsidiaries (Narrative) (Details)

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Noncontrolling Interests In Subsidiaries (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 3 Months Ended 3 Months Ended
Mar. 31, 2012
Dec. 31, 2011
Oct. 28, 2011
Series C Preferred Stock [Member]
Mar. 31, 2012
Participation Rights [Member]
Mar. 31, 2012
Future Developments [Member]
Mar. 31, 2012
Office Buildings [Member]
Noncontrolling Interest [Line Items]            
Internal rate of return       10.00%    
Preferred stock issued     $ 25      
Preferred unit in operating partnership     25      
Rebalance of ownership percentage $ 0.1          
Percentage of noncontrolling interest 12.20% 12.20%        
Excess net cash flow remaining after the distribution to the Company       50.00%    
Number of real estate properties         2 4
Square footage of office buildings           860,246