Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies (Details 2)

v3.3.1.900
Summary of Significant Accounting Policies (Details 2) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Accounting Policies [Abstract]      
Minimum adjusted taxable income to be distributed to shareholders to qualify as a REIT (as a percent) 90.00%    
Subsequent period during which entity would be disqualified as a REIT if during any tax year entity fails to qualify as a REIT (in years) 4 years    
Dividends Payable [Line Items]      
Approximate amount by which basis of assets and liabilities for tax reporting purposes is lower than amount reported on consolidated balance sheet $ 224    
Common Shares [Member]      
Dividends Payable [Line Items]      
Ordinary income (as a percent) 38.30% 64.50% 71.80%
Long-term capital gain (as a percent) 61.70% 6.50% 22.40%
Return of capital (as a percent) 0.00% 29.00% 5.80%
Preferred Shares [Member]      
Dividends Payable [Line Items]      
Ordinary income (as a percent) 38.30% 90.90% 76.20%
Long-term capital gain (as a percent) 61.70% 9.10% 23.80%
Return of capital (as a percent) 0.00% 0.00% 0.00%