CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010
U.S. Treasury Securities, pledged assets	$ 352,820,000	$ 660,823,000
Agency Mortgage-Backed Securities, pledged assets	90,406,535,000	67,787,023,000
Agency debentures, pledged assets	567,383,000	1,068,869,000
Receivable for advisory and service fees, from affiliates	16,245,000	13,020,000
Intangible for customer relationships, accumulated amortization	$ 5,432,000,000	$ 9,833,000,000
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	1,987,987,500	1,987,987,500
Common Stock, shares issued	970,161,647	631,594,205
Common Stock, shares outstanding	970,161,647	631,594,205
6.00% Series B Cumulative Convertible Preferred Stock [Member]
Preferred Stock, shares authorized	4,600,000	4,600,000
Preferred Stock, shares issued	1,331,849	1,652,047
Preferred Stock, shares outstanding	1,331,849	1,652,047
7.875% Series A Cumulative Redeemable Preferred Stock [Member]
Preferred Stock, shares authorized	7,412,500	7,412,500
Preferred Stock, shares issued	7,412,500	7,412,500
Preferred Stock, shares outstanding	7,412,500	7,412,500