Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Series J Preferred Stock [Member]
Preferred distributions per depositary share
Ordinary income	$ 0.3130	$ 1.4652
Ordinary Income as a percentage of distributions	23.02%	80.84%	0.00%
Long term capital gains			$ 1.3697
Long term capital gains as percentage of distributions	0.00%	0.00%	75.57%
Unrecaptured Section 1250 gain		$ 0.2423	$ 0.4428
Unrecaptured section 1250 gain as percentage of distributions	0.00%	13.37%	24.43%
Return of Capital	$ 1.0402
Return of capital as percentage of distributions	76.52%	0.00%	0.00%
Qualified Dividends	$ 0.0062	$ 0.1050
Qualified dividends as percentage of distributions	0.46%	5.79%	0.00%
Preferred distributions per depositary share	$ 1.3594	$ 1.8125	$ 1.8125
Preferred distributions, percentage	100.00%	100.00%	100.00%
Series K Preferred Stock [Member]
Preferred distributions per depositary share
Ordinary income	$ 0.3130	$ 1.4652
Ordinary Income as a percentage of distributions	23.02%	80.84%	0.00%
Long term capital gains			$ 1.3697
Long term capital gains as percentage of distributions	0.00%	0.00%	75.57%
Unrecaptured Section 1250 gain		$ 0.2423	$ 0.4428
Unrecaptured section 1250 gain as percentage of distributions	0.00%	13.37%	24.43%
Return of Capital	$ 1.0402
Return of capital as percentage of distributions	76.52%	0.00%	0.00%
Qualified Dividends	$ 0.0062	$ 0.1050
Qualified dividends as percentage of distributions	0.46%	5.79%	0.00%
Preferred distributions per depositary share	$ 1.3594	$ 1.8125	$ 1.8125
Preferred distributions, percentage	100.00%	100.00%	100.00%